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Hi Yvon,
Looks like you are over propped. here is a quote from a prop speed web page:http://www.hoverhawk.com/propspd.html
" To produce maximum thrust from your propeller at full power your tip speed should fall between .88 and .92 mach. To move between .88 and .92 mach usually takes a change of about 110 to 120 RPM depending upon the diameter of your prop. This of course varies depending on your particular propeller and the temperature. Try different temperatures then you will see just how much the speed of sound can vary. You would ultimately want your propeller to reach its redline (.88 to .92 mach) at the same time your engine reaches its maximum rpm limit, its redline. "
You should be turning the engine 6500-7000 rpm on takeoff (not static) for best thrust.
Bulent "Buly" Aliev
FXE Ft lauderdale, FL
http://tinyurl.com/s5xw8
On Aug 6, 2006, at 4:56 PM, Yvon Cournoyer wrote:
I have replaced my old wood 2 blades 74'' propeller with a new 3 blades 72'' Warp Drive, ground adjustable.
I have set the pitch to obtain about 4800 engine static rpm, which is what I began flying with my old wood prop, some years ago.
No other changes, yet in spite of abnormally hot and humid weather, I find that both oil and coolant cool better and will allow longer full power static runups.
I have not flown the new prop yet, but I am eager to verify its performance at altitude.
Yvon.
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