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Old Oct 10, 2012, 02:08 PM
jesolins is offline
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United States, TX, San Antonio
Joined Feb 2007
15,136 Posts
I have the bulk 716 motors with 1mm shaft, red/blue wires. The LB and all other micro quad motors are a bit more powerful 720 type. We still need to find a decently priced bulk source for those... I just recently used a bulk 716 motor on my v939 to check and test a right rear nodding issue to see if it was motor related. I was surprised that even though it is a lighter(716 = 2.4g vs. 720 = 4.6g) less powerful motor, there was no difference in the flight performance of the v939 to include fast climb outs. So maybe there are differences in the motors that they sell on Aliexpress? There are two places to that sell them on Ailexpress now too:

I did bin one of those bulk motors that I noticed the red wire was hanging on by one strand. There is no way to fix or re-solder that as it goes through and into the motor housing.

BTW during the 716 motor substitution test the v939 right rear nodding was still there and I eventually found it was a bad FET. And it was actually the left front FET. The nodding was from the left front speeding up sporadically and not a weaker right rear motor as I had previously suspected. The FET is marked A2shb. They are used on both the V929 and V939. I scavenged/borrowed an FET from one of my spare V929 flight controllers and it has been working fine since then. They are N-channel MOSFETs in the SOT-23 package. Mouser has them as

A2shb MOSFET Data Sheet:

Quadrocopter and Tricopter Info Mega Link Index

Originally Posted by dave1993 View Post
i dont have a v939 but my s107 and .7mm ali motors have more than enough lifting pwoer for my diy even with camera. it even beats my friends lb. 23 grams with 138mah battery for the 30cm one and 28 grams for the 60cm. a 600mah battery only adds about 10 gram so it dont look like weight is the problem. maybe this aliexpress dealer is not a reliable source although 2 guys who dont post here had no trouble lifting with them. and at least 3 guys are using the s107 motors from focalprice w/o problems. dj also said his lifted ok but i forgot what type of motors.

maybe its good i didnt change the parts list in post #1 because those motors are known to be ok. there are at least a dozen sources for 7mm motors so maybe its time to compile a list and keep track of what works. my 1mm ali motors should be arriving shortly so that will be interesting.
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Last edited by jesolins; Oct 10, 2012 at 02:44 PM.
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