Doug Sipprell's blog archive for July, 2010 - RC Groups
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Archive for July, 2010
Posted by Doug Sipprell | Jul 22, 2010 @ 12:57 PM | 10,083 Views
Some time back, I purchased a Speedy 400 from Hobby Lobby Intnl. The plane was essentially a pylon racer trainer, powered by a brushed Graupner Speed 400 motor, pulled by a 6x4 folding prop, and fueled via an 8 cell AA NIMH 1100 battery pack. The first flight clearly indicated I was having a problem flying the plane, it was constantly "late" on aileron input. No rudder on this plane, just barn door ailerons and elevator. I was up and down (Speedy was very sensitive to elevator movement!) and all over the place in trying to maintain level flight.

The problem was the central mounted servo/bowden cable arrangement for the ailerons. I went up on RCGroups and asked for help. A fellow in Switzerland replied, advising I install individual servos for the ailerons, as the stock system allows for non-centering of the ailerons due to friction of the bowden cable within the plastic tubing that located the cable within the wing. Wow! What a difference. I used Hitec HS-55's, used a Y-cable arrangement, and the problem was solved.

After flying the Speedy 400 on it's stock motor arrangement, I decided to go brushless. Wish I knew then what I know now. I grossly over "motored" the Speedy by installing a Mega 16/15/3 brushless inrunner. Talk about high prop rpm's and eating amps. The NiMH 1100 packs would barely hold voltage, got so hot the plastic wrap melted! Then I discovered Lipos. A 2-cell 2100 Thunder Power 12C pack would provide more...Continue Reading