DM20BB experiment

[t-turley]

http://www.rcmicroflight.com/upload/DM20BB.jpg

The above is my homemade DM20BB setup. I haven't had a chance to get a full flight out of it yet, but test hops in my driveway were spirited - much more so than with the GWS system. I hope to give a better flight report later this week.

Tony Turley

[flyingbuddy]

About 7 years ago, I tested the Kyosho DM20BB which was fit inside a VL Products 4.9:1 planetary gearbox. A 1/32" shim was used to fit it. I seem to remember that the combo weighed 49g. All of my R/C stuff was stolen 4 years ago, so I have to rely on memory.
As I recall, the thrust with the 7x4.7 VL prop was about 4.0oz with a 6 cell NiCd at 4.0 amps., or 28 watts.
With a higher gear reduction and a bigger prop, it might be viable.
Mike's Tiny Models seems to believe in these motors, which were hard to beat a few years ago, but I'm not so sure now.
It looks like you have an APC prop on a Pico Cub or Tiger Moth.
Good luck! I hope it works well!

[t-turley]

John,

You are correct in that the model is a GWS Pico J3, with an APC 8x6. I didn't get to fly this evening like I had hoped, but the way the thing leaped into the air on my test hops in the driveway, I think it will be a winner (fingers tightly crossed!!). The gear ratio is a little more than 6:1, and I'm using 8 300NiMH.

Tony Turley

[t-turley]

I slipped out this morning before it got too hot, and flew the remotored GWS Cub. No gear slippage on the shaft this time. This setup draws almost 4A at full power, but with judicious use of the throttle, I got over ten minutes -including several landings and takeoffs. Even with the pack about 75% depleted, it flew out of my hand with a gentle push. Needless to say, I am very pleased. This may not be a viable option for everyone, since I had someone available who could machine part of my setup for me, but it should last a lot longer than a GWS motor.

Tony Turley