Homemade Helicopter: For the People.

[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

 

[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 .

 

[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, that's 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]

What about a Homemade Helo without a swash plate?

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.

 

[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.

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

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 not sure why there has not been more severed heads in the world

 

[morrijon]

Micro-RC Helicopter

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 process 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 a lot 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 a lot 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]

scaling up

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 realize 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 realized 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 realize 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 realized 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

Ron

 

[mtworkowski@o]

helicopter from junk!

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 garbagety 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)
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.
And I have not even put my wildest idea forward yet.

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

 

[mtworkowski@o]

subscription

Go to "My PF" and look again

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.

Now let's hear it

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.

Now let's hear it

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.