My quick comparison - Prince climb prop vs Sensenich

[GraemeSmith]

It's a bit of a Catch 22....... Bryan could not know that it was a minor change to his aircraft until he had tested it. So that implies back to Phase 1 to find out the prop change was not major. Perhaps we should ask Major Major.......

At some point you've got to apply some common sense. If I called the FAA every time I changed pitch on my ground adjustable prop, they'd start blocking my calls :-)

But you tested all the pitch possibilities in Phase 1 and documented them - right? ;-)

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To Mike's point - I was discussing putting the plane back into Phase 1 to test aileron gap seals. I mean - that IS major - right? Change in handling and aerodynamic qualities. The inspector at the FSDO was like - "notify me - oh - if you must.......".

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Another way to look at it might be - when you sell the plane - are the possibilities documented enough for the buyer to be safe applying them?

[Bryan Cotton]

Good discussion all. I went from the Prince prop to the Sonex recommended prop. Mostly I noticed a change in RPM vs airspeed, but not top speed. Climb seems similar but I am going to grab some takeoff performance data and some fuel burn data while I have this prop. It does not feel like a major change to me. Then back to the Prince prop once Lonnie repairs it for me.

when you sell the plane

I don't go to that church!

[Bryan Cotton]

Here is takeoff performance test flight at 1141 lbs today. I think the Prince prop definitely did better, but I have to find that file.
X axis is feet of runway travel. Y axis is altitude. Note that we are still working on smoothness on the 3 point takeoffs. This one was a jump to ~20' so not the best, but still valid data.

Sensenich takeoff performance.png (24.96 KiB) Viewed 2428 times

Runway 12
Winds 070@5
Temp +2C
Alt 30.07
3 point takeoff with one notch of flaps

Basically it took us 3000' to clear a 50' obstacle.

[Bryan Cotton]

Here is my plot for the Prince prop at 1150 lbs from phase 1. I don't have all the particulars of wind & temp handy, but 2500' to clear a 50' obstacle.