max42

I've searched through most sites for information on the Shockwave. I found several build threads, all nice info. I just finished mine and put an e-flite 370 on it with a 10x4.7 prop, AUW was 15.9 oz with the LG and a 1320 Lipo. Here's the issue, too much current for the 370. I was measuring about 18A and that little motor gets hot quickly.

What I didn't see in other posts was hardly a mention of prop size. I have a 9x3.8 that I could use but don't think it'll bring the current down enough. I would probably have to go with an 8inch or smaller prop but don't know how it would fly with that size. What prop sizes are people using?

Do I just need to get the eflit 400 to carry the current? What prop size seems to be the concensus for best performance.

Ryguy

My Feedback: (1)

A Park 400 would be best, 16oz is on the heavy side for that motor. However, you should still be able to hover. 18A full throttle static isn't too hard on the motor, because in the air whenever you use full throttle, with the exception being accelerating from a hover, you have airflow already so you won't be pulling as many amps. If you still don't want to fly with the 10x4.7, try a 10x3.8 APC SF, E-flite even recommends this prop with it, or if you'd rather have more speed and sacrafice a little thrust, go with the 9x4.7SF.

max42

it doesn't look like a 400 gives much more current handling. I thought I looked it up and it could handle 17A. A quick search now showed the 400, 740kv 7A continuous and 10A burst; 400, 920kv 10 A continuous, 13A burst; while the 370, 1360kv supports 9A continuous, 13A burst.

Do you think the 9x3.8 prop would fly this plane with plenty of power, some 3D, and slow flight?

Ryguy

My Feedback: (1)

Those are just the manufacturer recommendations, and if you're not over amping your motor you're not flying 3D! Go for the 9x4.7 or 10x3.8.

Wait, you have the Park 370 1360Kv? That's really a two cell or higher speed park flyer motor, not a 3D motor. Either get the Park 370 1080Kv or a Park 400 920Kv. The 920 Kv though only rated for 10A continuous and 13A burst is really good for about 13A continuous and around 17-20 burst.

WhtBronco

IMO that's simply not true. I am currently running a Hacker A20-20L on a 14oz AUW 3D plane. Using a 10x4.7 I can't even pull the max amps the motor can handle yet it climbs out of a hover at truely ballistic speeds. The motor, ESC and battery barely get warm, just above ambient temp. If you ask me if the motor gets hot and does it quickly and you know you're pulling too many amps you are just quickly reducing motor life, possibly battery life as well. You need a motor and ESC that can handle the power you want and you can have it and still have a light weight plane that 3D's great.

The Hacker A20-20L is about $65-70 and would a perfect match for your 16oz plane. It's even the recommended motor for planes up to 20oz from 3D Foamy.

The motor and battery in my T-Rex heli get extremely hot when flying hard and I know this is pushing the limits of both and will significantly reduce their useful life. In this situation I except it as it's normal in helis. A bigger pack won't fit and all the motors run hot. This is not necessary on planes.

max42

Thanks, I guess I'll upgrade to the 400 920kv.

Ryguy

My Feedback: (1)

WhtBronco, that was just a joke. Over amping your motor is not a good idea, however, if trying to minimize weight while maximizing power, over amping is often ok. Many manufacturers ratings are less than what the motor can handle, but it still always a good idea to try to stay within those ratings.