I have an OS 120ax engine... I used a 16x4W prop with 20% nitro fuel content... I snapped the blade on second flight, both sides of the 2bladed prop gone... my question is when going up in nitro one needs a larger prop probably from what I have experienced... if I go down to 5% (still have extra 5L left) can I use then a smaller prop like a 15x6? thats what OS recommends(prop), but on tower they recommend again 16x10-12 or 15x10-12... but they don't mention with which fuel... (naturally by decreasing nitro content you get less engine power?)