Originally Posted by
the Wasp
I don't know,,, could be,,,, although Saito's Home Page also suggest the same prop size
http://www.saito-mfg.com/single-file...80foreign.html
no-p, not to me, as I said a few people have reported that their Saito 180 pulled 8,800 to 9,100, I'm sure a 15X8 would rev up higher, I'm betting closer to 9,600,, 9,800, ,, again, I'm just wondering how much a 15X8 would unload in the air
Jim
A 15x8 would need to rev to about 10,100 RPM to absorb 2.8 HP. What would it be good for? Hovering maybe 3-D but not for an airframe that would be attaining any airspeed. If Saito specs maximum HP at 10,000 RPM , maximum torque is probably around 7,000ish.
Would you put a 6200 RPM stall converter on a street driven small block Chevy? Same thing as propping a Saito FA-180 @ 10,000 RPM static.
As far as how much ANY prop will unload in the air? That would depend on the airframe. It would unload a lot more on a P-51 @ 80 MPH than it would on a J-3 doing 40 MPH..
I think an 18x8 at 7900 RPM static would unload a lot more than a 15x8 because @ 7900 RPM it would already be in the fat part of the power band ready for more, not gasping for air at the top end.
The 15x8 @ 10100 RPM would generate 14# of thrust while the 18X8 @ 7900 RPM would generate 18#. What's the point in the 15x8 anyway?
I think that the 15x8 would be a great prop for an FA-115 CDI and that's what I plat to try on mine.
At 9300 RPM it will absorb 2.2 HP and that's about what I estimate the FA-115 with CDI and 15% nitro will make.