ORIGINAL: BillS
I use the prop sweep to indicate volume loading and the results are as follows:
Load
11-10 950
12-9 1017
13-8 1061
14-7 1077
14-6 923
15-4 707
It is also very important to keep the engine in the power band.
Bill
The problem with volume loading only, is that it ignores the greater frontal area & wetted area of the longer blades.
My personal experiernce with engines in the 40 - 90 size, & their associated props, is that 1" of diameter approximates 2" of pitch in engine load. This correlation is best demonstrated with engines that have relatively steep power & torque curves -- they are more sensitive to load, & the RPM changes are more pronounced.
A TT 42 GP is an excellent example. My 42 GP turns 13,000 RPM with an APC 10-6, 11,700 with a 10-7, 13,100 with an 11-4, 11,600 with an 11-5, 10,900 with an 11-6 & 11,100 with a 12-4.
It very nicely fits the 1"dia = 2" pitch correlation.