I am using Sharma Diesel Engine.... a very reliable and robust Indian engine and also the OS 25. I don't know how to set my OS to run the 4 2 4 break as I have no clue how to adjust the fuel while in flight. This is the engine I been using.... been using these since 1982 onwards... as thats a very popular small engine here in India.

Today I tried a 9x4 prop on the Sharma 3.2CC instead of the 9x6 I was using always.... The model flew slower but had good tension on the lines. I managed to do one overhead figure of 8.

That was the icing on the cake.