ORIGINAL: downunder
..."In this case, a 10x6 would load the engine like an 11x4."[/b] I disagreed with you but had nothing to back up my disagreement so I did this experiment precisely according to the prop figures you mentioned. Now, because the results I got showed it had no affect, you're shifting the goal posts and making silly arguments about what I should have done (in your opinion).
You did not do the experiment precisely enough!
The fact that you needed to run the engine richer with the 11x4 prop, since it obviously unloaded the engine less than did the 10x6 prop, resulted in making the engine run cooler, or is that also a myth, according to your opinion?
This is one major imprecision.
As for inferring that I might be using a totally worthless type of thermocouple to fault my readings, I use a contact type thermocouple which plugs into my digital tacho/multimeter and has been calibrated using the phase transition points of di-hydrogen monoxide.
I precisely wrote 'not one of those totally worthless, infra-red, visual thermometer'. Reread my post!
Thank you for clearing that up.
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If by writing 'trying to reason with him' Dave meant 'to make me accept a common misconception', then you really are pi$$ing against the wind... Misconceptions are! I prefer facts. I analyze, so I understand; instead of just following in the footsteps of others.
The only reason those 'big names' are all telling you to use a prop of the same pitch and a 1" smaller diameter, or the normal 6"+ pitch, chopped 0.5" from each blade, is that they
all fear cooling could be impaired by using a flatter prop.
Or, do you think there is another concrete reason for this? What is it?
You may want to do the break-in in Antarctica in August, just to prove an engine doesn't need cooling...