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
[EMAIL PROTECTED] wrote: > > Charlie, If I remember correctly, for the 75 it should be a 73" dia. > with 71" perhaps being the minimum for repair. The pitch is finer than > that of the 85 prop, so it should be 7351 (I think) for the 75. If you > install a 85 HP prop on the 75, you "may" get the same performance as the > 85. 85 props are 7150 std, and 7148 climb, with 69.5" being the min. for > repair. The shorter prop allows for the acheivement of the higher rpm > of the 85. The 75 hp McCauley specs are in the Service Bulletins and > Memos. The spec for the 85 hp McCauley prop are in the Univair catalog. > > Speeds. We used to fly 3 Ercoupes in loose formation with a Cessna 140 > with 85 hp. The other two Ercoupes airspeed indicators read higher than > mine. They said, "they cruised at 110." My coupe, indicated 100 (110 > WIDE OPEN LEVEL !) was faster than theirs regardless of the indicated > airspeed. And, alas, the Cessna with the same prop and engine could > steadily pull away from me when I was wide open. My prop is a 7150 which > now measures at minimum diameter of 69.5". I have had people tell me > their coupe cruises 110 and even 120 but it ain't so. In the real world, > and if their airspeed indicators were right, more like 100, 105, 109, > depending on model, engine, etc. > > Engine condition. Prop. Rigging. Drag (mucho antennas, etc.) Getting > on the step. All of the above, and more, impact top speed and cruise > speed at a given rpm. Oh, and the top of the canopy is a real source of > drag. Do you fly with yours cracked? I have put a shade panel in mine > and the two side windows which used to meet at the top not just come up > to the edges of the shade window which is Smooth on top. Really, a 75 > ought to go just as fast as an 85 hp model, assuming both have engines > that are not "tired." > > Grover > 99398 > Columbus, GA > On Thu, 25 Feb 1999 10:00:39 -0500 "Charlie Nightingale" > <[EMAIL PROTECTED]> writes: > >Need to know if anyone has the following: > > 1. What is the correct Mccaully prop for a 75hp Ercoupe under > >cruise > >conditions.The numbers on mine have been overmarked and > >are not readily readable. It looks like CM 71.??. My speed is only > >about 98 > >mph by GPS AT 2450. I believe it is a CLIMB prop?? > >Charlie N555CN Farmville,VA. > > > > > > ___________________________________________________________________ > You don't need to buy Internet access to use free Internet e-mail. > Get completely free e-mail from Juno at http://www.juno.com/getjuno.html > or call Juno at (800) 654-JUNO [654-5866]
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