# video 1Comet ultralight glider with fairing, tow to 1100m

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#### patrickrio

##### Well-Known Member
I've been working on conceptual design for a 15M self launching electric sailplane that weighs under 120kg.
Any rough drawings/cad render pics you care to share???

#### Donat

##### New Member
Nice! Good talent on that team, I've flown with Eric.

Without spoilers/air brakes that eats up a landing field. Hope the price is less than a F-35.
We installed a drag chute. But youre right: for practical reasons we need spoilers. Spoilers will be on second prototype, currently under construction

#### Donat

##### New Member
Air brakes -
Side stick instead of "stick from roof" -
So... any idea of expected price?
not yet, we try to be lower in price than the Archeopteryx, but we´ll be more expensive than the Swift.

#### patrickrio

##### Well-Known Member
not yet, we try to be lower in price than the Archeopteryx, but we´ll be more expensive than the Swift.
Nice to see you here Donat.

Do you have any info on the motorglider version yet? HP required, Expected Cruise speed, Expected Stall Speed, Expected empty weight, engine/motor you plan you use, Expected Max level Speed, etc.

I really like the design.

#### Donat

##### New Member
Is that related to the Archaeopteryx foot launch glider? It looks very very similar.
Both gliders are high wing aircrafts, the pilot is close to the glider CG and both gliders are nice to fly. But everything else is quite different. Aspect ratio 19,5 vs 14.5, airfoil 13.5 % vs 17 %, upper transition at max. L/D at 65 % vs 35 %, sandwich surfaces all over vs D-tubes with Oratex. The cockpit of the Archaeopteryx is super comfortable and very wide, our´s is narrower and more streamlined. So, there is an important performance difference especially at high speed, comparable to the difference of laminar sandwich glider to a fabric covered glider. The performance of the 1comet measured in calm 8 o clock morning conditions corresponds to our calculations. At high speed, we were even a bit better than we thought.

#### Donat

##### New Member
Nice to see you here Donat.

Do you have any info on the motorglider version yet? HP required, Expected Cruise speed, Expected Stall Speed, Expected empty weight, engine/motor you plan you use, Expected Max level Speed, etc.

I really like the design.
I`ll update my homepage, hope to find some time soon. Eric Raymond has nearly finished the molds for the electro version. We already bought via LZ design the folding propeller, the electric motor, 2 battery packs and the controller.

#### peter hudson

##### Well-Known Member
Any rough drawings/cad render pics you care to share???

It's still mostly an analysis experiment; (shown is openvsp model) to see if, after detailing the structure, it's possible to make a standard 15m sailplane shape into a part103 or 120kg self launcher with maybe 8-10 minutes of power. The 1comet comes pretty close to this and I have more weight budget since it's not intended for foot launch. The bigger difference is I aiming for homebuilding with lots of flat ruled surfaces and fewer/smaller molds

#### patrickrio

##### Well-Known Member
View attachment 109220
It's still mostly an analysis experiment; (shown is openvsp model) to see if, after detailing the structure, it's possible to make a standard 15m sailplane shape into a part103 or 120kg self launcher with maybe 8-10 minutes of power. The 1comet comes pretty close to this and I have more weight budget since it's not intended for foot launch. The bigger difference is I aiming for homebuilding with lots of flat ruled surfaces and fewer/smaller molds
Interestingly, I think that a structure like the 1Comet might be a good general direction for homebuilders too... primarily depending on the availability and price of suitable structural tubes for tail booms. The 1Comet general structure lets you make smaller molds for a streamlined cabin, Seems like it makes changing wing structures easier too since you can more easily bolt wings to the top and also more easily move the whole wing forward and backward on the pilot pod to locate center of lift correctly over pilot CG for various wing designs. Tail feathers are also more easily changed when they sit at the end of a tube like that I think....

for power, put the motor around the boom with a folding propeller maybe....

#### peter hudson

##### Well-Known Member
The 1Comet general structure lets you make smaller molds for a streamlined cabin, Seems like it makes changing wing structures easier too since you can more easily bolt wings to the top and also more easily move the whole wing forward and backward on the pilot pod to locate center of lift correctly over pilot CG for various wing designs. Tail feathers are also more easily changed when they sit at the end of a tube like that I think....
Having the individual components as separate structures isn't off the table for me. I really do want a two piece wing, and to incorporate auto hook-up controls (wing and tail) and have the power be optional. Right now (in my head) power is a self contained plug-in electric motor pod. But I do like the idea of the tailboom mounted prop hub. My tail boom is a straight tapered cone bonded to a molded fuselage pod. I do feel that the fewer bolted joints between components I have, the more likely I can make the weight budget. As I work through the structural analyses, I'll get a better feel for my options with respect to adding fittings and modularity. I do assume some hand shaped interface fairings between wing/fuse and stab/fin to allow changes in incidence and perhaps different stab/elevator size to be dialed in during testing.

Being able to move the pilot/wing around for CG is pretty compelling. Those items are pretty well fixed in mine. With the electric, I do have a lot of options with battery location to fix CG, but as a glider only, it would take ballast or a major mod.

One other configuration difference with respect to CG, is that 1Comet is designed for foot-launch (very cool) which wants the empty CG to be forward pretty close to the loaded CG to make pick-up and ground handling manageable. I want the empty CG pretty far aft so the pilot can sit well forward for upward visibility. I really don't want the pilot under the wing at the CG.

#### Gurka

##### New Member
Hello home builders
I'm trying to find a company who can provide me folding propellers for electric motors, please if some body can help... Thanks

#### John.Roo

##### Well-Known Member
Hello home builders
I'm trying to find a company who can provide me folding propellers for electric motors, please if some body can help... Thanks
Try to contact prop producer HELIX
Einsatz

#### Gurka

##### New Member
Thanks Jhon, we will contact them