In the real world that 1/3 less fuel translates to about 1/4 - 1/6 less fuel actually used.

In practice I find my four strokers are not saving me anything significant in terms of fuel usage over the 2 stroke engines I could have used in their place.

Not that there is anything wrong with four stroke engines ( I do like them ), but this is not the big factor that it seems made out to be.

When dealing with .40 - 1.20 sized planes cost savings are not significant.

Going larger things change, but by the time I hit 1.80 CU I'm buring up so much glow fuel on my four strokers, that I'm better off going to gas instead.

My 1.80 CU four strokers seem to go through a gallon and a half a day at the airfield at a minimum.