## Help Design a Human-Powered Helicopter

If "Gossamer" manpowered planes work, at least I cannot see anything preventing two such planes connected together circulating around a common center = "helicopter". That may be boiled down to a man powered helicopter where the rotor is not driven by center shaft, but from from smaller propellers at rotor wing ends. Wing units (perhaps several parallel layers as in WWI combat planes) behind towing propellers, placed rather far out from center
shaft. Propellers could be driven by wires as in garden trimmers.

I agree it may appear less efficient letting rotor be towed by propeller - but I can see
gossamer planes (towed by propeller) lift while manpowered helicopters (driven by center shafts)
don't lift. In aerodynamics not always common sense applies.

 Quote by M Grandin If "Gossamer" manpowered planes work, at least I cannot see anything preventing two such planes connected together circulating around a common center = "helicopter". That may be boiled down to a man powered helicopter where the rotor is not driven by center shaft, but from from smaller propellers at rotor wing ends. Wing units (perhaps several parallel layers as in WWI combat planes) behind towing propellers, placed rather far out from center shaft. Propellers could be driven by wires as in garden trimmers. I agree it may appear less efficient letting rotor be towed by propeller - but I can see gossamer planes (towed by propeller) lift while manpowered helicopters (driven by center shafts) don't lift. In aerodynamics not always common sense applies.
Sorry, according to http://flight.engr.ucdavis.edu/~smla...dSaiki1990.pdf
that kind of solutions have earlier been developed. But evidently not a success. At least not
hitherto.
 I've read every paper on this subject and will be happy to answer any questions. I will say this, it's certainly possible, but you walk a very fine line. I see a lot of misinformation being stated in this thread. Fred, PM me your email address. I can't send you pms because you have it turned off.
 Blog Entries: 2 Recognitions: Gold Member Science Advisor It seems to me that for a helicopter to achieve free flight (outside of the ground effect) it needs to push enough air down to have sufficient mass flow to maintain altitude. Based on the power requirements of other helicopters which are engine powered, it would have to have more than 10 horsepower available, far more than any bicyclist can achieve. Edit- any 130-lb bicyclist anyway. Weight is the #1 killer on these things.

 Quote by Mech_Engineer It seems to me that for a helicopter to achieve free flight (outside of the ground effect) it needs to push enough air down to have sufficient mass flow to maintain altitude. Based on the power requirements of other helicopters which are engine powered, it would have to have more than 10 horsepower available, far more than any bicyclist can achieve. Edit- any 130-lb bicyclist anyway. Weight is the #1 killer on these things.
No, this is wrong and not based on any sort of calculation. Run the numbers and you will find you are off by an order of magnitude.

You are about right on the weight of the cyclist though.
 Do the rules prohibit offsetting the load with, say, lighter than air wings?

 Quote by BenchTop Do the rules prohibit offsetting the load with, say, lighter than air wings?
Lighter than air construction, and energy storage devices are explicitly prohibited. Check out the www.vtol.org website for the official rules, which goes over everything in detail.

 Quote by russ_watters After looking at the rules, I believe the contest is doable. It only says you need to momentarily exceed 3 meters and total hover time is only 1 min. A cyclist can put out a lot more power for 1 min than s/he can for three hours. Just keep in mind, this is nowhere close to the achievment of the Gossamer Albatross, which actually had sustained, controllable flight for close to 3 hours. This "helicpoter" prize seems pretty pointless to me.
Then you need to study helicopters so you wont make such a naive statement! This is, in fact, harder, than a human powered airplane. McCready said so himself - if you don't know who he is Google him.
 I had a thought (beware)... A lot of stuctural weight is required to support the pilot in the middle. Now, it's well established by the Gossamer Albatross that a single Bryan Allen can power a plane over a comparatively long time span in straight and level flight. Flying in circles would require a bit more work, but over a shorter span of time. Four of these things, tethered to fly in a circle, mutually constrained by relatively light weight struts and cables, and powered by four Bryan Allens would be capable of achieving the desired result. The craft should have an overall diameter of about 400 feet. That would take a big gymnasium.
 Useless facts. The largest hanger in the world wouldn't be enough. http://www.distant.ca/UselessFacts/fact.asp?ID=165 "CargoLifter hangar, located in Brand, Germany (60 kilometres south of Berlin) on a former Soviet military airport, is the largest self-supporting hangar in the world. With 360-meters in length, 210-meters in width and 107-meters in height the hanger was designed to accommodate the planned CargoLifter CL 160, a 260-meter long airship." Self propelled helicoptering should be an outdoor sport.

 Quote by Phrak Useless facts. The largest hanger in the world wouldn't be enough. http://www.distant.ca/UselessFacts/fact.asp?ID=165 "CargoLifter hangar, located in Brand, Germany (60 kilometres south of Berlin) on a former Soviet military airport, is the largest self-supporting hangar in the world. With 360-meters in length, 210-meters in width and 107-meters in height the hanger was designed to accommodate the planned CargoLifter CL 160, a 260-meter long airship." Self propelled helicoptering should be an outdoor sport.
Provided you have very calm winds, yes. Large indoor areas pose problems because the circulation of the air inside the (Gymnasium!) as a result of the induced velocity will cause the rotorcraft to inevitable drift outside the limits of the (10?) meter box.

 Quote by Cyrus Provided you have very calm winds, yes. Large indoor areas pose problems because the circulation of the air inside the (Gymnasium!) as a result of the induced velocity will cause the rotorcraft to inevitable drift outside the limits of the (10?) meter box.
It may be moot, since the widest indoor flat area I could find was about 260 meters, but I'm not following. The helicopter will induce some toroidal flow of air--up on the outside, and down in the middle. Will off-center cause positive feedback to draw it further off-center?

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 Quote by Cyrus No, this is wrong and not based on any sort of calculation. Run the numbers and you will find you are off by an order of magnitude. You are about right on the weight of the cyclist though.
What formulas should I be using to calculate the required power for a helicopter?

I looked at it from a thrust standpoint, and used the weight of the DaVinci III as a guide for human-powered helicopter dimensions. With a weight of 227 pounds, and an induced wind velocity of 35 mi/hr (I just guessed at this, the DaVinci III report had no specs), you have to push 142 lb/s of air for a total of 111,600 cfm, and that works out to 10.5 horsepower required to gain stable flight outside of the ground effect.

 Quote by Mech_Engineer What formulas should I be using to calculate the required power for a helicopter? I looked at it from a thrust standpoint, and used the weight of the DaVinci III as a guide for human-powered helicopter dimensions. With a weight of 227 pounds, and an induced wind velocity of 35 mi/hr (I just guessed at this, the DaVinci III report had no specs), you have to push 142 lb/s of air for a total of 111,600 cfm, and that works out to 10.5 horsepower required to gain stable flight outside of the ground effect.
You should write and run a BEMT code. I have no idea where your ad-hoc numbers come from. As a first order analysis, you could just use momentum theory itself (which does not require any code).

$$P = T^{3/2}/\sqrt{2\rho A}$$

Using R = 50' and T = 227lb, the power is 559.59 (whatever units it is fl-lb/s, or something...) or about 1.01 HP. This is obviously a first order analysis and one would have to use BEMT for better estimates at HOGE. An order of magnitude less than your estimate! (And we have not even gotten into any of the actual hard technical challenges!)

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 Quote by Cyrus Then you need to study helicopters so you wont make such a naive statement! This is, in fact, harder, than a human powered airplane.
You misunderstood my point. I know it is harder than a human powered airplane - and that's why they have to make the prize for such a small achievement.

In other words, you can't fly this thing across the English Channel.

 Quote by russ_watters You misunderstood my point. I know it is harder than a human powered airplane - and that's why they have to make the prize for such a small achievement. In other words, you can't fly this thing across the English Channel.
My bad. You would have a hell of a time flying this thing even in a straight line! The power requirements are horrible, and the rotation of the blades mean the stresses quickly kill you, because things have to be build bulkier. It's a hell of a problem compared to the human powered airplane (HPA).