AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Engine doesn't make minimum static rpm          AirTalk.org Forum Index -> Owning Airplanes View previous topic :: View next topic   Author Message Bob Fry Guest Posted: Tue Jun 21, 2005 4:36 am    Post subject: Engine doesn't make minimum static rpm Aircoupe Alon A2 with C90 engine with two props, one 48" pitch and the other 52". It doesn't make the static runup RPM minimums with either one, for instance the 48" prop should be 2225 to 2325 rpm, I averaged out to 2162 rpm. Likewise the 52" prop falls short 100 rpm or more. Three years ago when I checked the tachometer, it read a little slow--maybe 10-20 rpm at speed, that is it would indicate 2300 and the electronically measured rpm would be 2310 or so. Assuming that's still true, what would cause the engine to not make minimum rpm? Where should I start troubleshooting? Back to top tony roberts Guest Posted: Tue Jun 21, 2005 4:56 am    Post subject: Re: Engine doesn't make minimum static rpm I would start with the Tach. Tony -- [email]Indiacharlieecho (AT) hotmail (DOT) com[/email] Tony Roberts PP-ASEL VFR OTT Night Cessna 172H C-GICE Quote: Where should I start troubleshooting? Back to top papenfussDIESPAM@juneauDO Guest Posted: Tue Jun 21, 2005 11:04 am    Post subject: Re: Engine doesn't make minimum static rpm In rec.aviation.owning Bob Fry <bobfry (AT) mailinator (DOT) com> wrote: : Three years ago when I checked the tachometer, it read a little : slow--maybe 10-20 rpm at speed, that is it would indicate 2300 and the : electronically measured rpm would be 2310 or so. Assuming that's : still true, what would cause the engine to not make minimum rpm? : Where should I start troubleshooting? In rough order of liklihood - Tach - Mixture (Here at 2100 MSL, often too high DA to get full RPM in the summer) - Timing - Air filter - Muffler blockage - Compression - Ignition (plugs) - Ignition (others... unlikely: mag internal timing (egap), wires) -- ************************************************************************* * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * ************************************************************************* Back to top Stubby Guest Posted: Tue Jun 21, 2005 12:47 pm    Post subject: Re: Engine doesn't make minimum static rpm tony roberts wrote: Quote: I would start with the Tach. Good suggestion. There is a program available for a Palm Pilot that indicates RPM using its built in microphone. Back to top Jim Burns Guest Posted: Tue Jun 21, 2005 3:18 pm    Post subject: Re: Engine doesn't make minimum static rpm Borrow a optical tach from a A&P. Dynamically balance the prop(s) Cory hit upon a good idea ie muffler blockage. You could have a blown baffle or collapsed tube in your muffler. Jim Back to top klmuller@snet.net Guest Posted: Tue Jun 21, 2005 3:18 pm    Post subject: Re: Engine doesn't make minimum static rpm I just went thru this with my Beech Sundowner. It was not making minimum static rpm and would not go over 2500 at 7500 ft leaned. Everything checked out, then pulled the prop and had the prop shop check it and it failed. Not enough metal to overhaul it and it surprised me cause it looked good. Put a new prop on it and now getting 125 rpm more at static. Bob Fry wrote: Quote: Aircoupe Alon A2 with C90 engine with two props, one 48" pitch and the other 52". It doesn't make the static runup RPM minimums with either one, for instance the 48" prop should be 2225 to 2325 rpm, I averaged out to 2162 rpm. Likewise the 52" prop falls short 100 rpm or more. Three years ago when I checked the tachometer, it read a little slow--maybe 10-20 rpm at speed, that is it would indicate 2300 and the electronically measured rpm would be 2310 or so. Assuming that's still true, what would cause the engine to not make minimum rpm? Where should I start troubleshooting? Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         AirTalk.org Forum Index -> Owning Airplanes All times are GMT Page 1 of 1   Jump to: Select a forum Aviation----------------alt.aviationAviation safety EnhancementPlanes, gliders and flying in AustraliaAviation et pilotage (Français)rec.aviationAviation (Aerobatics)Hot air, gas balloons and airshipsHang-gliding, paragliding, foot-launched flightAircraft Design & BuildingInstrument Flight RulesAviation (Classifieds)Military AircraftNaval AviationAviation (Miscellaneous Topics)Owning AirplanesAviators (General Discussions)Aviation related productsAircraft RestorationHelicopters and rotary wing aircraftsFlight SimulationSailplanesAviation (Students)Light aircraftFlying related activities in the UK Airports----------------alt.airportsEdinburgh Airport Glasgow Airport Humberside Airport Luton Airport Aberdeen Airport Glasgow Prestwick Airport  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.