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batballs's blog
Posted by batballs | Apr 27, 2010 @ 11:01 PM | 2,450 Views
This is my second "own design" glider. Purpose built as a DS trainer to be tough, stiff, tough, easy to repair, fast and tough. Also a proof of concept for the philosophy behind the layout - I did think about the design even though it doesn't look like it.

The airfoil is HS130, a German section used for "fast planks". I gave it a wide chord for pitch stability and twin fins to kill the tip vortices and improve efficiency at low aspect ratio. It seems to work, keeping it stable through the shear.

It has a two 8mm fibreglass spars (very tough and stiff) and taped plywood and foam ailerons. The front spar is as close to the LE as possble for balance. Because a lot of the mass is in the spars the straight wing is fairly evenly loaded in flight, so it doesn't get the big bend at high G. It's was also easy to build.

Servos are GWSNaro2BBMG mounted on a ply plate between the spars. The foam core is "composite"; the back 80% is fairly stiff white foam and front ~20% and the nose is closed cell PE foam - soft and bouncy to absorb impact.

I really didn't hold much hope for it after the first few flights, although I had one good session at a ridge at Camperdown in good lift. It sucks until you get up to a decent speed - seems to wallow around on the edge of a stall. But once it gets "on the step" it transforms - tracking straight and solid and keeping a lot of speed.

After its first session at Johanna it is definitely more fun to DS than fly frontside. Very stable compared to the Bat but still with more than enough response and great penetration.

When Roger first saw it he said "could you make it any uglier?" I decided I couldn't so I just added the coloured patches to make it harder to ignore


EDIT: After many flights TUT is dead. Too ugly to live, after many attempts, it finally succeeded in taking its own life by diving into the ground at Mt Black. With it go two servos - or at least the cases. RIP