First Human-Powered Ornithopter

spasm writes "A University of Toronto engineering graduate student has made and successfully flown a human-powered flapping-wing aircraft. From the article: 'Todd Reichert, a PhD candidate at the university's Institute of Aerospace Studies, piloted the wing-flapping aircraft, sustaining both altitude and airspeed for 19.3 seconds and covering a distance of 145 metres at an average speed of 25.6 kilometres per hour.'"

Comments

Awesome stuff, but it doesn't take off like a bird

[vivin]

The article doesn't make it clear that the aircraft still needs to be pulled for it to glide into the air (you can see this in the attached video). I was under the impression that it took off like a bird. The "flapping" of the wings is really cool to see though, once the craft gets airborne.

Either way, really neat.

Re:Why Still Pursuing This?

[GraZZ]

Speaking as this guy's former roommate, one of the draws for him was that the aerodynamics and mechanics of flapping wing flight was not fully understood.

The science here is understanding aerodynamics to the point that a human-scaled device can be built.

Not the first, by any means

[MobyDisk]

This is not even close to the first human powered ornithopter. One of the most significant recent attempts is Yves Rousseau who crashed and became a paraplegic as a result of one of his flights.

The Internet: magical fact verifying machine

[spun]

Do you remember when, back in the day, you could write or say anything about anything, no matter how uninformed you were, and if you communicated authoritatively enough, your audience would just eat it up with a spoon and not question you? Yeah, we have the Internet now.

http://en.wikipedia.org/wiki/Human-powered_transport

In the 1989 Race Across America, one team (Team Strawberry) [1] used an experimental device that consisted of a rear wheel hub, a sensor and a handlebar mounted processor. The device measured each cyclist's power output in watts. In lab experiments an average "in-shape" cyclist can produce about 3 watts/kg for more than an hour (e.g., around 200 watts for a 70 kg rider), with top amateurs producing 5 watts/kg and elite athletes achieving 6 watts/kg for similar lengths of time. Elite track sprint cyclists are able to attain an instantaneous maximum output of around 2,000 watts, or in excess of 25 watts/kg; elite road cyclists may produce 1,600 to 1,700 watts as an instantaneous maximum in their burst to the finish line at the end of a five-hour long road race.

Yes, the flapping is keeping it in the air

[Just_Say_Duhhh]

I looked at all the videos available for the flight. It is obvious that the flapping is maintaining flight - if he just started gliding at the release point, there is no way the flight would have been as long. This is probably the best view, and it also lets you hear what this thing sounds like when it flaps.

Re:Just in time...

[hitmark]

Iirc, the transport of harvesters where done by carry-all's.

Re:Awesome stuff, but it doesn't take off like a b

[hitmark]

consider that most birds do give themselves a first start with their legs rather then wings. Hell, the swan basically runs like crazy before getting of the ground. And iirc, the wright brothers flier was pulled along a rail using a weight and pulley system to get enough speed. But once up to speed, the motorcycle engine was enough to keep it up there unless the pilot did something crazy.

Re:Why Still Pursuing This?

[ebuck]

Dude, stop propagating an urban legend originated in 1934. Nobody said that bees can't fly, they said that an airplane wing traveling at the speed of a bee can't fly. Airplane wings needed more laminar air flow to generate lift according to Bernoulli's principle, and that means more forward speed to generate the minimal air flow than a bee displays in it's forward flight.

Then the anti-science crowd then created a misinterpretation of this famous statement to read that "according to Science, bees can't fly" so it must be "God's work." Later it was softened to "According to science, bees can't fly so we don't know everything."

It doesn't take a lot of insight to imagine how flapping a wing can sustain slower air speeds than a fixed wing aircraft could sustain. But the original findings have been so misused, that using the quote is paramount to spreading anti-Science propaganda.

Re:Awesome stuff, but it doesn't take off like a b

[gringer]

You can open the login link in a new tab (or window, if that gets your fancy). Then when you preview/submit, you'll be logged in.

Re:Why Still Pursuing This?

[IndustrialComplex]

Bees would violate the laws of aerodynamics for fixed wing airplanes. Fortunately for them they operate more like a helicopter and get more sufficient lift by beating their wings. Do people still seriously believe this?

Speaking as someone with experience with Helicopters. Designing those damned things is more an art that is reinforced by scientific knowledge. There are a lot of things about rotor aircraft that until recently have been way too complex to model. So in a manner of speaking, we did not know the aerodynamics of bees if you set your definition of know to be an exhaustive knowledge of the physics.

A rotor spinning in place you could model, but add in any bit of wind current and motion and it became an aerodynamic mess.

Re:Awesome stuff, but it doesn't take off like a b

[getmerexkramer]

Nah, olympic level cyclists can generate up to 2000 watts for brief periods and elite level road cyclists over 400 watts for periods up to an hour.

Re:Awesome stuff, but it doesn't take off like a b

[Falconhell]

I do actually hop im a glider and use various forms of lift to maintain flight.

Famous glider pilot and designer Paul McReady
desigend the aircraft below.

http://en.wikipedia.org/wiki/Gossamer_Albatross

This was the most sucessful attempt at a human powered aircraft. It required 400w to maintain level flight. Powered by pdeals and a propellor,
it would be significantly more efficient than a wing flapping system, which produces large vorticies.

It was very fragile to acheive its 100KG auw and an encounter with even mild turbulance would have destroyed it.

Re:Awesome stuff, but it doesn't take off like a b

[Falconhell]

http://en.wikipedia.org/wiki/Human_power

tells the story nicely.

Re:Why Still Pursuing This?

[evilviper]

Just because you repeat it many times does not make it true.

Neither will denying facts make them false. You can blindly deny our incomplete knowledge all you want, but it makes you look like the idiot...

but to imply that there was some fundamental error or shortcoming in the understanding of flight over the past 60 years does not do justice to the way that modern science and technological understanding develop.

Okay, how's this:

"the performance of insect wings, when tested under steady conditions in wind tunnels, is too low to account for the forces required to sustain flight"

It is only in the past few years that the fact that "flapping wings generate additional forces during stroke reversals." was determined as a solution to the problem.

"the source of extra lift remains unknown." ... "An intense leading-edge vortex was found on the down-stroke, of sufficient strength to explain the high-lift forces. The vortex is created by dynamic stall, and not by the rotational lift mechanisms that have been postulated for insect flight"

When did the "hindsight" issue crop up? Only after the full 60 years or maybe it was after 2 hours with a paper and pencil back in the 1950s when someone said "hey, bees fly pretty slow compared to our jets - what's up with that?"

It's easy to recognize that something doesn't add-up. That's worlds away from having a plausibly-complete understanding of exactly how it DOES in fact work. Einstein certainly knew where General Relativity broke down, but he wasn't able to come up with a solution for it, and he had well more than "2 hours with a paper and pencil".

I see now it's not in-fact hindsight in your case, but unadulterated ignorance, which just happens to be pro-(omnipotent)-scientists rather than the more common opposite. I suppose you'd have been claiming we had a complete understanding of insect flight 15+ years ago, when there were many fundamental blanks in the equations. I'm sorry I wasted my time.

If you or anyone else are interested in the topic and would like to edify themselves rather than blindly tear-down others, here are a couple jumping-off points:

http://www.nature.com/nature/journal/v384/n6610/abs/384626a0.html

http://www.pnas.org/content/102/50/18213.full

http://www.eurekalert.org/pub_releases/2008-03/uosc-lev030108.php

http://discovermagazine.com/2000/apr/featphysics

http://www.sciencemag.org/cgi/content/abstract/306/5703/1960