BirdGlider

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Aerowerx

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I just ran across this.

Excellent well drawn plans. One of the best I have seen. And free!

A foot-launch tube-and-fabric glider. Made mostly of round tubing bolted together.I thought it would be of interest, considering the recent activity concerning the A-plane, airbikes, Ranger, etc.

What is with the controls? It appears to be a 3-axis control system, but there are 2 joysticks. That would work but might cause some transition training problems for those who learned with a conventional stick or yoke.

Possible electric self launch, maybe?
 

bmcj

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What is with the controls? It appears to be a 3-axis control system, but there are 2 joysticks. That would work but might cause some transition training problems for those who learned with a conventional stick or yoke.
Look at page 283. The right control stick controls both the elevator and ailerons. The left stick only moves fore and aft, so I’m guessing that it might be:

1. Tow release
2. Trap door for foot launch
3. Spoilers (as if this plane would need them), or
4. Flaps.

I’m going with flaps since the each wing’s trailing edge control surfaces appear to be split into two different sets (I.e. - aileron and flaps).
 

Aerowerx

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bmcj, I haven't gone through the drawings in detail. Probably it is tow release.

By the way, this was built by the same guy that has "nest of dragons" website. According to the FAQ, it was designed by some aeroengineers after he told them what he wanted. So the structure should be sound for what it is. He claims it is designed as an alternative to a hang glider.

Website here.

Still, I have the question. Why can't a similar design be done with rivets instead of bolts?
 

Aerowerx

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Just took a look at the website. The Birdglider appears to have flaps, so that is what the extra joystick is for.
 

radfordc

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Still, I have the question. Why can't a similar design be done with rivets instead of bolts?
I think it could! This design seems inordinately "busy" with tons of small parts, fittings, etc. I'll bet there are more parts in just the front half of the fuselage than in my entire Eindecker. Using riveted gussets should be more than strong enough and greatly simplify things.
 

bmcj

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I think it could! This design seems inordinately "busy" with tons of small parts, fittings, etc. I'll bet there are more parts in just the front half of the fuselage than in my entire Eindecker. Using riveted gussets should be more than strong enough and greatly simplify things.
I agree.

I say ditch the whole control system and go with a series of pull ropes terminating with a ball handle in the dash panel. Label each pull rope appropriately... up elevator, down elevator, right aileron, left aileron, flaps up, flaps down, left rudder, right rudder, and (last, but not least) cabin vent open. :p
 

12notes

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Just took a look at the website. The Birdglider appears to have flaps, so that is what the extra joystick is for.
It's way more confusing than that. Page 287 of the plans is titled "BirdGlider Control Lines Rudder handle", but it also has rudder pedals, the control lines from the rudder stick go to top and bottom of the left rudder pedal, the control lines to the rudder to to the top of each pedal. Other than a concession for someone who lacks the use of their legs, I do not know why the rudder stick exists.

The flap handle is a pull down handle located on the top tube (page 285).

There's way too much .090" 4130 with odd bend angles like 40.9 and 155.59 degrees, or 12.2 degrees right next to a 90 degree bend, There's at least one .090" 4130 U-bracket less than 1" wide. There's some really difficult to manufacture nylon quarter mood shapes with a precision angle notch in the back, and also some U-brackets made from .125" 6061-T6 with hard right angles, no bend radius.

It is an untested design, and even the designer gave up on their build. I don't blame them.
 

FritzW

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also some U-brackets made from .125" 6061-T6 with hard right angles, no bend radius.
I think those were meant to be cut out of an extrution like a piece of "U" channel.

>>>

It's a neat glider but it sure looks like it was designed by a guy who never had to cut, file, bend and drill a million little fittings.
 

bmcj

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It's way more confusing than that. Page 287 of the plans is titled "BirdGlider Control Lines Rudder handle", but it also has rudder pedals, the control lines from the rudder stick go to top and bottom of the left rudder pedal, the control lines to the rudder to to the top of each pedal. Other than a concession for someone who lacks the use of their legs, I do not know why the rudder stick exists.
Yep, you appear to be correct. I’m not sure why a rudder stick would be presented in the primary plans instead of as a separate modification option.
 

Sockmonkey

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There are people here who haven't explored nestofdragons?
That's where I learned about how fleas and other tandem wing designs work.
 

proppastie

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lots of work in those drawings and the web-site.....but I did not find a record of any flying.
 

FritzW

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It is hard to keep your feet on the rudder pedals when foot launching.
If everything is trimmed up, it might not matter for the 1 or 2 seconds it takes to get your feet on the pedals.

EDIT: foot launching doesn't bother me, I'm just glad it's not foot landed ;)
 
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FritzW

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I just scrolled through the endless pages of the plans again. I'm starting to think that the number of parts isn't the problem, it's the number of drawings. I realize that he had to fit a lot of stuff on to 8 1/2 x 11 sheets but it's way over drawn. ...IMHO

Some of the parts are off the shelf ultralight parts, some of them could, maybe, be 3D printed and the rest could be cnc'd pretty easily.

Page 3 of the plans warns about putting a motor on it but I think it could be a good candidate for a small electric self launch setup.
 
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