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Idle Science

Human Powered Helicopter Aims To Break Records 87

Posted by samzenpus from the icarus-airlines dept.
An anonymous reader writes "A team of 50 from the University of Maryland has developed a human-powered helicopter, 'The Gamera,' which took two years to complete. The size of the helicopter is one third of a football field. The helicopter is made from light materials such as balsa, mylar, carbon fiber and foam and weighs about 210 pounds. The team aims to have it hover at least 3 meters off the ground."

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Human Powered Helicopter Aims To Break Records More

Human Powered Helicopter Aims To Break Records

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  • Misleading summary (Score:4, Informative)

    by Pheran ( 104478 ) on Tuesday May 10, 2011 @10:05AM (#36083464) Homepage

    The article summary is quite misleading given that the 210-pound figure includes the weight of the pilot.

  • Finally! (Score:3, Funny)

    by Anonymous Coward on Tuesday May 10, 2011 @10:08AM (#36083508)

    Someone figured out an appropriate use for the football field.

  • So... a carnie wearing stilts will look down at you and laugh?

    • Re: (Score:3)

      by vlm ( 69642 )

      So... a carnie wearing stilts will look down at you and laugh?

      Not is your "ground" is actually a deep body of water...

  • DaVinci (Score:1)

    by Anonymous Coward

    DaVinci would be jealous.

    www.awkwardengineer.com [awkwardengineer.com]

  • Stored energy (Score:3, Insightful)

    by Iamthecheese ( 1264298 ) on Tuesday May 10, 2011 @10:17AM (#36083664)
    I'm sure they wouldn't allow a helicopter that uses air earlier compressed by the human pilot so what about stored momentum in the blades and machinery? Also do air currents count as stored energy? Obviously this couldn't fly without the ground effect [wikipedia.org]... Just some thoughts.

    • Re: (Score:2)

      by h4rr4r ( 612664 )

      So how do you build a helicopter that does not store momentum in the blades? How do you make one that is not influenced by ground effect?

      Seems to me this is the same as every other heli.

      • Re:Stored energy (Score:5, Informative)

        by tlhIngan ( 30335 ) <slashdot.worf@net> on Tuesday May 10, 2011 @11:38AM (#36084730)

        How do you make one that is not influenced by ground effect?

        Easy, fly higher.

        Ground effect only happens when you're close to the ground. A rule of thumb is that it's effect is negligble after you reach a height equal to half the wingspan.

        So a rotor blade (or wing) of 3m length (6m rotor disc/wingspan), once above 3m in height, would have to be flying out of ground effect.

        And yes, ground effect is a big deal - it lowers the amount of lift you actually need by quite a bit. Student pilots find this out on landing when all of a sudden the airplane floats down the runway. Experienced pilots find it when their plane seems to take off, but only bobs above the ground without really gaining altitude.

        • Re: (Score:2)

          by h4rr4r ( 612664 )

          That is not a solution to my question. That is merely a confirmation that this impacts all other aircraft as well. There are even ground effect aircraft, the Soviets built several of them.

          Again I ask, how do you make one that is not influenced by ground effect?

          • Well looks like the first step would be designing, building, and testing a human-powered rotorcraft that can fly with the positive lift benefits of ground effect and then improving on that design.

          • To answer your question literally, you design it so that at rest, the blades are high enough off the ground that the ground effect is insignificant.

            To test that a given helicopter does not rely upon ground effect, insist that it take off from a surface consisting mostly of holes, such as a chain link fence suspended horizontally 100 feet in the air.

        • Re: (Score:1)

          by Anonymous Coward

          Helicopters have different aerodynamics. Hovering in ground effect takes less power than hovering out of ground effect, but still requires massive amounts of power.

          Effective Translational Lift (ETL) occurs at around 15-20 knots and *dramatically* reduces the amount of power required to attain altitude. Any helicopter pilot has the experience of holding near 100% torque to hover, and needing to drop the collective 30%-ish as soon as you hit 15 knots or so.

          • To make this a little more obvious, consider that a hovering helicopter stays in one column of air, and that column of air is in downward motion caused by the helicopter pushing on it. The helicopter is trying to climb by grabbing air that is falling. As soon as the helicopter moves out of that falling column of air, it's grabbing on to stationary air, which is a lot easier.

            When it's near the ground, there can't be any falling column of air because the ground is blocking the airflow.

        • The fact sheet says the rotor diameter is 42 feet or almost 13m. So it appears the design aims for sufficient ground effect at 3m height.

      • The problem with ground effect is that it makes it easier to fly and hover, but it only works when you're really close to the ground (hence the name). A helicopter isn't very useful if it can only fly within a few feet of the ground, so if you've built one that depends on it, your machine has no practical use as a helicopter.

        The whole problem with helicopters is that they require an enormous amount of energy to stay aloft, which is why making a human-powered one seems like a complete waste of time to me.

        • Totally agreed. A helicopter that relies on the ground effect isn't practical. But neither is a human-powered helicopter. Practicality is obviously not the point here.
    • Using energy stored as momentum would only allow for a temporary hop off the ground, until that momentum is used up - if the pilot can't sustain the power required for flight, the rotor would quickly slow down.. It sounds like the requirement that it fly for at least 60 seconds means that the human pilot has to be able to maintain the momentum of the rotor by pedaling with the power required for actually flying.

      • Re: (Score:3)

        by v1 ( 525388 )

        Using energy stored as momentum would only allow for a temporary hop off the ground,

        Though one of the requirements of the challenge is at some point in the flight to get 3M off the ground. Using inertia in the blades would be an excellent way to do that. Get the blades up to speed, lowering their angle as you increase their speed and maintain a hover, (thus storing energy in the blades' inertia) then suddenly pitch the blades up at the 55 second mark or so when the pilot is exhausted, and the craft shoul

        • Re: (Score:2)

          by tibit ( 1762298 )

          I don't know if they'll have enough structural load limits to be able to do any quick hops like that. I think that it will all have to go very, very smoothly. To a point where the pilot would be able to break something if he were to push too hard on the pedals.

  • ....without a ramp. (HPV = human powered vehicle).

  • Fuel (Score:4, Funny)

    by RazzleFrog ( 537054 ) on Tuesday May 10, 2011 @10:20AM (#36083724)

    So is it fueled by Soylent Green?

    • Re: (Score:2)

      by syousef ( 465911 )

      So is it fueled by Soylent Green?

      No, but Soylent Green is what you become if you stop peddaling at sufficient height.

  • Da Vinci would be proud.
  • Why was this posted in IDLE?

  • This looks like a near-clone of the Yuri I (the last successful human-powered helicopter), but slightly bigger and heavier:

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

    My quick back-of-the-envelope calculations say that it won't get more than 1 meter off the ground for any significant length of time. If it was much bigger (2 or 3 times) it might have a chance, but at this small size it will be depending too much on ground effect for extra lift, just like the Yuri I did. Fly too high - over 1 meter or so, i

  • Not nearly enough real action with only the tiny snippets... Bleh

  • Yet another premature article (Score:3)

    by jklovanc ( 1603149 ) on Tuesday May 10, 2011 @10:59AM (#36084256)

    The test flight is supposed to happen tomorrow. Why not wait till there are results before posting an article?

  • How much excess power does vertical flight require (Score:4, Interesting)

    by Viol8 ( 599362 ) on Tuesday May 10, 2011 @11:04AM (#36084322) Homepage

    ...compared to just climbing up a ladder?

    What I mean is the human body has easily enough power to raise itself up a vertical ladder or rock face so presumably a huge amount of this power must be lost just moving air around when that power is used inside a human powered helicopter. But how much power is wasted , or to put it another way , how much power put into the system is actually used to raise the mass of the helicopter?

    • Yeah, but once you're on the ladder, you're on the ladder. (Unless you manage to fall off).

      Energy wise this would be like continually jumping up and down.

    • Re:How much excess power does vertical flight requ (Score:4, Informative)

      by vlm ( 69642 ) on Tuesday May 10, 2011 @11:22AM (#36084556)

      ...compared to just climbing up a ladder?

      What I mean is the human body has easily enough power to raise itself up a vertical ladder or rock face so presumably a huge amount of this power must be lost just moving air around when that power is used inside a human powered helicopter. But how much power is wasted , or to put it another way , how much power put into the system is actually used to raise the mass of the helicopter?

      You're mixing mass, power, and impulse all together. impulse = F * delta t = m * delta v

      So the force is pushing down with the combined weight of the vehicle for a certain time in order to hover in place, which is equivalent to accelerating a mass (lets say, the vehicle) to a certain velocity. So hovering for 10 minutes takes the same impulse as accelerating (lets say, horizontally) to some absolutely ridiculous velocity. I forget the crossover but, hovering a copter for X minutes is equivalent to pushing a car 0 to 60.

      The power level is in the low single digit horsepower for a good athlete for a minute or two. Good luck dissipating even one horsepower for a "long time".

      Also note that people climb extremely slowly. Over a long term, best expressed as seconds per foot rather than ft/sec. Classic high school physics problem is having the strongest track athlete try to climb a flight of stairs as quickly as possible, with the horsepower result usually being pretty depressing.

      • Re: (Score:2)

        by Arlet ( 29997 )

        I think a major part of a successful outcome is to ask a world class athlete to fly the thing.

      • Re: (Score:3)

        by Nick Ives ( 317 )

        Also note that people climb extremely slowly. Over a long term, best expressed as seconds per foot rather than ft/sec.

        I think you mean best expressed as inches per second or even better, cm/s. If you were moving seconds per foot then you'd be in some kind of Braid style dreamworld where motion in a given direction affected the flow of time.

        • Re: (Score:2)

          by vlm ( 69642 )

          I think you mean best expressed as inches per second or even better, cm/s. If you were moving seconds per foot then you'd be in some kind of Braid style dreamworld where motion in a given direction affected the flow of time.

          Seconds per foot is just the reciprocal of feet per second. Useful when the numbers are much less than 1. Think of ancient bipolar transistor alpha vs beta, once alphas got too high making all transistors 0.99-something the industry pretty much switched to reporting betas. For example an old person might climb at 0.14286 feet per second but its easier to say 7 seconds per foot.

          • Re: (Score:2)

            by Nick Ives ( 317 )

            Or how about approximately 4.4cm/s?

            It's confusion around units of the kind you're encouraging that caused the loss of Mars Climate Orbiter! :)

    • ...compared to just climbing up a ladder?

      What I mean is the human body has easily enough power to raise itself up a vertical ladder or rock face so presumably a huge amount of this power must be lost just moving air around when that power is used inside a human powered helicopter. But how much power is wasted , or to put it another way , how much power put into the system is actually used to raise the mass of the helicopter?

      I'm not exactly sure what you're asking here, but think about it this way. Gravity is accelerating you downwards. When you stand on a ladder, the ladder's structure is resisting your weight, which is why you stay up. With a helicopter or airplane, you don't have a structure to hold you up, so instead you accelerate air downwards using wings. You push the wings through the air, they accelerate air downwards, you get supported.

      So the easiest answer to your question is *all* the power put into the system a

      • Ultimately any human powered helicopter would have to have some type of gliding mechanism to be practical. People can put out sustained effort for only so long. But if you make it more like a bicycle where you can coast and rest between bursts of intense activity, then you may really have something. We need to be aiming for a "bicycle of the air" with this, not mimicking what machines typically do for us.

        Oh, and fail-safe too. If you get exhausted at 1000 feet up, it needs to gently drift to ground.

        • Re: (Score:2)

          by tibit ( 1762298 )

          I'm sure a copter with enough aerodynamic efficiency to support human-powered flight will be a joy to autorotate. Autorotation is the standard helicopter failsafe: if your engines fail and you're high enough and have some forward speed, you disengage the rotor clutch and let it spin freely, "gently" getting you to to ground. In a normal helicopter a proper autorotation IIRC is only designed to be survivable, in this human-powered one it should be not only survivable but very gentle, too.

  • Not to diminish their considerable task, but their rotor sizes means they are required to hover within ground effect, which considerably reduces the overall challenge. Again, that's not the same thing from saying their challenge is easy - as it most definitely is not.

    • If the Yuri I is anything to go by - and this craft looks almost identical to the Yuri I - the ground effect at these low power levels - even for this size of rotor - don't extend much above 1 meter or so. They're going to have a hard time climbing above that.
  • Pride is certainly one of them, and they spell it out in the promo. I have to hand it to the PR group at the UM that seem to have done a better job of actually finishing their project than the HPH have done to date. Setting up testing apps, fixtures are all great, but really what is the world is this going to do for practical aviation based on technology that is 100s of years old now? What is the economic and ecological footprint of this project? To achieve a goal, sure it is notable. But is it really

    • Re: (Score:3)

      by digsbo ( 1292334 )

      Then you go ahead and do what you see as beneficial to humanity, and let them do what they see as worthwhile. But before you criticize people attempting something amazing that you don't see as worthy of your blessing as being beneficial to humanity, ask yourself if you always apply the same judgment to your own actions. I'm sure the ecological footprint of the energy you've used to post on ./ is well worth it for disseminating your grand wisdom to the rest of us. Sorry to be a dick, but boy you come acro

    • Presumably things could be learned that have practical applications for powered aircraft.

      • Presumably things could be learned that have practical applications for powered aircraft.

        How far is it from human powered to solar powered? Probably a lot closer than from internal combustion powered to solar powered... Didn't we just see an example of "perpetual flight" that used that result for fixed wing flight?

        So, imagine a solar powered predator helicopter hovering silently over your home, just waiting... hmmm... I wonder if the size of the solar array might cause a noticeable shadow at ground level? Probably wouldn't have to be much larger than the afore-mentioned football field...

        Just

    • While I've yet to enter college, my thoughts on seeing this were of how their findings along the way actually could be used. They're doing everything they can to reduce weight in a small hpv aircraft, so they may make advances there. They're testing different kinds of rotor shapes, which is practical for this application, which provides the best lift etc. for two, and I'm sure there's quite a bit of aerodynamic testing and experimenting as well. If this project doesn't lead to at least one advance in techno

  • idea! (Score:3)

    by roman_mir ( 125474 ) on Tuesday May 10, 2011 @11:39AM (#36084738) Homepage Journal

    I have an idea! How about they take a small 2 stroke engine and add it to the thing. Also a closed cockpit would be nice. Make the vehicle a bit more compact, maybe 1/4 of the size and then we can start having a conversation about something that's useful.

  • reading the article only - ignorinig the video, I can only think: what record to break?
    The record of measuring size in football fields? Please, give me something my non-American brain can relate to.
    The record of measuring height using the metric system and weight using imperial? Done with little succes by NASA I believe.
    After viewing the video, I know what record they'll break: The record of winning a prize...

    schmellz like PR bs.

    • The world's first human powered helicopter maybe?

    • From the article: "If Gamera makes it off the ground, the team has the potential to capture a world record for human-powered helicopter flight with a female pilot on board."

      So the record they are going after purely based on the sex of the pilot? That's weak.
  • As in, Big Giant Turtle That Flies? You know, friend to children, Japanese movie monster, serious under-bite, shoots flames from mouth, extremity holes, etc.

    I can't help wondering if multiple blades fastened to some sort of really thin but strong ring would be better? Like three blades would be a lot more stable? But what do I know?

    PS Someone should take the footage, speed it up, make it black and white and play player piano music in the background.... :-)
  • Most of these designs use only immediately available energy. What precludes them from storing some of it to achieve the 60s + 3m goal? Or is it forbidden in the Sikorsky price rules?

    You could have someone pedal the thing for a couple of hours to store energy before attempting the flight.

    I don't think it's easy, but it might open up some interesting possibilities.

  • Even if they get all the rest right, I didn't see any directional controls on Gammera, so staying in the 10 meter box might be the biggest challenge, especially if they are depending on weight shifting of the pilot for control while she is peddling like mad with both hand and feet!

  • "Fuck you I'm not peddling anymore!" :)

  • And the summary forgot to include that the test flight is today [umd.edu] ?

    Supposedly... don't have silverlight.

    Press release [umd.edu]

  • It was a fail sadly they are trying again today looks very cool! http://www.suasnews.com/2011/05/5475/human-powered-helicopter-has-part-failure/ [suasnews.com]

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