Human Powered Flight

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Kyle Boatright

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I realize the Kremer prize was awarded 45 years ago, but is anyone currently pursuing human powered aircraft? Are there structural applications where carbon fiber could result in significant weight savings over the Aluminum tube/foam/mylar aircraft MacCready designed and built? I'm still fascinated by the topic, even though I realize it has no practical application.

Which reminds me of the Klein-Fogleman airfoil.

As I remember, both subjects (human powered flight and the Klein Fogleman airfoil) were topics in the 3 minute science blurbs sprinkled into Saturday morning cartoons when I was a kid.
 

BBerson

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McCready moved to carbon fiber tubes on the advanced Albatross that crossed the English Channel.
There was many Kremer prizes, might still be one out there.
The most advanced flight was 72 miles from Santorini to Crete by MIT Daedalus team. Read about that in the book: The Fullness of Wings by Gary Dorsey.
 

Stephen Asman

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As I recall, the Gossamer Albatross MacReady's second plane, designed to fly across the English Channel, used a carbon fiber wing spar and was 20 lbs lighter (50 lbs vs 70).
 

b7gwap

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It’s a fascinating subject. A testament to human ingenuity. It also humbles me to remember just how little power even our strongest muscles produce in comparison to internal combustion and electric motors. I think of a Hirth F33 as a minimum power plant, but it’s got something like 50 times or more power than my legs, let alone a cycling athlete’s.
 

jvliet

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How about the "Japan International Birdman Rally" held each year above lake Biwa in Japan ? Contest for HPA teams, HPA take off from a ramp on the lake shore and are scored on how far they fly before they dunk into the water. In recent years several HPA have made it all the way across the lake (approx. 32 miles) 鳥人間コンテスト|読売テレビ
 

jedi

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Chimps are much stronger than humans. How bout a chimp powered aircraft?

When I was in high school in the 60's. Humans were the only intelligent animals. Now, thanks to the internet I see they can go to McDonalds and order a cheeseburger. I bet we could teach one to fly.

Some do know how to ride a bicycle. Flight would be "One small step for ?? Chimp kind?" With a little effort they could probably even be trained to deliver packages.
 

pictsidhe

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There are two Kremers left. Marathon, 26 miles in under an hour. And sport, 3x500m triangular course, twice in under 7 min total. The really fun bit is the minimum wind speed of 11mph. It also needs to pack in and out of a 26' container.

With
P = thrust power in watts
m = mass in kg
g = metric gravity
L/D = lift to drag ratio
V = speed in m/s (1 m/s = 2.3 mph)

V = (P * L/D) / (mg)

the internet tells me that top athletes can manage 400W for an hour. 100kg may be total weight. We need a pretty good L/D for any kind of speed.
That means a lot of span. McCready pointed out that at low speeds, the drag from wires etc isn't great and allows more span in the very limited weight budget.
 

Sraight'nlevel

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There are two Kremers left. Marathon, 26 miles in under an hour. And sport, 3x500m triangular course, twice in under 7 min total. The really fun bit is the minimum wind speed of 11mph. It also needs to pack in and out of a 26' container.

With
P = thrust power in watts
m = mass in kg
g = metric gravity
L/D = lift to drag ratio
V = speed in m/s (1 m/s = 2.3 mph)

V = (P * L/D) / (mg)

the internet tells me that top athletes can manage 400W for an hour. 100kg may be total weight. We need a pretty good L/D for any kind of speed.
That means a lot of span. McCready pointed out that at low speeds, the drag from wires etc isn't great and allows more span in the very limited weight budget.
I wonder if the last word has been said in the subject...or will there ever be a day when those are everyday travel means ?
 

Dana

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I wonder if the last word has been said in the subject...or will there ever be a day when those are everyday travel means ?
No, because no matter how good materials get, the laws of physics and aerodynamics don't change. Even if you had zero structural weight the amount of power necessary to fly a human in any practical conditions for any practical length of time is beyond what that human can put out.
 

Sraight'nlevel

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No, because no matter how good materials get, the laws of physics and aerodynamics don't change. Even if you had zero structural weight the amount of power necessary to fly a human in any practical conditions for any practical length of time is beyond what that human can put out.
Are you saying the last two Kremer prizes will never be presented to anyone ?
 

nerobro

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There are two Kremers left. Marathon, 26 miles in under an hour. And sport, 3x500m triangular course, twice in under 7 min total. The really fun bit is the minimum wind speed of 11mph. It also needs to pack in and out of a 26' container.

the internet tells me that top athletes can manage 400W for an hour. 100kg may be total weight. We need a pretty good L/D for any kind of speed.
That means a lot of span. McCready pointed out that at low speeds, the drag from wires etc isn't great and allows more span in the very limited weight budget.


So.. the hour record on a bicycle is 58km. Which is 34.9 miles. That.. kind of gives us a budget. That's roughly 650 watts. Given we need to go 26mph... that's 306 watts. So we have something like 340watts to fly on. Mind that's a ~World class athlete~.

3km in 7 minutes? Given we need to take corners that's probally closer to 4km... That just means going 21mph. And for 7 minutes... there are people who can do.

The 4000m record for track bikes is 37mph. Or about 800 watts. I think the closed course record is definitely do-able. The marathon might need some.. silly tricks. You'd have nearly 600w to fly on, and assuming your Cd is the same as a bicycle.
 

Sraight'nlevel

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So.. the hour record on a bicycle is 58km. Which is 34.9 miles. That.. kind of gives us a budget. That's roughly 650 watts. Given we need to go 26mph... that's 306 watts. So we have something like 340watts to fly on. Mind that's a ~World class athlete~.

3km in 7 minutes? Given we need to take corners that's probally closer to 4km... That just means going 21mph. And for 7 minutes... there are people who can do.

The 4000m record for track bikes is 37mph. Or about 800 watts. I think the closed course record is definitely do-able. The marathon might need some.. silly tricks. You'd have nearly 600w to fly on, and assuming your Cd is the same as a bicycle.
I counted that yesterday..it needs only 300-400 watt constant.....depending of the weight of the pilot. L/D 35ish.

Rochelt had his weight reduced to 41 kg for the record.

---

I figure the L/D to 40 is the easiest to do.
 
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goney3

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I read a human powered vehicles book once, it said that some study pegged the available power at 100 watt constant. I'll have to go through my library when I get home and see what the title of it was. This definitely creates a design challenge with limited power availability.
 
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