ORIGINAL: STG
ORIGINAL: Flyer95
This engine responds good to a tuned pipe. My ST90 on a tuned pipe turns a APC 15x6@10000, APC 15x4W@12000 and APC 13x8@12000rpm. I am currently running a Master Airscrew 16x7 to keep the rpm & noise down
The 15x6 and 13x8 should be much closer in RPM -- the load in not that far off.
STG,
This is not accurate.
Within the prop sizes most of us use, the load (and hence, RPM) is kept about the same, when 1" in diameter is equivalent to 2" in pitch.
This means a 13x8 prop would be spun by an engine at about the same RPM, as a 14x6 prop of the same design.
APC props I have tested exhibited a difference no larger than 100 RPM (to the 13x8's advantage), on an MVVS .91.
This is also true of 12x4, 11x6 and 10x8 APC props (on an MVVS .49).
Differences may change a bit more, since high pitch props tend to cool the engine better than low pitch props that have the same load.
And as to thrust; even though the HP output is the same, at identical RPM levels, the static thrust is greater with large diameter, low pitch props, than with small diameter, high pitch props.
This makes one wonder why some thrust calculators use HP x 6, to calculate static thrust...