The tack was overhauled, cleaned and hour meter reset to 000. We have checked with a calibrated optical tach that count the RPM. it’s very close at high rpm.
Sent from my iPhone > On 28 Aug 2023, at 13:29, Phillip Matheson <phillipmathe...@bigpond.com> > wrote: > > I had the tach overhauled, ASI checks out > I’m looking at props and prices. The same male prop, 60 x 68 is around $2700 > Aust > > Your saying 156 mph (135 kts) not a hope > My 70 “ pitch gets 120 kts 2300 > > My prop 60 x 70 p > > 70 x 2300 x 60 / 12 /5280 = 152 mph. (132 kts) > Phil. > > Sent from my iPhone > >> On 28 Aug 2023, at 00:45, Larry Flesner via KRnet <krnet@list.krnet.org> >> wrote: >> >> >>>> On 8/27/2023 4:18 AM, Phillip Matheson via KRnet wrote: >>> FYI I removed my 60 x 70 today and put a 68 x 59 ( too low of a pitch) but >>> gave it a single flight >>> Static, brakes wouldn’t hold but around 2400 >>> Climb 2500 70kts over 1000 rpm >>> WOT over 2750 only 100kts >>> >>> Phil. >> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> Phil, >> >> Have you verified your tachometer and ASI? Generally speaking a longer prop >> is more efficient. Your numbers for ground run and climb with the new prop >> seem to be in the ball park but your cruise number looks to be in serious >> error. In theory that prop should result in 150+ mph at 100% efficiency. >> (pitch in inches X 2800 rpm X 60 minutes / 12 in. per foot / 5280 feet per >> mile = 156 mph ) . We can't expect 100% efficiency but often the numbers >> compute that way. >> >> Any chance you can get the original prop re-pitched? With a good set of >> wheel covers and a properly sized prop you should get a cruise at 2500 rpm >> in the 150 to 160 mph range. Keep working at it. You'll get there. >> >> Larry Flesner >> >> -- >> KRnet mailing list >> KRnet@list.krnet.org >> https://list.krnet.org/mailman/listinfo/krnet > -- > KRnet mailing list > KRnet@list.krnet.org > https://list.krnet.org/mailman/listinfo/krnet -- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnet
