Homemade Helicopter: For the People.

[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 explanations.

 

[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"

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"

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)
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: http://en.wikipedia.org/wiki/YH-32_Hornet"

 

[Mech_Engineer]

Some very cool "helicopters" are the http://en.wikipedia.org/wiki/Fairey_FB-1_Gyrodyne" . 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 let's 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 let's 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 let's 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.

http://www.rotorway.com/index.php"

 

[RonL]

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

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.

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.

10 chars

 

[Guinea_Pig]

Hello, this thread made me sign up

engine wise it has got to be a motorbike engine. I am 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 can't 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?