up and down

i cant seem to get my heli to hover at one particular altitude, i have raptor with tt36 and sanward6000 tx. the engine either revs too high gaining altitude if i let off just a little the rpm drops quite a bit and descends too much. i am new to this but other guys i see flying their engines seem to stay at a more constsnt rpm. thanks for your help

[Andrew]

I would first check your physical throttle linkage setup. Make sure you get full travel and the correct angles like your manual likely asks for.

Second, I would check on your throttle curve on the transmitter. You can adjust this so that your RPMs stay constant over your blade pitch range. Alternatively, you could invest in a governer to keep a constant engine RPM. I've never used one, but hear they work quite nicely.

Third, if all else fails, find someone in your area who has tuned that engine before. It's sometimes difficult to diagnose engine problems on the internet.