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Thermik-Delta Variant

Thermik-Delta variant - back yard test

This one is based on the Thermik-Delta 201 plan (alternate location here). As near as I can make out, it is intended to be a low-wind kite for flying in thermals. There is something of a Kitebuilder Forum discussion on it here - Thermik-Delta 201 / Dan Leigh Clipper variant.

The original uses four sticks that are 180 cm long, giving it a wingspan of 3.6 meters (11 ' 10 ") and an area of 3.24 square meters (34.9 square feet). Mine uses nominally 48" x 1/4" (122 cm x 6 mm) carbon fiber tubes, so the wingspan ends up around 8 feet (2.44 meters), and the area is 16 square feet (1.49 square meters). That's a bit less than half of the original size. The spreader is actually only 47.5 inches long, because for the type of fittings I made, it has to fit between the leading edge spars.

May 8, 2011 - After a week and a half of rain, or too much wind, or other distractions, I finally took it out to the back yard for a photo-op, on a short line. The wind was still too strong and turbulent so it usually wove back and forth until it crashed. Once in a while though, when the wind died down to nothing, it usually went flat, floating like a glider, but not moving forwards or backwards. That suggests to me that the balance is not too far off.

Later that day I took it to a better location a tried it on a longer line. The wind was still too strong, averaging 15 km/h and gusting to 20, and the kite usually straight went up and swooped back down to the ground off to one side or the other. It helped a bit when I added a fuzzy tail, but it most often ended up like this:

Thermik-Delta, grounded

I'll come back with more details after I get to try it in lighter winds, (5 km/h or less would be good) and I will probably switch to thinner spars. main index < kites <