ORIGINAL: asupervee72
I appreciate your oppinion on the matter. The number you are coming up with is unloaded rpm. Eagle tree logging will show u that a motor rated at a certain kv will not reach that kv under load.
Correct, but the motor still TRIES to reach it's KV rating and that has nothing to do with it's efficiency.
Anything less than the KV rating represents power loss to the prop or wasted as heat.
ORIGINAL: asupervee72
Also this motor is rated up to 4s so 14.8 x 50 (the max rated amps) and that is where 750 watts comes from.
Correct.
ORIGINAL: asupervee72
On 2s you would need to pull 100 amps to pull close to 750 watts. So I am effectively using the motor with a 7x5 on 2s.
Incorrect for the very reason you stated; that to run close to 750 watts you DO need to pull 100amps from the motor, something your ESC and batteries cannot attain. That's the point.
ORIGINAL: asupervee72
A fully charged 2s lipo will read 8.4 v. But under a load they sag to 7.4 or even lower rather quickly.
In a properly configured system, the voltage output from the battery will start at around 8.4v and run that way for well over 1-2 minutes, then drop to around 7.4v or slightly below and stay that way when the plane unloads in the air.
If you are getting more sag than that, your battery pack is not up to the task.
ORIGINAL: asupervee72
Although ill suited, these electronics work just fine. Flew today for solid 6 min motor came down at 120 esc was 97 as were the batts. Tons of vertical power. It also does a little better in the wind with the added weight. I'm happy with it.
It is still an ineffective use of what you have. You are using LESS than 30-40% of the motor's capacity at MAX.
Your motor can produce far more power than what you are pulling from it, and you are yanking the excess weight this represents around in the air on the plane. A smaller motor would likely do better, weighting less and running more efficiently.
While you may not destroy your electronics ( only prematurely use up the batteries ) given what you are currently doing, you came here seeking advice which you received as to what problems exist with your reused electronics.
That being the case why come here in the first place and ask if you were already dead set on doing things as you've done?