National Aeronca Association Bulletin Board

Hi, I'd like to beat this dead horse a few more times, I'm thinking about installing the Aircraft specialties 100hp upgrade kit in my c85-7BCM. I've looked around in your archives and couldn't find anything on prop compatability. The way I understand it is this upgrade gives you a 100hp at 2475rpm. My prop is a 72"X39" McCauley so I get lots of rpm out of it on the c85. I don't think this is much good for the upgrade, so I guess the question is, what props are being used with this instalation and what are the results?
bob

Robert,
I believe it allows the installation of a 100 HP crankshaft (O200). The prop would be the same as any C85 would use.
Paul

The STC does not call out another prop for use so you are bound by what is utilized on the C-85. I am using a 1b90 McCauley 71x44 and get great perfomance 2525 rpm static and about 2475 on climb out. Cruise is about 87mph this time of year and in the summer O.A.T. 80 degrees or better its about 82 or 83 cruising at 2350rpm. First off the ground and last back down but then again a Champ aint no speed demon. I like being able to get in and out of these little ultra light fields with no problem and I'm 250 lbs, she's 130lbs and 20 gal. of fuel

Capt Kelly could chime in on this thread. He bought a new prop for his super 85 from Don Swords. According to several folks, they built a new prop designed to optimize the performance of this little engine. Give me a few months and I can tell you a little more. Hopefully by then I will have my engine completed!

It is true that we have a Champ with a Don Sword C85/0200 engine. It runs like a sewing machine, or a Honda...if you will. I can't remember the specifics on the props we have, but if you can be a bit patient, I'll get it and report tomorrow. The new wood prop is a bit slower than the metal one it replaced, perhaps 5mph slower. However, we still cruise at 90-95 mph. What the wood Sensenich does provide is another ~20 pounds of useful load, instant throttle response, very smooth power, and a better takeoff and climb. Our C-85 engine uses the 0200 case (STC'd). About the only actual C85 part it has is the camshaft. Using this cam, the updated C85 peaks at 2475 rpm, not the 2750 rpm that a 0200 delivers. Our Champ engine is exceeding sweet to operate, climbs well at gross weight (1300#), and makes this Champ a real joy to fly.
I'm sold.
Specifics on the props tomorrow.

Mike

The prop is a Sensenich W72GK44.

Doug