ORIGINAL: FlatSpin
rmh,
Thank you for the great inputs! My assumption was that the max RPMs were achieved in a dive based on hearing the engine wind up as it was descending. I noted the min/max RPM numbers after I landed and assumed (yep, made an ***** out of myself!) that the max was in the dive. I will most certainly have an observer next time to read the numbers out as I climb and dive to confirm what the engine is doing.
Dave
The early evolution gassers had a tattletale in the ignition- we would fly the models and never use full throttle except in level flight- OR- climbing everything else was at low throttle
After landing we would read the ignition rpm display
this way, we got good reading of max rpm under load . We compared readings with the observed aircraft performance.- It is a cut n try thing.
The exercize was to find best setup for max performance such as sustained verticals with snaps . On the 26 it proved to be at about 9,500 to 10, 000 rpm when working -
typically the smaller the engine the faster it must turn to extract max output NOT just max rpm.
the smaller pops get less efficient so they have to turn faster.
For nice sport flying this is perhaps over the top but - you can't get more power just adding a bigger prop - - there is a narrow window of max power and you have to stay in it.