Aerovelo's Human-Powered Helicopter Wins $250,000 Sikorsky Prize

Flintstones did it by Anonymous Coward · 2013-07-11 04:36 · Score: 1

Yabba-dabba-doo!

That thing is bigger than a by Spy+Handler · 2013-07-11 04:42 · Score: 0

Pave Low that I shot down last night. Do I get a killstreak reward if I were to swat it with a flyswatter?

COOL! by Anonymous Coward · 2013-07-11 04:45 · Score: 1

what blows my mind is how slowly the wings move.

Re:COOL! by Anonymous Coward · 2013-07-11 05:55 · Score: 0

Yeah, that looked odd to me too. You wouldn't expect it to be able to fly with them rotating at that speed. But, considering how much surface area they have, apparently it still pushes enough air to pick the thing up. (And that may not be a lot. Did anyone see where it said how much it weighs?)

Thrust by tom17 · 2013-07-11 04:50 · Score: 1

Congrats guys.

This pretty much proves that a human athlete has enough power to provide enough thrust/downforce for lift. So my question is, would it be feasible to generate this same level of thrust in a smaller area using the same amount of power?

I'm guessing that by having such large rotors with low air speeds and low thrust per unit area, that efficiencies are kept high and this is why it works.

Would there be that huge an efficiency decrease if the same amount of thrust were generated on a smaller area? If that's what it boils down to, then we will never be able to make this work at 'reasonable' scales :(

Re:Thrust by CanHasDIY · 2013-07-11 04:55 · Score: 1

Congrats guys.
This pretty much proves that a human athlete has enough power to provide enough thrust/downforce for lift. So my question is, would it be feasible to generate this same level of thrust in a smaller area using the same amount of power?
Gear reduction, perhaps?

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Re:Thrust by PRMan · 2013-07-11 05:27 · Score: 2

That's exactly it. I think they increased the surface area to ridiculous lengths to their advantage. It's not very usable that way, but they did manage to meet the parameters of the contest. I'm not sure this design could ever be shrunk enough to be usable, but maybe as a way to put a small electric motor on a helicopter that you can slow enough not to kill you in a crash landing, this could have merit.

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Peter predicted that you would "deliberately forget" creation 2000 years ago...
Re:Thrust by h4rr4r · 2013-07-11 05:41 · Score: 1

I think the point was to meet the parameters of the contest. Why does this need to have any other application?
A proper helicopter can autorotate.
Re:Thrust by Moofie · 2013-07-11 06:01 · Score: 2

I'm sure they built it that huge just for funsies. Surely it didn't occur to them to use smaller rotors, you know, like every single helicopter ever built on Earth. They probably just didn't think of it.
Man, people who do things that have never been done before are so dumb...

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Re:Thrust by ShanghaiBill · 2013-07-11 06:25 · Score: 5, Informative

So my question is, would it be feasible to generate this same level of thrust in a smaller area using the same amount of power?
No. The amount of thrust goes up linearly with the velocity of the airflow, but the amount of energy required to move that air goes up as the square of the velocity. So for the fixed amount of energy that a human can produce, you will get more thrust by it pushing down a large mass of air at a low velocity than a smaller amount of air at a high velocity.
Re:Thrust by ChrisMaple · 2013-07-11 06:29 · Score: 1

I'm not an aero engineer, but I think that ground effect is becoming significant when the area swept by the blades > the periphery of that area times height. That appears to be the case here. If the lift area becomes smaller, there's less ground effect for the same height.
Even ignoring ground effect, smaller rotor area is similar to smaller aspect ratio in wings, and leads to less lift for a given power input.

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Re:Thrust by tom17 · 2013-07-11 06:38 · Score: 1

Explained perfectly. It's kind of what I *thought* in a fuzzy kind of way. Good to see it explained :)
Ta.
Re:Thrust by Procrasti · 2013-07-11 09:49 · Score: 1

Congrats guys. This pretty much proves that a human athlete has enough power to provide enough thrust/downforce for lift. So my question is, would it be feasible to generate this same level of thrust in a smaller area using the same amount of power?
Gear reduction, perhaps?
No, unless I'm mistaken, you can't use gears to change power, only to alter speed and torque. There are some (mostly negligable) losses in gears, but anything else would imply that gears can generate power, then you'd have a perpetual momentum device.
Re:Thrust by CanHasDIY · 2013-07-11 10:05 · Score: 1

Congrats guys.
This pretty much proves that a human athlete has enough power to provide enough thrust/downforce for lift. So my question is, would it be feasible to generate this same level of thrust in a smaller area using the same amount of power?
Gear reduction, perhaps?
No, unless I'm mistaken, you can't use gears to change power, only to alter speed and torque. There are some (mostly negligable) losses in gears, but anything else would imply that gears can generate power, then you'd have a perpetual momentum device.
I was assuming GP was using the term "power" as a substitute for "work." Since his question is whether or not it would be possible to generate the same amount of thrust across a smaller airframe, while still doing the same amount of work, I presume that gear reduction could be a valid method of achieving that goal, because you would be able to increase the speed of the prop (and thus, generate more lift) without the power source (the cyclist) having to expend any more energy than before.
'Course, IANA Mechanical Engineer, but I did stay at a Holiday Inn Express last night...

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An enigma, wrapped in a riddle, shrouded in bacon and cheese
Re:Thrust by Procrasti · 2013-07-11 10:45 · Score: 1

Again, no... I'm pretty sure work and energy are exactly the same thing... or rather work is the change in the energy of the system between two states... so the work you do is exactly equal to the energy you put in.
Power is just the change in energy over time, or the work over time... or the rate at which you are working or creating energy. P = dE/dt.
So, what I said before about generating power applies to generating energy or work, and gears cannot do that, or otherwise you would have a perpetual motion device.
Now, as I said, gears can be used to trade speed and torque... the reason this is confusing I think, when you think about say gears on a bike, it isn't the amount of work you are doing that changes but instead there is an optimal speed and torque at which your muscles produce work most efficiently... similarly with car engines having an optimal speed/torque range and why we gear them.
Re:Thrust by Anonymous Coward · 2013-07-11 13:17 · Score: 0

Congrats guys.
This pretty much proves that a human athlete has enough power to provide enough thrust/downforce for lift. So my question is, would it be feasible to generate this same level of thrust in a smaller area using the same amount of power?
Gear reduction, perhaps?
No, unless I'm mistaken, you can't use gears to change power, only to alter speed and torque. There are some (mostly negligable) losses in gears, but anything else would imply that gears can generate power, then you'd have a perpetual momentum device.
I was assuming GP was using the term "power" as a substitute for "work." Since his question is whether or not it would be possible to generate the same amount of thrust across a smaller airframe, while still doing the same amount of work, I presume that gear reduction could be a valid method of achieving that goal, because you would be able to increase the speed of the prop (and thus, generate more lift) without the power source (the cyclist) having to expend any more energy than before.
'Course, IANA Mechanical Engineer, but I did stay at a Holiday Inn Express last night...
gears = weight, rotational inertia, centrifical force, and remarkably, gears do actually lose significant amounts of power if you make a large reduction in one set. We in the R/C world are constantly fighting loses in our helis. The above are just a few.

Congratulations - by Anonymous Coward · 2013-07-11 04:50 · Score: 1

My congratulations to Aerovelo for a job well done! Also consolation and respect to the UMd team, which made a convincing effort and came so so close.

That guy piloting it: by Anonymous Coward · 2013-07-11 04:59 · Score: 3, Interesting

That guy piloting it: same guy who flew the human powered flapping wing aircraft: https://www.youtube.com/watch?v=0E77j1imdhQ

Re:Ground effect by rotorbudd · 2013-07-11 05:02 · Score: 5, Informative

With the speed those rotors are turning, I don't think there'd be much in the way of ground effects generated.

Just an old helicopter mechanic tho, not an aeronautical engineer So I might be completely wrong..

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Great example of why prizes exist by Covalent · 2013-07-11 05:02 · Score: 4, Insightful

Human-powered flight is unlikely to ever be a real player (look how hard he has to pedal just to stay 10 feet off the ground for a minute!)

However, the engineering and material science that was used to make this possible could easily translate into lighter helicopters, electric vehicles, drones, you name it.

Just as flying solo across the Atlantic wasn't really something anybody did much after Lindbergh, neither will anybody do much human helicoptering (?) But the fact that it can be done will help humanity long term. Well done!

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Re:Ground effect by lxs · 2013-07-11 05:03 · Score: 5, Insightful

Who cares? It's human powered. It hovered. The thing looks like it's escaped from a Laudanum dream. Give the cyclist a stovepipe hat and a suit and reclaim steampunk from the dorks that think gluing a couple of gears on a USB stick is something to be proud of.

Now go back to plane spotting and leave us alone with this awesome contraption.

Really? by Anonymous Coward · 2013-07-11 05:04 · Score: 0

I'm not convinced that it's actually real. The video is too slick. There are clearly things hanging from the ceiling to hold it up. The rotors turn awfully slowly.

Improvements by Valentinial · 2013-07-11 05:11 · Score: 1

I realize this is probably supposed to stay "human powered" but why not improve with ambient energy as well. As slow as those rotors are turning, a solar power assisted setup might alleviate some of the grueling pedaling you have to do. Though I do suppose batteries bear weight but I wonder what the trade off is for battery weight versus lift it can supply.

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@Valentinial

Re:Improvements by PRMan · 2013-07-11 05:28 · Score: 1

I can assure you that the weight of the batteries would negate most of the advantage in flying.

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Peter predicted that you would "deliberately forget" creation 2000 years ago...
Re:Improvements by Anonymous Coward · 2013-07-11 05:45 · Score: 1

a quick search yields the following:
avg human can produce 7200 Joules of energy in an hour (at 200 Watts per second)...surely this athlete is above that...but Lithium Ion batteries can store 460000 Joules per Kilogram.
even if he produces 40 times the average human (questionable) , a single Kg battery could store more energy...right? coupled with some solar trickle-chargers, i'd love to see an energy system applied to such a beautiful machine.
or are my thoughts way off track?
Re:Improvements by gmuslera · 2013-07-11 06:39 · Score: 1

With the surface area of those rotors gathering solar power (even when not flying) this could be a good combo for solar/human powered device.
Re:Improvements by wonkey_monkey · 2013-07-11 07:15 · Score: 1

avg human can produce 7200 Joules of energy in an hour (at 200 Watts per second)
Watts are already "per second" - a Watt is one joule per second, so a human could generate 720,000 Joules in an hour - right?

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Re:Improvements by wagnerrp · 2013-07-11 07:20 · Score: 1

at 200 Watts per second
A quick read yields the following:
You don't know much about physics or units of measurement.
Re:Improvements by Anonymous Coward · 2013-07-11 07:33 · Score: 0

First, 200W for an hour is 720kJ, not 7200J.
Second, yes a battery could be used - battery powered helicopters already exist, you can buy one for ~$25 - no news there.
Lastly, to both yours and the grandparent asking about solar, batteries are the last thing you'd want if you wanted to add solar, then you've got the weight of the panels and the battery I'd expect that just the weight of the panels (they're not very efficient) would be what is prohibitive, rather than the batteries.

Amazing by DaMattster · 2013-07-11 05:13 · Score: 1

The efforts of Aerovolo are laudable! The video is simply amazing and they deserve that prize win. As technology improves and knowledge gains are made, this may be one day practical.

Re:Amazing by wagnerrp · 2013-07-11 07:24 · Score: 1

Nope. Human powered flight will never be practical. We simply don't have the power output to function usefully as motors. World class bicyclists are good for about half a horsepower in a sprint, and maybe a third of a horsepower for sustained output. Your average handheld drill is more powerful.
Re:Amazing by Anonymous Coward · 2013-07-11 10:14 · Score: 0

That is absolutely right. Human-powered flight is, and will always remain, at the absolute limits of the achievable.

Re:Ground effect by Anonymous Coward · 2013-07-11 05:21 · Score: 1

Ground effect depends heavily on rotor size, and those rotors are enormous.

biggest quadcopter ever? by r2kordmaa · 2013-07-11 05:32 · Score: 3, Interesting

This could go into guiness records, on more grounds than one. What i dont quite see is how this thing is stabilized, there must be more than steampunk behind the scenes.

Re:biggest quadcopter ever? by ChrisMaple · 2013-07-11 06:39 · Score: 1

I think leaning is at least part of the steering. At one point in the video, he's clearly leaning to the viewer's left.

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Re:biggest quadcopter ever? by r2kordmaa · 2013-07-11 06:51 · Score: 1

Likely from huge effort, no amount of leaning will stabilise something like this. Little disturbances in air, variations in rotor profile, imperfections in transmissions, quaqcopters are notoriously unstable. If you take the electronic stabilisation out of quadcopter(the regular electric kind) its basically uncontrollable.

Re:Ground effect by h4rr4r · 2013-07-11 05:38 · Score: 1

How is that not flying?

Re:Ground effect by gl4ss · 2013-07-11 05:41 · Score: 2

Ground effect depends heavily on rotor size, and those rotors are enormous.

well.. isn't what it really depends on the speed of air put down.. I don't think ground effect played that much of a role. it flies by any definition of flying. fyi wright flyer 1 barely broke 10 feet in altitude.

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Inefficient by Reliable+Windmill · 2013-07-11 06:04 · Score: 1

Why would they use a pedaling mechanism instead of a rowing mechanism? With a rowing mechanism he can deliver the same power with much less effort, or much higher power with the same effort. The operator can exert a large amount of force using his upper body, but he's just sitting there relaxing and letting his legs do all the work.

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Re:Inefficient by Caesar+Tjalbo · 2013-07-11 06:25 · Score: 1

Why would they use a pedaling mechanism instead of a rowing mechanism?
It looks like it's hard enough already to stay nearly stationary.

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Re:Inefficient by ChrisMaple · 2013-07-11 06:42 · Score: 1

It may be that rowing would make control more difficult, since the pilot's center of gravity would be constantly shifting.

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Re:Inefficient by jklovanc · 2013-07-11 07:48 · Score: 1

Because the rowing motion is much more efficient in the pull than the push. That would cause the energy input to vary greatly. over a longer period. A cycling mechanism is much higher frequency and, other that dead top and dead bottom, there relatively stable energy input.
Re:Inefficient by Anonymous Coward · 2013-07-11 10:17 · Score: 0

You are welcomed to bring your "more efficient" rowing mechanism to market.
There is a really good bunch of reasons bicycles look like they do.

Re:Ground effect by OglinTatas · 2013-07-11 06:09 · Score: 4, Funny

a stovepipe hat and a suit

That should have been specified in the Sikorsky prize rules

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Re:Ground effect by dywolf · 2013-07-11 06:21 · Score: 2

Downward velocity component (affects the trapped/confined pressure differential), altitude of wing (affects confined pressure differential, and the formation of wingtip vortices (and their disuroption) which is part of GE), and wing dimensions/properties (wingspan, chord, airfoil shape, affects downward velocity and the confinement of the differential). and indirectly weight of the aircraft (not because it causes ground effect, but because it determines the effectiveness of it as the force opposing lift)

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Re:Ground effect by ace37 · 2013-07-11 06:42 · Score: 4, Informative

With the speed those rotors are turning, I don't think there'd be much in the way of ground effects generated.

Just an old helicopter mechanic tho, not an aeronautical engineer So I might be completely wrong..

Typically about 1.5 rotor diameters are where it stops helping a traditional helicopeter. In this case, at 10 feet up with a 30 foot diameter, the slow rotor speed notwithstanding it will make a significant contribution. The air below the rotors can't freely move downward until the momentum of the wind dissipates; this energy creates lift.

Ben Berry from Gamera was actually a previous coworker before he went to work on their HPV project.

Source: Aero engineer, rules of thumb there are from asking around at Sikorsky years ago. Also, I don't like how they say this at all, but it at least says the ground effect is significant:

Three years ago, as Staruk and his UMD team began building their first iteration of Gamera, they quickly encountered the boundaries of current aerodynamic understanding. To rise off the ground, human-powered helicopters are helped by a phenomenon called ground effect, in which wings close to the surface of the earth experience a sharp reduction in drag. It's very helpful in getting off the ground but difficult to model. "Ground effect is a very complex phenomenon; there are all sorts of vortices," Chopra says. "You can only validate experimentally. There isn't much theory."

Re:Ground effect by ace37 · 2013-07-11 06:47 · Score: 3, Informative

I forgot to mention the most important part -- the majority of the flight is done very low:

Power required is shown for rotor height of 60 cm (2 ft) above the ground. The 60-second duration flights will be flown as close to the ground as possible to increase ground effect advantages.

http://www.agrc.umd.edu/gamera/gamera2/gamera2-rotor-blades.html

Intent of the Prize Criteria? by Beorytis · 2013-07-11 07:09 · Score: 1

I can see that the pilot/prime mover stays within the 10m×10m box, but the vehicle won't even fit in a box that size at rest.

Re:Intent of the Prize Criteria? by Rudisaurus · 2013-07-11 08:40 · Score: 4, Informative

The AHS publication of the Sikorsky prize regulations, Flight Requirements 4.4.3, states that "a reference point on the non-rotating part of the machine will be established as a means whereby the observers can judge that the machine stayed within the confines of the 10-meter square", thereby clearly indicating that one point on the machine must remain within a 10 m x 10 m square, not the entire machine.

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Re:Intent of the Prize Criteria? by Beorytis · 2013-07-11 08:58 · Score: 1

IOW, the intent was not to require a human-scale machine, merely one whose horizontal movement can be controlled to this extent.

might have been able to find a better rider by SuperBanana · 2013-07-11 08:07 · Score: 2

As someone who has started learning about power and cycling - this was a job for an cat 1 / "elite" racer, or at least someone significantly lighter than the guy in the video. I ride pretty regularly but not competitively, and I'm able to do about 300W for a minute. That's piddlesticks in the world of racing, for my weight.

A sprinter would be able to put out massive power (probably 5-7 times what I can do) but sprinters also tend to be heavy. Someone who isn't a sprinter would have less power, but could weigh 50lb less. There are cyclists who specialize in races with climbing, mostly through being light, pacing themselves properly, and having excellent technique.

I'm wondering how much of a warmup he did - in order to do an effort like that, you really do need to be properly warmed up.

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Re:might have been able to find a better rider by Splab · 2013-07-11 08:12 · Score: 1

How many sprints have you seen that took 64 seconds?
Re:might have been able to find a better rider by Trax3001BBS · 2013-07-11 08:46 · Score: 1

As someone who has started learning about power and cycling - this was a job for an cat 1 / "elite" racer, or at least someone significantly lighter than the guy in the video. I ride pretty regularly but not competitively, and I'm able to do about 300W for a minute.
I can't find it now but a girl was the first to make a record - linked from the end of the video; also from those links 3 different guys 1 crash
https://www.youtube.com/watch?v=emK-qIbuJ-k so a lot of peddlers (?).

I'm wondering how much of a warmup he did - in order to do an effort like that, you really do need to be properly warmed up.
Not an answer but an indication (also linked from the end of the http://www.aerovelo.com/ video)
From the description http://www.youtube.com/watch?feature=player_embedded&v=Q2Njtel-Es0#at=177 [youtube.com]
"The one-minute power test is meant to simulate the flight of the Atlas helicopter, which starts at a relatively high power during the climb and then drops down to a more reasonable 500-600 Watt range for the remainder of the flight.
The test were performed on October 5th and 6th, 2012, following an intense taper, weight loss program and peak at the end of August, and then a 2 week recovery phase. The results were lower than Todd's personal best (1 minute into the 460 Watt stage, and 773 Watt average for the minute power test), but as expected given the training phase."
Re:might have been able to find a better rider by adolf · 2013-07-11 11:57 · Score: 1

773 Watt average for the minute power test
That's more than 1 horsepower, on average, for sixty seconds.
(I'm sure his lady-friends enjoy his, uh, company.)

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Re:might have been able to find a better rider by Anonymous Coward · 2013-07-12 00:13 · Score: 0

Riders that excel in the individual pursuit (a type of bicycle track race) are probably good candidates. This event selects for modest size and sustained power for a minute or two. Many of the human powered land speed records (with streamlined bicycles) have been held by pursuiters and similar track riders. Stage racers (Tour de France riders) and sprinters (enormous peak power for less than a minute) have not been so successful in human powered vehicles (hpv).
We measured the Olympic-alternate pursuiter who powered my hpvs . When he was all trained up he could hold something less than one horsepower (from memory it was about 600 watts) for a minute, and his body weight was about 165 pounds. This was a few years after he was on the Canadian Olympic squad, so he was probably down a bit from his absolute peak. In his case, we tested at different cadence (pedal rpm) and concluded that his best power for a minute was between 120 and 130 rpm, so we gave him suitable gearing to stay within this range as he accelerated the vehicle. His legs were extremely coordinated and smooth, once when he was warming up on a velodrome (in a lower gear), I watched him pedal smoothly at a cadence of 180 (three revolutions of the pedals per second), while the rest of his body just moved along with the bike.
Elite athletes are not like normal people.

Re:Ground effect by White+Flame · 2013-07-11 13:19 · Score: 1

...reclaim steampunk from the dorks that think gluing a couple of gears on a USB stick is something to be proud of.

Obligatory: http://www.youtube.com/watch?v=TFCuE5rHbPA.

Congratulations by Anonymous Coward · 2013-07-11 23:21 · Score: 1

Congrats to Cam, Todd, et al. Terrific job! You guys have poured your hearts and souls into these projects, glad to see it paying off ^__^

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Aerovelo's Human-Powered Helicopter Wins $250,000 Sikorsky Prize

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