View Full Version : Headspeed - stock MX400
hueyman
06-26-2007, 01:45 PM
purchased a 3550kva motor with an 11tooth pinion... advertised as a good Trex powerplant. Well, i see the Trex main is 150 tooth and the MX400 is 138 tooth which puts the MX400 headspeed with a 3S lipo around 2500 rpm. (Fully charged battery at WOT gives around 2900RPM) :shock:. Same setup in a Trex would give about 2000 rpm. I have to lower the throttle curve to 50-60% max to to stay around 2000 rpm. I don't want or need 2500 rpm headspeed. is the Trex main gear a direct fit on the Helimax MX400?
Thorimmortal
06-27-2007, 09:58 AM
no the trex main gear will not fit , the counter gear and motor mount are not spaced enough to squeeze the 150 in between them not to mention the frame cut out is too small for this gear, what is the altitude where you are ?
hueyman
06-27-2007, 10:16 AM
I'm in the chicago area so altitude is not a factor. i can regulate hs with the curves for now but i'm sure it's not good for the esc. I don't think the stock head and blades can take much over 2200. did some extensive searching and ordered a 10t pinion. Looks like the easiest solution.