Hi Jeff,
I know where you are right now, after 17 years of fixed wing I still had no idea how to tune a heli engine. The methods we use for planes just aren't possible.

There are others on this fourm much better placed than me to answer this question, and have done in the past. Do a search at the bottom of the page in this fourm and you should find some good info.

I put an OS 50 Hyper into my Titan last year, I strongly suggest putting a prop driver and propeller on the engine and running it in on the bench before you fit it to your heli. This will do two things for you.
Firstly. Better access to play with the needles and learn your engine settings, without putting your heli at risk. The prop wash also keeps it cooler. You can lean out the engine on the final tank at full throttle and listen to it to determine the best neddle setting. Then back off from this between a quarter and a half turn and the heli will be somewhere near right. When you do fly, at the end of the flight land and spool down the blades, immediately touch the back plate of the engine. If you can keep your finger on it for 4-5 seconds things are good, if it is too warm you are too lean, take the neddle out another half turn and try again.
Secondly. Once the engine is run in (about 8 tanks of fuel) you can setup your final throttle and pitch curves from the start. If you fit a new engine you will need to run it rich at first, and therefore less power, so run more throttle or less pitch to compensate.


Hope this helps.