Sensenich ground adjustable prop on C90 or other small Continental.
Ington6 T tempdoug PATRON nd western NY Steve Pierce BENEFACTOR Graham S Sturgill MEMBER Farmboy MEMBER Middlebury S Sikorsky Registered User
I was wondering if anyone here is running this prop...
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I had an early (2017) C76AF, GA composite Sensenich that got installed and tested on my (essentially a) PA-18-95 experimental.

There were some growing pains as the early Blade alignment pins were not clocked properly but it was small hurtles that they overcame.

The prop itself was phenomenal as compared to a metal prop. Personally I think these props make a much larger difference on small horsepower engines, or perhaps aircraft with a lower HP-to-Weight ratio.

The ultra low swing rate would set me back in the seat on takeoff due to the near instant spool up time and the aggressiveness of the blade bite would just launch me. It would make me smile every time.

Sensenich composite props are measured for angle a bit differently than others so it’s hard to compare one prop number to another without actually trying it. But, due to the flex and ability to design a composite blade different than metal, the blades were very effective at getting you off the ground and picking up cruise speed.

The biggest hurtle I had on that setup was oil temp, which I attributed to the round blade root that transitions from a wide hub out into the airfoil.

But, I also feel there was more to it than that.

In my armchair engineer perspective my opinion is that the composite allows a design that will stay loaded longer through the speed range, effectively more efficient at always providing thrust at all speeds. I noticed it more when I tested an over-propped Cato but in level flight at a constant rpm, after a bit of setting time, the plane would literally step ahead a notch and pick up a few miles an hour, as if the blades relaxed out into a cruise position. I’m a firm believer that the pitch changes on a composite prop throughout the speed range.

Back to the oil - because it’s working all the time, and the blade airfoil was not compressing air into the cowl, I had to look for better cooling methods. The last thing I tried, and it was working, was a complete new lower cowl design with a larger low pressure area to help excavate the heat.

So after this C76AF on the C90, they were kind enough to make me a bigger version for an O-290. It was a 2F0K6C76AF and worked equally as well, but the wag aero airframe was draggier and the 290 in my opinion is an engine that markets more hp than it really has.

Similar temp issues but on the 290 I had mixture control and could feed it more fuel to help cooling.

Can’t say enough good about the prop design from a fly-ability perspective. I’d buy another one today if I was flying a small continental.

Transmitted from my FlightPhone on fingers… [emoji849]

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