US Hawks Hang Gliding Association

My son Matt sent me this link to the inflated HG. Pretty neat!

https://www.youtube.com/watch?v=dYlZ2GG ... gs=pl%2Cwn

In the first video i was surprised at how quickly it got off a shallow hill. Especially since it appears to have a nearly symmetrical airfoil which is not a high lift shape. However, the symmetrical airfoil would explain pitch stability with out needing reflex (constant center of lift).

In another 2nd video that followed the 1st, when I watched it, someone is soaring it quite effectively and making good turns. I can't figure out how they are turning it because it shouldn't be very good at weight shift roll control but the short span is helping that. Maybe the airfoil flattens out some on the side that the weight goes to and expands on the lighter side. In that case the inflated foil would be acting like sail billow shift in a flex wing glider. Unfortunately, that 2nd video doesn't always show up after the 1st one, so you may have to search for it. But the soaring flight is quite impressive!

Interesting the rectangular control bar instead of a triangle. Probably has to do with how it had to be attached to a wing without a keel tube.

I wonder what they are doing about pressure changes with altitude and temperature?

JoeF, here's your bussable hang glider!

Frank

Here you go from June 18th of 2012:

    http://ushawks.org/forum/viewtopic.php?f=2&t=1047&start=8

and here from July 07th of 2012:

    http://ushawks.org/forum/viewtopic.php?f=22&t=1087

It's hard to find anything Joe Faust doesn't know about portable wings.   

Frank Colver wrote:I wonder what they are doing about pressure changes with altitude and temperature?
Frank

Frank,

The Woopy-Fly is not a sealed inflatable (like a swimming-pool raft). There are two ram-air scoops under the wing that keep it inflated in flight, behind the control bar to each side. There is a small battery-powered fan in each scoop, to inflate the wings before flight. I don't know if the fans run constantly during the flight, or not.

It is definitely a backpack unit, though, even with an engine. It's almost a cross between a HG and a PG ( . . . did I say that? ).

Ha, I spotted those ram tubes and wondered if that was what they were.

This is interesting because I have given some thought to an inflatable hang glider (even talked with Alpacka Raft about building one) and assumed that I would have to have a fan running all the time to keep a constant pressure. From what you say, it looks like that works & with help from ram air.

In views from underneath the wing I noticed a dark shadow line inside the wing right about where a cross spar would be. I wonder if there is a rigid spar inside. I think there would have to be one there because the air chambers run chordwise so where would spanwise strength and stiffness come from without a rigid spar?

My son had his computer translate the Japanese which is pretty garbled. But one statement was that it was "almost a hang glider". I think they are thinking it's a cross between PG & HG also.

Frank

Frank Colver wrote:I wonder if there is a rigid spar inside. I think there would have to be ...

This video might help:

Related to topic:

https://www.pilotmix.com/woopy-fly

So, that shadow I saw was a rigid spar.

The spar construction gave me an idea for my HG Basic Trainer. Since it is in compression I could narrow it down out near the tip. Ideal would be a tube tapering constantly from center to tip, but forget that!

BTW - Notice the Whoopi Fly is flown in the mode of seated pilot.

It would be fun to have one of these (unpowered of course) at Dockweiler.

Frank