FYI http://www.pj260.com/Continental/O-200%20Manual.pdf
this is the 30010 To: [email protected] From: [email protected] Date: Thu, 19 Nov 2009 20:29:20 +0000 Subject: [ercoupe-tech] Re: Proper mag check rpm Bill and everyone, Since you can't achieve 2575 RPM on the ground doing a static runup, I would say the 2050 RPM in the 415-D Flight Manual for the C-85 is a more realistic approximation of full throttle. 2000 is just under what I can get at static full thottle, and I get around 2150 on the runway as the airplane begins its roll; RPM then increases as speed increases. But I agree with your analysis, and that it was probably related to propeller life as well as engine operating RPM. I just don't see the need to do a 2000 RPM run-up to check my mags. 1700-1800 should suffice as long as I'm also checking my full throttle RPM on the runway and am prepared to reject the takeoff if I'm not getting 2100 RPM or above as I start the takeoff roll. Also agree that since there is no idle cut-off function for the Stromberg mixture control, that is not applicable to engines with the NAS3A1. Just wish I had a copy of the 1980 X-30012 document to supplement my X-30010. If you have a PDF or know where to download it, I would appreciate it! Thanks, Dave --- In [email protected], William R. Bayne <ercog...@...> wrote: > > > Hi Ed, Dave > > You are both making reference to the same FAA approved Overhaul Manual, > Form X-30010 of 02/80. > > If you refer to page 106, the table of "Test Operating Limits" > following overhaul calls for magneto drop testing "at Full Throttle > (RPM)" which is specified in the top column as 2275-2325 for the C-75 > and 2575-2625 for the C-85. They specify that such testing on the C-90 > and 0-200 be done at 1800 RPM. > > They repeat this on the following page in their "Start Oil Consumption > Determination" table following the Period 5 Warm up. > > In my experience, mag drop is not significantly different over 1700 > RPM. With reference to Ercoupe Instruction Manual recommendations of > "full power" runup, remember that the long props swung by the 65 HP > original Ercoupes could not turn up as fast as the later C-75 and C-85. > Since full power runups are even more damaging to (the original) > wooden props than today's metal ones, it may well be that the adverse > effect on propeller service life of increased static RPM from increased > horsepower was never reexamined by ERCO. > > Consider that the 0-200 spins the smallest diameter prop the fastest > (additional ground clearance) and the C-90 spins a 71" prop. These > engines are of higher compression and displacement because of greater > stroke than the C-75 and C-85. If 1800 RPM is considered sufficient > for their testing, it makes absolutely no sense to me to subject the > same 71" prop on a C-85 to possible foreign object damage during full > throttle operation up to 2625 RPM sitting on the ground, or the 73" or > 74" prop on a C-75 at 2325 RPM. > > I took the trouble to go further into my files and drag out my 1980 > version of the FAA approved Continental Operator's manual, Form X30012. > There, big as life, on page 15 again appears the direction to check > magneto drop at 1700 RPM. (This is the recommendation in the Flight > Manuals for the Alons and M10s). I am not aware of a later version. > On page 16 Continental suggests then increasing RPM to 2200 RPM to > check operation of the Mixture control, but the wording used suggests > this pertains to engines with Marvel carbs in referencing "idle > cutoff". I would ignore this inasmuch as Forney, Alon and Mooney > specify no such testing. > > Interestingly, Forney recommends 1500 RPM for their mag checks, the > figure Ed used. If I were contemplating using a dirt strip I would > check in advance (on a hard surface) what kind of mag drops occur at > 1200 RPM and, if satisfactory, use that RPM on dirt or gravel strips. > > When all else fails, use judgment ;<) > > William R. Bayne > .____|-(o)-|____. > (Copyright 2009) > > -- > > On Nov 18, 2009, at 22:05, Ed Burkhead wrote: > > > > > > > In the Overhaul Manual for the C-75, C-85, C-90 and O-200, Section VII > > OPERATING INSTRUCTIONS (page 40), it instructs the operator to "open > > the throttle gradually until the engine is running at approximately > > 1200 R.P.M. Do not exceed this speed until oil temperature has > > reached 75° F." In the next section, "GOUND TEST," it says to do the > > mag check but nowhere does it say to increase the rpm above 1200 rpm. > > http://www.pj260.com/Continental/O-200%20Manual.pdf > > > > Ed > > On Nov 19, 2009, at 00:35, bigbrownpi...@... wrote: > > > Bill, > > > > Strange that they didn't carry it over to the Feb 1980 copy of the > > A/C/O-200 Overhaul Manual I have (Form X-30010). I looked at Para 7-4 > > under "Ground Test" on Page 39-40, and it does not specify what RPM at > > which to perform the mag check. Thanks for your reference. I have > > copies of several checklists being used by others and they seem to use > > anywhere from 1600-2000 RPM. The 415-D AFM says Full Thottle approx. > > 2050 RPM, the 415-C Instruction Manual says Full Throttle 2000 RPM > > approximately, so that's probably where I got the 2000 RPM I used in > > my checklist. That seems excessive to me, so I would probably go with > > the lower RPM in the TCM document. > > > > Thanks, > > Dave > _________________________________________________________________ Hotmail: Trusted email with Microsoft's powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141664/direct/01/ http://clk.atdmt.com/GBL/go/177141664/direct/01/
