Report on Sensenich vs Prince P-Tip

[mike.smith]

I have an AeroVee with 315 hours on it. I flew the ground adjustable Sensenich for about 2 years. It sucked. I had it on its finest pitch and that was not fine enough to get full RPMs out of the engine. Climb performance was anemic. I lost the prop with a prop strike (now I had a good excuse to change!) and so went to the Sonex-suggested fixed pitch prop. I ran that for about 2 years. It did a little better than the adjustable, but was still anemic in climb and I never felt I was getting everything out of the engine. It also didn't come with black paint on the back side so I had to add that myself (the adjustable had a flat black back side).

So this year I bit the bullet and bought a Prince P-Tip. I tested both props with the same weather conditions and the same RPMs, testing in 100 RPM increments, and testing climb performance. In summary:
- The Prince out performed the Sensenich in every way
- At WOT I got at least an extra 120 RMP out of the Prince, and an 11 knot increase in top speed
- IAS and TAS were always higher with the Prince. For instance:
- Sensenich 2900 rpm = 87kt IAS = 90kt TAS
- Prince 2900 rpm = 93kt IAS = 97kt TAS

- Sensenich 3000 rpm = 90kt IAS = 94kt TAS
- Prince 3000 rpm = 97kt IAS = 102kt TAS

- Sensenich 3100 rpm = 99kt IAS = 106kt TAS
- Prince 3100 rpm = 102kt IAS = 109kt TAS

- Sensenich WOT = 3250 rpm and 109kt
- Prince WOT = 3370 rpm and 120 kt

Climb performance has consistently been at least 100 fpm greater at gross weight with the Prince; more when I was lighter. And anecdotally, when at gross weight on a hot day (90+ deg F), climbing out over the trees at my home airport with the Sensenich was downright scary. Like, really scary! I've taken a couple of flights this summer at gross weight, 95 deg F with the P-Tip and have had a much better time climbing out. 80 hp isn't going to climb very fast no matter what, but it's not scary any more.

So I would have to say that both by the numbers and anecdotally, if you are trying to decide on a prop for your project I would recommend the Prince P-Tip over the Sensenich. The P-Tip also shipped nearly twice as fast as the Sensenich (7 weeks versus 13 weeks).

I'm going to hold onto my Sensenich should anything happen to the Prince in the future (so I don't lose flight time), but I hope I'll never have to use it.

[GordonTurner]

Thanks Mike. Awesome report.

Anybody with a Corvair motor tried a Prince prop? Experience?

Gordon

[RodgerC]

My experience with the Prince Prop is similar to Mike’s....I too suffered a prop strike as a result of an aborted takeoff that I largely attribute to the dreaded Nikasil barrels. In the ensuing rebuild I elected to increase my displacement to 2276cc and change my prop to a Prince P-tip 54 x 42. (Lonnie Prince’s suggestion).

During takeoff roll my “static” RPM is up 150 RPM on the Sensenich’s 2950 to 3050 RPM, which is getting me closer to that mythical 80 HP number. In cruise at 3200 RPM I see 115 to 120 Kts which is around 8 kts better than the 54 x 44 Sensenich.

I you can afford a few extra dollars, I’d highly recommend the Prince P-tip alternative. (and with the P-tip you get to explain to the punters at flyins that you bought a “pre-ground struck” prop)