RE: Run In
Hi,
Thanks for writing.
The break-in proceedure is the same for all of them. The only thing different is the prop selection and the rpm target you are looking for.
You want a prop that is basically one "size" smaller than you will be flying with. The concept is to take the engine to a clean 2 cycle, properly loaded, and approach its intended ground rpm while the engine is running just slightly rich (running without risk of overheating).
For the 35, an 8x6 works well - target 18,500
For the 60LX we usually recommend using an APC 8.8x8.5 or an 8.75x9W clipped down to about 8.25" diameter. Target 18,500
(Prop selection in this particular case mainly because the hubs on a standard 9x6, 9x7 are not really suited to turning 18-19-20K rpm)
For the SJ-90 we usually use an 11x6 or 11x7 - target 14,500
For the 90LX engines one can use the 11x7 as well, but target for around 15-15,300 for break-in. (engine flys great with that prop too).
Fuel..... break in on what ever you plan to run the engine on. Any decent fuel is ok, and we recommend using a synthetic/castor blend fuel. Our baseline published information is using 15% nitro. Nitro content from 5% to 30% is ok (some folks have asked in the past about using their heli fuel, just because the 'have it', and that is ok).
I personally fly the same 15% powermaster fuel in all of my engines (except the OS160).
I hope this is helpful
Bob