Homemade Helicopter: For the People.

[Imop45]

Ok, I heard that you could make a cheap, but good helicopter, that's a 1-2 seater, relatively easy. How could this be done?

[FredGarvin]

Helicopter and cheap are two words that never go together. Are you referring to something like an autogyro kit that you find in the back of Popular Mechanics and the like?

[Mech_Engineer]

Ok, I heard that you could make a cheap, but good helicopter, that's a 1-2 seater, relatively easy. How could this be done?

I think "cheap" is like $20k or $30k, cheap for a helicopter, but not that great. AND not very safe.

[brewnog]

I'm waiting for the "how can I build a spaceship to take me to Mars for under $60?" thread.

[Imop45]

Ok, to clarify, I meant cheap as in, building a Helicopter and not buying a$15,000 motor and things. Yeah, i'm not going to buuld the frame out of duct tape.......I was saving that for the motor parts.

[Imop45]

I know cheap isn't going to be cheap.

[FredGarvin]

Again, this may be what you are thinking of, but they are not helicopters.

http://www.popularmechanics.com/science/aviation/1280656.html?page=2&c=y

[brewnog]

Imop, I don't wanna brush you off cos I used to have all these amazing genuine aspirations to build all sorts of creations when I was younger, but do you really think companies would spend hundreds of millions developing things like cars, hovercraft and helicopters if all there was to it was welding some tubes together in your shed? That's not to say it can't be done, but do you know what's involved?!

Again, not trying to brush you off, but have a look at some of the other threads about building go karts/hovercraft/planes in this forum and see what kind of level of detail you need to go into to do it yourself. Lots of people here have done engineering degrees, and many have years of experience behind them, but I doubt anyone here would feel confident designing something like this in its entirety, from start to finish, on their own!

Having said that, if you have any specific questions here's an excellent place to start asking...

[Mech_Engineer]

Lots of people here have done engineering degrees, and many have years of experience behind them, but I doubt anyone here would feel confident designing something like this in its entirety, from start to finish, on their own!

I might be willing to try, if I won the lottery and was bored... But I don't know if I'd be brave enough to fly in it :rolleyes:

[Imop45]

Imop, I don't wanna brush you off cos I used to have all these amazing genuine aspirations to build all sorts of creations when I was younger, but do you really think companies would spend hundreds of millions developing things like cars, hovercraft and helicopters if all there was to it was welding some tubes together in your shed? That's not to say it can't be done, but do you know what's involved?!
No. I don't. Thats why I wanted to learn what was involved. My Grandfather was actually wanting to look into, as he wants a ultralight plane or something related to it. Thanks though.

[Danger]

My cousin was planning to build a Scorpion II, and I was certainly looking forward to playing with it. Unfortunately, he died before he had a chance to do it. :frown:

[magnum40]

not really a helicopter more like a mix stears like a plane

THE GYROBEE
http://users2.ev1.net/~gyroman/downloads/gbeer50.pdf

Total BEE Kit
http://www.starbeegyros.com/productdetail.asp?ID=177&kits=1

[wolram]

not really a helicopter more like a mix stears like a plane

THE GYROBEE
http://users2.ev1.net/~gyroman/downloads/gbeer50.pdf

Total BEE Kit
http://www.starbeegyros.com/productdetail.asp?ID=177&kits=1

I am sure i read some where that auto gyros were grounded due to rotor strikes on some part of the air frame, in the uk any way.

[kleinjahr]

Didn't PM have ads for plans for a one man chopper. I seem to remember one type with jets/rockets at the blade tips.

[DaveC426913]

Helicopter and cheap are two words that should never go together. :rofl:


I'm waiting for the "how can I build a spaceship to take me to Mars for under $60?" thread.
Waaay less scary! If your spaceship breaks, you've got plenty of time to fix it.:biggrin:

[Francis M]

The problem I see with this is not so much that they might be cheap (read in: not built well). I'll go out on a limb and say that maaaaaaybeeeeee these have been designed by an AE with a kit plane idea so they decided "hey why not try a kit helicopter, I've got the skills". My problem is that the adds seem to give the impression that you can "send in your money, buy our kit, throw it together and enjoy hours and hours of hovering fun." :rofl:

Next up is correspondence courses on "Learn to be a Quantum Physicist in your spare time! That's right folks, for just the price of a cup of coffee a day....." :biggrin:

[Matson]

I think "cheap" is like $20k or $30k, cheap for a helicopter, but not that great. AND not very safe.

For $98 I found plans for a propellor driven backpack used in tandem with a ram chute. They provide blueprints, manufacturers and suppliers of propellors and motors. You can use a body harness or build a little 3 wheeled, kayak looking thing. They both work on the same principles.

They say you can be flying for as little as $2,500 or less. The ram chutes are about $800 used and costs vary on construction.

[Ki Man]

You'd have to go to flight school first and check for how legal the projects are in your area.

They have build it yourself kits for relatively low prices where you can build a small one seat or two seat helicopter. either that or you can get an R22 if you find 200,000 cheap.

[FredGarvin]

For $98 I found plans for a propellor driven backpack used in tandem with a ram chute. They provide blueprints, manufacturers and suppliers of propellors and motors. You can use a body harness or build a little 3 wheeled, kayak looking thing. They both work on the same principles.

They say you can be flying for as little as $2,500 or less. The ram chutes are about $800 used and costs vary on construction.Finding plans and trusting life and limb to them are two different things. Also, I don't know how many people would be comfortable flying a chute without some kind of previous experience. Caveat Emptor to the ultimate degree.

[Panda]

I don't know what the law is over the pond but in the UK whilst you can build a car, plane, helicopter, spaceship in your back garden, unless you own sufficient land such that it cannot come into contact with unsuspecting members of the public, you need to get it cleared as fit for purpose.

I've built cars and raced them on circuits because when the wheels fall off they are contained within the catch fencing.
An aircraft is much harder to contain, as your fences need to be slightly higher, so they tend to calculated how far it could go in a straight line with a full tank of fuel, draw a circle round that and any member of the public in that radius means you can't fly.
This even goes for professionally built stuff, We generally test in the middle of deserts or over the sea to ensure that no body gets hurt when we type the guidance algorithm in backwards... a surprisingly common occurance.
I think that these kits may not make it clear that yes you can build your own plane, it's just you won't be able to fly it.

[Matson]

Finding plans and trusting life and limb to them are two different things. Also, I don't know how many people would be comfortable flying a chute without some kind of previous experience. Caveat Emptor to the ultimate degree.

I was parachuting for sport in the 80s. The bottom line is that you are wearing a parachute the whole time. I can cut off my motor and safely land, so worries about my well being are moot. The downside is, parachute harness's are REALLY UNCOMFORTABLE! LOL!

I saw a special on the "gadgets of 007." They showed the autogyro that was featured in one of them, still sporting the fake rocket tubes. The old man that builds them has around 20 of them that are operational. He had single and double occupancy models, open and closed models.

He swears it is the safest way to travel. After watching him roll one out, jump in and take off, I was sold. He said he can shut down the motor at any time and land it safely. I can only find RC autoguro models, though...and SCREW THAT.

[Ki Man]

He said he can shut down the motor at any time and land it safely.


with no wings, how are you supposed to glide to the ground? And how does an autogyro counter the spinning force from its main rotor without the smaller rotor that appears on hellicopters

[Mech_Engineer]

It's really not that hard to do a little searching on how Autogyros work...

http://en.wikipedia.org/wiki/Autogyro

[Ki Man]

but it depends on a rotor to act like the wings of a glider, but if the rotors stop, how are you supposed to take it down safely?

[Mech_Engineer]

but it depends on a rotor to act like the wings of a glider, but if the rotors stop, how are you supposed to take it down safely?

Here's what I found after some quick searches in Google:

There is one other major advantage that autogyros have over airplanes and helicopters- safety in event of an engine failure. If an engine fails in an autogyro, the same thing would happen as if the pilot tried to fly too slow. The aircraft would slowly descend until landing. In fact, the procedure for landing an autogyro after engine failure is the same for landing an autogyro under ordinary circumstances.


Autogyro technology looks a lot like helicopter technology, but aside from appearances, they are quite different. Technically speaking, an autogyro has much more in common with an old-fashioned single-prop airplane than it does with a helicopter. An autogyro's rotor is unpowered, providing lift in a way similar to a fixed wing, but caused to spin by its forward motion through the air. The thrust that provides lift comes from an airplane-like propeller– in the case of the PALV, a small pushing-type propeller mounted to the rear of the vehicle.

[Matson]

Here's what I found after some quick searches in Google:

For all us guys that don't have John Travoltas $$$, Backpacks with ramchutes and autogyros is STILL flying. The ramchute backpack I mention has a speed of 30 MPH and you can climb 10 feet a minute, a slow ride when you're hanging by your crotch...BUT HEY!!! You're FLYING!

[Matson]

You'd have to go to flight school first and check for how legal the projects are in your area.

They have build it yourself kits for relatively low prices where you can build a small one seat or two seat helicopter. either that or you can get an R22 if you find 200,000 cheap.

That would not apply to people with a natural contempt for authority.

[Ki Man]

While rummaging through sites on aircraft, I found a good heilopter kit site and remembered this thread. if anyone is still into this,Rotorway (http://www.rotorway.com/) makes some pretty good, low cost kits

[FredGarvin]

IIRC, there was a show on the Discovery Channel that had a British guy building and then flying his own aircraft kits. I believe that was the helicopter he made. It was a nice kit, but a lot of work (obviously).

[Ki Man]

IIRC, there was a show on the Discovery Channel that had a British guy building and then flying his own aircraft kits. I believe that was the helicopter he made. It was a nice kit, but a lot of work (obviously).

i think this company is based in arizona

[icanbuildit]

Why are there so many that think building a home made helicopter is so far out there, I have built several things just using common sense, books and a few books?

[Danger]

I can't get a decent lock on that link, but I'm pretty sure that RotorWay is the manufacturer of the Scorpion series that I mentioned earlier. They seem to make a good quality product.

[Mech_Engineer]

Why are there so many that think building a home made helicopter is so far out there, I have built several things just using common sense, books and a few books?

The answer is simple, it takes a LOT more than just common sense to build a helicopter. You obviously don't have any idea of what would be required to make one.

[icanbuildit]

No, your right and for some it would not even be a thought! I am sure there are many things I have not considered for when I plan on building one. I have built race cars, kayaks, canoe's, lap strake row boats and many other thigns that take simply put knowledge andmore than common sense. I think no one should ever say they can't, because they have not tried. I lost three fingers building one of my kayaks and have built harder projects than a little boat since then.

[Danger]

I lost three fingers building one of my kayaks

That might be an indication that your approach to construction is somewhat flawed. :rolleyes:
Just getting the swash plate assembly correct is more complicated than any of the things that you've mentioned in their entirety.

[icanbuildit]

Missing the point you say, being able to read a book, understand datum water lines, convert on computer, cut your fingers off and finish with one hand says something I am pretty sure. I have 4. GPA, can build anything and have, I'm not the guy who finished at Hardvardand never lifted a tool, but finished and can build my own house, not have to pay some one, then build this flying machine everyone thinks is so hard, gees?

[Mech_Engineer]

Missing the point you say, being able to read a book, understand datum water lines, convert on computer, cut your fingers off and finish with one hand says something I am pretty sure.


No, really, you DON'T understand. Helicopters are very complex (and potentially dangerous) vehicles. They have complex rotating parts that have to operate at high RPM's, and must be built of very light and strong materials. If you lost three fingers building a kayak, I shudder to imagine the consequences of an accident involving a heli's rotor :bugeye:

Despite your building houses, boats, racecars, whatever; none of these "proves" your worthiness. While I have to admire your "can-do" attitude, experts here and elsewhere will say you're out of your mind if you think building a functioning helicopter is anything close to these other projects you have worked on. You'd be much better off even trying to build a glider or ultralight (or auto-gyro) than what you are proposing.


I have 4. GPA, can build anything and have, I'm not the guy who finished at Hardvardand never lifted a tool, but finished and can build my own house, not have to pay some one, then build this flying machine everyone thinks is so hard, gees?

Despite your GPA (is that GPA in applicable engineering courses, btw?), I would give a Harvard graduate with a firm understanding of aerodynamics, control systems, and composite materials my vote... at least I hope he (or she) would know when they were in over their head...

[icanbuildit]

You guys are killing me, is there no faith unless you have some degree in building a rocket, did those guys just finish school or did they actually read a book, ask some questions, is everything you do certain, outcome always known, how many times has smoke come from some lab, test and trial. I would not presume to go strap a V8 to some pile of tubing made from the lawn mower. Books, lots of math, lots of questions but to think unless I am already an engineer I can't do, well that's just funny, everyone starts some where. How about instead of dogging me, give a man some advice besides trying to be as smart or giving up, I'd rather blow myself up than have never tried or say it looked good on paper but I just never had the balls.

[FredGarvin]

Missing the point you say, being able to read a book, understand datum water lines, convert on computer, cut your fingers off and finish with one hand says something I am pretty sure. I have 4. GPA, can build anything and have, I'm not the guy who finished at Hardvardand never lifted a tool, but finished and can build my own house, not have to pay some one, then build this flying machine everyone thinks is so hard, gees?When you say "home built" do you mean a kit or one from scratch? Because if you're talking about from scratch then I would say you have a death wish.

[icanbuildit]

Good question, I have not seen anything worth building, I mean the nicer ones, best lines, engines lift and all, you might as well buy someone elses design. I think I would prefer to use the best as far as engine and controls but changes the over all appearance. I do not have the time or know how as most have said to do from scratch.
I would not buy a kit, right parts, right help, copter pilots I have known for years but desing my own yes. I woudl be man enough to say I am over my head but then again why build something easy?

[icanbuildit]

You stink, I will build it, prove simplicity, hard work and yes I will read up on engineering and see how many did it right the first time, (NOT) you should read history books now and again, not everything was made in CHINA, most all carved out of the hands of Americans.

[FredGarvin]

Anyone who knows what a dead man's curve is would tell you to rethink that.

[Mech_Engineer]

You stink, I will build it, prove simplicity, hard work and yes I will read up on engineering and see how many did it right the first time, (NOT) you should read history books now and again, not everything was made in CHINA, most all carved out of the hands of Americans.

There is no way you can "prove" the simplicity of a helicopter, because it isn't SIMPLE!!! :cry:

I know enough about the engineering of helicopters to know it can't be done (safely or economically) by someone who has no engineering background and no idea what goes into making one.

BTW, Fred IS an engineer that works on helicopters. If you should listen to anyone, it should be him.

[DaveC426913]

I am confident in saying that losing three fingers qualifies as a failed project in any sane person's books.

And in Icanbuildit's case, his future projects are limited: a mere 2.333 left.

[AKHS]

"Great minds discuss ideas; Average minds discuss events; Small minds discuss people." - Elanore Roosevelt---- Roosevelt also have a small mind, like me!!!!!

[Nijelboswell]

It all depends on how well it is built. If the Vehicle is impractically built, the flight will be disasterous. If it is practical with multiple mistakes, it will crash. There can be no mistakes on the building.
Perhaps if you are going to build your own Flying machine, Make sure you have it properly Examined and inspected. Get it Thoroughly checked...

[RonL]

Just to show that progress is being made.

http://www.dailymotion.com/video/x3pj1w_helicoptere-

[FredGarvin]

While I have a very hard time calling that a real helicopter, it is certainly some nice work. That's pretty neat. Do you happen to know if the controls are RC or if the person hanging underneath controls similar to the way an ultralight is controlled?

[RonL]

I believe it is all weight shift, and speed is controlled with the left hand. Counter rotating blades reduce the need for a powered tail rotor.
I think this falls under ultralite rules, so a 5 gallon max. will limit time of flight.
The link below is older technology, but also shows a possible area of personel transport, with high speed computer control, pilot input error can be eliminated, making this a very stable platform.

http://www.youtube.com/watch?v=dmSCyy0_OX4

[Breadboard]

Again, not trying to brush you off, but have a look at some of the other threads about building go karts/hovercraft/planes in this forum and see what kind of level of detail you need to go into to do it yourself. Lots of people here have done engineering degrees, and many have years of experience behind them, but I doubt anyone here would feel confident designing something like this in its entirety, from start to finish, on their own!

I agree in principle, but disagree in general! :rolleyes: Yes, building something like a small personal air vehicle of whatever type, would certainly involve a huge amount of work, and be quite expensive. But the parts and equipment are commercially available, and a design simply needs to incorporate the mechanisms of putting these all together. The most significant obstacle to overcome is the very strict regulations regarding airworthiness. The EASA regulations, even for small aircraft, are based around commercial, multi person craft, and do not reflect the needs and considerations of the small home builder because this was not a central concern when they were being drafted. The regulations I believe have also stifiled private aviation advancement for decades because the cost of design and research & development, in order to comply with the regulatory requirements, is outside the realm of the private inventor/builder. I'm not so sure about the FAA reg's. The entire market is drowned in very strict regulations which in some cases are very necessary, but in other cases could be re-drafted to be much more flexible, while still ensuring a reasonable level of safety. Complying with these regulations, and awaiting assesment at the various build stages is a major contributing factor to why home building takes so long.

Re. IcanBuildIT post's previously, and the replies. I think nobody is questioning the complexity of building a heli, however this does not mean it cannot be done with relative success and a reasonable flight safety level, by someone who is willing to spend time learning and 'carefully' building with attention to detail. Remember we are NOT talking about a heli with all the bells and whistles of a modern multi million dollar commercial design. Simply a basic design equivalent to decades ago. The first heli in 1907 was built by private designers unrestricted by modern limitations of technical and regulatory natures. It was still a 'helicopter' and it still flew.....I wouldn't trust my life to it, but it worked. It can be done. People nowadays are blinded by the complexity that something can, but does not have to, have. There are two kinds of people...those who do, and those who talk about doing!

Didn't PM have ads for plans for a one man chopper. I seem to remember one type with jets/rockets at the blade tips.

If memory serves me correctly ( Which it may not! :uhh: ) the russians developed a heli using rockets at the tips of the rotor blades. I can't remember if there was a safety purpose, to assist in rotation of the blades after a main engine failure, or simply for powered assistance during takeoff/flight.

[RonL]

This page might be of interest to anyone thinking of rocket tip rotors.

http://inventors.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=inventors&cdn=money&tm=23&gps=574_1179_938_631&f=00&su=p554.2.150.ip_&tt=3&bt=1&bts=1&zu=http%3A//www.tecaeromex.com/

Look at tab "Isabel" and "rocket helicopter"

[RonL]

Tom Berry is near to having a back-pack helicopter that can be purchased in the future, details and price at this time are still unknown as he continues to test and improve it.
They fall into the ultralite category, which limits weight to 254 pounds, and a 5 gallon fuel supply.
The general agreement for power is 20-30 Hp, this at present, average efficiency will give around 45 minuets of flight time.

http://www.sporthelo.com/

I'm thinking he will show a better video soon:smile:

[Cyrus]

While I have a very hard time calling that a real helicopter, it is certainly some nice work. That's pretty neat. Do you happen to know if the controls are RC or if the person hanging underneath controls similar to the way an ultralight is controlled?

Looks like an utlra light heli to me!

[DaveC426913]

The video looks pretty straightforward for the first 33 seconds - a normal, if slightly robust RC heli.

And then at 34s I was absolutely gobsmacked to see that it has a seat. I did a classic double-take :bugeye::bugeye::bugeye:.

[FredGarvin]

Since he is pushing that under Part 103, I wouldn't trust Mr. Berry as far as I could throw him. I also hope that people understand exactly what the ultralight tag implies when it comes to what one can do with one.

Even looking at the "corporation's page", I can't find anything discussing the qualifications of the designers or the work they are doing. I would certainly hope that this isn't Cooter going out in his back yard and trying different things. It's a big leap to go from an electric stair chair and trailer mounted generator to an ultralight. I wish them the best, but to say he is near selling it when it appears that there has only been tethered flights is a big leap.

[RonL]

Since he is pushing that under Part 103, I wouldn't trust Mr. Berry as far as I could throw him. I also hope that people understand exactly what the ultralight tag implies when it comes to what one can do with one.

Even looking at the "corporation's page", I can't find anything discussing the qualifications of the designers or the work they are doing. I would certainly hope that this isn't Cooter going out in his back yard and trying different things. It's a big leap to go from an electric stair chair and trailer mounted generator to an ultralight. I wish them the best, but to say he is near selling it when it appears that there has only been tethered flights is a big leap.

I agree with most of what you are saying, the first link that i put in the thread does show a man in actual flight, and not a tethered flight. As for selling it to a mass of people, thats another thing, as an example, the GEN-4 Helicopter, made by a fellow in China is a well designed machine, the price of around 30,000$ US is very high, i can't find record of one sale going back to 2002, but there are lots of people that this amount of money is of no concerne. Untill a few machines are put into actual use, and at least some sense of safety established, there will be no market.
I think i like the Hiller Flying Platform best, with that you can have a parachute on your back.

[Breadboard]

Surely with the 80 pounds excess lift capacity alluded to on the page, incorporating blade jettisoning and a parachute assembly would not be impossible.

[RonL]

Surely with the 80 pounds excess lift capacity alluded to on the page, incorporating blade jettisoning and a parachute assembly would not be impossible.

There is a thread that discussed that a little, however that 80 pounds extra weight really puts a challenge in finding a power supply that can give the horsepower needed and at the same time not exceed the 254 weight limit (really a tight line here).

[morrijon]

I have a RC micro-helo that is naturally very stable, hovers by itself and has no swashplate assembly. It has a pre-set main rotor that adjusts lift merely by speeding up the rotor and it is naturally stable because of another mini rotor (not counter-rotating) above the main rotor that has weights on the end. I know nothing about physics but have been fascinated with the dream of building a "flying machine" of any nature. Why don't people build full size replicas of these things? Or maybe they do and I have never seen one. I can litterally throw this thing into the air, suddenly press the "accelerator" on the RC control and the helocopter rights itself from a mid-air tumble and hovers! Wow! To me that seems pretty full proof. I presume the mini rotor and weight system acts like a gyro to stabilize this very light weight contraption. I would add a small prop out the back that would provide forward thrust and the tail rotar would provide left/right turning. What do you guys think? Again, I am a total novice so I apologize if I said anything "obviously" stupid.

[RonL]

I have a RC micro-helo that is naturally very stable, hovers by itself and has no swashplate assembly. It has a pre-set main rotor that adjusts lift merely by speeding up the rotor and it is naturally stable because of another mini rotor (not counter-rotating) above the main rotor that has weights on the end. I know nothing about physics but have been fascinated with the dream of building a "flying machine" of any nature. Why don't people build full size replicas of these things? Or maybe they do and I have never seen one. I can literally throw this thing into the air, suddenly press the "accelerator" on the RC control and the helicopter rights itself from a mid-air tumble and hovers! Wow! To me that seems pretty full proof. I presume the mini rotor and weight system acts like a gyro to stabilize this very light weight contraption. I would add a small prop out the back that would provide forward thrust and the tail rotor would provide left/right turning. What do you guys think? Again, I am a total novice so I apologize if I said anything "obviously" stupid.

I have been looking, with a lot of interest, at some of these RC's.
The ones that have software which isolates the frequency of operation, so that you do not interfere with other fliers, i think is very good.
In the long run this might be a cheap way to learn about a helicopter.:cool:

[FredGarvin]

I have been looking, with a lot of interest, at some of these RC's.
The ones that have software which isolates the frequency of operation, so that you do not interfere with other fliers, i think is very good.
In the long run this might be a cheap way to learn about a helicopter.:cool:
They used to be replaceable crystals that were for a particular frequency. You just swapped crystals if someone was using your freq. They do it by software now, eh?

You do have to a bit careful with RC helicopters simply because they violate a lot of physics that the real ones have to follow. You won't ever find a real helicopter doing an inverted tail pivot.

[RonL]

http://www.hobbywarehouse.com/Products/RC-Helicopters/EFLH1250-E-Flite-Blade-CX2-RTF-Elec-Coaxial-Heli

This is what caught my attention, I'm not sure how the software eliminates interference,(detailed description) the model is small, thus not likely to do much damage:smile:

I have never been too excited about larger RC helicopters, because they look too much like my lawn mower at eye level, upside down and with no housing:surprised not sure why there has not been more severed heads in the world:confused:

[morrijon]

They used to be replaceable crystals that were for a particular frequency. You just swapped crystals if someone was using your freq. They do it by software now, eh?

You do have to a bit careful with RC helicopters simply because they violate a lot of physics that the real ones have to follow. You won't ever find a real helicopter doing an inverted tail pivot.

What laws of physics to these things violate? I am not sure what an inverted tail pivot is, but either way, I still don't understand why these things with relatively few and uncomplicated parts are so stable, when large helicopters are not? In other words, if I replicated my micro-rc helicopter to full size and figured out the specs it would need to be in order for me to "fly" it, it seems like it would be pretty full proof. (Relatively speaking of course). Of course, it wouldn't be a "real" helicopter with a swashplate and pitch changing blades and all, but who cares, it would hover, go up/down/left and right. It sure would beat those strange contraptions strapped to people's backs! Not only that, but it would need only simple electric controls to manipulate engine speed(s) instead of complicated hydrolics or heavy manual controls. The more I study this thing, the more I want to build it.

[Z-Abercrombie]

Hello, new here and found this to be an interesting thread. been interested in trying different designs in large scale RC helicopters and I have a couple of questions about counterrotating systems.

First is this: in a coaxial arrangement is it necessary that both rotors tilt or could the bottom one be left alone and all of the direction control be done with the top rotor(with yaw taken care of by airfoils like the airscooter and a few others)?
Second question is would the idea of having one rotor under the carriage (like the PAM 100b) and the other counter rotating one overhead be a stable platform? and if not why? If it is a legitimate option it would seem to really simplify the coaxial rotorhead issue by not having to worry about interfereing with each other.

Now for a quick intro: I teach high school Spanish but am fascinated by all things mechanical. Lately I have been playing with homebuilt cnc and hovercraft.

[mtworkowski@o]

Iv'e been looking at the comments on homemade helicopters. The problem is not that you can't build one. We built everything as kids and when something was impossible, we worked around it. The problem is that the learning process is very dangerous. You could be killed before you learn anything. You're not going to learn all the math and have all the lab equipment etc. So the way to build something is to pototype fast and dirty. Build a cheap prototype and test to destruction.
I think a really central part of the proccess is going to be the question of how we evolve designs from bad to good. Aerodynamics aside for the moment. We all know when something works beautifully or if something is wrong. The next question is whether it's going to work fine and then fail.
Get on it and don't listen to the naysayers. If you can't do it, you'll find out for yourself. Just learn the material and be safe.

[mtworkowski@o]

What laws of physics to these things violate? I am not sure what an inverted tail pivot is, but either way, I still don't understand why these things with relatively few and uncomplicated parts are so stable, when large helicopters are not? In other words, if I replicated my micro-rc helicopter to full size and figured out the specs it would need to be in order for me to "fly" it, it seems like it would be pretty full proof. (Relatively speaking of course). Of course, it wouldn't be a "real" helicopter with a swashplate and pitch changing blades and all, but who cares, it would hover, go up/down/left and right. It sure would beat those strange contraptions strapped to people's backs! Not only that, but it would need only simple electric controls to manipulate engine speed(s) instead of complicated hydrolics or heavy manual controls. The more I study this thing, the more I want to build it.
Yes, exactly. Why can't we scale up? Is it in the materials? Has anyone done the math to see if the weights and strengths are all in the right areas? Maybe a full size helicopter has to be made of carbon fibor and foam. I think the motor and drive line are too heavy in the full size. I don't own one of these RCs, but I bet alot could be learn really fast by a few weights and measures.

[DaveC426913]

What laws of physics to these things violate? I am not sure what an inverted tail pivot is, but either way, I still don't understand why these things with relatively few and uncomplicated parts are so stable, when large helicopters are not? In other words, if I replicated my micro-rc helicopter to full size
Aye, there's the rub.

Scaling factors. Things that push the limits of mass, strength and power do not scale up very well.

http://en.wikipedia.org/wiki/Square-cube_law

It is the same reason why there are no humans sixty feet tall.

[FredGarvin]

Yes, exactly. Why can't we scale up? Is it in the materials? Has anyone done the math to see if the weights and strengths are all in the right areas? Maybe a full size helicopter has to be made of carbon fibor and foam. I think the motor and drive line are too heavy in the full size. I don't own one of these RCs, but I bet alot could be learn really fast by a few weights and measures.Yes. My company has done this in our applications. We got it to work, but, like the link Dave posted, it is not a direct/linear scale factor for just about everything. It gets much more complicated when things like bearing dynamics and fasteners are concerned. It also gets hairy when dealing with the aerodynamics. Some areas did scale well, but other areas were very difficult to scale.

[mtworkowski@o]

In scaling up, only the intent can be scaled up. The actual form is dictated by the parameters of stregnth and weight. The construction of a violin is an efficient way to follow the parameters. Light, strong, does the job it was designed to do. Hot air balloon baskets is another example. Rattan because it's right for the job of containment, protection and resists impact shock. I mentioned carbon fiber and foam as examples of material that excel in certain areas. I'm also looking at the power plant to see what can be done with the weight. The old ways can't be used anymore. Fuels with cooler combustion temps. Cylinder walls supported by webs of material cooled with forced air. Something...

[mtworkowski@o]

Bravo

[mtworkowski@o]

BRAVO and very well put. What you say is true and relevant. Thank you!

[mtworkowski@o]

BRAVO and very well put. What you say is true and relevant. Thank you Breadbord.

[mtworkowski@o]

I remember my father scoffing at all the negative feelings about homemade flight. He took an old washing machine apart and replaced the drum and agitator with rotor blades made of styrofoam covered with fiberglass. I don't know what the foil profile was because I was just a kid. When he plugged in the electric motor the thing tried to pull itself from it's moorings. It had more than enough power to lift itself and then some. Understand, this was a piece of junk with no consideration to weight or anything else. My uncle owned a bike shop and wanted to build a real version to fly. It never happened but I was convinced that it could have.

[redargon]

This is a very interesting topic and seems to be a battle between the well grounded engineers (who studied their butts off for years and then worked their butts off to gain years of experience, so please respect their comments and advice) and the dreamers. Please also remember that most engineers are dreamers too and this is usually the reason why they studied engineering, in an attempt to realise these dreams, efficiently and safely). For the dreamers without a lot of background knowledge, use the inputs from the guys with knowledge and experience. You don't have to believe everything they say either and you can try to prove or disprove theories as you seem fit. Often dreamers stumble upon new ideas and concepts and break through to a new level. For entire projects though, this is often accompanied by sound advice from professionals. Einstein did not go through life thinking Newton was an uneducated toad, he realised Newton's contributions and added to them and molded them into a new more complete understanding of the universe.

For the dreamers who are serious about new designs or ideas, first learn a little design or ideation methodology. Have your idea, make sure you understand the idea and the requirements. Break it into simpler parts. Do some feasibility analysis of different concepts. Find solutions to each part (with or without help is up to you). Put it together and solve the entire problem. Double check everything. Put the plan into action. Keep people here up to date with your progress so that everyone knows where you are and where you're heading. Finding a plan on the internet could be like finding other "miracle cures" on the internet. There may also be good work in an interent plan, but use it wisely and question it, just as you question the experts here.

Let's see some brainstorms on here, I mean real diagrams, ideas, feasibility studies. Attach the work you've done. Ask questions like: Should I consider carbon fibre, because while reading about fracture mechanics, I learned... or: How can we model the drag of the rotor if I use these dimensions or this airfoil? What sort of powerplant would be a good option and what fuel does it use and how can I store this fuel? etc. You can argue all you like, but if a dream is to become a design, you have to put some work on the table. Let the critics dissect it and learn and grow and oppose too. This is the best way to move forward with any design.

This is just my 2 cents and an attempt to be neutral and helpful to all parties concerned. I hope this makes the following progress smoother.

In hoping for a brighter future with new designs, that are better than the last.

[mtworkowski@o]

Thanks for the note redargon,
It sounded like you where scolding me for something. Like maybe being too unrealistic, ignorant and lazy. That's just one of my faults. I'm working on it though. Sometimes I get sick of the naysayers. I guess it came out in my posts.
Thanks again.
ps I don't know which of my posts made you react that way or was it all of them?

[RonL]

This is a very interesting topic and seems to be a battle between the well grounded engineers (who studied their butts off for years and then worked their butts off to gain years of experience, so please respect their comments and advice) and the dreamers. Please also remember that most engineers are dreamers too and this is usually the reason why they studied engineering, in an attempt to realise these dreams, efficiently and safely). For the dreamers without a lot of background knowledge, use the inputs from the guys with knowledge and experience. You don't have to believe everything they say either and you can try to prove or disprove theories as you seem fit. Often dreamers stumble upon new ideas and concepts and break through to a new level. For entire projects though, this is often accompanied by sound advice from professionals. Einstein did not go through life thinking Newton was an uneducated toad, he realised Newton's contributions and added to them and molded them into a new more complete understanding of the universe.

For the dreamers who are serious about new designs or ideas, first learn a little design or ideation methodology. Have your idea, make sure you understand the idea and the requirements. Break it into simpler parts. Do some feasibility analysis of different concepts. Find solutions to each part (with or without help is up to you). Put it together and solve the entire problem. Double check everything. Put the plan into action. Keep people here up to date with your progress so that everyone knows where you are and where you're heading. Finding a plan on the internet could be like finding other "miracle cures" on the internet. There may also be good work in an interent plan, but use it wisely and question it, just as you question the experts here.

Let's see some brainstorms on here, I mean real diagrams, ideas, feasibility studies. Attach the work you've done. Ask questions like: Should I consider carbon fibre, because while reading about fracture mechanics, I learned... or: How can we model the drag of the rotor if I use these dimensions or this airfoil? What sort of powerplant would be a good option and what fuel does it use and how can I store this fuel? etc. You can argue all you like, but if a dream is to become a design, you have to put some work on the table. Let the critics dissect it and learn and grow and oppose too. This is the best way to move forward with any design.

This is just my 2 cents and an attempt to be neutral and helpful to all parties concerned. I hope this makes the following progress smoother.

In hoping for a brighter future with new designs, that are better than the last.

An excellent post, and welcome to the forum.
It sure is good when people say a little about themselves.

I would like to step up to your request in regards to new designs, and brainstorming, but to meet all the steps of your post would take me quite a distance into the future.
If I throw out the basic idea, with just a hand drawn sketch or two, then maybe it would motivate me to do the rest.

How far into the future do we take this first step ? I'm getting pretty old:frown:

Ron

[mtworkowski@o]

I've got some time and the weather is nice so i've decide to get this home made helicopter thing on track. I found a gear reduction gearbox with right angle drive and I want to hear some opinions. This is the gearbox from a direct drive wahing machine. 150 bucks new. They last for 20 yrs in washing machines. I figure it should be a good starting point. Does anyone know what rpm these electric motors run at? On spin my machine sounds like around 250. I'm thinking that's right in the range I need for the rotors.
Sorry to be so rediculous but that's the way I've always built things. I'd use a razor blade to build a radio. And sometimes my stuff even works!

[mtworkowski@o]

That's a pretty high and mighty attitude from where i'm sitting. I've been through enough tech analysis and all the other crap for a lifetime. Most of the stuff we buy in the store is crap. And who designs it. Rignt. Now I don't want to implicate anybody but a nice answer would be something like: Check this and that and this is really important and if you have any questions ask. That's why we're here. We're not morons just because we don't live in the tech mainstream.

[Mech_Engineer]

Well I'm pretty sure a washing machine's gearbox will not do for a home-made helicopter. The reason they last 20 years is because they are paired with a properly-sized motor and were designed specifically for that application; not because they're indestructible due to massive over-engineering.

[mtworkowski@o]

I think your absolutely right, but I just can't help thinking that the torque load on the rotor shaft is comperable to a fully loaded washing machine. And I do believe that the thing is over spec. I'm going to get an old one and use my torque wrench to go max to break. How much drag do you think is on a 20 ft rotor at full collective and 500 lb. of weight? Climb can be a shitty number. Let's just get a feel for the whole thing. Is drag the only thing I should look at in terms of torque loading on the gear box?

[Mech_Engineer]

You need to look at power throughput requirements and weight. A washing machine's motor is around 1-2 hp, the smallest ultralight helicopter kits I have seen use a 40hp 2-stroke engine. They also run the main rotor at about 400-500 rpm.

It seems to me that if a chopper is putting out 40 hp of lifting force at 400 rpm on the main rotor, that means the torque being imparted on the main rotor is 525 ft-lb (712 N-m). If you had a hypothetical rotor that only turned at 250 rpm (would have to be bigger, more drag) then you would need 840 ft-lbf for the same 40 hp.

[mtworkowski@o]

You need to look at power throughput requirements and weight. A washing machine's motor is around 1-2 hp, the smallest ultralight helicopter kits I have seen use a 40hp 2-stroke engine. They also run the main rotor at about 400-500 rpm.

It seems to me that if a chopper is putting out 40 hp of lifting force at 400 rpm on the main rotor, that means the torque being imparted on the main rotor is 525 ft-lb (712 N-m). If you had a hypothetical rotor that only turned at 250 rpm (would have to be bigger, more drag) then you would need 840 ft-lbf for the same 40 hp.

Thanks for the response. By power throughput I assume you mean that the required power is being drained off by losses in the driveline and that upstream power reqs are much higher than merely rotor reqs..Excellant point.
Would show me the crunch on those numbers? Just briefly. I'd be interested.
thanks

[Mech_Engineer]

With power delivery through rotating shafts, power is torque multiplied by angular speed. So, in the case of the engine on the chopper, if we assume all of the power produced by the engine is going to the main rotor then 40hp/400rpm gives you 525 ft-lb of torque (after some unit conversion, dividing the power in Watts by the angular speed in radians/second gives you the torque in Newton-meters). This probably isn't a very good approximation because the tail rotor would take power too and the transmission would not have 100% efficiency, but as a worst-case estimate it gives a ballpark idea of the transmission requirements.

The input shaft for the transmission will be going the same speed as the engine itself, which could be around 4000-5000 rpms (we'll call it 4000 for calculation simplicity, making the transmission a 10:1 gearbox). So if the engine is putting out 40 hp at 4000 rpms, its producing 52 ft-lb of torque. Basically this means the chopper's transmission needs to be able to handle an input shaft speed of 4000rpm and input torque of 52 ft-lb, and the output needs to be able to put out 10 times that torque at 1/10 the speed. I'm sure you'll find a washing machine's right-angle drive transmission is grossly undersized based on these requirements.

[mtworkowski@o]

With power delivery through rotating shafts, power is torque multiplied by angular speed. So, in the case of the engine on the chopper, if we assume all of the power produced by the engine is going to the main rotor then 40hp/400rpm gives you 525 ft-lb of torque (after some unit conversion, dividing the power in Watts by the angular speed in radians/second gives you the torque in Newton-meters). This probably isn't a very good approximation because the tail rotor would take power too and the transmission would not have 100% efficiency, but as a worst-case estimate it gives a ballpark idea of the transmission requirements.

The input shaft for the transmission will be going the same speed as the engine itself, which could be around 4000-5000 rpms (we'll call it 4000 for calculation simplicity, making the transmission a 10:1 gearbox). So if the engine is putting out 40 hp at 4000 rpms, its producing 52 ft-lb of torque. Basically this means the chopper's transmission needs to be able to handle an input shaft speed of 4000rpm and input torque of 52 ft-lb, and the output needs to be able to put out 10 times that torque at 1/10 the speed. I'm sure you'll find a washing machine's right-angle drive transmission is grossly undersized based on these requirements.

Am I right here? Power= Torque X RPM / 5252 so...........Torque = Power X 5252/RPM
40hp X 5252/400 =525.2 ft.lb.

[mtworkowski@o]

You know we've made some assumptions here. A torque of 525 strikes me as the torque of 300hp Pontiac 389 from the early 60s. I think it was actually 425 lb.ft.
I know we're just dropping in that 40hp spec. for fun and it probably is close if it's being used by others, but something has to off here. Do you agree?

[mtworkowski@o]

No. I just got it. 10 to 1 gearing. thank you.

[Mech_Engineer]

Am I right here? Power= Torque X RPM / 5252 so...........Torque = Power X 5252/RPM
40hp X 5252/400 =525.2 ft.lb.

Yup, that's correct.

[mtworkowski@o]

Thanks boss.

[RonL]

While you guys are calculating, I have been watching my lawn sprinkler and thinking about how air would spin it, if it were to be hooked to a air hose.

Now concerning a very light machine (almost anything can be done):wink:
Without considering the source of air, but only the results, how much volume and pressure would produce thrust enough to lift 400 pounds, if there are two counter rotating rotors, seventeen feet in diameter ? (4 tips discharging air, pushing the blades in a forward direction).

I know there are many other factors involved, and speed of the rotors will depend mostly on pressure, but it seems that larger volume, lower pressure will be easier to produce.

Any help with the calculations ??

Ron

[mtworkowski@o]

I like it. I always thought compressed air was a really portable power source. Wait, you made me think of propane. A little diversion. Before Whittle envented the jet engine in England, a guy someplace else took a piston engine and ran a piston compressor to force air into a combution chamber with fuel. That's a jet engine. You know that propane tank near the grill. If you use propane instead of compressed air you will be getting the benefit of a fuel. The plumbing remains the same.( o rings etc.) I'm thinking ceramic chambers on the tips. No the whole thing is nuts. You had a better idea.
Carry on. Smoke 'em if you got 'em.

[RonL]

I like it. I always thought compressed air was a really portable power source. Wait, you made me think of propane. A little diversion. Before Whittle envented the jet engine in England, a guy someplace else took a piston engine and ran a piston compressor to force air into a combution chamber with fuel. That's a jet engine. You know that propane tank near the grill. If you use propane instead of compressed air you will be getting the benefit of a fuel. The plumbing remains the same.( o rings etc.) I'm thinking ceramic chambers on the tips. No the whole thing is nuts. You had a better idea.
Carry on. Smoke 'em if you got 'em.

I think some of my ideas about the use of propane, has gotten me on almost everyones ignore list.:biggrin:
And I have not even put my wildest idea forward yet.:cry:

Ron

[mtworkowski@o]

go for it. there is no list.

[Mech_Engineer]

Compressed gas is really a poor method for storing energy, since it takes large, heavy tanks to hold a large and/or high-pressure volume. Because aircraft need to be light, they need a high-energy density fuel that doesn't weigh much, and compressed air isn't even close to petroleum-based fuels in terms of energy per pound.

[mtworkowski@o]

I would agree. I use air powered tools now and then and the are excellent. But it's only because the real power source is my local electric grid via an air compressor. No, it's hard to beat the IC engine. And why bother?
Recently I saw the new aerotwin helicopter motor. Less than 100 lb. Some reasonable amount of HP. Liquid cooled. What's the big deal? Tell me why a motorcycle engine could'nt do a reasonably compitent job.

[RonL]

go for it. there is no list.

Go to "My PF" and look again:smile:

[mtworkowski@o]

Go to "My PF" and look again:smile:

Thanks, it looks like all is well.

[RonL]

Compressed gas is really a poor method for storing energy, since it takes large, heavy tanks to hold a large and/or high-pressure volume. Because aircraft need to be light, they need a high-energy density fuel that doesn't weigh much, and compressed air isn't even close to petroleum-based fuels in terms of energy per pound.

How quick the mind jumps to the negative of how things are done, do we need to store compressed air in large heavy tanks ? why not use it at the same rate we produce it ? my proposal would be to make the compressor (vane style) section a part of the rotating group (the hub section) the blades are hollow and serve as a momentary tank, the energy to start the process is positive and needs to be supplied from some external source, as kinetic energy builds in the rotating mass, the resistance of compression takes place at a 6" to 12" radius, while the thrust of the jet ejection takes place at a radius of 8-1/2 feet (quite a bit of leverage I think ?).
If intake volume, and compression are matched to supply the discharge at the outside diameter, then additional energy that needs to be supplied to the system, should be enough to compensate for bearing friction, compressor friction, and some thermal loss as the compressed air moves through the blades to the tips (one benefit might be less chance of ice buildup on the blades in some conditions).

This almost completely eliminates losses associated with conventional ICE driven compressor systems, (think carefully).
Also with a counter rotating set of blades, each blade rotating 180 degrees, makes one full cycle for the compressor, as one rotor turns the compressor rotor, and the other rotor turns the compressor housing.

With as little as two to five horsepower additional energy, you might get the same results as that 40 horsepower ICE produces.

Now i have given away some more of my IP rights.:cry:

Now lets hear it:uhh::rolleyes::eek:

RonL

[mtworkowski@o]

Ron,
I'm sitting here putting my whole brain into this one. I think we have to go over this a bit slower and with more explanation. Words are 1/1000 of a picture, you'll remeber.

[redargon]

How quick the mind jumps to the negative of how things are done, do we need to store compressed air in large heavy tanks ? why not use it at the same rate we produce it ? my proposal would be to make the compressor (vane style) section a part of the rotating group (the hub section) the blades are hollow and serve as a momentary tank, the energy to start the process is positive and needs to be supplied from some external source, as kinetic energy builds in the rotating mass, the resistance of compression takes place at a 6" to 12" radius, while the thrust of the jet ejection takes place at a radius of 8-1/2 feet (quite a bit of leverage I think ?).
If intake volume, and compression are matched to supply the discharge at the outside diameter, then additional energy that needs to be supplied to the system, should be enough to compensate for bearing friction, compressor friction, and some thermal loss as the compressed air moves through the blades to the tips (one benefit might be less chance of ice buildup on the blades in some conditions).

This almost completely eliminates losses associated with conventional ICE driven compressor systems, (think carefully).
Also with a counter rotating set of blades, each blade rotating 180 degrees, makes one full cycle for the compressor, as one rotor turns the compressor rotor, and the other rotor turns the compressor housing.

With as little as two to five horsepower additional energy, you might get the same results as that 40 horsepower ICE produces.

Now i have given away some more of my IP rights.:cry:

Now lets hear it:uhh::rolleyes::eek:

RonL

Your description is a little complicated. Not trying to be negative, but isn't what you are talking above coming close to perpetual motion? ie. using the rotor to generate lift and compress air to be used to spin the rotor to generate lift to compress air, etc.

[RonL]

Your description is a little complicated. Not trying to be negative, but isn't what you are talking above coming close to perpetual motion? ie. using the rotor to generate lift and compress air to be used to spin the rotor to generate lift to compress air, etc.

Very close indeed, and as I understand the first two laws of thermodynamics, there are three limits imposed. At what efficiency rate does a machine need to transfer energy in order to maintain it's own movement ?

I'm not sure where the complication is, if one understands the vane compressor, it will need to have a dual intake and exhaust ports system (two compression cycles) to keep things in alignment, and balance. Having a throttle control system at the tip discharge points might be needed. Other than a few design details, it is basically Air In, and Air Out.

Throwing in a small amount of electrical design, (storage and usage), really gets me excited.

[RonL]

Very close indeed, and as I understand the first two laws of thermodynamics, there are three limits imposed. At what efficiency rate does a machine need to transfer energy in order to maintain it's own movement ?

I'm not sure where the complication is, if one understands the vane compressor, it will need to have a dual intake and exhaust ports system (two compression cycles) to keep things in alignment, and balance. Having a throttle control system at the tip discharge points might be needed. Other than a few design details, it is basically Air In, and Air Out.

Throwing in a small amount of electrical design, (storage and usage), really gets me excited.

Maybe a better way to think of this is to forget the mechanics for a moment, and consider the thermal conditions of the air.

If each cubic foot of air that is taken into the compressor has a temperature xx, or xxx degrees, the energy to keep rotation going against compression, thrust, friction, and thermal loss (through conduction), will be reflected by a reduction of temperature, and pressure at the discharge points of the rotors. Each horsepower will require 42.44 BTU/Min. so the air will be cooler based on the energy needed to maintain this motion. The hotter the air the better this will work.

The losses between compression, and discharge will be small in relation to the large mass of air moving through the system.

Very few losses of energy outside the system.

After typing all this I'm not sure it makes any more sense.:rolleyes:


Ron

[Mech_Engineer]

do we need to store compressed air in large heavy tanks ? why not use it at the same rate we produce it ?


If you propose to use compressed air for a power source, you need to carry it on-board. Otherwise you'll need to carry your required energy to compress the gas on-board in some other form, like gasoline.


If intake volume, and compression are matched to supply the discharge at the outside diameter, then additional energy that needs to be supplied to the system, should be enough to compensate for bearing friction, compressor friction, and some thermal loss as the compressed air moves through the blades to the tips (one benefit might be less chance of ice buildup on the blades in some conditions).


This isn't sounding good. You're saying you use the kinetic energy from the blades to drive a compressor that pumps air to spin the blades, so at most all this thing could do is spin the blades for a little bit until they run out of kinetic energy (you're neglecting external air drag on the blades also, probably one of the largest factors on a helicopter rotor).

With as little as two to five horsepower additional energy, you might get the same results as that 40 horsepower ICE produces.


With 5 horsepower of input, that will be your maximum output as well. The point of a helicopter's engine is to put out enough power to create a downward flow of air that in turn creates a thrust in the opposite direction. Moving all of that air takes a lot of energy, and since your special blades aren't "creating" any energy no matter how complex the rotary vane compressor approach is, they're just spinning around and will completely dependent on additional power input if they need to lift something.

Very close indeed, and as I understand the first two laws of thermodynamics, there are three limits imposed. At what efficiency rate does a machine need to transfer energy in order to maintain it's own movement ?


Being "very close to a prepetual motion machine" is probably not a good thing... To answer your question the only fundamental efficiency that all machines must live by is that their efficiency will be less than 100%. For a machine to continue moving indefinitely, it must have a power input that is equal to all losses in the system.

Your problem is that you're thinking of the rotor as the system, where all it needs to do is keep spinning. In fact the rotor is one part of a helicopter as a system, and the rotational kinetic energy stored in the rotor is small compared to the energy required to keep the helicopter aloft for say 5 minutes.

[mtworkowski@o]

It's OK Ron. Just stick your face out the door and close it hard on your head about 5 times. That usually clears my head. Keep thinking.

[mtworkowski@o]

What ever happend to Icanbuildit?

[Mech_Engineer]

Hopefully he didn't lose the rest of his fingers building his new helicopter...

[mtworkowski@o]

who did he say stunk? I think he was OK.

[Mech_Engineer]

He's a can-do guy, I was simply referring to one of his posts in this thread:

I lost three fingers building one of my kayaks...

[mtworkowski@o]

He's on page 3. I couldn't stop laughing. He's right though. Things can be done. You just don't want to get killed doing them.

[RonL]

If you propose to use compressed air for a power source, you need to carry it on-board. Otherwise you'll need to carry your required energy to compress the gas on-board in some other form, like gasoline.



This isn't sounding good. You're saying you use the kinetic energy from the blades to drive a compressor that pumps air to spin the blades, so at most all this thing could do is spin the blades for a little bit until they run out of kinetic energy (you're neglecting external air drag on the blades also, probably one of the largest factors on a helicopter rotor).



With 5 horsepower of input, that will be your maximum output as well. The point of a helicopter's engine is to put out enough power to create a downward flow of air that in turn creates a thrust in the opposite direction. Moving all of that air takes a lot of energy, and since your special blades aren't "creating" any energy no matter how complex the rotary vane compressor approach is, they're just spinning around and will completely dependent on additional power input if they need to lift something.



Being "very close to a perpetual motion machine" is probably not a good thing... To answer your question the only fundamental efficiency that all machines must live by is that their efficiency will be less than 100%. For a machine to continue moving indefinitely, it must have a power input that is equal to all losses in the system.

Your problem is that you're thinking of the rotor as the system, where all it needs to do is keep spinning. In fact the rotor is one part of a helicopter as a system, and the rotational kinetic energy stored in the rotor is small compared to the energy required to keep the helicopter aloft for say 5 minutes.



First I think I need to extend an apology, after re-reading my response to you it sounded condescending, and in no way do I feel that.:redface:

Now to defend as best I can my thoughts, first air that is compressed in a sealed environment, will return almost all the energy of compression with the exception of friction in both directions, and loss of thermal value through the confining walls. In a conventional system the force of compression is spread over the surface area of say a piston, and any energy returned would be spread over the same area and plane of movement.

In the start of any compression cycle the required energy is low, and as pressure builds the energy demand grows, and in all designs that I'm aware of power is applied very near the main shaft, close to the center of rotation, the least effective place to put torque.

In the design that is being talked about here, the initial energy input will cause movement in both directions, and as air pressure, and kinetic energy increase, a throttle of some design will start bleeding air at the point of maximum torque application.... (An example that comes to mind is something I'm sure almost everyone has done, Washing a tire that is free to spin, the tire turns quite fast if water is directed on the outer diameter, but putting pressure at the hub near the bearings will produce very little turning, if any).

As this is pretty much a flow through design, good insulation in the right places will prevent most thermal loss.
Thrust produced by the turning of the rotors, should be around 90%+ of the power absorbed from the tip jet discharge. As stated in the past post, air temperature at the intake, and temperature of discharge, will give the sum of energy conversion within the system.

Would this not be a little along the same lines as a heat pump, that gathers much more BTU value than is required by the driving power unit, that moves the gas through the cycle.
A COP in mechanical form?

The rotors and compressor halves, do make the system, along with a few control features.
Consider an electric motor that is set in a bearing mount that will allow both, armature, and housing to turn, each unit is attached to a proper propeller (1 tractor, and 1 pusher) and the leads supplied a voltage(two contact rings on the housing), each part will rotate in opposite directions, and at a speed equal to the division of the sum of both props. If one prop has a different thrust than the other one, speed will divide accordingly and the prop with less thrust will run faster.
Air has energy based on it's temperature, and if BTUs are liberated through the compression and expansion cycle, how are those BTUs any different than those liberated through combustion of fossil fuel??

I think Rudolph Clausius made comment about the exactness of "work into heat, and heat into work"

So many thoughts, I'm about to go brain dead.:shy:

Ron

[AndySmith]

Hi, I've been reading the thread and would like to offer a different suggestion for a very light weight personal helicopter.

1. Four ducted fans powered by light electric motors would provide approx 14hp of lift (large rc modelling engines weigh <1kg each for this thrust)

2. Lithium poly batteries (37v ~4Ah for 800g)

3. Mount them on a backpack style arrangement

4. Wear one of the flying fox type suits to allow cruising at reduced hp - transition might be tricky :-)

5. Some gyro's, a range finder and some electronics to give you a safe landing process (optimised lunar lander scenario)

6. If it was me I'd want an emergency parachute...

[mtworkowski@o]

Got my coptor up and goin'. Ha Ha. This is cool. Pics to follow. Too windy here and very nervous about first experience. This is totally illegal. Woa, this is great. I almost lost my laptop. I don't think I want any more power. OK I'm comin' down. Wew, that was cool. Loud and scarry.............................just kidding. Givin' you all a taste of it.

[harpreet singh]

As far as i can think over it helicopter without that expensive motor to lift the entire weight is not possible.. If u have an idea then plz post it and tel me..

[mtworkowski@o]

harpreet singh
Hi. Haven't seen your name up yet. Welcome. We're just pushing ideas back and forth. Some of us are wanting to build our own conpters. Others have got factories that turn them out like bread. We're just talking things over. What's on your mind?

[harpreet singh]

I am new to this group. I am pursuing my B.E. degree and I have no intentions to build my own copter. I just wanted to knew what was the idea in the back of the mind of that person who posted this thread of making cheap helicopters without those expensive motors..

[harpreet singh]

I am working on another problem if u can help me in that,

I have to calculate strain energy of a clamped circular plate with governing equation in polar coordinates. The plate is loaded uniformly. And deflection is in transverse directon to the plate. Can u help me out in finding the required equations and the values of the coefficients of D matrix involved in it....

[redargon]

I am working on another problem if u can help me in that,

I have to calculate strain energy of a clamped circular plate with governing equation in polar coordinates. The plate is loaded uniformly. And deflection is in transverse directon to the plate. Can u help me out in finding the required equations and the values of the coefficients of D matrix involved in it....

maybe you should move this to a new thread to try and keep the heli one just for helis. Word of advice if you want help with the problem, try and be a little more specific. The guys on here are really good at giving advice, they just need details. Eg. How is the plate clamped? at one point, two points, all the way around the circumference of the plate? Maybe an attached sketch would help. Seeing that it is a circular plate, I would guess polar co-ordinates make sense. For the rest I can't remember what equations would govern a deflected plate. Deflected beams with different cross sections were 1st year statics, but putting strain on plates sounds something along the line of simplifying shear strain on aircraft skin panels, for example, from 4th year aircraft structures. What sort of level of detail are you going into here?

[RonL]

For everyone that thinks we need 40 horsepower to fly a helicopter, may I suggest we start here, and work up the power ladder to the point where height, and duration becomes worthwhile.:wink:

This is I guess the least power, and the least exciting performance that anyone would want.:rolleyes:

The spec sheet.
http://www.calpoly.edu/~wpatters/davi.jpg


the web site
http://www.calpoly.edu/~wpatters/helo.html

Now I'll see if anyone has more comments, before I speak up again.
Anyone interested in Energy Engineering should have a very strong belief in the quest for efficiency, and that there is much room for new, and slightly different design applications, using old and proven technology. (anything new and different will certainly not be in the books, where it is easy to see and understand (just my thinking)).

Ron

[Mech_Engineer]

For everyone that thinks we need 40 horsepower to fly a helicopter, may I suggest we start here, and work up the power ladder to the point where height, and duration becomes worthwhile.:wink:

Considering this quote from the site:

The flight reached an altitude of 8 inches for a period of 8 seconds. The machine was not stabilized. Later attempts with a stabilized machine were considered but not accomplished.

The "Davinci Helicopter" is a very extreme example that cannot be compared to a fully-functioning helicopter outside. This thing barely flew 8" above the ground in a gymnasium. With a 50' rotor span, it's also not at all practical.

[mtworkowski@o]

Hensen and Stringfellow flew an elastic powered machine 100 meters before it encountered a stationary object.

[Mech_Engineer]

Hensen and Sringfellow flew an elastic powered machine 100 meters before it encountered a stationary object.

What machine are you referring to? Link?

[mtworkowski@o]

It's line from the 1965 film "Flight of the Phoenix". Hardy Kruger is very convincing as an aeronautical engineer.

[mtworkowski@o]

RonL
Well said and worth saying.

[Mech_Engineer]

A helicopter that is able to fly out of the ground effect (e.g. altitude greater than the rotor's diameter) will have larger power requirements, hence why the human-powered Davinci helicopter's power requirements are not applicable. Given that the Davinci copter was at an "altitude" of 8in, and has a blade diameter of 50 feet, it was obviously well within the ground effect phenomenon.

Ground Effect

When hovering near ground or water surfaces at a height no more than one-half of the rotor diameter, the helicopter encounters a condition referred to as ground effect. This condition is more pronounced nearer the ground. Helicopter operations within ground effect are more efficient due to reduction of the rotor tip vortex and the flattening out of the rotor downwash. The benefit of ground effect is lower blade angle of attack, which results in a reduction of power requirements for a given load.

http://www.cavalrypilot.com/fm1-514/Ch2.htm

[mtworkowski@o]

Mech Engineer,
That website was very informative and easy to read. Just the thing for dopes like me. It reminds me of a book I read 30 yrs ago. Calculus Made Easy by Sylvanus P. Thompson. Motto: Cut to chase. I like those simple explainations.

[DaveC426913]

It's line from the 1965 film "Flight of the Phoenix". Hardy Kruger is very convincing as an aeronautical engineer.
"Heh heh heh heh HAH HAH model planes HAH HAH He builds model planes! AH HAH HAH HA HAH"

(I have the 1:72 scale Flying Boxcar model kit still in its shrinkwrapping waiting for the day when I build the diorama of the film.)

[FredGarvin]

Mech Engineer,
That website was very informative and easy to read.

It's what Army aviators need in their instructional sources. No big words. Just the way we like it.

[mtworkowski@o]

DaveC426913,
thank you for recognising a joke. By the way that was a great movie. Check out IMDB.COM. Some interesting stuff. Out......














S

[RonL]

"Heh heh heh heh HAH HAH model planes HAH HAH He builds model planes! AH HAH HAH HA HAH"

(I have the 1:72 scale Flying Boxcar model kit still in its shrinkwrapping waiting for the day when I build the diorama of the film.)

Might be that your a "real engineer":rolleyes::biggrin:

1.The Wright brothers had instant success, and acceptance ?

http://en.wikipedia.org/wiki/Wright_Brothers#Childhood

2.Model airplanes, and real ones powered by rubber ?

http://www.rubberbandit.org/

3. The power of leverage has been, and can be used almost everywhere.

http://en.wikipedia.org/wiki/Image:SFTMHandcar.jpg

If one man can supply movement to things like this, stop and think of how a double acting piston can move air through a rotor, to tip jets.
The first few strokes will be harder, then as the air pushes the rotor to faster RPMs the movement of the piston becomes much less of an effort. (think of a rotor moved by air, as a streamlined balloon, like the example of Newton's law in almost every physics book).



Gyro pilots prespin their rotors by hand, which reduces the takeoff distance required.
All I'm trying to say, is things that seem too simple, or, not likely to work, get passed over very quickly.

Because of limits on budgets this kind of, "crazy stuff" falls into the realm of modeling in most cases.

"There's POWER in crazy stuff":surprised:biggrin:

Ron

[mtworkowski@o]

Right on Mr. Ron.

[FredGarvin]

For a pure hover, more power is required than what a fixed wing will need for a rolling take off. The numbers won't lie if you apply them correctly.

[mtworkowski@o]

For a pure hover, more power is required than what a fixed wing will need for a rolling take off. The numbers won't lie if you apply them correctly.

That even seems intuitive. Analogous to winding roads going up a mountain as opposed to trying to drive straight up the side. But I would thind more power would be required throughout he whole flight, as compared to fixed wing. Are you saying that hover requires more power than cruising along?

[RonL]

While you guys are calculating, I have been watching my lawn sprinkler and thinking about how air would spin it, if it were to be hooked to a air hose.

Now concerning a very light machine (almost anything can be done):wink:
Without considering the source of air, but only the results, how much volume and pressure would produce thrust enough to lift 400 pounds, if there are two counter rotating rotors, seventeen feet in diameter ? (4 tips discharging air, pushing the blades in a forward direction).

I know there are many other factors involved, and speed of the rotors will depend mostly on pressure, but it seems that larger volume, lower pressure will be easier to produce.

Any help with the calculations ??

Ron

Fred,
I agree that you are correct with that statement. (which takes me back to this post)

Can this question be answered using the information provided? I think blade width, and airfoil design can be adjusted based on other performance needs, but for pure hoover (above ground effect).

I feel it will be beyond human power, but far less than most people would think.

[Mech_Engineer]

I've done quite a bit of research into power requirements for helicopters (and airplanes), and the definitive answer is there is no definitive answer. Calculating the power required depends on too many variables like efficiency of the rotor, geometry of the body, altitude, air properties, etc. Basically, all you can do is look at a bunch of different helicopters and their power/weight ratio for an attempted scaling (although scaling linearly is probably not accurate).

That being said, ultralight helicopters in the "economy" performance category tend to have about 40 hp for a gross weight of 400-500 lbs. That is considered a "bare minimum" power requirement, and higher-performance versions will have 70-100 hp for the same weight. Interestingly, ultralight airplanes in similar GWR classes have similar power requirements (but ultralights with 40hp are considered sluggish).

Example: G-1 Ultralight Helicopter

G-1 Details http://www.vortechonline.com/g1/

Length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 ft
Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7 ft
Height. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5½ ft
Main rotor diameter. . . . . . . . . . . . . . . . . . . . . . . 12 ft
Tail rotor diameter. . . . . . . . . . . . . . . . . . . . . . . . 2 ft
Empty weight. . . . . . . . . . . . . . . . . . . . . . . . . . . 150 lbs
Gross weight . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 lbs
Useful payload . . . . . . . . . . . . . . . . . . . . . . . . . . 270 lbs
Engine (typical) . . . . . . . . . . . . Kawasaki or Rotax, 40+ hp
Fuel capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 gals
Fuel consumption . . . . . . . . . . . . . . . . . . . . . . . . 4 gals/hour
Speed (max.). . . . . . . . . . . . . . . . . . . . . . . . . . . 80 mph
Altitude (max.) . . . . . . . . . . . . . . . . . . . . . . . . . 10,000 ft asi



Regarding tip jets:
Tip jets

Another single main rotor configuration without a tail rotor is the tip jet rotor, where the main rotor is not driven by the mast, but from nozzles on the tip of the rotor blade; which are either pressurized from a fuselage-mounted gas turbine or have their own turbojet, ramjet or rocket thrusters. Although this method is simple and eliminates torque, the prototypes that have been built are less fuel efficient than conventional helicopters and produce more noise. One example, the Percival P.74, was not even able to leave the ground, and the Hiller YH-32 Hornet had good lifting capability but was otherwise poor. The Fairey Jet Gyrodyne and 40-seat Fairey Rotodyne flew very well indeed. Possibly the most unusual was the rocket tipped Rotary Rocket Roton ATV. None have made it into production.

http://en.wikipedia.org/wiki/Helicopter

Example of a tip-jet helicopter: YH-32 Hornet (http://en.wikipedia.org/wiki/YH-32_Hornet)

[Mech_Engineer]

Some very cool "helicopters" are the Fairey FB-1 Gyrodyne (http://en.wikipedia.org/wiki/Fairey_FB-1_Gyrodyne) and the Fairey Rotodyne (http://en.wikipedia.org/wiki/Fairey_Rotodyne). They are very cool mixing of tip-powered rotor technology and autogyro technology.

[Dragonich]

Hi Guys,
I'm new - I just joined about 30 seconds ago, after seeing this page. Me and my friend (though pretty much just me) are working on making our own aircraft. I'm covering helicopters, and he's meant to be covering fixed-wings. Anywayz, I've been testing out some very basic fuel (bi-carbonated soda+vinegar) but I'm trying to make it be released slowly, as right now it's going out in less than 2 seconds. I've tried a couple of thing but they've failed. So, my question to anyone who can be bother answering this (thanks if you do), how could I make bi-carbonated soda+vinegar be released slowly?

[RonL]

Hi Guys,
I'm new - I just joined about 30 seconds ago, after seeing this page. Me and my friend (though pretty much just me) are working on making our own aircraft. I'm covering helicopters, and he's meant to be covering fixed-wings. Anywayz, I've been testing out some very basic fuel (bi-carbonated soda+vinegar) but I'm trying to make it be released slowly, as right now it's going out in less than 2 seconds. I've tried a couple of thing but they've failed. So, my question to anyone who can be bother answering this (thanks if you do), how could I make bi-carbonated soda+vinegar be released slowly?

What are you using as a pressure vessel ?

[mtworkowski@o]

Hi Guys,
I'm new - I just joined about 30 seconds ago, after seeing this page. Me and my friend (though pretty much just me) are working on making our own aircraft. I'm covering helicopters, and he's meant to be covering fixed-wings. Anywayz, I've been testing out some very basic fuel (bi-carbonated soda+vinegar) but I'm trying to make it be released slowly, as right now it's going out in less than 2 seconds. I've tried a couple of thing but they've failed. So, my question to anyone who can be bother answering this (thanks if you do), how could I make bi-carbonated soda+vinegar be released slowly?

I'm no kind of scientist but I would think that the pressure vessel should have a very small hole to release the gas.

[DaveC426913]

I'm no kind of scientist but I would think that the pressure vessel should have a very small hole to release the gas.That will release the same amount of gas, just at a higher pressure/velocity. What you want to do is limit the rate at which the fuel components mix before formng the gas.

I have no experience in this area but it seems to me that one way to do that is to limit the amount of area whereon the powder and liquid can mix. I'm thinkin' don't bother with a big tank o bi-carb soda and a big tank o vinegar and small dispensing devices, that you lay it out so that the vinegar run through down a tube that's got powder in it. This restricts the rate at which they can come into contact.

(If you examine how the solid boosters on the shuttle work, you'll see that there's no throttling mechanism for fuel/oxy mix at all; there is simply a carefully arranged surface area of solid fuel that only lets a certain amount of oxy react with the exposed solid fuel.)

[mtworkowski@o]

That will release the same amount of gas, just at a higher pressure/velocity. What you want to do is limit the rate at which the fuel components mix before formng the gas.

I have no experience in this area but it seems to me that one way to do that is to limit the amount of area whereon the powder and liquid can mix. I'm thinkin' don't bother with a big tank o bi-carb soda and a big tank o vinegar and small dispensing devices, that you lay it out so that the vinegar run through down a tube that's got powder in it. This restricts the rate at which they can come into contact.

(If you examine how the solid boosters on the shuttle work, you'll see that there's no throttling mechanism for fuel/oxy mix at all; there is simply a carefully arranged surface area of solid fuel that only lets a certain amount of oxy react with the exposed solid fuel.)

DaveC
You're evolving this thing nicely, but the q was how to release slowly. Now the slow mixing is fine but if all the gas is generated at once and has to go through a small orafice, won't that accomplish the same thing thing as mixing slowly?

[FredGarvin]

That will release the same amount of gas, just at a higher pressure/velocity. What you want to do is limit the rate at which the fuel components mix before formng the gas.

I have no experience in this area but it seems to me that one way to do that is to limit the amount of area whereon the powder and liquid can mix. I'm thinkin' don't bother with a big tank o bi-carb soda and a big tank o vinegar and small dispensing devices, that you lay it out so that the vinegar run through down a tube that's got powder in it. This restricts the rate at which they can come into contact.

(If you examine how the solid boosters on the shuttle work, you'll see that there's no throttling mechanism for fuel/oxy mix at all; there is simply a carefully arranged surface area of solid fuel that only lets a certain amount of oxy react with the exposed solid fuel.)
That's right. The cool thing about solid props is that the arrangement of the propellants in the solid stage are designed to try to maintain the same surface area during the entire burn process.

It seems to me that if you mix them all together at once, you'll need a pretty good pressure vessel to contain it. That means weight. If you take the opportunity to slow down the rate of the chemical interaction by controlling how much of the reactants come into contact, you can get away with a lighter structure.

[DaveC426913]

DaveC
You're evolving this thing nicely, but the q was how to release slowly. Now the slow mixing is fine but if all the gas is generated at once and has to go through a small orafice, won't that accomplish the same thing thing as mixing slowly?
This is what I'm sayin' won't happen. I'm sayin' the gas will just come screaming out at higher velocity. As Fred points out, to throttle it after the reaction you'd need a good pressure vessel and a strong, small orifice. (no jokes from the cheap seats please).

I just think you'll have much better results controlling the reaction than the byproducts.

[mtworkowski@o]

That's right. The cool thing about solid props is that the arrangement of the propellants in the solid stage are designed to try to maintain the same surface area during the entire burn process.

It seems to me that if you mix them all together at once, you'll need a pretty good pressure vessel to contain it. That means weight. If you take the opportunity to slow down the rate of the chemical interaction by controlling how much of the reactants come into contact, you can get away with a lighter structure.

that is a good point.

[RonL]

I don't know what power can be produced by what quantity of material, seems like it would be a fast depletion, but the first thought in my mind based on Fred's post, would be feed it to the rotor(s) and let the spin forces move them (through internal tubes) to the tips where mixing would take place. Might need two or more mix chambers at each tip so that there would be a high and low pressure cycle.

How heavy would the raw materials be for any significant power time cycle ?

[Fon]

Hi,
1. For built homemade helicopter for of all you have to determine main parameters: Dia. of main and tal rotors, power, parameters of transmission....and only later - disaing of ULH
2. We have wide choice of structures of ULH... see internet. It is no problem.
3. When you define main parameters of heli, you will understand, that multy construction planes of ULH's, which offering - are garbidge!!! For example G-1, Mini-1 etc.
4. My handbook/broshure "Designing a homebuilt UL helicopter" can help beginner a) to make right choice and for all b) giving new method of calculation and with help of diagrams and tables to define parameters for next design of structure in during 15-20 minuts.
5. Book was issue same years ego and was sold ~ in 10 countries USA, Canada, India, Iran, New Zeland, S. Korea, Belgium, Poland etc
About it you can see on internet "Design a homebuilt UL helicopter" and read in magazine
"homebuilt rotorcraft" (2000, may)
Safety fly
Thanks

PS. if you have questions (concretic) please.. <fsat92@hotmail.com>
In during few days I will try to ansvere

[Fon]

G1 is "garbidge", because construction plan G1 contents many seriosly mistakes
Who will be used this plan lost money and self-murderer

[Fon]

Hi,
Let me to say
1. Main problem - it is calculate main parameters Dia of rotor, power, parameters of transmission.
ULH is very sentitive foe correct (optimum) parameters.
The second step chose of prototype ULH and design...
My book "Designing a homebult ULH" will can deside prablem in during 20 min
Book sold in ~ ten contries Thanks
fsat92@hotmail.com

[Topher925]

This is your best chance of building a helicopter and surviving.

Rotorway Helicopters (http://www.rotorway.com/index.php)

[RonL]

This is your best chance of building a helicopter and surviving.

Rotorway Helicopters (http://www.rotorway.com/index.php)

They had 4 very helpful videos during the Oshkosh event, they were short, but a joy to watch. The close up views of the assembly of a helicopter, helps to understand why it is so much better to consider a kit, rather than fabricate your own parts.

But then, the pride of doing your own thing is what helps make people who they are.:tongue2:

Ron

[DaveC426913]

But then, the pride of doing your own thing is what helps make people who they were before they were killed in a tragic mishap. :biggrin:

10 chars

[Guinea_Pig]

Hello, this thread made me sign up

engine wise it has got to be a motorbike engine. Im into my Bike Engined Kit cars and am embarking on an R1 Powered one... this engine... 132Kw (180hp) from a new one at 12500rpm and the engine cant weigh anymore than 70kg... oh and that includes a 6 speed sequential gearbox.... not that you would need it.... also turboing such an engine is fairly realistic and as you run a helicopter at constant RPM setting a safe level of boost would be feasible and could be set up to not be detrimental to the engine or performance... i fly RC helis also so do have a basic understanding as to how helis in general work...

another thought is has anyone considered mounting pulse jets to the rotor tips? surely this way you can build the engines relatively cheaply yourself and if they fail you can auto rotate?

[FredGarvin]

The thing with pulse jets on the tips, you run into some issues like getting fuel to them through a complicated mechanical system of blades and swashplates. Also, they are extremely loud. Also, helicopter blades need to be twisted so the angle of attack where the pulse jet is is not in line with the plane of rotation. That may or may not be an issue.

[Guinea_Pig]

those are fair points that i had not considered. angle of attack of the pulse jets id imagine are a big deal. i wonder what the tip speed is... maybe even ram jets are feasible its about 400mph is it not where they become effective...

i guess that a hollow mainshaft would allow fuel to pass through, and maintain a 0* AOA on the engines could be achieved by a feathering shaft the length of the blades. OK so you are increasing the rotational mass... but surely thats a pretty good thing as the more energy stored in rotation the longer you have to auto rotate etc... if you guys would like i could draw up a crude diagram as to how i would address those issues.. and you guys can point out where im being stupid (as im certain i have missed a point)

[JerryL]

I don't know if anyone is still using this thread, but there is the mosquito helicopter kit for around $35,000. And as for using a transmission. I believe rotorway's scorpion and the mosquito both use belt drives for main rotor power with the redution achieved by a much larger pulley on the rotor shaft than the motor output shaft. Using a large cog belt they have become much more reliable.

[Orion84]

Hello, this thread made me sign up

engine wise it has got to be a motorbike engine. Im into my Bike Engined Kit cars and am embarking on an R1 Powered one... this engine... 132Kw (180hp) from a new one at 12500rpm and the engine cant weigh anymore than 70kg... oh and that includes a 6 speed sequential gearbox.... not that you would need it.... also turboing such an engine is fairly realistic and as you run a helicopter at constant RPM setting a safe level of boost would be feasible and could be set up to not be detrimental to the engine or performance... i fly RC helis also so do have a basic understanding as to how helis in general work...



The small problem with that engine choice, or even the one I was thinking (Rotary engine) is that conventional autmotive ICE's are not designed to sit at their max rpm or peak hp RPM for extended periods of time. They are designed to be brought up to peak hp, then shifted, thus dropping to lower RPM and reducing the amount of heat created. So with that in mind you can not choose an engine based on it's peak numbers, but more it's useable numbers. You would want an engine with a flat torque curve and suitable hp at that tq. I was thinking that with a properly built 2 rotor (12A or 13B, or even the 16X which makes me giddy) I could have 200+ hp (300+ in the case of the 16X) at 10K RPM. The flaw in that plan is the engine would need ridiculous cooling to cope with those prolonged high engine speeds. Rotary's are notorious for their heat production, but at 12.5K, a bike engine would be boiling it's coolant as well. Running it at a lower RPM with gearing would make it more suitable, but also drastically reduce the hp available since such small engines make it all up top. Turboing the engine would indeed give you the higher hp/tq at lower RPMs, but again it comes back to heat. Sustained RPMs with boost, even at 4K would create a lot of heat, so a very serious cooling system would need to be in place. Since a helicopters forward speed is limited, so is airflow through the radiators, but big scoops increase drag and reduce speeds. Sitting and hovering would require the fans to be pulling a very large amount of air to cope with the heat produced by the engine strain caused by the increased load on the engine. The right fan choice wouldn't be hard. However all this adds weight. Unless you plan to fly for a couple minutes at a time then stop to let the engine cool down, there's no way around it, you must choose the right engine. Something more along the lines a of a larger displacement V twin engine -if we're thinking bike engines- would allow for the lower rpm/higher tq - hp needed.

[JerryL]

You don't need to run for long periods of time at full rpm, simply get a gearbox to drop you desired rpm down to main rotor rpm you desire, around 600.

[JerryL]

this small helicopter uses a 4 cyl subaru engine165hp. How large did you want to go?

http://www.ask.com/bar?q=hot+rod+helicopter&page=1&qsrc=0&ab=0&u=http%3A%2F%2Fwww.vortechonline.com%2Fhrh%2Fmain. htm

[JerryL]

your cooling wouldn't be limited to the crafts forward speed you have a very large cooling fan on the top of your craft forcing large quantities of air downward.

[Orion84]

I was thinking (read: dreaming) of using a 1.3L two rotor engine. Possibly the Renesis out of the RX-8. Claimed hp of 240 at the flywheel, however dyno results have shown it closer to about 210. I like the idea of the rotary. It's small, light, very powerful for it's displacement, extremely simple and reliable. Unless you throw boost at it. The 12A two rotor is known to be nearly indestructible as far as rotarys go. Can pump out 150 flywheel horsepower with just an upgraded carb and free flowing exhaust. Not that a carb would be the best choice in an aviation application, but they can be relatively inexpensive to convert to F.I.

Thank you Jerry, I completely forgot that a giant fan was actually what the motor would be driving. I can't believe I missed that. I guess a decent scoop would be more than enough to handle cooling duties.

Also I live up in Canada, so screw the FAA. Although I'm sure our counterpart would have some things to say.

Just to clarify for everyone, I just got it in my head that it might be cool to build a rotary powered helicopter. Not sure why but I've been thinking about it rather intensely for a few days now. I am a rotorhead, I own an 84 RX-7 that's been modded and just love what the engine can do. Maybe it's because I went to the Red Bull Air Races in Windsor, ON on the 14th, and the choppers they had performing were pretty cool. It won't happen. Hell, I can barely be bothered to go strip the useless wiring out my engine bay, so I can't imagine digging up the funds to have an airframe built, mold a body of carbon fibre and amass all the parts necessary, let alone properly engineering it. Not going to stop dreaming though.

Chris

[JerryL]

You could probably use the same basic plans as those for the Hot Rod Helicopter just tweek the motor mounting. That takes care of the engineering. Fabricate your own air frame as per the plans. I know what you mean I've been dreaming myself but no money for it.

[JerryL]

I've looked at many helicopter kit sites. There is a lot information you can get from them and lots of ideas to appropriate. I'd check the local regs. no point in getting a fine if you can avoid it. Good luck with your dream.
Jerry

[RonL]

If you are planning on building a ultralight FAA rule 103 limits max housepower to around 65 hp. You also don't need to runn for long periods of time at full rpm, simply get a gearbox to drop you desired rpm down to main rotor rpm you desire, around 600.


http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/8CF133AD5A5BA4B3862569DE005BD75A?OpenDocument

This might help anyone interested.

I don't think power is limited, but speed is (55 knots) or 65 MPH

Open the pdf doc on the right, I'm not sure if rules have changed recently.

Ron

[Orion84]

Thanks

Well I'll outline the idea I had.

Similar in shape to the Cobra attack helicopter but obviously smaller. Tandem seating, narrow fuselage with a twist. A propeller driven off the tail rotor shaft to provide forward thrust. As I mentioned it would use a rotary which creates a ton of heat, so there would be some ducting for the radiators and oil coolers and to allow hot air to escape, as well as a proper exhaust because an uncorked rotary would most likely cause the ears to bleed. They have a lot of exhaust energy, considerably more than a piston engine and can be quite unbearable even at idle if there is no muffler. Inflatable pontoons for trips up to the cabin. I don't have one, but I may get an invite one day. A pod type storage compartment underneath, similar in principle to the A600 Talon. It could also be swapped for an extended range fuel tank.

The theory being that the forward propulsion would allow the main rotor to deal solely with lift and turning and the propeller would handle forward flight, hopefully reducing fuel consumption. I know the added drag on the tailshaft would use fuel, but was thinking the forward propulsion would outweigh that. It would also provide a higher top speed and cruise. Disengage it for take off and landings, or use it in conjunction with wheels for a very short take off. This would aid in lowering the amount of fuel used for take offs. Body made entirely of carbon fiber, because it's light and looks real pretty. Plexi-glass bubble canopy, as well as part of the floor so I can see any ground obstructions as I land. Something along these lines would be great for long trips, as it uses regular 87 octane gasoline, and reduces travel time. I took a trip from southern Ontario to Manitoba last October and it was a 20 hour drive with cutting through part of the US. I was very tired afterwards. A vehicle like this would allow me to cut straight across Georgian Bay and hop over parts of Lake Superior, instead of driving around it. When it's gas time, simply land in a field near a gas station, and a few walks back and forth with a decent sized gas can and she's full and I'm off again. A little longer for fuel stops than in a car, and I'm sure I could figure out a better method, but time saved would be greatly increased compared to driving. Also how cool would it be to give your friends rides in a helicopter you built with your own two hands.

That's what was floating around in my head.

[JerryL]

Something I forgot. It is not necessary to build a airframe and mold a carbon fiber body.
Go uni-body combine airframe and body like the Mosquito XE
Jerry

[JerryL]

Sounds almost like an auto-gyro, except for the verticle take off. are you familiar with the principles of the auto-gyro? It's main rotor is not motor drive but driven by the forward airflow. I don't know about a prop pushed helicoper. A small company around Wichita Falls Texas is is working on a commuter craft slightly similar except thay want to use the rotor like a wing after verticle take off. The Have spent millions on the research. Last time I checked they were up to tethered tests. I think your rotor head and blades may be a bit fragile for too much push. Not really designed for it. you may talk to the guy who designs choppers he has the chinook helicopter logo by his user name if I'm not mistaken. You might stick with a regular Heli if you need the verticle take off, or an auto-gyro if not.
Keep looking around till you find the bits you want then put them together.
Jerry

[JerryL]

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/8CF133AD5A5BA4B3862569DE005BD75A?OpenDocument

This might help anyone interested.

I don't think power is limited, but speed is (55 knots) or 65 MPH

Open the pdf doc on the right, I'm not sure if rules have changed recently.

Ron

It's been a while since I looked at them. My memory was faulty I have removed that error.
getting old I guess. (Regulation language causes brain Damage!)
Thank you for the correction
JerryL

[Orion84]

Actually during the Vietnam war era the US army (or a company did it for them) tried developing an attack chopper using a propeller to provide forward thrust. It was never put into production, I believe because the Cobra performed better or was more readily available for the war. This was when they were looking to replace the Huey gunship models with purpose built attack craft. Can't say for sure since it's been a number of years since I saw that show, so details are sketchy at best. I'll have to remember to look it up. Anyhow that's what gave me the idea in the first place.

[FredGarvin]

Actually during the Vietnam war era the US army (or a company did it for them) tried developing an attack chopper using a propeller to provide forward thrust. It was never put into production, I believe because the Cobra performed better or was more readily available for the war. This was when they were looking to replace the Huey gunship models with purpose built attack craft. Can't say for sure since it's been a number of years since I saw that show, so details are sketchy at best. I'll have to remember to look it up. Anyhow that's what gave me the idea in the first place.
You're thinking of the Cheyenne program. It's a shame since Sikorsky is essentially doing the same thing right now with a compound rotor version.

[JerryL]

I apologize for my Ignorance. I am not an engineer or helicopter mechanic. I had not heard of that helicopter design and was concerned about the increased stress on a motor driven main rotor, since it is the only thing holding the craft in the air. After having been informed about the Cheyenne I did some research and this link may be useful.

http://www.internetage.com/cartercopters/pics9.htm

This is an excerpt from the website below, it might warrant consideration.

http://www.ask.com/bar?q=Cheyenne+helicopter&page=1&qsrc=0&ab=1&u=http%3A%2F%2Fwww.aviastar.org%2Fhelicopters_eng% 2Flok_cheyenne.php

The flight test programme revealed several significant problems with the aircraft's innovative propulsion system, problems which ultimately resulted in the fatal crash of one of the ten prototypes.

I admit it is a beatiful craft and if it could be done I wouldn't mind one myself.

Jerry

[vapl153]

Smallest, affordable, safe helicopter on the market: Mosquito
http://www.innovator.mosquito.net.nz/mbbs2/boxx/modules/mosquitohelicopters/contact-dealers-air.asp?dealerID=7

[Cyrus]

The Cheyenne is an interesting helicopter. I was talking with a retired air force colonel who knew test pilots that flew it. Every test pilot loved it because it flew like a fighter and not a helicopter. It has a rigid rotor system, like the Sikorsky ABC (Advancing Blade Concept) concept demensontrator. Note, both aircraft suffer from significant vibration problems, but the Sikorsky X2 has vibration suppression systems. Second note, this is not the first time Sikorsky has made such a helicopter.

http://www.aviastar.org/foto/gallery/sikorsky/sik_s-69_1.jpg

I was told by people involved in this aircraft that it required three people to operate. A pilot, copilot and a guy on throttle. The guy on throttle was busy 100% of the time adjusting the engines that gave it forward propulsion and torque for the main rotors.

The x2 is different in that it has a rigid rotor with a significantly reduced rotor hub size. (The one pictured above is huge).

[JerryL]

How would you calculate the stall angle for the main rotor airfoil. You wouldn't your collective , cyclic total pitch angle to get that high. Stops to keep the pitch within a proper range wouldn't be that hard, but how do you calculate that range.

Some of you might want to check this site. They may start open a factory in Wichita Falls, Texas soon.

http://www.ask.com/bar?q=carter+copter&page=1&qsrc=0&ab=0&u=http%3A%2F%2Fwww.cartercopters.com%2F

[Cyrus]

I'm trying to identify the mission statement of this thread, and it's all over the place. Could someone close it, as PF is not the place to ask how to build your own helicopter.

Some of the posts are off-topic to making your own helicopter, but interesting. I think they would be better served moved into a new thread with a more reasonable thesis.

[JerryL]

I don't agree that this thread should be closed.
Any non distructive (homemade rpg not being one of them) project that open the mind to solve a problem is benifical. It gets someone thinking outside of their normal processes and perhaps gets them into an area that they would not normally consider. Or an area that they thought was beyond their grasp. Many people would not normally turn to physics, unless they needed it to solve a problem.

I see no problem with a thread about something that is not designed to intentionally hurt or maime another human being, but does challenge the imagination and intellect and relates to
physics. You must admit that there is lot of physics involved in the flight of a helicopter.

Jerry Lunsford

[Cyrus]

I don't agree that this thread should be closed.
Any non distructive (homemade rpg not being one of them) project that open the mind to solve a problem is benifical. It gets someone thinking outside of their normal processes and perhaps gets them into an area that they would not normally consider. Or an area that they thought was beyond their grasp. Many people would not normally turn to physics, unless they needed it to solve a problem.

I see no problem with a thread about something that is not designed to intentionally hurt or maime another human being, but does challenge the imagination and intellect and relates to
physics. You must admit that there is lot of physics involved in the flight of a helicopter.

Jerry Lunsford

I know the physics behind the flight of a helicopter, which is why I find this thread to be ridiculous. More to the point, I don't actually see anyone here building a helicopter. It's all talk.


Ta-Da:

http://www.rotaryforum.com/forum/forumdisplay.php?f=34

Lots of posts there, and better than what I've read here.

[JerryL]

After some research on NASA's website I found it is almost impossible to calculate the stall angle for an airfoil so thanks anyway.
Jerry

[JerryL]

I know the physics behind the flight of a helicopter, which is why I find this thread to be ridiculous. More to the point, I don't actually see anyone here building a helicopter. It's all talk.


Ta-Da:

http://www.rotaryforum.com/forum/forumdisplay.php?f=34

Lots of posts there, and better than what I've read here.

Yes, Cyrus you may know all of the physics behind helicopter flight but do you want to deny others who don't a place to do it.
I beleive you would agree that a LOT of talk would be a good ideal before attempting to start a build. It would save a lot of time and possibly lives.
Do you consider this thread ridiculous because you think that an average person could not build a helicopter?
While building a helicopter is quite a challenge it is possible.

[Cyrus]

Yes, Cyrus you may know all of the physics behind helicopter flight but do you want to deny others who don't a place to do it.

I'm not denying anyone the place to do it. If you want to, by all means knock yourself out.


I beleive you would agree that a LOT of talk would be a good ideal before attempting to start a build. It would save a lot of time and possibly lives.

Actually, no. I think you need to calculate something. Otherwise, all this 'talk' is worthless. You have to be able to calculate if you want to design your own helicopter.

Do you consider this thread ridiculous because you think that an average person could not build a helicopter?

No, an average person cannot build their own helicopter. The exception would be if they bought a kit and assembled it.

While building a helicopter is quite a challenge it is possible.

Yeah, uhuh. Okay.

I think you should read this review by Dr. Celi (who teachers helicopter courses here) on Amazon (http://www.amazon.com/Helicopter-Theory-Wayne-Johnson/dp/0486682307)to give you some education on what you're proposing:

Looking for information on how to fly a helicopter? Look elsewhere. Trying to design and build your own helicopter? Yeah, right, how about performing a quadruple bypass on your own heart? But if you are an aerospace engineer interested in helicopters, or if you are studying to become one (an engineer, not a helicopter), this is a must-have book.
This *is* an advanced textbook, which will take you from the fundamentals of helicopter aerodynamics, dynamics, and flight dynamics, all the way to the advanced topics. The book came out in 1980, and helicopter engineering has made a lot of progress since then. However, much of what is in the book remains current. The extensive bibliography gives a comprehensive picture of the state of the art until 1980.

Want some bedtime reading? Get Patricia Cornwell. Want to read stories about airplanes and military hi-tech? Read Dale Brown or Tom Clancy. Serious about learning helicopter engineering? Get this book.

If you really, honestly want to build a helicopter. I suggest you start showing me some calculations if you want me to take you seriously.

[JerryL]

I can't show you any calculations as I do not have enough knowledge of aerodynamics to produce them.
Never the less, one day I plan to build a helicopter. I don't know how long it will take to scrape up the money and information but I intend to do it.
Until that time I learn what I can and design parts as I can.

[Cyrus]

I can't show you any calculations as I do not have enough knowledge of aerodynamics to produce them.
Never the less, one day I plan to build a helicopter. I don't know how long it will take to scrape up the money and information but I intend to do it.
Until that time I learn what I can and design parts as I can.

I guess I wont be taking you seriously then.

[Cyrus]

I can't show you any calculations as I do not have enough knowledge of aerodynamics to produce them.
Never the less, one day I plan to build a helicopter. I don't know how long it will take to scrape up the money and information but I intend to do it.
Until that time I learn what I can and design parts as I can.

I don't want to dissuade you from aviation. I think it's great that you like helicopters. I just think your time and money would be better spent taking helicopter lessons and learning/reading the fundamentals of helicopter flight so you have a better respect for it.

There is a reason why it took guys with engineering degrees to design the first helicopters. Unlike airplanes they are far, far more complex.

[JerryL]

I guess I wont be taking you seriously then.

It doesn't matterr to me if you take me seriously or not.
I am studying what I can about helicopter aerodynamics and flight, including the FAA Helicopter Flight Handbook and Nasa pages on aerodynamics

[Cyrus]

It doesn't matterr to me if you take me seriously or not.
I am studying what I can about helicopter aerodynamics and flight, including the FAA Helicopter Flight Handbook and Nasa pages on aerodynamics

That does not qualify you to design a helicopter.

[JerryL]

I never said that I was Qualified to design a helicopter. I said I was going to build one.
I am not going to start on it soon. I said that I was learning so I could.

This is not helping me reach my objective and is only marginally on topoic so good bye.

[Cyrus]

To be clear, do you want to design a helicopter, or do you want to build a kit? If you're trying to build a kit, then the helicopter forum I linked to earlier is exactly where you should be posting.

If you want to design one, then I would kindly ask you not waste our time posting because this is a serious technical forum.

That being said, if you have technical questions on helicopter theory, make a new thread specific to your question and I will try and answer it for you there.

[WhoWee]

I never said that I was Qualified to design a helicopter. I said I was going to build one.
I am not going to start on it soon. I said that I was learning so I could.

This is not helping me reach my objective and is only marginally on topoic so good bye.

Don't be discouraged. Put your ideas to paper and mark the date. As you learn more, revise and date your changes. Who knows, maybe one day we'll be talking about your latest designs.

[Cyrus]

Don't be discouraged. Put your ideas to paper and mark the date. As you learn more, revise and date your changes. Who knows, maybe one day we'll be talking about your latest designs.

The blind should not lead the blind.

[WhoWee]

The blind should not lead the blind.

No, by all means listen to the negative people who tell you you can't do something, that you're not qualified and lack the ability to achieve your goals. Be uninspired and accept your place in the world.

Is that your advice to this person Cyrus?

[Cyrus]

No, by all means listen to the negative people who tell you you can't do something, that you're not qualified and lack the ability to achieve your goals. Be uninspired and accept your place in the world.

Is that your advice to this person Cyrus?

He is not qualified, and does lack the ability to design a helicopter. I already stated this. Get over it.

PS: I can't wait until someone comes by claiming to want to build a space ship and equally gets your support. Your comments are equally outlandish to my engineering eyes. Does the engineering degree mean nothing to you?

[FredGarvin]

Is that your advice to this person Cyrus?No. It's more along the lines of, like surgery, there are some things people without a certain level of knowledge should not attempt. Gain knowledge first, then try. With knowledge comes the ability to see more things that can pop up and kill you. Even Igor Sikorsky almost killed himself a few times and he went to one of the most prestigious aircraft design schools in the world at the time.

[JerryL]

If you want to design one, then I would kindly ask you not waste our time posting because this is a serious technical forum.

That being said, if you have technical questions on helicopter theory, make a new thread specific to your question and I will try and answer it for you there.

I am not wasting your time. You chose to start this exchange therefore you are wasting your own time. Yes this is a serious technical forum I suggest you look back at your posts on this forum. Ummm yes very technical, in fact I find it hard to understand them care to clarify for us non techies

Looks like an utlra light heli to me!

The Cheyenne is an interesting helicopter. I was talking with a retired air force colonel who knew test pilots that flew it. Every test pilot loved it because it flew like a fighter and not a helicopter. It has a rigid rotor system, like the Sikorsky ABC (Advancing Blade Concept) concept demensontrator. Note, both aircraft suffer from significant vibration problems, but the Sikorsky X2 has vibration suppression systems. Second note, this is not the first time Sikorsky has made such a helicopter.



I was told by people involved in this aircraft that it required three people to operate. A pilot, copilot and a guy on throttle. The guy on throttle was busy 100% of the time adjusting the engines that gave it forward propulsion and torque for the main rotors.

The x2 is different in that it has a rigid rotor with a significantly reduced rotor hub size. (The one pictured above is huge).

I'm trying to identify the mission statement of this thread, and it's all over the place. Could someone close it, as PF is not the place to ask how to build your own helicopter.

Some of the posts are off-topic to making your own helicopter, but interesting. I think they would be better served moved into a new thread with a more reasonable thesis.

I believe that these are all of the post ou made to the thread before You started this exchange( copied from your posts with the exception of the photo).
All very technical, couldn't grasp them with out engineering training.
Enough said. I will no longer respond to anything on this subject as it is a waste of my time to correspond with a closed minded person.

[JerryL]

I never said that I was Qualified to design a helicopter. I said I was going to build one.
I am not going to start on it soon. I said that I was learning so I could.

This is not helping me reach my objective and is only marginally on topic so good bye.

As I stated earlier I am trying to learn.
No. It's more along the lines of, like surgery, there are some things people without a certain level of knowledge should not attempt. Gain knowledge first, then try. With knowledge comes the ability to see more things that can pop up and kill you. Even Igor Sikorsky almost killed himself a few times and he went to one of the most prestigious aircraft design schools in the world at the time.


Thank you Mr. Garvin, I know form your ealier posts you think that I should attempt this but you aren't telling me can't do it. You are telling to learn the subject first which is what I am trying to do. It is impossible for me start on it any time soon due to cash flow. So this is the otimum time to learn. could you recomend websites or books on the subject.
Jerry L

[Cyrus]

You are telling to learn the subject first which is what I am trying to do. It is impossible for me start on it any time soon due to cash flow. So this is the otimum time to learn. could you recomend websites or books on the subject.
Jerry L

I hope you realize a typical helicopter costs roughly $1000/lb. So a 2,000 lb helicopter is on the order of $2 million dollars. A robinson R22 (probably one of the smallest you can get) is on the order of $240k.

Again, are you serious?

[FredGarvin]

One really good book that covers a lot of the ideas (not a theoretical book) and has a lot of good information is Coyle's book "The Art and Science of Flying Helicopters." It has great overviews of different systems and also of the peculiarities of helicopter flight that you would never guess if you were thinking like a fixed wing pilot.

http://www.amazon.com/Art-Science-Flying-Helicopters/dp/081382169X

[Cyrus]

I gave you a link to a book (and book review) on Amazon.com Jerryl.

[JerryL]

Thank you sir. I will take a look at it. I am looking into the more technical side as well as the practical. What I want to do is build a small helicopter, FAR 103 compliant. This might be a little on the small side for you but it's big enough for me. Once again, thank you for your time.
Jerry L

[WhoWee]

No. It's more along the lines of, like surgery, there are some things people without a certain level of knowledge should not attempt. Gain knowledge first, then try. With knowledge comes the ability to see more things that can pop up and kill you. Even Igor Sikorsky almost killed himself a few times and he went to one of the most prestigious aircraft design schools in the world at the time.

I agree with you Fred. That's why I posted this response.

"Don't be discouraged. Put your ideas to paper and mark the date. As you learn more, revise and date your changes. Who knows, maybe one day we'll be talking about your latest designs."

I encouraged use of pencil and paper, learning and review.

Unfortunately, once again, Cyrus found it necessary to arrogantly attack me personally with his "blind leading the blind" comments.

[FredGarvin]

I am looking into the more technical side as well as the practical. Well, there is the opposite end of the spectrum with Johnson's book on helicopter theory.

http://www.amazon.com/Helicopter-Theory-Wayne-Johnson/dp/0486682307/ref=sr_1_1?ie=UTF8&s=books&qid=1251320111&sr=8-1

[Cyrus]

Well, there is the opposite end of the spectrum with Johnson's book on helicopter theory.

http://www.amazon.com/Helicopter-Theory-Wayne-Johnson/dp/0486682307/ref=sr_1_1?ie=UTF8&s=books&qid=1251320111&sr=8-1

I love this review of the book:

I found this book to be an extremely advanced treatise on design aerodynamics. My experience as a Navy Pilot (where I was privileged to have participated in countless hours of classroom aerodynamics) and 33 years as an Airline Captain was not adequate for an understanding of 99.99% of the discussions in this book.
If one is seeking to design an advanced helicopter, he will find this book to contain most anything he needs, that is, if he could find someone to explain what is in print.

This book is suitable only for someone with a PHD in Helicopter aerodynamics, or one seeking a PHD in that field.

It is DEFINITELY not a book for a helicopter pilot seeking to improve and or increase his knowledge of flying techniques and/or flying theory.

HINT HINT, Jerry.

[JerryL]

Thank you Mr. Garvin.
I believe I'll start with the tricycle (simpler texts) and work my up the more advanced stuff.
I would be interested in what you think of this website.

http://www.dynamicflight.com/aerodynamics/basics/

I have just started to study it and was wondering your opinion.
WhoWee I dont know your background or I would have asked for opinion also if you are learned in field I would like your opinion also.

Thank you for your time. I hope you don't think I am not wasting it.

Jerry L

[JerryL]

I love this review of the book:



HINT HINT, Jerry.


I would not insult or run you down for attemping to improve yourself in a field that I knew and you did not. Lay off.
I want to learn.
I have done nothing to you.

[Cyrus]

Can you do nothing but put someone else down? Does it make you feel superior?
I would not insult or run you down for attemping to improve yourself in a field that I knew and you did not. Lay off.
I want to learn.

There is a difference between attemping to improve yourself and boasting you're giong to build your own helicopter with no money or technical knowledge. I am fully willing to help people that are reasonable in their propositions. I gave you reasonable advice earlier, which you ignored. Aviation is not cheap. If you cant afford to play in this game, don't even bother. Stop being stubborn and listen, because I do fly and I do aircraft design. You have no idea what goes behind the scenes in terms of engineering analysis and tooling to make parts for things as simple as the chair you sit on inside the cockpit of a helicopter. This is one of those threads where if you have to ask, you probably shouldn't be doing it.

Anyways, I told you I would help you on questions about theory if you made a thread specific to your question.

[01012010]

how can I make the helicopter main rotor blade & main rotor gear box?

[Brian_C]

1. Obtain an advanced degree in mechanical/aerospace engineering.

2. Spend 15+ years working in the field of helicopter design and manufacturing.

3. Become a master CNC machinist or hire a bunch of CNC machinists.

4. Quit your day job and spend 5-10 years designing, fabricating, and testing your helicopter design.

[FredGarvin]

how can I make the helicopter main rotor blade & main rotor gear box?
:bugeye:

[RonL]

how can I make the helicopter main rotor blade & main rotor gear box?

Not sure if this is a hit and run post, or if you are in Jr. High, nothing in your profile to indicate what you can do, or if you have any qualifications to justify an answer.

Brian C sure went overboard on requirments:bugeye: I know several people that can and some have built blades and gear boxes, using limited shop equipment and some parts from rear axels of junk trucks and cars.

Basic skills and study, along with access to the proper tools can produce almost anything :cool:
Now to qualify that statement, using tools properly requires a learning curve that can be quick for some and quite long for others.

Ron

[minicoper]

happenly come across this video clip, seems the chinese are one step ahead already, they have DIY their cheap helicopter and made it fly in air already, and according to it, the total cost is just around $4k. though looks very scary when in flying. :-)

http://hi.baidu.com/tblc/blog/item/d4657d1e6b85baf11ad5762f.html

[Cyrus]

happenly come across this video clip, seems the chinese are one step ahead already, they have DIY their cheap helicopter and made it fly in air already, and according to it, the total cost is just around $4k. though looks very scary when in flying. :-)

http://hi.baidu.com/tblc/blog/item/d4657d1e6b85baf11ad5762f.html

In what way are they a step ahead?

[minicoper]

the guy made the thing out there and it works, though looks dangerous, and we are still under discussion and in theory.... :-)

[Cyrus]

the guy made the thing out there and it works, though looks dangerous, and we are still under discussion and in theory.... :-)

These types of small helicopters have been around for well over ten years.

See this link:
[1] http://www.aviastar.org/helicopters_eng/light.html


Your statement about us 'still being in theory' is a puzzle to me. We (technical experts who have given advice, not the yahoos asking the questions) have simply said that this is a stupid idea to be attempted by someone without training in helicopter aerodynamics. No one is actually trying to calculate or prove anything here theoretically.

[FredGarvin]

The cheap, Chinese (redundant) helicopter link didn't work for me.

Aviation + Chinese = no friggin' way. With the amount of copying and downright fraud when it comes to spec'd hardware and components, there is no way I would even entertain the notion.

[mugaliens]

These types of small helicopters have been around for well over ten years.

Counting the Bensen autogyro (http://en.wikipedia.org/wiki/Bensen_Aircraft), make that 58 years!

[Cyrus]

Counting the Bensen autogyro (http://en.wikipedia.org/wiki/Bensen_Aircraft), make that 58 years!

Note the inventor: Dr Igor Bensen

[mugaliens]

Note the inventor: Dr Igor Bensen

Ok, noted. I'm curious as to why, for the "Bensen autogyro" has gone by that name, without the academic accolade, since it's inception. Even his company, Bensen Aircraft, exists sans the doctorate, similar to Freeman's "Dyson sphere." It's not the Dr. Dyson sphere, and having met the man while visiting a good friend from high school who attended Princeton, I'll say "wow" as in "extremely mentally adept," but I'm thankful he never lorded his credentials.

I never met Dr. Bensen.

Plans for homebuilders of his Bensen B-8 remain available to this day. Remarkably capable aircraft! I've flown two helos, a Hughes 500C (369HE), used as a sherrif's helo, and a UH-1N. The Huey was solid as a rock, although it tended to slowly beat you like a washing machine, while the 500 was a bit squirrely!

[Cyrus]

The note was for the people thinking they should build one in their garage with no expertise. :wink:

The fact that its still in use says a lot because there are many home builds that fell by the waist side due to unsafe designs.

[mugaliens]

The note was for the people thinking they should build one in their garage with no expertise. :wink:

The fact that its still in use says a lot because there are many home builds that fell by the waist side due to unsafe designs.

It's true: Amature-built aicraft experience experience approximately 3.5 times the accident rate of FAA-certified general aviation aircraft.

However, I'm not so sure that's a function of design or poor quality workmanship as it is the psyche of your typical amateur bilder! Most of them accept more risk than your average pilot, as evidenced by the fact they enter the home-build arena at all.

Having said that, I'm a very meticulous garage mechanic (i.e. I work on my own cars), builder of R/C models (though not since high school), and an aero engineer.

If I ever decided to enter the home-built market, I would rework all calcs, as I'm not about to sit my butt in an airplane that may contain hidden defects! But that's just me...