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Sraight'nlevel

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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.
The dude who cycled to an island with Daedalus 99 km was using 240 watts average. Normal man pedals at 100-150 watts...for 100 km.

But the dudes who cycle 144 km/h at Battle Mountain use even 2 hp at best ....1500-2000 watts. That is what a man is capable of for few seconds...in cycling world....reaching 71 km/h at best....with an upright bike.
 

henryk

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This definitely creates a design challenge with limited power availability.

BTW=in "Oscillating Wing Propulsion " methode of dr Wolf the WHOLE wing works as a THRUSTER and lift generator !

-in ornithopter (flapping wing) ONLY auter parts of wing are working as thrusters ...
 

Sraight'nlevel

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Where do I find one of these world class bicyclists to power my airplane?

Seems like the fixed costs - room and board, continual training, etc. - could be more than my Lycoming.


BJC
It takes time and concentration to cycle steady 100 km trips at 30 km/h speed. There are plenty of those in every city world wide. I know fellows who cycle 3 600 km in 6 days. When it becomes an hobby it is like a disease...you cycle almost every day. Look at Gunther Rochelt who put his weight to 41 kilos to do two Kremer records....just like Rocky Balboa....just do it !

They ought to make of movie of him.
 

nerobro

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Where do I find one of these world class bicyclists to power my airplane?

Seems like the fixed costs - room and board, continual training, etc. - could be more than my Lycoming.


BJC
This week? France. The tour is there this week and next week IIRC. There's a solid 200 riders, most of which could get within 20% of those numbers.

So I'm seeing lots of numbers here. And, depending on the circumstances, they're all vaguely right. Untrained people? you can figure they'll do 90ish watts continuous. The genetic freaks in the top echelon of the cycling community, can do lots, lots more. Personally, when I was at my best, I was doing something like 140w continuous. (This is not a good number. Just reality.) But I could do 200w for a while, and near a kilowatt for a few moments.
The dude who cycled to an island with Daedalus 99 km was using 240 watts average. Normal man pedals at 100-150 watts...for 100 km.

But the dudes who cycle 144 km/h at Battle Mountain use even 2 hp at best ....1500-2000 watts. That is what a man is capable of for few seconds...in cycling world....reaching 71 km/h at best....with an upright bike.

You need to be real careful working with peak numbers. Track sprinters can top 2000w for a few moments. But only.. moments. That's why I used the 4000m track rider numbers, as opposed to the 330m numbers.

The fact deadalus was 240w average really shows how hard the power output of a human drops off.

My post was mostly so people had "outer bounds" for what one could expect to have available power wise.
 

John.Roo

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Where do I find one of these world class bicyclists to power my airplane?

Seems like the fixed costs - room and board, continual training, etc. - could be more than my Lycoming.


BJC

Absolutelly :D World class bicyclist will be very expensive.
I would recommend to install 300-500 W pedelec. It is not so heavy and every 100 W of extra power will help a lot ;)

Motor installation will need arround 5 kg + battery (weight depend on how long you want to fly).
Simple, safe and well tested technology ;)
 

Sraight'nlevel

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=Vladimir Toporov (not athlet !) was achived allmost take off speed (50 km/h)
jn his 12m AZAZEL1 ornithopter...

He was started do construct 20 m span wings,but health problems stopped them !

20 m AZAZEL2 should be selflauntching.


I can understand the health problems....Rochelt died in late 1998...as the Musculair II flew in the summer of the same year.

rochelt.jpg

Just in cycling everything has to be perfect to cycle 60 km...at even 25 km/h. Just a small problem in the ball bearings or alignment makes everything hell.
 

ARP

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This years Icarus Cup HPA competition will be held at Lasham airfield from 23rd July to 31st July. I am looking for volunteers to help marshal the event so if your interest is in HPA's and you want to get close to the action please contact me.
 

Dana

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Just for perspective, a thought experiment:

Assume a 170# “FAA standard” pilot and a magical 30# aircraft, or a 200# pilot and even more magical zero weight aircraft, either way, 200# gross weight. Then assume a 20 mph (30fps) airspeed, about what a paraglider does and probably the lower limit for safe handling in anything but dead calm conditions. Finally, assume a high end sailplane L/D ratio of 50:1, which means slick composites which weigh a lot more than zero or even 30 lbs, but hey, it’s a thought experiment:

So, with a 200# weight and 50:1 L/D, that’s 4# of drag which means 4# thrust, 120lb-ft/s or 0.22HP or 163W, just to maintain level flight. If you want an abysmal 50fpm climb, that requires an additional 0.3HP or 226W, so now you’re up to over 1/2HP.

And, that’s assuming 100% efficiency in the drivetrain and propeller, also not realistic.

So, the point of all this is that while it’s certainly possible to build a HPA that will fly, and even meet some narrowly defined task, it can never be practical even for any kind of sport flying.

Unless you consider a foot launched hang- or paraglider to be a HPA, but only if you carry it and hike to the mountain top, no driving allowed.
 

Sraight'nlevel

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Just for perspective, a thought experiment:

Assume a 170# “FAA standard” pilot and a magical 30# aircraft, or a 200# pilot and even more magical zero weight aircraft, either way, 200# gross weight. Then assume a 20 mph (30fps) airspeed, about what a paraglider does and probably the lower limit for safe handling in anything but dead calm conditions. Finally, assume a high end sailplane L/D ratio of 50:1, which means slick composites which weigh a lot more than zero or even 30 lbs, but hey, it’s a thought experiment:

So, with a 200# weight and 50:1 L/D, that’s 4# of drag which means 4# thrust, 120lb-ft/s or 0.22HP or 163W, just to maintain level flight. If you want an abysmal 50fpm climb, that requires an additional 0.3HP or 226W, so now you’re up to over 1/2HP.

And, that’s assuming 100% efficiency in the drivetrain and propeller, also not realistic.

So, the point of all this is that while it’s certainly possible to build a HPA that will fly, and even meet some narrowly defined task, it can never be practical even for any kind of sport flying.

Unless you consider a foot launched hang- or paraglider to be a HPA, but only if you carry it and hike to the mountain top, no driving allowed.
Right, but if you add a bit of solar panels...and use the pedals to add capacity to the system...we might be getting somewhere.
 

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.
Sailplanes do 70 L/D today.

Let's assume 65 for the L/D...weight 30 kg...man 245 lbs ( 110 kg )

We have a man/pilot that can pedal at 200 watts constant.

This yields 44,3 km/h speed...thus enabling the "supaman" to win the trophy ( Kremer Marathon ).
 

Dana

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But you're not going to achieve 70 L/D (or 65 or even 50) in a structure light enough to work for HPA.
 

John.Roo

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Sailplanes do 70 L/D today.

Let's assume 65 for the L/D...weight 30 kg...man 245 lbs ( 110 kg )

We have a man/pilot that can pedal at 200 watts constant.

This yields 44,3 km/h speed...thus enabling the "supaman" to win the trophy ( Kremer Marathon ).
Forget super high L/D ;)
Concentrate on as low as possible weight (= simple construction) and minimum sink rate.
High end gliders are achieving best L/D on speeds you can never reach with human powered airplane ;)

P.S.
200 W constant? Try 100 W for 10 minutes.... :cool:
Or try first "takeoff power" for 30-60 sec and than measure how long you keep 100 W....
 
Last edited:

jedi

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Sahuarita Arizona, Renton Washington, USA
Just for perspective, a thought experiment:

Assume a 170# “FAA standard” pilot and a magical 30# aircraft, or a 200# pilot and even more magical zero weight aircraft, either way, 200# gross weight. Then assume a 20 mph (30fps) airspeed, about what a paraglider does and probably the lower limit for safe handling in anything but dead calm conditions. Finally, assume a high end sailplane L/D ratio of 50:1, which means slick composites which weigh a lot more than zero or even 30 lbs, but hey, it’s a thought experiment:

So, with a 200# weight and 50:1 L/D, that’s 4# of drag which means 4# thrust, 120lb-ft/s or 0.22HP or 163W, just to maintain level flight. If you want an abysmal 50fpm climb, that requires an additional 0.3HP or 226W, so now you’re up to over 1/2HP.

And, that’s assuming 100% efficiency in the drivetrain and propeller, also not realistic.

So, the point of all this is that while it’s certainly possible to build a HPA that will fly, and even meet some narrowly defined task, it can never be practical even for any kind of sport flying.

Unless you consider a foot launched hang- or paraglider to be a HPA, but only if you carry it and hike to the mountain top, no driving allowed.
Now run those numbers on the moon in a pressurized sports stadium and you can see why returning to the moon is a high priority and where the funding will come from.
 

Sraight'nlevel

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Messages
386
Forget super high L/D ;)
Concentrate on as low as possible weight (= simple construction) and minimum sink rate.
High end gliders are achieving best L/D on speeds you can never reach with human powered airplane ;)

P.S.
200 W constant? Try 100 W for 10 minutes.... :cool:
Or try first "takeoff power" for 30-60 sec and than measure how long you keep 100 W....
That makes a lot of sense.

Kenellopoulos pedalled nearly 4 hours using 240 watts.

 
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