View Single Post
Old 09-13-2017, 02:27 PM
smokyray's Avatar
smokyray smokyray is offline
Join Date: Jan 2005
Location: TX32
Posts: 1,801
Default Prop me up!

Originally Posted by Dreamin9 View Post
Here's some numbers from a recent test flight, I'd like to find more speed in the 6.5 to 12.5 altitude range. Considerations are re-pitch or new prop or burn gas.

RV-9A, O-320 160hp, 405hrs
Prop Sensenich metal 70/79 (actually 69.5 after repair from nose collapse/flip at 13 hrs)
Power set to 75% after initial climb for CHT cooling, leaned to peak, AS in knots, static +/- 2200
This engine runs smoothly LOP; FF/RPM/speed/CHT's drop off quickly LOP.


Rotation 750 2140 2275 29.4 93 12.5 72

Level@ 1800 3100 2380 25.1 78 12 138

Level@ 6500 7800 2470 23.4 76 8.4 144

Level@ 8500 9815 2510 22.5 70 7.5 147

Level@ 10500 11840 2480 20.9 67 7.1 148


I've never been a fan of the Sensy FP metal props for the 0-320. Why? Having tested nine different props on my RV4 over a 10 year period it was the worst of the lot. I kept the results in a log I shared with the prop makers afterward.
As Sam pointed out, it's heavy metal, 2600 RPM restriction and not revving up enough to give you rated HP(0-320 is rated 150HP@2700) poor takeoff performance and aerobatics not recommended by MFR. Three major strikes for me, I'm out. Van's used to post a MP/RPM formula that roughly translates %power. Take the 1st 2 numbers of RPM and MP and add them. 48 is roughly 75%. That said, a prop turning 2700 with 20"MP (WOT) at 11,500 is around 65% power. You're not hurting the engine running higher RPM at higher altitudes.

Test Results: My 0-320 RV4 with single Electroair EIGN/1Mag and a Carb: WOT at 11,500' leaned out.

1. Ed Sterba Wood 69X69 2850 at 168 KTAS and 8GPH.
2. Catto props 69/69 2900 165KTAS 8GPH
3. Gary Hertzler Silver Bullet. 170KTAS 2600 7GPH
4. Sensy Metal 70CM/77 160KTAS 2500 8GPH
5. Bernie Warnke 69/70 167KTAS 2550 7GPH
6. Margie Warnke 70/69 169KTAS
7. Catto 3 blade 165KTAS at 3000 RPM 8.6GPH (great takeoff and climb)
8. MT Fixed Pitch 69/69 167KTAS at 2650 8GPH
9. Catto Gen-3 2 Blade 70/72 (RVX 180HP) 170KTAS at 2600 8.8GPH

My favorites were (in order) the Silver Bullet, Catto Gen 3 and the Sterba. The Sterba wins the economy award for best bang for buck. Great value.
If it were me I would sell the Sensy metal online and install a woodie or composite or get it re-pitched so it will turn 2600 at 11K.

My Dos Centavos...

PS: Last year I delivered a 0-320 9A with a Catto 2 blade from OR to TX at 11,500'. 2800 WOT at 7.5 GPH 165KTAS.
Performed very well at lower altitudes, good STOL.

Last edited by smokyray : 09-13-2017 at 02:34 PM.
Reply With Quote