Ok, I am learning here but there seems to be the power absorption coefficient of the propeller missing, as in BHP=P X RPM3.

Where P is that coefficient and running on the assumption that the recommended prop for a Cox 049 diesel is indeed a 6x3 the power increase between 14000 rpm and 16000 could be as low as 1 ounce/inch (going from 0.45 to 0.55) bearing in mind that small diameter props have a far flatter power increase curve than larger ones.

Or as high as 0.75 to 1.5 when using a 7X3 APC prop.

Based on -
http://adriansmodelaeroengines.com/c....php?cat_id=57

But either way 50% is a massive power increase from just a 3% fuel additive.

Thanks.