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Part 103 low speed ultralight glider design (wing)

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Idea with wing for glider

  • biplane (wing size: 6 x 1.2 meters, s1210 airfoil)

    Votes: 0 0.0%
  • biplane (wing size 6 x 1 meters, clark y airfoil with flaperons 6 x 0.4 meters or 0.4 Fowler flaps)

    Votes: 1 100.0%

  • Total voters
    1

avs123

New Member
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Oct 26, 2019
Messages
2
I need ideas of wing system for ultralight glider (such as Chanute, EasyRiser or Primary Instruction Glider) (may be biplane) low speed (25 - 40 hm/h) , weight of glider < 40 kg).
My idea is next:
biplane (wingspan - 6m, wing chord - 1.2m),
S1210 airfoill (http://airfoiltools.com/airfoil/details?airfoil=s1210-il).
There is no talk about materials. This is question about design only.
Please, write what do you think about this idea or suggest better idea (airfoil, flaps, ...).
Thanks for answers.

For example see:
http://spicerweb.org/chanute/buildgli.aspx
http://www.theaerodrome.com/forum/showthread.php?t=40227
http://www.2040-parts.com/pig-biplane-glider-plans-on-cd-primary-instruction-glider-rare--i611334/

upload_2019-10-26_14-2-12.png
 

Victor Bravo

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First, please explain what you are trying to accomplish that will be DIFFERENT than the already existing designs including:

Sandlin BUG
Sandlin GOAT
Super-Floater
Start + Flug (Ursula Hanle) "Hippie"
Existing classic primary gliders, SG-38, etc.

My question is... do you want to foot launch, or do you want higher performance, or do you want absolute minimum weight? Are you willing to use a flying wing (tail-less) design or are you restricted to "conventional" wing and tail?
 

avs123

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Minimal weight ( < 40kg) + minimal speed. Must be both foot launch and towable. Conventional wing and tail is preffered. Wingspan must not be big (6 - 7 meters), so biplane variant is preffered
 
Last edited:

pictsidhe

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Have a google for 'biplane interference'. Airfoils thay work nicely on monoplanes will behave differently on biplanes. There will be a nozzle formed between the wings. I don't know, but I strongly suspect that there are special biplane airfoils.
 

henryk

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Minimal weight ( < 40kg) + minimal speed. Must be both foot launch and towable. Conventional wing and tail is preffered. Wingspan must not be big (6 - 7 meters), so biplane variant is preffered
-it is possible to build flying wing <10 kg...
http://www.reaa.ru/yabbfiles/Attachments/Zdj__281_cie148_003.jpg
https://etnomuzeum.eu/zbiory/model-skrzydel-jana-wneka
=not exactly (airfoils, controll wires...)

=preprototype from 1866 year, (Jan Wnek from Odporyszov).

https://powiatdabrowski.pl/aktualnosci/samorządowcy-z-radgoszczy-uczcili-pamięć-ikara-z-powiśla.html

-the place of tragical fall in 1869...

http://www.energykitesystems.net/hgh/t3.html

+many,many others...
 
Last edited:

Dana

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Look at Mike Sandlin's "airchair" designs, Goat, Bloop, etc. Not foot launchable but could be made to be so.
 

proppastie

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might want to look at the Carbon Dragon "Irv Culver" airfoil plans at the Irish site my signature block.....No idea how it would work with a short or bi wing. It is 12" thick at the root.
 

Victor Bravo

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Minimal weight ( < 40kg) + minimal speed. Must be both foot launch and towable. Conventional wing and tail is preffered. Wingspan must not be big (6 - 7 meters), so biplane variant is preffered
Although not all designed for conventional wing+tail aircraft, you might look into some of the the thick low speed airfoils designed by Martin Hepperle.

Also, maybe look at Irv Culver's thick airfoil for the Volmer VJ-23 "SwingWing" hang glider of the early 1970's.
 

Bille Floyd

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Look at Mike Sandlin's "airchair" designs, Goat, Bloop, etc. Not foot launchable but could be made to be so.
Here is the goat, on a mountain launch, no engine. I've known
the pilot for 40 years ; Great guy, and awesome pilot .

 

Aesquire

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Love the Goat. None of the local hang glider sites has as nice a ramp, but a few are suitable for a wheeled launch if the grass is freshly mowed.

Tailed gliders like that are problematic for cliff launch as the tail wheel/skid may strike on takeoff and pitch the nose down, which depending on terrain & wind may not be recoverable. Because of tail clearance issues, most hang gliders are tailless. I almost built a version of Sandlin's Sundog back in the day. My version was going to have a bigger wing ( 200 lb. Pilot ) and I have the Original Quicksilver plans & notes. I bought the plans with the Flexi-flyer plans, which I did build.

http://www.m-sandlin.info/xgliders/xgliders.htm

But. A few of the best local hills have full cliff or very steep take off sites, and are hazardous with tails.

Towing is, of course, not an issue at all with tails.

The Easy Rider Is IMHO, the best biplane hang glider ever in production.
http://pioneerflyer.com/Easyriser.html

That used a LM7610 airfoil derived from old Eiffel airfoils. It's the balance of ease of takeoff and landing, decent performance, and a solid stability geometry that made it successful. The downside was transporting required a big rooftop box, or small trailer, because the fabric covered wing panels Must be solidly mounted and braced to not bounce around in each other. The wind loads at 60mph are substantial. At a minimum, shaped foam blocks between wings and under the redundant straps. Better, a custom rack, and then a plywood box to keep out road debris and permit low strap tension & stress on the airframe & fabric.

I'm not suggesting you copy the Easy Riser, but it's a good metric for success.

I find the stability geometry elegant. A swept wing biplane with positive stagger, and the rear/lower wing permanently rigged at a lower angle of attack than the front/upper wing.

The front wing stalls first, so like a canard or tandem wing, you have forgiving stall characteristics and positive pitch stability. The original advertisements described the lower wing as a close coupled tail. But tandem wing is correct!? Both wings are lifting in normal flight.
 

pictsidhe

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Thick airfoils work poorly on biplanes due to the interference between top and bottom wings. And I'm a thick foil afficionado!
 

Victor Bravo

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Although I've never been a foot launch pilot, I have spent many many hours thinking about how to have a tailed foot launch glider. I believe the bottom line is that there will simply be a lot of primitive and odd-ball launch sites you just couldn't operate from.

The Sandlin style rolling launch, and new versions of the 1920's bungee launch, and little electric or compressed air catapult mechanisms may well be the key to ONE future for "hang gliding". I'm not saying that the traditional foot launch is wrong, or fading away into obscurity.

I'm saying a lot of people are getting older and have already worn out their knees and ankles, and I'm saying that tailed gliders have some really nice advantages. I'm also saying that some stubborn pig-headed mules like me really really like aerodynamic controls, especially when flying around terrain in turbulent air. So Sandlin-style gliders, horizontal tails, and ailerons are very attractive to more than a few people.

To make that work in the real world of driving up to a hill and launching off that hill, may take some extra equipment. A bungee or crossbow type of catapult mechanism might allow extra safety margin for this type of glider in that environment. I'm talking about some sort of mechanism that gets "charged" by a farm jack, or a ratchet crank, or a come-along mechanism.
 

pictsidhe

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200 odd horsepower into failing gears (for whatever reason), generates a tremendous amount of heat. The oil would indeed have had a story to tell.
 

Aesquire

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Victor Bravo, you are correct about aging knees, etc.

experience tells me that hau!ing, assembling, and breaking down a launch mechanism is more trouble than it's worth on a mountain. And the sites that are not "tail friendly" may require hiking in the surplus steam catapult from the Enterprise . ;) Cliff launches aren't usually bungee launch suitable either.

Some local launches can be driven right up to. Or only need a few hundred foot trail yards to reach. Those are still easily accessible to a rigid wing that needs assembly from wing panels. Even at double the assembly time of a modern flex wing, for some that's a viable price to pay to fly. I recall hiking miles to fly Mt. Tom because fire hazard conditions had vehicular traffic closed the last 1500 ft. vertical. That would have been too much effort for a multiple part wing.

I usually had a driver, or flew with another pilot so we could leave a vehicle at the landing zone. On cross country flights we often joked that retrieval crews had more danger than the pilots. "Hang Driving, the Most Dangerous Sport" . The point is having a second person to help drive & set up isn't uncommon.

I won't argue weight shift vs. aerodynamic pitch control, except to note you don't need a tail to have elevators/elevons.

Tails don't make foot launch impossible. Just more limited choices.
 

Bille Floyd

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For me , the foot-launched thing is the most dangerous part
of flying my Rigid-wing HG ; launching from a dead stall
to minimum-sink airspeed has gone bad for many a pilot.
A few years ago, a HG pilot died launching off Chrestline
Ca.
Yesterday , (Halloween) i turned 67. My body can still
move quite well, even with the fake legs ; but i'm thinking
it's time to launch the HG with an Electric motor and folding
prop, and land on wheels . I think, the risk would be reduced
a Bunch , by flying from off the valley floor, and powering
up to thermal altitude ?

BTW : i'm learning a Lot from you guys ; the search function
leads me to near every question i have had, for ways to MOD
my Exxtacy HG, and make it powered . ------------ THANKS !!!

Bille
 

Bille Floyd

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Good to have you with us, Billie, and hope to learn from you as well. I have followed the Goat, et al, for some time.
So there is no confusion :
The pilot of the Goat in my post # 10 ; His first name is Floyd.
The legless guy who posted the video ; my name name is
Bille Floyd. The other Floyd in the Goat ; he is a Way better
pilot , than me !

BTW : Floyd F, sold that red Goat, and is now building a way improved
version of the Super Goat. Can't hardly wait to see it !! He owns a
machine shop in San Diego.

Bille
 

pwood66889

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Hope I got it straight now, Billie. Floyd F. is the Goat pilot on Mike's site. Do we call you Floyd #2??? :)
I'm an invariable leg puller, but very happy to have you on board.
Percy in Sopchoppy, FL, USA
 
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