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99lb/45kg primary glider

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tdfsks

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From one of my old sketch books but redrawn just now to adjust a few weights since the original was meant for the 155 lb Part 103 weight limit for gliders. Separate elevator and aileron control surfaces on the trailing edge like a Monarch (not separate elevons like the B10 with a mixer)

IMG_8681.JPG
 

Hephaestus

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I don't think it is possible without liberal use of the carbon strips. Or a filament wound carbon windsurfer mast tube for the spar, with a vertical web somehow inserted into the tube.
The ulf-1 I'd forgotten about and was surprised it was 100lbs (or 120 depends on what website you believe) but yes very delicate by outward appearances.

I'm guessing there's going to be lots of carbon involved. Sketch I was just playing with using your drawing really ends up looking like a Genesis :)

Now here's the rub... Pull out Stelio frati's book. It ballparks a wing weight of 4.5kg/m² with external bracing (still just running with sandlin goat1's numbers as a baseline). 72kg for the wing...
 

tdfsks

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The plans for the ULF-1 (Sheet 1) state "Empty Weight 46 kg" (101.2 lb).

The following weight breakdown is also provided:
wing weight 46 lb
fuselage + fin + rudder 46.3 lb
horizontal tail as 7.7 lb

However a lot of balsa is used, even in fuselage framing, not just for fairing. Also all metal fittings are intricate with every possible weight saving idea (lots of lightening holes etc).
 

John.Roo

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Hangar beers discussion last night that got me curious.

What we were discussing is an option to get back to "old school" glider training. Students spend a bunch of time waiting around between flights, most of the time getting "busy work". While primary gliders operating as hang gliders don't get logbook time, they could be valuable stick and rudder time. Especially if they could be winch launched.

Canadian rules at times suck. Don't really have an equivalent to part 103 glider class.

However we are allowed 45kg/99lb hang gliders in a pretty much deregulated class.

Eyeballing the Sandlin goat / compact 110, most use the American rules - so they run 30-40lbs heavier.

But the swift hits the target at 100lbs... But at costs approaching 6 figures.

All of them suffer from the 170lb pilot weight issue, pretty sure 210lbs is the new minimum at least in our vicinity.

I don't suppose any of you have put any pen and paper time into a project that might come close? Or have some great thoughts as to how to achieve a 99lb primary glider?
Hello!
The requested EW 99 lb / 45 kg is really very low.
But maybe ATOS A.I.R. WING without propulsion could fit :)
1594262577470.png

P.S.
Quick "google" search.
Weight of ATOS A.I.R. hang-gliders is between 35-47,5 kg (depends on type) so there is only a very small weight reserve for "fuselage", control lines etc....
 
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jedi

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The glider proposed in Does this aircraft have any use?
Could meet the 100# requirement and relative low cost/build time. See post #19 for a crude description.
Post on above thread for more details if interested. It is not standard construction and is experimental.

...........

I think VB is on the right path, provided that the flight handling was representative of gliders the students would fly later. The Mitchell B10 wing was 68 lb (including tip rudders), 34 ft span and 136 sq ft. All wood and a cantilever. That suggests a wing for a Monarch type glider could be made for a similar weight. Add a basic fuselage like on the LAK16 and a rudder framed with aluminium tube and I am sure the weight can be met. I don't think the use of carbon is required as the spar caps in a B10 are small enough that they do not weigh a lot anyway.

...........
My B 10 Mitchel weighs 98 to 100 pounds with the hang cage and has likely gathered some dirt since.
 

tdfsks

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My B 10 Mitchel weighs 98 to 100 pounds with the hang cage and has likely gathered some dirt since.
Sounds about right. The number I quoted (68 lb) is for the wing alone. It is right out of the Mitchell B10 literature although they use both 68 and 70 lbs in their documentation. That includes the control stick and tip rudders ... but no cage.
 
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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
Do you have a topview of this one?
 

erkki67

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The LAK-16 shown in this video is heading in the right direction but its weight is twice the 99 lb weight limit that the OP is looking for.

For me the interesting thing in that video is the winch setup ..... looks like the winch lines are diverted 90 deg suggesting that they might have some sort of arrangement where they have parallel winch lines and one is recovered as the other pulls the glider making for a very efficient operation and little downtime between launches (assuming you had enough gliders).



There were never any drawings of Ron Wheeler's Scout. It was, I think, the first factory finished ultralight in the world. Ron was a sailmaker and he used a lot of ideas from the yachting world. The wings used an extrusion for the leading edge spar not unlike a yacht mast and the sail slid into a groove in the back of the spar.


I think VB is on the right path, provided that the flight handling was representative of gliders the students would fly later. The Mitchell B10 wing was 68 lb (including tip rudders), 34 ft span and 136 sq ft. All wood and a cantilever. That suggests a wing for a Monarch type glider could be made for a similar weight. Add a basic fuselage like on the LAK16 and a rudder framed with aluminium tube and I am sure the weight can be met. I don't think the use of carbon is required as the spar caps in a B10 are small enough that they do not weigh a lot anyway.

The Compact 110 was mentioned above. Did any of these every get completed and fly ? Has anyone seen the drawings ? What did it really weight ?

The original Klaus Hill Superfloater with the metal D box wing weighed just 90 lb and meets the requirements of the OP ? Span 32 ft, Wing area 132 sq ft. L/D = 12 .... which is irrelevant since the glider will generally be under tow and more or less in ground effect.
At the Website of Koen, you’ll find the answer regarding the Compact110!

 

Hot Wings

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Do you have a topview of this one?
Keep in mind that these are little more than sketches. I'm comfortable enough with SW now that I use it in place of a napkin* for some things. The double sweep was an attempt to reduce the adverse yaw of the forward sweep and the multiple control surfaces on one side were part of a Prandtl/Bowers/Arduino/FBW day dream.
Top w.JPG

*easier to store and less prone to damage from spilled drinks ;)
 

cluttonfred

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For the mission described, I think the simplicity and stall-resistance a pure plank wing with outboard elevons and a single central fin and rudder makes the most sense, basically an open Marske Monarch fuselage with a Backstrom EPB-1C wing and vertical tail.
 

jedi

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...........

I think VB is on the right path, provided that the flight handling was representative of gliders the students would fly later. The Mitchell B10 wing was 68 lb (including tip rudders), 34 ft span and 136 sq ft. All wood and a cantilever. That suggests a wing for a Monarch type glider could be made for a similar weight. Add a basic fuselage like on the LAK16 and a rudder framed with aluminium tube and I am sure the weight can be met. I don't think the use of carbon is required as the spar caps in a B10 are small enough that they do not weigh a lot anyway.

...........
Keep in mind that these are little more than sketches. I'm comfortable enough with SW now that I use it in place of a napkin* for some things. The double sweep was an attempt to reduce the adverse yaw of the forward sweep and the multiple control surfaces on one side were part of a Prandtl/Bowers/Arduino/FBW day dream.
View attachment 99121

*easier to store and less prone to damage from spilled drinks ;)
Now if you would sweep back the outboard wing section......... It would 1) look better, 2) improve pitch damping, 3) give better control authority, 4) IMHO improve stall recovery and post stall aerodynamics, 5) not complicate the structure., 6) reduce unfavorable torsion in the inboard wing section.
 

Hot Wings

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Now if you would sweep back the outboard wing section.........
Would like to but......
1) Tend to agree
2) A plug in fixed HZ tail would do a better job. A straight spar - zero/negative/or positive sweep is probably the best compromise?
3) Junkers for the mission here. A little more damage prone but also easy to swap in the field.
4) See #3
5) Simple is always good
6) From simulations, when X-plane was still in single digits, I just could never get a seagull shape wing to fly well. See #2.

I'm thinking at this point that a straight spar Mitchell B-10ish wing on top of a LAK-16ish fuselage with a plug in fixed HZ tail boom* is a reasonable path.

* could even be aysemetrical to clear the central rudder.
 

jedi

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Would like to but......
1) Tend to agree
2) A plug in fixed HZ tail would do a better job. A straight spar - zero/negative/or positive sweep is probably the best compromise?
3) Junkers for the mission here. A little more damage prone but also easy to swap in the field.
4) See #3
5) Simple is always good
6) From simulations, when X-plane was still in single digits, I just could never get a seagull shape wing to fly well. See #2.

I'm thinking at this point that a straight spar Mitchell B-10ish wing on top of a LAK-16ish fuselage with a plug in fixed HZ tail boom* is a reasonable path.

* could even be aysemetrical to clear the central rudder.
With reference to #6) - any idea what the issues were?
 

REVAN

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Would like to but......
1) Tend to agree
2) A plug in fixed HZ tail would do a better job. A straight spar - zero/negative/or positive sweep is probably the best compromise?
3) Junkers for the mission here. A little more damage prone but also easy to swap in the field.
4) See #3
5) Simple is always good
6) From simulations, when X-plane was still in single digits, I just could never get a seagull shape wing to fly well. See #2.

I'm thinking at this point that a straight spar Mitchell B-10ish wing on top of a LAK-16ish fuselage with a plug in fixed HZ tail boom* is a reasonable path.

* could even be aysemetrical to clear the central rudder.
My reply to 2 and 6: My guess is that you were not defining enough washout at the wing tip, and/or had too crude and high drag of a wingtip profile. A well designed wing should outperform a crude wing with a tail to cover up the mistakes. I'd say don't give up on the 'W' shaped wing. I think it's worth more experimentation.
 

Victor Bravo

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The original parameters for this design exercise were for a 99 pound glider that was safe enough, and robust enough, to use as a primary training glider.

IMHO there are several exotic and complicated things that could be created under 99 pounds (All carbon 15 meter Horten Piernifero, Basalt fiber 3D printed ULF-1, EPS foam and packing tape Moller SkyCar, 21st Century Gossamer Albatross) but remember the original mission.

He wants to put cadet kids, or scouts, or brand new ab initio students into this thing. Short load paths, low parts count, and "not spindly" is the only kind of configuration that is going to make it past the first flight.
 

Hephaestus

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Yeah after sleeping on it, I pm'd boku - figure he might have some valuable knowledge in this area.

As much as I like wierd configurations - really wondering if it can't be brought back to the original standard primary glider configuration.

The Sandlin goat wing is 42lbs / half. So 84lbs total. Pretty sure where I need to focus is getting that down into the <60lb range. Then things start to work out.
 

Hot Wings

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With reference to #6) - any idea what the issues were?
Don't remember the specifics but they all just felt 'twitchy'. Could have been the software wasn't up to the job or it could have been my GIGO?
My U-2 and B-10 sims of the same period seemed to fly just as real U-2 pilots had reported.

He wants to put cadet kids, or scouts,
If this project were limited to kids in the under #120ish bracket we could probably do it with sub 100 pounds of plane.........and survive training day flights. Stuffing a modern >#200 adult in the thing is a real challenge.
 

Victor Bravo

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Look at the "Hippie" designed by Ursula Hanle in Germany in the 1970's. She was/is a highly qualified composite structures builder (widow of Eugen Hanle, founder of Glasflugel)

Wing span: 10 m / 32 ft 9.75 in
Wing area: 9 sq.m / 96. 9sq ft
Length: 18 ft 8.5 in
Height: 4 ft 7 in
Empty Weight: 48 kg / 110 lb
Gross Weight: 133 kg / 298 lb
Wing Load: 14.8 kg/sq.m
Max speed: 37 mph
Aspect ratio: 11.11
Airfoil: FX S 02
L/DMax: 12 at 45 kph
Min Sink: 1.3 m/s 40 kph





 
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Hephaestus

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Look at the "Hippie" designed by Ursula Hanle in Germany in the 1970's.
300px-Hippie_H-111_at_Sinsheim.jpeg
106lbs, with 200lb max pilot weight.

Pretty much exactly what I had in my head when I started...

Now to go see what I can dig up on it, of course it has to be German and not kit...
 
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