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- Jul 9, 2009
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I did some takeoffs and timed climbs yesterday with 85-12 which I rebuilt two winters ago 100 hrs SMOH. Cub is pretty lean, no extra gear except external antennae. Half a tank of gas, pilot weight 235. temp 68 humidity 67, 1000 MSL. Strip a little soggy but no ruts. Static rpm 2350 and climbout rpm 2300 full throttle.
I timed climbs at 55, 60 and 70 mph indicated.
70 indicated gave best rate of climb. Take off run 330' three point liftoff, 51 sec first 500 ft; 140 sec next 500; 223 next 500; 318 last 500.
Computes to 600fpm, 310fpm, 360fpm, 310fpm.
I tried to hold steady heading and airspeed, but wavered some and slipped 5 mph some, but I think you can get a feel for what this prop does on a new 85.
I'm sure there is some error inherent here, but I was surprised that the first 500 ft is twice the next three increments.
I timed climbs at 55, 60 and 70 mph indicated.
70 indicated gave best rate of climb. Take off run 330' three point liftoff, 51 sec first 500 ft; 140 sec next 500; 223 next 500; 318 last 500.
Computes to 600fpm, 310fpm, 360fpm, 310fpm.
I tried to hold steady heading and airspeed, but wavered some and slipped 5 mph some, but I think you can get a feel for what this prop does on a new 85.
I'm sure there is some error inherent here, but I was surprised that the first 500 ft is twice the next three increments.
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