In case you haven’t heard, the Sikorsky Prize, an aeronautical challenge to build a human-powered helicopter that can hover at three meters for a full sixty seconds, has been claimed. This incredibly difficult engineering feat was accomplished by AeroVelo, along with a lot of help from the University of Toronto and a host of companies involved in the design and manufacture of rotorcraft. This prize has stood unclaimed for thirty years, and it’s not from lack of trying; in the 80s and 90s, universities in Japan tried their hand at the challenge, and recently a team from the University of Maryland had a go at it.
But as far as human-powered flight goes, a helicopter is just about the least efficient way to get off the ground. Helicopters need power to provide their own lift and thrust, whereas airplanes only need to generate some forward momentum.
From the bicycle-powered crossing of the English channel in 1979, human-powered flight has come a long way, so far that next the Royal Aeronautical Society will be hosting the Icarus Cup 2013. It’s a competition where teams of human-powered aircraft enthusiasts will compete in challenges measuring distance, speed, endurance, and landing accuracy.
No, it’s not an ornithopter from Da Vinci’s notebook, but human pectoral muscles aren’t powerful enough for that anyway.
Thanks [DainBramage1991] for sending this one in.
congratz to the team for winning, I Wonder if this would be an efficient way of travelling across the moon/mars surfaces?
Considering the lack of atmosphere, no.
Mars has enough of an atmosphere, and perhaps as technology progresses, we can get a flying rover to mars. It also has less gravity.
The current system delivered by ion thruster would be the most efficient. With refinements across the board on designs to reduce energy consumption and by-products.
There are also material sciences to convert radiation into electricity, where solar is too low. I think radiation batteries with long life cycles are also already in use.
There is also a staggering lack of work being done on the earth atmosphere exit stage. It’s still too expensive and wasteful, but hey this is all for politicians who can barely do core mathematics to decide..
Umm.. for the record, the same team (AeroVelo) built a human-powered ornithopter as well: http://www.aerovelo.com/projects/ornithopter/introduction/
I would argue that a helicopter is the *most* efficient way of getting off the ground, as almost all the energy (excluding that used to power the tail rotor, irrelevant with the U of T team’s design) is used to provide lift, whereas in a plane most of your energy is devoted to forward motion. Of course, it’s hideously efficient if you want to actually go anywhere besides up.
The guys involved with the team also build high-speed racing bikes with ultrastreamlined shells (I know a few of them from another U of T club). It’s telling that at the core of all their projects is an olympic sprint biker…
Your argument is wrong, because the amount of power needed to get off the ground with a human-powered helicopter versus a human powered fixed wing aircraft is dramatically different.
I’m having surprising trouble finding altitudes for human powered fixed wing, but Daedalus is said to have flown between 15 and 30 feet on its last flight. The Gamera team got all excited about 8 ft not that long ago. So if up is the direction you want to go, on your own power, a fixed wing aircraft will get you higher. You might also want a pogo stick or trampoline, honestly.
Helicopters are inefficient for multiple reasons.
During forward flight, there is lift asymmetry: on one side of the rotor the blades have greater effective speed, and on the other side the speed is reduced.
They also have to deal with “dirty air”: turbulent distortions caused by the rotor. In comparison, planes are always flying into “clean” air.
If you weren’t lazy you could use basic physics and mechanical engineering to make a pedal powered helicopter that uses thust to get you up to altitude, and then rotates the prop forward after it extends it’s convertible wings and tail for lift. It would need a transmission to produce enough thrust from reasonable pedal RPM.
You could also use a transmission for typical hobby helicopters.
It’d be mechanically simpler to make a gyrocopter with a transmission between the rotor and a prop.
Sorry to moan, but are there any links to this that are better than Youtube? I don’t particularly care about seeing it in motion, I’d rather know how it was all done, in writing. Do the team have a web page about it?
Youtube links pop up a lot nowadays on Hackaday. They don’t really teach you anything, and I can never be bothered with watching them anyway. I’d prefer if you used them less, or at least as a second alternative to a proper written page.
It’s a manufactured geared bike, and a secondary link on it’s drive train goes in linear to each prop. The frame they use to support the prop size is light enough for the thrust to work, the prop sizes and position give enough thrust and stabilize the body.
It actually looks like they go their idea from early 20th century dutch research, except used a bicycle instead of a low power engine..
Also, this can be done with a single 8 foot prop if you have the resources to do a transmission for it, and it’ll even take less human effort to operate..
Here’s a decent link:
http://www.engadget.com/2013/02/01/the-highs-and-lows-of-human-powered-flight/
Google “Sikorsky prize” if you want more.
I’m a little sad that the sikorsky prize didn’t put a limit on rotor size (and maybe craft size). Without such a limit the competition become one of building the largest lightest craft possible with rotors big enough for 3m height to be well withing good ground effect. These craft are more hovercrafts than helicopters. I’m not saying it’s not cool and I’m definitely not saying it’s easy (jaw-dropping engineering, as odd as they are), but a helicopter is not one that uses ground effect as primary basis of it’s flight.
The problem then would be “how can we make a human output more power”, not “how do we make a more efficient aircraft”. The thrust produced by a “push air out the back” type system – /any/ of them – is the mass flow rate out the back times the exit velocity, but the power required to do it is 1/2 of the mass flow rate times the /square/ of the velocity. To get more efficient you /must/ interact with a larger cross-section of air (or change the density of the working fluid). To produce the 686N of upward thrust to lift just a 70kg human within the ~2kW power output of an elite sprint cyclist you need to eject at at least 115kg of air downwards at less than about 6m/s; given that the density of the air involved is essentially constant at 1.225kg/m^3, that means that the area of the air the vehicle is accelerating must be at least 15.5m^2, which means an absolute lower bound of a 4.5m prop to lift just the human.
On the other hand, making the height it has to hover at scale with the vehicle size would make sense.
Thought the same thing. Would have liked to see actual flying instead of exploiting ground effect.
Just how far has human-powered flight come since 1979? I guess there have been many advances in engineering and material sciences since then, but looking at some clips from Icarus Cup 2012 leaves me wondering if any of the entries would be ready to cross the English channel.
@Markus
@Personguydude
Nobody uses transmissions, hence why they have to use big distribution..
A dual-vertical 8 foot prop with a simple transmission can out perform these designs economically and physically using less work..
Also, the mid 20th century is only verified human flight, fully working and stable designs go back to at least 18th century. For instance the winner of this, shown in the video, is identical to a century’s old dutch inventors design..