Since the Corvairs are turning roughly 3300 RPM and the Franklin produces it's power at roughly 2800 RPM, the prop pitch for a Corvair isn't much help for a guy looking for a prop for a Franklin.
Call or write to one of the manufacturers of props for homebuilts. Most want to know the engine, HP, and expected RPM at and expected speed. They will custom build a prop to suit your needs. Some prop builders are better at it than others. You may also wish to use one of the many ground adjustable props. I think there are several available in Europe, as well as the Warp Drive here in the US. Stay away from the IVO prop. The IVOs are accidents looking for a place to happen. Read Orma's problems with the IVO <http://kr-2.aviation-mechanics.com/AlertIVOProp.htm> if you need a reminder. Jeff Scott N1213W http://www.vla.com/jscott/kr/2005mods.html On Sun, 17 Sep 2006 17:43:31 -0400 Joe H Horton <joe.kr2s.buil...@juno.com> writes: > Andy, > I am using a 54 x 60 Sensenich on a 3100 cc corvair that gets > 3350rpm in cruise at 172mph true airspeed and 2950 rpm climb at 80 mph > and 1000 to 1500 foot per min. climb -depending on the weather. > > Joe Horton, Coopersburg, Pa. > joe.kr2s.buil...@juno.com > > On Sun, 17 Sep 2006 16:40:53 -0400 "Colin Rainey" > <brokerpi...@bellsouth.net> writes: > > WW recommends the Sensenich 54 x 54 for that hp range (some Corvairs are > > approaching that). I would start there and depending on your particular > > construction (ie: how clean) adjust the pitch from there. This is also > > depending on prop clearance being 8 to 9 inches to allow for max gear > > compression and still no prop strike. You may want to call Sensenich and ask > > what they recommend as a starting point with 125 hp... Might be 54 x 60 > > (Mark L bogged his 3100 cc down with that). > > > > Colin Rainey > >> Hi Guys, > > > > I`m from Hamburg Germany and bought a used KR2S in boot stage with an > > new Franklin engine with 125 hp. Does anyone have experience with this > > engine ??? > > > > If yes what kind of prop should i use ??? > > > > thanks a lot in front > > > > Andy
