by Jim Worley » Mon Jul 08, 2013 7:28 pm
Kota,
My 61 250 had an APP cowl on it when I purchased it so I can't speak to performance improvement. I don't have cooling problems. I have a slightly high 5&6 cylinder, but I'm pretty sure it's my baffles and not the cowling. I really like the cowling. No cowl flaps is a great thing. It looks cool, is very distinctive, and goes off and on very easily when MX is required. In 10-15 minutes I can have the nose completely uncowled. I've never went out and done a max speed test. These are my normal cruise numbers.
2400 RPM, 153 KTAS, WOT, 10-15 deg LOP
8.5K - 9.5K MSL - 11.2 GPH - 66% power
10.5K - 11.5K MSL - 10.7 GPH - 65% power
12.5K - 13.5K MSL - 10.1 GPH - 61% power
From my very limited Comanche perspective, I would recommend it.
v/r
Jim