Hi John,
Actually, Stunt does have throttling: the governor is throttling constantly, and as quickly as the ESC settings command.
My first inclination is to tell you to use the most retarded timing. It sounds like that didn't work? It beats me: what is your running current when the ugly sounds happen?

Dean P.

Russell,
So what was the PWM originally set to and what did you change it to? What ESC are you using and what did you set the timing to?

Best,           DennisT

Well more testing and this is what I found out.  I set the Turnigy Plush 60 speed controller back to low timing.  This was the setting from the previous test that ran the motor the smoothest.  On a freshly charged 4S Li Po it tacked out at 9400 rpm with a 3" spinner and the APC 14x8 EP prop.  This is about what I expected from a 750 KV motor on a 4S battery.

As I stated earlier I have a RC style throttle controller operating the setup.  I can go from 0 RPM to full RPM by moving the throttle stick on my controller. (pictures are posted on the LA-5 thread on the scale board).  When moving the  throttle stick at a reasonable rate everything works great.  The motor RPMs track the stick and the motor sounds normale.  However when I change the stick abruptly the motor goes into what I would call a missfire mode. However it recovers and operates normally again.  Next test I ran I removed the 3" spinner.  The problem still existed but to a lesser extent.  I then ran the test with the prop removed.  The problem was now gone.  So it seems to me to be a rotational inertia/load problem.  If you change the output from the speed controller faster than the motor can respond it seems you get a timing mismatch between location of the magnets and the current flow in the winding.  I suspect this upsets the back EMF and funny things happen.

Anyway as it stand I really don't have a problem because in actual flight the throttle is never snatched back and forth as I did in the testing.  All scale flying is at a controlled fairly slow rate to simulate the real aircraft.

So having said the above any further thoughts?

Hello John,
There should be a throttle response time or rate setting in the ESC setup menu. Set it to medium or slow, not fast. This will accomplish the same as throttling up smoothly, without forcing you to remember.
Dean

Hello John,
There should be a throttle response time or rate setting in the ESC setup menu. Set it to medium or slow, not fast. This will accomplish the same as throttling up smoothly, without forcing you to remember.
Dean

Tried the medium start up mode on the Turnigy Plush 60 speed controller.  Motor would not run right at all.  It just kinda putted along and never would come up to speed.  I tried the middle timing again and that seems to work the best.  I will put the tack on it tomorrow and see if the RPMs are OK.  I will also hook up my amp meter and see if their is a current difference between normal timing and middle timing.

John
Have you tried a smaller prop?. The RC guys seem to be running 12 and 13 inch props. Timing is normally set to low. Haven't heard of any trouble similar to yours.
PS
I just looked at the OS spec's It appears a 14x8 is too much prop , note they quote 30-40 amps for normal operation.
Specs attached

John
I understand you are flying with throttle. Most of my flying is done that way. However I have found some motors that act funny when over prop'd. While you probably won't over heat anything you might find that a smaller prop will repspone to you throttle input better, and still have enough power for scale maneuvers.