Different Helicopter Design
 

Noncompetition (engine eject) model.
Takes about 45 seconds to prep.

http://www.youtube.com/watch?v=t41u3quyi5M

Tom

That is very neat!

Yours?

I noticed how much the rotor design resembled the symbol of the triskelion. Pretty cool!

Yeah my design. I was kind of excited when fliskits came out with tiddlywink, I had been trying the combined rotor fin units for about 6 months -- nice to see somebody else thought it was a good idea. This has no body tube, just an engine mount on one of the rotor fins. I thought it would throw the balance off, but seems to spin pretty well. No nose cone, just a folded card stock nose "pyramid". Not sure whether that gives better or worse aerodynamics. I have always wondered whether the typical rotor attachment like the rose a roc must give a heck of a lot of drag.

I like the "triskelion" name--- although I guess it has already been taken

Triskelion is a general term for any three armed heraldic device with a common direction of the arms (or I suppose legs in that case). It is common in Celtic symbology and still persists on the flag of the Isle of Man, from which the image is sourced. So name away!

Very neat indeed!!

Please post the critical dimensions for this copter here for those of us (read: ME) who would love to build one! Stuff like the rotors widths and lengths, as well as balsa thickness, and of the added on fins.

I thought I saw something very similar, but with 4 'fins', someplace else recently.

This looks like a perfect no frills sport copter. Depron and Readiboard are not really suited for long rotors like these, so I may have to get may grubby mitts on balsa if needed.

Couple pics would be great.

From the you tube video I can see the hinge and springs, I can see the triangluar locks holding the two blades in place until the motor ejects. What I cannot figure out are the apparent dowels (around 1:08) which flex from the rotor tip to about mid span?

Details of the Gyskelion Helicopter Rocket
 

http://www.youtube.com/watch?v=vs_dkMWvXSs

Parts:
Poster Paper nose-pyramid (not really a cone)
Duct tape and dental floss hinges (light, incredibly strong, not difficult to do but you do need a sewing needle)
1/8 inch balsa (need the stiffness)

Rotor Fins are 18 inches long. Front 2 inches are used to make a "hub" Angle of attack is 15 degrees.
Fin parts are 7 inches long,-- 2 inches wide) they stick out perpendicular to the rotors. They are actually attached at a 45 degree "joint"
Rotor stops are double ply 1/16 inch balsa, one piece cut with the grain, the second across the grain. When these are attached, they are very strong in any direction of stress. The are set to position the rotors at a 15 degree dihedral nose-down.
On the tips of the rotor stops are short segments of coffee stirrer straw, 1/2 diameter. This makes a "trough" to hold the pull strings away from the body of the rocket.
4 triangles are cut out of plastic "hotel key cards" (could use card stock. Cannot use balsa as needs to be strong in all directions) These are 3 7/8 on each edge, to fit just INSIDE the fins.
Two of these attach the motor mount, a 1 1/2 inch BT-20 segment, plugged at the nose end to force rear ejection. One triangle each is placed on the other two fins, they are "staggered" below the opening of the motor mount tube. Small balsa strips are used to "brace" the triangles against the fins. The central holes are just big enough to pass the BT-20.
Pull strings made of kevlar (just cuz I have a huge spindle of it) are attached to the front of the balsa hub at the base of the nose-pyramid . These run about 1/2 way down the length of the body. Small dental floss loops are attached about 1 inch up from the tail end of the rotors to hold the rubber bands. Tiny S-hooks made of paper clip wire are used to attach the rubber bands to the pull strings. These are easily released when the rocket is stored.

Thanks Mark II for the Triskelion suggestion. Since Fliskits had a Triskelion, figured I'd use Tryskelion, but when I googled in turns out it is a pagan web site so figured I'd go with Gyskelion for Gyro-Triskelion.

Hope this helps.

Tom

Stupid me - I thought Gene Roddenberry just made it up!