any intrest in a 12.5 /4 carbon prop
There might be interest in a 3-blade that size. A 2-blade seems either a little too large for a muffled LA46, etc, and way too small for a piped 60-75. Even a 12.5-4 3-blade is on the small side for a 61. I am currently running a 13.5-3.75 3-blade cut down to 12.5, but the engine could handle much more.
If I was going to suggest something (no endorsement or obligation implied), maybe a 13-4 3-blade with a moderately wide blade and a flat or *slightly* undercambered airfoil. Not as much undercamber as the Eather 12-4 3b "red dye", more like the airfoil on the 12-4 "purple" where he sanded it into a flat-back prop. Maybe .025" concavity at the widest point at most. The deeper undercamber seemed to have too much "bucket" in the polars for a PA61/65, at least.
If you wanted to make a good LA46 prop, then a moderate-blade 12-4 with a semi-symmetrical airfoil. It can be cut down if necessary - not because engine can't handle it , but because the drag bucket issue would be exacerbated with no engine regulation. But then you are competing with the $2.50 APC 12.25-3.75 and similar.
The one prop I would be willing to buy directly is a direct copy of the Bolly 11.75-4.25, straight off an original, because that's the 40VF prop that I am nearly out of (after "loaning" out a bunch of them). If it's really the same, I would be willing to buy a few just to maintain the capability to use it again. NOS30 is up to 1987, meaning it won't be long before I can take my 40VF airplane from 1988 and fly it. Or build an Impact and paint it pink.
Brett
Topic: 12-1/2 in Di with 4 in pitch prop (Read 1166 times)