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Eliacim,

 

Until you've changed your prop, the engine can't spin to the power range of 85 hp.  You've still effectively got a 75 hp.

 

If  't were me, I'd have a good prop shop trim the length and repitch it.

 

Note that Coupes normally don't climb all that well unless you keep the gross weight down.  We fly a good speed with little engines - compare to 108-115 for the Cessna 152 which flies about the same speed - but, the small engine gives not-that-great heck, not very good climb.  I love Coupes but I can’t brag about their climb.

 

7152 = "cruise" prop.  Some engine/airframe/gross weight combinations can keep the plane from achieving the desired cruise speed - it bogs down.  You, flying at 1260 lb. max gross weight (you are, aren't you?) might cruise well with this pitch.  Climb is even more anemic than normal for Coupes.  Cruise speed at 2400 rpm might be 112 mph, as long as you don’t bog down.

 

7150 = "normal" prop. Somewhat less cruise speed, somewhat better climb.  Climb may still be an issue. Cruise speed at 2400 rpm is about 108 mph.

 

7148 = "climb" prop.  Popular.  Less cruise speed but adequate climb.  Cruise speed at 2400 rpm is about 104 mph.

 

7146 = “extreme climb” prop.  Just barely meets A-787 specification of 2225 static rpm.  Climb is good enough to get to 12,500 anytime you want – but it takes about an hour to get up there.  This is what I had and I was willing to give up some cruise speed for the short-field comfort and to climb above the bump-layer on thermally days.  (I still flew it coast to coast.)  Cruise speed at 2400 rpm is 100 mph.

 

Other things affect cruise speed including gross weight and parasitic drag such as venturis, landing gear fairings, gear mounted landing lights, etc.

 

Choose your number, find a good prop shop and send it off.

 

Ed Burkhead

http://edburkhead.com

ed -at- edburkhead???.com          (change -at- to @ and remove "???")

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