Service Ceiling for a C85 powered 415-C?

52 is kind of way on the cruise side. I’ve had a 7149 for many years and I got 105-115 mph speeds at 2400 and it climbed really great. I used to fly into some shorter runways and that pitch worked out very well. And I had the C-85 with the O-200 crank STC. I think you would be amazed at the increased horsepower you get with the shorter prop. If your prop was really 73 you were basically flying a C-75!

Dropped off the prop at East Coast Propeller Services today. Fortunately that's only a 2 hour drive for me so I didn't have to deal with packaging & shipping.

Fingers crossed for the prop to pass the overhaul measurements & inspections. Once that happens, they'll be trimming it from 73 to 71 inches and increasing the pitch to 52 - seems that's a good set of measurements for the C-85 Stroker.

All remaining fingers crossed for a performance increase after the overhaul.

Larry,

Good catch! The prop hub is definitely marked 73/49 so I will have my A&P look at it. I know I'm meeting the static RPM, the prop was overhauled once (maybe shortened? Definitely was repitched) and I remember someone telling me that there's a trick to measuring the length of rounded tip propellers.

Will report back with findings.

UPDATE: Yup... looks like a visit to the prop shop is in order.

Brooks, if you have a 73 inch propeller on your airplane with a C85 you are illegal! Read the rather convoluted information in TCDS 718. The legal lengths of a McCauley on a C85 range from 69.5 to 71 inches. The 73 was for the C75 only. I believe if you go to a 71 you will see a marked increase in power.

I've been curious for a long time. Since I'm a sport pilot, I'm not allowed above 10,000, except to avoid terrain... and there's nothing tall enough on the east coast to qualify.

I have flown to 9900 (C85 "stroker" with a McCauley 1A90 73/49.) At that point I was still climbing at 250-300 FPM - solo with slightly more than half fuel. It was an interesting flight since it was 97 degrees on the ground, and as I climbed it became more comfortable to close the windows and then to crack open the heater. On the way down, experiencing the return to 97 degree heat was a lot less fun.

Sweet, good memories, sounds like a great trip!