Excessive head speed on VE, need setup advice

[gpontis]

Voyager E, Feigao 540S-10 with 17t pinion, 3S LiPo, G410T with HS-5925MG

I have been flying this heli at a basic level using a HiMax 3200 KV motor and 15t pinion. After a crash I was trying to figure out what went wrong and was led to low head speed. Sure enough, it was only 1410 RPM. I also measured the battery current at 25A while pinned down with full up collective. So I purchased and installed this Feigao motor. It is a good size for this heli in terms of size and fit.

While playing with pitch and throttle curves, I had the bird pretty well reved up on the ground, and before lift-off one of the tail grip screws let loose. It was broken clean off right where it exits the aluminum tail hub. I replaced the now bent shaft and hub but did not have extra 2x10mm screws to reinstall the TR grips and blades. I tested the main rotor RPM with the skids pinned down. As best I could tell, it was able to rev the head to 2000 RPM or more. I am not sure exactly what the pitch was in this condition, but it was at least 5 degrees up and probably closer to 7-8. I am thinking that this is excessive for a stock head and wood blades, and was probably the cause of the TR self-destruct. It would also explain the strong climb performance that this bird has now. I might add that I had to reduce the gyro gain to compensate for the increased tail rotor speed. Makes sense in retrospect but I did not anticipate it.

So here's what surprises me. This motor is rated at 3524 KV, well under the 39xx KV for the popular hacker motor. I would have guessed that this one and the Hacker are of comparable torque, and did not expect to get this kind of headspeed. Did I misjudge the motor/battery combination or were the measurement conditions inappropriate ?

Once I get the right pinion in there, are there any suggestions for pitch and throttle curves for normal mode ? I have the mechanical setup as per the VE manual.

Thanks,
George

[gpontis]

After some judicious experimenting I found that this Feigao 540S 10t motor works well in the VE with a 16t pinion (Traxxas 3946) and a throttle curve that provides 90% under normal flying, only going to 100% between 80 and 100% collective input. At hover and easy flying this provides a bit over 1750 RPM head speed at 29A average draw from a 3S/4200 Thunder Power. At max collective the current can spike up to 55-60A and RPM drops to 1600 RPM. This is with stock JR blades and mechanicals according to the manual. I am using a 36mm motor heatsink from Maxx Products / MPI and motor temps seem very reasonable. I should also mention that the overall gear ratio with this pinion is 21.875. This puts motor speed close to 40K RPM, which is well within the motor ratings and probably a good operating point for efficiency. WIth a lesser battery than the