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Prop test

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Well-Known Member
Supporting Member
Feb 25, 2007
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Back to back prop test
46 J3, O-200, no wing tanks, no VG's
91 degrees F, no wind, grass strip, about 8 or 9 gallons fuel, pilot 214 pounds, (no manifold pressure gauge)
rpm with the 7142 was down a little -- I think I could have stood a plug cleaning.
Static mag drop 100 rpm both mags
O-200 rated 2750 rpm

McCauley Prop 7142 7535
Static rpm 2580-2590 2680-2690
rpm 60 mph climb 2660 2800
WOT rpm level flight 2850 3100
Speed at WOT 112mph 108 mph
On a cold day, WOT with the 7142 is 118 mph at 2950 rpm
Speed at 2350 rpm 80-82 mph 74-76 mph
Takeoff Roll 190 feet 150-160 feet

I didn't have time to try rpm at 50 mph climb at altitude, or indicated stall speed at WOT. Got dark on me.
Some observers were stepping off takeoff roll as 130 to 150 feet, but I don't believe them.
Deck angle at low speed climb at altitude WOT was impressive.
Acceleration after liftoff to climb speed was impressive
Acceleration during ground roll was improved.
Prop was quite smooth.
I was impressed

JimR, the compression checker is in the J3 baggage compartment.

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