Elastic, camber changing flaps

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Bille Floyd

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Sep 26, 2019
Messages
428
The Jantar 2 sailplane, has elastic camber changing flaps, which spreads the
hinge-point over a longer aria of the cord , of the upper skin ; does anyone know
what composite materials were used for that ? I'd think fiberglass would be
too brittle for that job , and who made a flexible epoxy, back then ; or was
that hinge , made of a rubber type substance ?

I believe another sailplane , did the same type flex-skin for it's ailerons ; can't
remember what glider though ? I bet the stick pressure, was kinda high, on it.


Bille
 

Victor Bravo

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KWHP, Los Angeles CA, USA
The Jantar used fiberglass skin for the hinge I believe. I have a friend who owned one, I'll ask him next time we see each other. The guys flew those for seven and eight hours at a time, and I never remember hearing that the control pressures were higher than anything else.

I think the Grob 104 "Speed Astir" glider had this kind of skin hinge too. I will assume it was also glass. I knew one guy who raced one of those briefly, but he had to leave it in a hurry after a mid-air at a contest.

Chris Heintz did one of his powerplane kits using the aluminum skin as the hinge, and did a bunch of research and calculation to verify it was safe.

But please believe me that the truth is you can do 99.99% as good aerodynamically, and with a lot less headache, and a lot easier engineering, with the mylar "wiper seal" strips that all of us used in contest gliders. A lot easier to deal with, a lot easier to maintain, and a lot easier to replace after any sort of damage.
 

Basil

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Aug 19, 2017
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40
Location
Countesthorpe UK
The Jantar 2 sailplane, has elastic camber changing flaps, which spreads the
hinge-point over a longer aria of the cord , of the upper skin ; does anyone know
what composite materials were used for that ? I'd think fiberglass would be
too brittle for that job , and who made a flexible epoxy, back then ; or was
that hinge , made of a rubber type substance ?

I believe another sailplane , did the same type flex-skin for it's ailerons ; can't
remember what glider though ? I bet the stick pressure, was kinda high, on it.


Bille
The Slingsby Vega had it on the flaps.
 

Bille Floyd

Well-Known Member
Joined
Sep 26, 2019
Messages
428
The Jantar used fiberglass skin for the hinge I believe. I have a friend who owned one, I'll ask him ...
Curiosity got me :
I read about the elastic flaps on the Jantar, after googling it this morning ; there
was one on wings & wheels for $12-K, and wanted to know the L/D.

Imagine a near 50:1 glide ; for that little money !!!!!! ... ...
When i do get a sailplane ; it will be a 15m, or less, in the low 30:1 glide range, with
flaps and speed-breaks.

Bille
 
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