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
