At 10:58 AM 3/3/99 +0000, you wrote: >Here's one for you. I have (supposedly) a C75-12. The prop on it, >according to the tag from the prop shop that was in the paperworks says >that the prop is a 1C90-LM7252. What engine is this prop supposed to be >on and what engine do I have? I say this becaused I cann't find >anything to indicate that my C75 was converted to a C85, but the dip >stick has been remarked to indicate 4.5 quarts and the plane has a tach >in it with markings for the 85 horse engine. Makes me wonder. >Dennis Schmaltz >Mission, SD >94715
Hi Dennis. I'm looking at the type certificate data...I don't see a "1C90-LMXXXX" prop at all. All I see that are anything close are 1A90CF or 1B90CM for the 415D with a 75. Is that what you have? If it's not in the engine logs and the data plate, I can't believe it's been converted. Later you said: >Jim, I checked it earlier and it was still the C75 nameplate, but the >engine runs like a scawled banshee. In cruise flight, I can easily run > out to 2550rpm at 5000 ft. msl. I keep it within the redline for a > 75 though. It will pull 2150rpm on the ground for a full power runup. >I believe the book says (I'm working from memory here) that the 75hp >should runup at 2100rpm. Anyway, it sure is a strong running little >engine. The prop may have been repitched to let the engine run faster. I had the wrong prop on my J3 once. It was the prop for the 75, and I had a 65. With the 75's prop, it ran like a 75, because all it did was let the engine run faster. It didn't make it a 75, but it sure ran like one. The TC data I have doesn't mention the correct pitch, only the min and max static rpm. Here's something that might help. Maybe you've seen this already, but it says "Conversion of the C75 engine to the C85 must be accomplished per Continental Service Bulletin M47-16 dated June 7, 1948 and the oil stick recalibrated..." and so on. Maybe there's a way to search the net and/or call Continental to see what the heck the service bulletin requires. Then maybe you could tell what you have. Let me know if you want me to fax you any of this. I got it off the net here somewhere, but I'll be darned if I can remember where it came from. I bet someone else here knows where it is. ---------------------------------------------------------------- Steve Dold ([EMAIL PROTECTED]) http://home.pacbell.net/sdold/ Say NO to useless over-quoting ----------------------------------------------------------------
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