wright3

Hi,

I just sent my inquiry to the E-power section by mistake so I'll repeat the gist of it here. I recently replaced my Formosa's 350 motor with a GWS 400 motor (3:1 ratio). At this point, I think I made a mistake. I'm using a Kokam 2S 1500 and Pixie 20 amp ESC. I've tried the folowing slow flyer props: 9x4, 9x7, 10x4, and 10x6. I rebalanced the plane by moving the battery back about 3 inches. Everything is working as it should. The plane's foreward speed is down with the smaller props and thrust seems down with the 10 inch props. I'm pretty sure the Kokam at 8C can handle the amp draw (the motor maintains wide open throttle).

Is the 400 motor just a dog compared to the 350? How would the 400 like another cell (3S Lipo)? I'm about to go out and buy the brushless I should have in the first place but I'd hoped the 400 would be a nice intermediate step on my way to brushless.

Thanks for all your help. You guys have helped make me capable of flying without crashing (too often). I have no one in my neck of the woods to help me with advice or assistance at the football field so I'm self taught. My Formosa has had about 40 15 minute flights with only a few easy to fix mishaps. I'm getting the hang of it and having a ball.

Randy

Dr Kiwi

Look at the Aeromicro charts for that motor - I believe you are "under-stressing" it on 2s with those little props. I think you should be running at least an 11x4.7 on that 400C with D-gearing (3:1) - even that is probably pulling no more than 7.5A: - try a GWS HD 11x7 or even a 12x8 GWS HD and see how it flies (your Kokams and the 400C should be able to cope with 10A or more).

Cheers, Phil

wright3

Thanks, Phil. I think you're right. I checked my voltage after flying for about 12 minutes, mostly at wide open throttle just to keep the thing in the air and my battery had only discharged from 8.3 to 7.65 volts. Battery was barely above the air temperature so I have to assume I wasn't working it very hard. I'll try the larger props. GWS doesn't recommend those bigger props on the chart I got with the motor, thats why I tried all the 9 and 10 inch sizes

Randy

Dr Kiwi

Here are the Aeromicro numbers - I reckon you should be able to safely extract a bit more than 8A (10A might be pushing too much) with a slightly larger prop on 2s:

EP1147 7.2v, 7.4A, 53.28W, 333g, 11.75oz, 6.25g/W

Cheers, Phil