Mera'din,
It's not your motor stalling. It's your Prop.
At full speed your motor is turning somewhere between 13320 and 15520 RPM. Nicer props will spec a maximum speed in terms of 40,000-200,000 RPM/in of prop, which would range from 4-20k RPM for your selected prop diameter. The actual spec is dependent on how the prop is built (shape, material, thickness), but typically the slower the prop the lower the number.
Don't know about the spec of yours, but the signs are there: tone in the motor changes to a warble, thrust drops dramatically.
Demo: (he's showing off reliability of prop savers, but runs a SF into a stall about 1:05)
Couple of options:
- If you have enough thrust before it dies off, you can dial the throw back in your radio, so you never give too much throttle. Make this setting on a freshly charged battery, since WOT RPM drops with charge.
- If you have a prop balancer, you could *carefully* trim a half inch or more from the prop and rebalance. just make sure your cuts are clean and sanded prior to balancing -- don't want it throwing off a dirty edge.
- Pick another prop: You can raise the diameter, while picking a faster pitch, should give you the amp draw+thrust increase. A nicer brand with a better prop design may or may not take the extra RPMs -- most of this is fighting the physics.
You've gotten just about all you can out of that poor prop, just before it stalls. If that's not enough, time to move to a new prop.