Looking at the pedalling setup, i think they could make it past 1 minute just by positioning the cranks for more efficient engagement of large muscle groups, especially the hand crank. And adding toe clips. And did the pilot load up properly on caffeine first? Cuz that was just so close it hurts.
25th June, 2012 @ 9:22 a.m. (California Time)
I may have my science wrong, but with a given blade shape, it is the speed of the air over the blades that provides more lift/thrust. so the faster you can get the air moving the greater the thrust. That being the case, why couldn't you have the pedal gears linked to smaller gear ratio, so when it gets to the blades(which could be a lot smaller and closer), with a gear-size step-down, they would be spinning significantly faster, generating more air flow. Additionally, if it was shunted through cone nozzles, it would concentrate the thrust even more. Have a few of these, perhaps 6 for lift and direction control, a gyro for stability, this would create a stable platform, easier to maneuver, much lighter, etc...
25th June, 2012 @ 9:59 a.m. (California Time)
Though I respect the effort, I think that the engineering students should be going over to the closest college with a good wrestling program and finding the lightest, strongest monkey they can. Tell him the bet is a six pack and keep $249,995 for themselves...
25th June, 2012 @ 11:14 a.m. (California Time)
The helicopter is powered by a single person pedaling with hands and feet, but still requires "spotters" to keep it under control for the duration of the 40 second flight. This video sums it up nicely http://su.pr/2mxQmM
25th June, 2012 @ 12:34 p.m. (California Time)
With any human powered flying machine, you look first for efficiency, not simply greater thrust. A large propeller rotating slowly is more efficient than the a small propellor rotating rapidly.
Secondly, it appears that the blades are mounted low to the ground so that they can operate in ground effect, where more thrust will be produced than at the same RPM but higher altitude (say 6 meters). It looks like being a long hard road from the altitudes so far achieved (0.3M?) to 6 M or more.
25th June, 2012 @ 7:38 p.m. (California Time)
That's not flight. It didn't even leave ground-effect. Also, the pedal setup is pathetic.
26th June, 2012 @ 3:48 a.m. (California Time)
Lots of room for improvement here. These kids obviously knows nothing about cycling. And that's a big part of this project. The pedaling position is EXTREMELY INEFFICIENT. It's like those slow bikes old people ride. Recumbments. Also, these are college geeks so they have no fitness as to speak of. Get a cyclist from the college team to hammer this thing (dunno if the rules allows for this). Otherwise just get someone to train semi-seriously for 6 weeks. And also use clipless pedals for goodness sake (you can pull and push on the pedals that way). They'll break through the 1 minute barrier like nothing.
26th June, 2012 @ 7:23 a.m. (California Time)
Fantastic and inspiring guys, keep up the great work!
26th June, 2012 @ 10:10 a.m. (California Time)
Calling this ground effect machine a helicopter is stretching it quite a bit. It'd have to go 3x's the rotor dia in height and still ground effct would be 20% of lift or so. Here 90% of lift comes from GE.
26th June, 2012 @ 10:12 a.m. (California Time)
looks like it needs the ground effect big time to work.
26th June, 2012 @ 10:22 a.m. (California Time)
Why not develop a "flywheel device" (pedal powered, of course) to gather the inertia for original lift off? Then, use the pedals to maintain the flight.
26th June, 2012 @ 11:32 a.m. (California Time)
I have to agree that the efficiency of the peddling position is very poor and using a trained cyclist would certainly be a improvement, however I have to think that a geared rowing motion would recruit more muscle mass. I don't know if the rules allow it but a flywheel would also prove useful!
26th June, 2012 @ 11:34 a.m. (California Time)
I agree with several posts here...the pedal layout is horrible. Having to lift his arms above his head for the hand pedals will make the blood drain out of the strong muscles. The seat needs more support so he can "put his back into it". And I highly agree with that fly-wheel idea. The pedals should input power into a flywheel setup and should not directly drive the propellers.
And that Ground Effect thing is also true. Those propellers need to be off the ground for any real lift!
College students indeed...anybody with common sense can tell you that this thing will only get off the ground with brute force!
26th June, 2012 @ 2:56 p.m. (California Time)
Recumbent bicycle positions actually provide higher efficiency than standard bike setups. recumbent positions allow the cyclist to press against the seat, rather than relying on their own weight to force the pedals down.
26th June, 2012 @ 4:10 p.m. (California Time)
"Why not develop a "flywheel device" (pedal powered, of course" I had similar idea, but with a twist. between the flywheel and the drive gears, add a band spring(like what is found in a large clock) wound by peddling. it would even out the thrust from the "pilot" and store power against flagging muscle power at the end, when the peddler is most tired. Add a stop or locking pin, to be released when the spring is fully charged.
Also, reduce the length of the arms and time the blades to intermix. this will reduce overall weight. Reverse the rotation of some blades as needed to intermix. At least a third of the weight of the arms could be removed this way. JMHO.
26th June, 2012 @ 4:13 p.m. (California Time)
Practical use is limited, but an excellent learning platform. The pilots pedaling position is obviously wack.
Bruce H. Anderson
26th June, 2012 @ 4:40 p.m. (California Time)
Practical use is $250,000 prize.
26th June, 2012 @ 6:34 p.m. (California Time)
All these suggestions to incorporate flywheels? Seriously, when 'minimum mass' must be allied to maximum efficiency? The intermeshing idea (or simply grade separation ie height separation) could be employed to reduce size & overall mass.
Agree about having the most efficient pedal 'interface' operated by a competition-grade cyclist.
yinfu99 made comments suggesting features that if implemented would surely add both to mass and to mechanical power-loss through change-in-motion friction. Maybe the cyclist for HIS version would need to be a trained adult chimpanzee with the expected triple-human level strength?
However, it may be possible that well-designed rotor-tip fins could be employed to counter air-pressure bleed from under surface to upper; thereby reducing both rotor size & mass?
The cruciform structure, also, with four separate rotors seems counter to low mass & maximum efficiency? I would opt for a simple cantilevered dual-rotor version; even with four-blade rotors. That should produce near to the same amount of lift though with less structural mass & lesser mechanical losses.
26th June, 2012 @ 9:54 p.m. (California Time)
"The pedaling position is EXTREMELY INEFFICIENT. It's like those slow bikes old people ride. Recumbments."
First, it's "recumbents." Second, yes, they sure are inefficient. That must be why all of the fastest human-powered land vehicles happen to be recumbents.
As for the comments suggesting energy storage devices like flywheels, I'm sure the competition rules prohibit those. Faster rotors would create more drag and require even more power to operate. And the team has almost certainly crunched the numbers and found that the four rotor design is optimal for disc loading, stability and structural efficiency. I'd like to think that they've gotten this close because they've done a little bit more work than the armchair engineers.
26th June, 2012 @ 11:58 p.m. (California Time)
It looked like the engine overheated he should have taken his shirt off before the attempt.
27th June, 2012 @ 1:12 a.m. (California Time)
Ride a regular bike and a recumbent (thx for the spelling correction) and feel for yourself. The issue here is gravity and not aerodynamics.
The reason the fastest human-powered land vehicles happen to be recumbents are because of AERODYNAMICS not because they generate more power. Aerodynamics (as far as forward motion is concerned) is not an issue here. It's about the application of the most power against gravity (you want max power with minimum weight).
In this application you are fighting gravity. Go see how well recumbents do going uphill (when power to weight comes to play and not just absolute power, and wind resistance is not so much an issue). That's why all those 'records' are on FLAT courses. They are not fighting gravity, but wind resistance. Again, go ride a bike and see for yourself.
27th June, 2012 @ 7:12 a.m. (California Time)
Please explain how it is that gravity holding you in contact with the pedals provides for more power than pressing into a cushion with more than your body weight.
27th June, 2012 @ 2:34 p.m. (California Time)
Ride a recumbent? I've owned several of them over the last 20 years, including a Lightning. The question is have YOU ever ridden a recumbent or are you just making unfounded assumptions? David Gordon Wilson, MIT professor emeritus and designer of one of the earliest record-breaking recumbents, knows a lot more than you do, and he has the experimental evidence to prove it. What does the evidence show? That a rider with back pressed against an immovable backrest can put force into the pedals that far exceeds body weight, something anyone who can do 450 pound leg presses can attest to.
And experienced recumbent riders can go up hills just fine, thank you very much.
27th June, 2012 @ 3:33 p.m. (California Time)
Yes, I know more than David Gordon Moore about cycling. I also know more than him about the profession I'm in. Most likely i know more on economics than him, some aspects of history, etc. Burt Rutan also knows more about flying than Mr. Moore does. Does that null and void any argument Burt Rutan makes? I off course could have used the name of a friend who is a pilot but you would not have recognized it. I don't think I'm Burt Rutan or has the knowledge in my field that he has in his field. What kind of a lame argument is that? Go and ask the honored Mr Moore why recumbents only race on flat surfaces. Your argument does not address the aerodynamics vs power to weight issue.
'...can put force into the pedals that far exceeds body weight...' How do you measure that. Is he producing pounds? Because that is what body mass is measured in. Are you saying that a cyclist on a traditional bike cannot produce more power in watts than his body weight in pounds? Pardon my ignorance but I really don't understand what you are trying to say. Any pro cyclist (which on average weighs 145 pounds or less) can routinely produce over 1000 watts of power on sprints and accelerations. In numerical terms he's producing more 'power' (in watts) than his body 'weight' (in pounds.)
So why don't we see a proliferation of cycling races involving recumbents? Again, you ignore the aerodynamics issue. See if a recumbent can set a record in a non time-trial Tour de France stage. I have ridden a recumbent and they are awful. I've never seen or heard of any racer on a recumbent beating a cyclist on a regular bike over a regular road course that involves hills. Recumbents work on aerodynamics and when it comes to going uphill they are useless. There are tons of uphill bike races all over the US. I never see any recumbents entered in those. Do you know why? I'm sure if it's not allowed you could create a recumbent category for these races. But I think I know why we don't see it. Downhill racing would be a different story.
Why don't you strap a powermeter to a cyclist on a recumbent and compare his output to the same cyclist on a traditional upright bike with clipless pedals? A cyclist on a regular bike can pull himself into the bike and one leg pulls while the other one pushes working in opposite directions which is the same effect as pushing against an object like the seatback on the recumbent. Also, a cyclist can stand and generate even more power, which the guy in the recumbent can't do. I would like to see the powerfigures for these tests.
28th June, 2012 @ 9:32 a.m. (California Time)
It's David Gordon Wilson, not Moore. He has written entire, highly respected volumes about the science of bicycling and was president of the International Human Powered Vehicles Association. His Avatar 2000 set records in HPV competitions. What exactly are your accomplishments in the field that let you say you know more than he does? You claim you "would like to see the powerfigures for these tests." Well, they're out there.
Why don't we see races with recumbents? You obviously don't know the history of recumbents. They were banned by the UCI in the 1930s because racers of only fair accomplishments were beating top-tier racers. That's why you don't see any recumbents in competition. FYI, the UCI is the international organization that sets the rules for all cycling competitions, and it's also affiliated with USA Cycling, which controls racing in the US.
You rode a recumbent once? It takes several months for technique and muscle groups to adapt, and you can't make snap judgements based on one ride.
28th June, 2012 @ 8:54 p.m. (California Time)
"All these suggestions to incorporate flywheels? Seriously, when 'minimum mass' must be allied to maximum efficiency? The intermeshing idea (or simply grade separation ie height separation) could be employed to reduce size & overall mass."
Even a lead balloon will fly if it is large enough. Just being the lightest possible, does not mean success. You are dealing with an engine that waxes and wanes, and works in spurts. A flywheel does not have to be very large to even out the output. and with a flywheel, the "pilot" could have enough time to shift drive gears like on a ten-speed bike.
28th June, 2012 @ 9:15 p.m. (California Time)
When a bicyclist stands up to increase power he is putting his full weight on the pedal, and a little more if he has toe clips, but he is limited by haw much torque he can counteract with his grip on the handle bars (It is why they weave back and forth when they do so) The recumbent rider has his back pressed against an "immoveable" object and can therefor put his full strength against the pedal which can be greater than than his weight + lifting strength of his other leg and it does not throw in steering inputs as a side effect.
I live near Denver Colorado and when I see a recumbent going uphill in the mountains they climb the hills just as well or better than the traditional bikes.
29th June, 2012 @ 2:26 a.m. (California Time)
congratulations with this success, keep on trying, the dream will become reality, never doubt.
1st July, 2012 @ 1:37 a.m. (California Time)
U.M. has an athletic department! Obviously underused by the engineering department. If toe clips are not used you're wasting ~30% of possible leg power. Hand Cycle: wheelchair racing anyone?!?!? These students need to go to the athletic dept head and say "We need an athlete that weighs X can produce watts Y for Z time who will also be in the history books". Their might be someone who can do it with just arms OR just legs, ie less weight and mechanical drag. They are on the cusp of success, Good Luck!
1st July, 2012 @ 7:14 p.m. (California Time)
Better than last year....
NO matter, for the Prize they need to be 3m off the ground for 60 seconds...
This craft has no control.... Drifts all over the place, would be dangerous if 3m up in the air.
If it were out of ground effect, there is no way it would be stable problem being that the spotters would be ineffective, and the pilot is to busy pedalling to do any control...
The hand crank are a problem because it is hard to locate them in an efficient way and still allow them to not interfere with the legs....
Better work on Just using leg power, leave the hands for control of the craft (if they ever want to get off the ground.) and if no control mechanism, use the hands on a couple of bar ends to allow force to be concentrated on the pedals.... (arms don't really produce that much useful effort.... better using the arms to focus the leg energy
Of course we are all armchair experts....
One more, to enable the craft to still be in ground effect at 3 m off the ground, the rotors need to be larger... That way less control effort is needed as the rotors are still in an air cushion evening out the lift force....
Say 3 (or 4 if you must) bigger diameter rotors (aerodynamicists optimise that), with shorter booms.... Optimise gear ratios for the cyclist allowing the most useful power to be developed....
Phew, do all of that and you should get at least 1 metre off the ground.... lol.
oh yeh get someone who can cycle... See who they got ride across the english channel in gossamer Albatross
10th July, 2012 @ 5:41 a.m. (California Time)
Watching the video again, it appears this thing already has a flywheel forward and ahead of the pilot. I missed that the first time through.
26th August, 2012 @ 12:31 p.m. (California Time)