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99lb/45kg primary glider

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Victor Bravo

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106lbs, with 200lb max pilot weight.
She didn't even have pulltruded carbon strips to play with back then. Or SolidWorks, or FEA, or lightweight Spectra fibers instead of steel rigging cable. You should be able to do a little better than she did, but it's pretty darn tough to out-engineer a German glider designer :)
 

Hephaestus

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She didn't even have pulltruded carbon strips to play with back then. Or SolidWorks, or FEA, or lightweight Spectra fibers instead of steel rigging cable. You should be able to do a little better than she did, but it's pretty darn tough to out-engineer a German glider designer :)
Kind of what boggles my mind with the comments of its not possible. :) That was designed and built almost 50yrs ago, now it's inconceivable.
 

Victor Bravo

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Frau Hanle transcends time... :)

The more I think about it, the more I think the Hippie could be built at 99 pounds:

Lighter covering materials now available (Oratex)
Wound carbon tubes available for wing struts, fuselage truss, control rods
Carbon spar caps available
Spectra or Kevlar now available for "flying wires" and rigging
Light plastic BMX and bike wheels now available
 

Hephaestus

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glider.jpg

I do like the tailboom on this one (found on an old HBA thread) - might leave an option later for a bit of sustainer/self launch capacity for someone else.

The Wortman fx 2 was a bit of a surprise. Very much not what I was expecting. 20% with a Cl of 1.25 or so at these RN?
 

tdfsks

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Yeah the Hippie is a good example.

Also consider the Volmer VJ-24 Sunfun. Not exactly what is going asked for because of the lack of a seat and the need to reconfigure the landing gear, but it was 110 lb empty and provides a yardstick to confirm that the requirement could be met with careful design.

Remember here that this glider could be designed for load factors less than a normal glider because it is not going to fly much out of ground effect and will not be subject any significant maneuvering or gust loads. So the structure could be lighter compared to the examples being put forward.

1594333267654.png
 

tdfsks

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Last edited:

tdfsks

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also BRO-23 (not sure of exact weight but clearly fairly light):

** Edit: If Wikipedia can be believed the empty weight is 184 lb .... **
Oškinis BRO-23KR Garnys - Wikipedia
So about twice was the OP was looking for ....

1594334787358.png

1594334835674.png
 
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Hephaestus

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Sat down with that Greek glider pdf's 3 pages on the hippie.

"It's main spar was just a web without spar caps. It seemed to be a stressed skin design. The problem was that the skin was not continuous"

Others have mentioned it's a carbon or graphite spar.

And Plywood aft ribs.

It's not striking me as particularly high tech.
 

erkki67

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A Plank design is a perfect way to eliminate weight, if built accordingly.

Miss Hänle did an outstanding design, for standard 3-axis layout with a front wing and a tailvolume, exactly my cup of tea.

But let’s think about the plank, with a similar idea in mind, but built with cheap available materials, like wood, plywood and styrofoam, and why not tubing.B801ADB1-A17B-45F0-99D9-308EB4FAF3A2.jpeg
I like this design, but it could be simplified with a plank designed wing, the fuselage could be built like this tubing layout, or like a wooden box like the Whing Ding, Aéro-Max, Marsk Monarch and others similar ones.

1903BFE7-7099-4E69-96AB-A17526077C06.jpeg

Even a Tractor layout could be imagined, for those who rather fly with their own thermals instead of the natural ones.
 

BBerson

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McCready's Solar Challenger construction was very light, yet able to handle high altitude operations and flight loads.
 

Hephaestus

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McCready's Solar Challenger construction was very light, yet able to handle high altitude operations and flight loads.
Had to go look it up again...

Hadn't noticed before the horizontal was upside down ch750 style.

Pretty sure it's possible now after looking, now the devil is in the details. Start seeing what I can do to make it actually workable.
 

erkki67

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Drag is cheap and light to add.
This is from an old 'what if' of mine similar to this thread, but based on US part 103 and patterned after the Monarch formula with a bit of second generation Lak 16 influence. For a data point SW says what you see weighs about 50 pounds - excluding - the wing.
View attachment 99074
What is the wingspan foreseen for this one?
 

nestofdragons

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There is a set of plans, which are for free. Yes, i placed them on the internet. It is a primary glider. 55 kg. Pilots up to 90 kg. Alu construction garage style. BirdGlider.

Before you go see the video, i need to tell you that the crowdfunding was a mistake of me. It gave the project a bad sound. History so far about the project: i paid two persons to build me this glider so it could be testflown (Aldo Sibi from USA and a industrial from Europe (need to check who his name is spelled)). Both did nothing and kept my money. Aldo recieved even all the connection parts of my own build-up to speed up his construction so it would be on Oshkosh the next year. Sad story. It shook my believe in the goodness of mankind. Anyway ... the prototype still hasn't flown. The plans are for free on the internet. I just got word that the link to the full 3D of the glider doesn't work. I need to check on that. It would be a rather low cost glider WITH CAPABILITY TO BE USED BY WHEEL CHAIR USERS.
Why do i not rebuild? Well, i changed my interest into motorised flying wing. The SilverDragon. But at this moment ... i am leaving aviation. No longer single guy. And i need to spend my money on other stuff. Sorry, fly-boys.

The website where you can find the plans is www.birdglider.net
Like i told you already. The 3D link went bad. I need to check that tonight.
Here is a video of a 3D presentation.
 

Hephaestus

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Hope Koen and NOD stays with us.

Trying to decide on wing shape / span / chord / layout.

H-111 was 10m, 9m², AR 11.1 15kg/m²
Goat was 11m, 16.2m², AR 7.2 8.3kg/m²
SG-38 was 9.9m, 16m², AR 6.76, 13.8kg/m²
G1 was 10.5m, 16m², AR 7, 11.5kg/m²

Half thinking out loud, half writing it down here in case sketch pad gets coffee'd again.

145kg MTOW, run the lower end of the wing loadings - 9kg/m², with 16m² of area 18' panels should be innately garage buildable, that results in a 11m span.

Don't suppose there's a roncz for gliders spreadsheet out there?
 

nestofdragons

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I just checked the BirdGlider website and the link to the 3D file should work again. The file can be found in the news section. Plans are also a bit hidden. Just to make sure that people do a effort to find them. I hope to avoid stealers that way. I hope to avoid problems which Mike Sandlin had or Nedo Lavorini. Anyway ... all info should be there.

About me and aviation. I collected data about weird stuff for decades. I just hope that people find me my website informative when they have the same questions i had when i started. If their learning curve goes faster than mine, maybe maybe ...aviation will evolve quicker. At this moment i have fun myself converting motorbike into aerodynamic recumbent motorbike to keep me drive while doing daily commuting and making cosplays costumes myself and metal artwork. So ... i am still creative, but on another level. I will always stay weird. ;)

By the way ... if somebody could get me in touch with Mike Sandlin, i would appreciate it. He might help me (without any cost for himself) to avoid seeing the BirdGlider die in a shelve. It is just too good to be lost due to my own bad choices of partners in building a prototype. This small glider might help to get more people into aviation in a affordable and more safe way. I really really cross my fingers.

By the way (part 2) ... i had tears when i read the reactions. Thanks. I am glad my time in aviation was not for nothing. It is the only world where i might look less a weirdo. :)
 

Hephaestus

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. He might help me (without any cost for himself) to avoid seeing the BirdGlider die in a shelve. It is just too good to be lost due to my own bad choices of partners in building a prototype.
Whatever you do, just please don't let nest of dragons disappear :) a few of us reference it fairly regularly.

There's probably a person or 3 floating around here who might be interested. Worth posting in the designs available for sale thread.

Or talk to the folks at open source ecology - I think they've got a page on Sandlins goat with musings about adding power. One of their web guys must be a pilot, they tend to accumulate a fair bit of aviation articles.
 
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