Dandy E205

This is not about a high-performance sailplane but about building something that you knew about maybe 30 years ago...

Graupner used to have a glider kit called "Dandy". I found a new-old-stock Dandy kit offered on eBay, but it went for what I considered way too much. So I decided to build something similar to the Dandy, and luckily found the web site http://www.koralpe.biz/dandy.html which has nice pictures of the original kit and a plane built from it.

I had also read about the Eppler 205 airfoil, both good and bad, so I decided to try that.

Finally, the "glider" should have an electric motor because using a high-start is somewhat cumbersome. The motor and prop combination was determined by trying various things in online motor calculators and by comparing with off-the-shelf models of similar wingspan, weight and type.

Wingspan	170cm
Length	105cm
Airfoil	E205
Stab	E193, 50 x 11cm
Wing Area	39.1 dm2
Weight	1156g
Wing Loading	29.6g/dm2
Decal Font	Optima Extra Black
Motor	Turnigy C3530-1100, Kv1075, 73g, 15A Max, later MVVS 10 2/1120
Prop	9x5 Folding Prop
Speed Controller	25A max
Battery	2200mAh 3S LiPo

The center of gravity came out somewhat too far in the back unless two batteries are packed into the front of the plane. The total weight of about 1.2kg includes the two batteries and radio gear. The original plane had a slightly smaller wingspan, weight of 1.0kg, and a wing loading of 16-29g/dm2.

First flight was on the morning of August 28, 2011. Two brief flights before breakfast. It flies nicely! I was surprised how slow. Current draw is 13A at full power, and about 5A when cruising around.

--

17 July 2016: Axis of Turnigy snapped off (!) during climbout. Managed to land ok, but prop vanished in the woods.
Replaced with MVVS 10 2/1120. On summer evenings using about 400 mAh for 10 minute flight.