# 99lb/45kg primary glider

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#### erkki67

##### Well-Known Member
Koen, young Aviators will admire your website for years to come, it’s a reference of its own!

#### dino

##### Well-Known Member
HBA Supporter
Koen, I suspect your effort is far more recognized than you imagine. I've found it referred to on many sites and use it with confidence. Your work is laudable.

#### WonderousMountain

##### Well-Known Member
GeoGull is at least one third attributable to N.o.D.

(canted tails not shown), there's always something missing.
Mike Sadlin is very approachable, and he knows someone
that can do math supposedly.

#### Hephaestus

##### Well-Known Member

Belites 103 carbon wing... 14lbs for 56sqft... that means I'd be in the 43lbs ballpark.

But the cost of appropriate pultlruded carbon spars to Canada is eye watering.

#### Hephaestus

##### Well-Known Member

Partly where it's sitting today. Before I rework the tail and wing a few more times. That won't be the wing profile though.

More supline seating compared to the original hippie. Arm rests so flaps/tow release are in expected position. Also so people don't feel they can fall out (biggest argument raised by people flying a friend's airbike)

Slotted flaperons - trading off some wing area for mixer. Those of us on the fluffier side - in training, a little block off plate/bolt to keep minimum 5° of flap - would keep speeds inline... After training - could be a bit more fun/versatile.

Can't seem to make a nose look right. Laid it out the seat/pedals in the shop, gotta rework those pedals, fine for the 30" and under inseam crowd. Maybe need to look at one of the gliders adjustable pedals mechanisms.

#### Victor Bravo

##### Well-Known Member
That looks GREAT... but please DEFINITELY consider curving the bottom of the nose upward, the shape of a ski or sled runner. I don't care if it looks cool or not (but it will). It will make a huge difference in the survivability / injury level of a hard landing, crash, off-airport landing. Chuck Slusarczyk figured this out 40 years ago with the the CGS Hawk, and I promise you lives were saved.

#### Hephaestus

##### Well-Known Member
That looks GREAT... but please DEFINITELY consider curving the bottom of the nose upward, the shape of a ski or sled runner. I don't care if it looks cool or not (but it will). It will make a huge difference in the survivability / injury level of a hard landing, crash, off-airport landing. Chuck Slusarczyk figured this out 40 years ago with the the CGS Hawk, and I promise you lives were saved.
Oh I absolutely will be, just trying to find a decent profile. Squared off end is just where I want it to end.

Thinking of looping it around up to a instrument panel to ensure rollover / frontal protection without needing an overhead hoop. Largely why the keel is so thick/deep still.

Panel - just a tablet mount with a glare shield. If it's not permanently mounted or required for flight, it's not airframe weight. I'll likely add a small UAV style pitot, I have one here connected to a esp32 for Bluetooth airspeed from lazybee testing - but it lacked sensitivity down low end of the speed spectrum. I'll have to see if I can find a better one.

#### WonderousMountain

##### Well-Known Member
Best primary landing configuration is Bicycle or full length skid

Will supply drawings,
LuPii

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#### Hephaestus

##### Well-Known Member

Fairings don't quite fit in the weight budget... Yet.

Yes the big wheelbarrow wheel disappeared, two 10" pocket bike front wheels are lighter and reduce the wingtip ding risks.

No struts yet... It is an 18% airfoil. Cantilever is possible - keeps going back and forth on needed or not as configuration of the wing keeps revising. Today's task is largely finding a not 5000$spar solution. #### Victor Bravo ##### Well-Known Member 'Festus I'm guessing there's likely more than enough drag on a basic glider like this to make drag reduction (from a cantilever wing) almost irrelevant. The struts are an off the shelf item, and will contribute greatly to easily mounting the fuselage under the wing. In fact, with struts, you can have only one central main spar/fuselage attach pin (and one central rear spar attach pin). Unless heavy, highly engineered fittings and structures are developed, the strut braced version will stand up to more bashing and crashing than a cantilever glider. Seems like an easy decision for the specific use and "clientele" you're aiming for. #### Hephaestus ##### Well-Known Member 'Festus I'm guessing there's likely more than enough drag on a basic glider like this to make drag reduction (from a cantilever wing) almost irrelevant. The struts are an off the shelf item, and will contribute greatly to easily mounting the fuselage under the wing. In fact, with struts, you can have only one central main spar/fuselage attach pin (and one central rear spar attach pin). Unless heavy, highly engineered fittings and structures are developed, the strut braced version will stand up to more bashing and crashing than a cantilever glider. Seems like an easy decision for the specific use and "clientele" you're aiming for. Nothing to do with drag... It's all weight with a little budget override thrown in. This morning's iteration it was 5.45kg just for 7075 tubes as struts (just tube no ends no fittings etc) - 4.2kg to omit the struts. That's wherein the fun lies - 45kg total is hard. We were discussing flying wires, so that may come yet... #### SMORGAN ##### Member Following this with interest, it reminds me of Mitjas thread of some years ago for an UL sailplane As far as reducing frontal area drag the pilot could be more reclined like the Archaeoptryx or the Millenium gliders: #### Hephaestus ##### Well-Known Member Following this with interest, it reminds me of Mitjas thread of some years ago for an UL sailplane As far as reducing frontal area drag the pilot could be more reclined like the Archaeoptryx or the Millenium gliders: Hey at least nobody is bringing up the raid area 51 "writer" I'll have to read through that, looks like we have some similar goals. Not too much trying to reduce drag right now. But those fairings did really did make it look better. Wind up the pant leg is only nice on really hot days, most of the year in Canada you'd probably not love it. #### Hephaestus ##### Well-Known Member Wing loads are making my head hurt. Mocked up the root 3' of what was working in theory. It's in the trash. No way that will survive handling. This is how you end up with heavy composite construction isn't it? Throw an extra layer or two on just to 'feel' right, even if the math says it's ok... Going back to an orion comment or two about stressed skin / monocoque... Does anyone have some ideas/pictures for root connections? I can't seem to find much other than diana2's assembled pictures. FEA tossed out some interesting ideas that aren't practical to build (less so to build light). #### Bille Floyd ##### Well-Known Member ... If you want true 3 axis controls to train with and don't want a flying wing you need a very spindly airframe, wire braced and you need to use as many tension solutions to long strains as possible. See Buckmeinster Fuller for bizarro tension designs. Carbon fiber is your friend but for a minimum weight but not your friend for minimum cost. Foam is your friend for minimum cost and minimum weight so somewhere between using those two is where the perfect design is. ... I totally agree ; but 5-Lb, of 50-K carbon tow, @$125 , is not really
that expensive, (for what you get). I am sure , there are better prices
than here ; ( Carbon Fiber Tow | Page 1 of 1 ) ?

Whatever you do, just please don't let nest of dragons disappear a few of us reference it fairly regularly.

...
YES -- and i am one of them !!

I think a king-post with spectra cord, for bracing the wings and tail , is
the way to go ; a cantilevered boom, or struts, for the wings, would be
way heavier

Bille

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#### Hephaestus

##### Well-Known Member
While flying wires makes it easy. It does pigeon hole the design...

Yes its starting as a 45kg primary glider.

With 24kg extra bringing it up to US part 103 glider rules. Fully enclosed cockpit is an option.

XFLR5 says 28:1 with fully enclosed cockpit, not sure I believe it (carbon dragon is 26:1), but that airfoil was designed for a high performance glider... So structuring around that option of a future higher performance version.

#### Bille Floyd

##### Well-Known Member
While flying wires makes it easy. It does pigeon hole the design...

Yes its starting as a 45kg primary glider.

With 24kg extra bringing it up to US part 103 glider rules. Fully enclosed cockpit is an option.

...
and they want 99Lb) ; and you ain't gonna do that without wire/cord
braced wings and fuse braced parts (.) If you really think you can ; then
Bring-It !!

Yes -- i'm being kinda, direct here ; but if you can, then i'm gonna
have the best rigid-wing hang glider, in the world , with the info you
provide !

Bille

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#### Hephaestus

##### Well-Known Member
and they want 99Lb) ; and you ain't gonna do that without wire/cord
braced wings and fuse braced parts (.) If you really think you can ; then
Bring-It !!

Yes -- i'm being kinda, direct here ; but if you can, then i'm gonna
have the best rigid-wing hang glider, in the world , with the info you
provide !
Yet there exist others that pretty much hit the mark (aerianne swift). No struts or wires I can spot.

Currently wings - happy accident good to 172kg at 4.8g. and should be 3kg under weight budget. That's based on imperfect wet layups.

Tomorrow hoping to test the skin not have a repeat of the first d-tube. Then we'll have to sort out a "not full wing" build to load test the monocoque to root ribs to carry throughs. Because I still don't trust software most of the time.

I don't think having a path forward for any design is a bad thing. At its core it'll be a 45kg primary glider. But if one registered it or lived in a less strict regulatory environment - there are options to improve on that base.

#### jedi

##### Well-Known Member
[QUOTE="Hephaestus, post: 540984, member: 32093"
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?
[/QUOTE]