Prop Performance

[JJ Campbell]

I sent the below to Sensenich "support" two weeks ago. Crickets...
I'm hoping someone in the group knows enough about this stuff to answer the question.
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I purchased my plane used about a year ago. The original owner replaced the prop (see logbook endorsement below). I have no complaints but it handles differently from the Tecnam Eaglets I trained in. I’m wondering if you can tell me what the difference is between the original prop and the current one in terms of performance characteristics. Everyone tells me “Your plane can really climb!”
JJ Campbell
Tecnam P92 Eaglet
N693JP @ KJYO

[JimParker256]

I'm not sure which prop is normally installed on the Tecnam Eaglet. Some of the European designs come with excellent props, and others not so much... It is possible that the Sensenich is simply a better prop for the Eaglet than the standard one. Or the previous owner may have just done an "better than average" job of optimizing the blade pitch settings to match the Eaglet's performance profile...

Propeller design has advanced a lot over the years. The latest iteration of Sensenich's ground-adjustable propeller has a reputation for improving performance pretty much across the board when compared to earlier props, such as the Warp Drive prop I have on my airplane. The Sensenich prop is designed to meet Rotax's "prop inertia" requirements, and has an airfoil that is optimized to operate within Rotax's normal RPM range and maximize thrust within the normal speed range of LSA in general. The slight "scimitar" shape of the blades is said to allow the prop to "flex" slightly under load, which some claim allows the blade pitch to flatten slightly during max performance climbs, thus effectively increasing climb performance without negatively impacting cruise performance. Note that Sensenich themselves don't make this "blade pitch flattening" claim (at least I've never seen it in writing), they just state that the blade design is optimized for both climb and cruise performance (or words to that effect).

But one of the less widely proclaimed advantages of the Sensenich ground-adjustable "system" is the mechanism they use for setting prop pitch. The process is far simpler than most, involving the use of indexing pins to set the blade pitch to the desired angle. It takes very little time and effort to re-adjust the prop pitch –– at least one Sensenich owner I know claims he can do it in <5 minutes, including removing and reinstalling the spinner. The pitch change process is also less subject to user error, and pretty much "automatically" ensures all the blades are set to the exact same angle each and every time. Having all the blades at exactly the same pitch may also help reduce vibration during operation. Taken together, all these improvements make it much easier to optimize the pitch of the prop for your airplane and your mission.