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Following is from four years ago. I did the test at 8,500'. My propeller is placarded not to run over 2,600 rpm.
![]() Configuration at the time: O-320, 160 hp, carb, 2 mags Standard fixed pitch Sensenich propeller: 70CM7S9-0-79 empty weight: 1084 lb polished aluminum, primer on fiberglass parts wheel pants and fairing on Now I usually cruise between 8-10k, at 65% power it does 140+ and burn less than 7 gph. Since conditions are different I can not give a single performance number. I know other 9As with better performance than mine. Mine is a little heavy and not perfectly built. |
Catto Pitch?
Tony,
I'm curious about your speeds. I have a Catto 3 blade ready to go on my 9A and am wondering if you have Craigs' recommended pitch for a 9A with 160HP or did you have him do someother pitch? I can't remember what it is off the top of my head but he was sure when I got mine that it would generate at least Van's numbers. Thanks |
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My Last Test
Hi Tony,
I sent mine back to Craig last year for a re-pitch. I did a WOT GPS test before and after. What I can say is that it didn't change.... When I got the prop back and tested it using the three way GPS method, the results were the same. 161 kts at 2700 ~ 2730 RPM with the DA at 11,500. (don't currently have % power #'s coming soon) My fuel burn is in the same vicinity, though a little less at the higher altitudes. I would agree with you about the climb pitch. It climbs very well. Something I've noticed flying with my CS friends (6A's). If we are in cruise they will leave me behind unless they pull some power. If we start into a climb configuration (to get over the rocks) I will gain on them and pass them unless I pull some power off! How much of this is wing efficiency at higher altitudes or the prop? I'm not an aerodynamics expert so I can't say. The Catto still remains about 5 kts faster than the original Sterba prop. I do think it could be pitched more. When I'm at sea level I've got almost half of my throttle pulled... fixed pitch props are always a compromise. Quote:
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I just received my re-pitched prop back from Catto. Here is a current screen shot. This was at W.O.T. 8kDA and full fuel and just myself.
![]() Here is the screen shot of prior to the re-pitch. Notice the high RPM compared to the current shot. ![]() |
Here is a picture that most pleases me. I switched back to KTS for my airspeed. Notice the 156 KTAS at 2550 RPM. Before my re-pitch I would have to run 2750 to get that. So far so good. I will try to post some pictures on my blog later of the nickel leading edge retrofit.
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Tony, looking great.
I like that the first two pictures show that before you were using 11.3 g/h and the after pictures shows that at the same speed you were using 8.1 g/h.
I know the flight conditions were a little different, but it is looking good. Kent |
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Yep, the first photo I wasn't leaned at all. One of the natural by-products of turning 2900 RPM was high CHTS and EGTS. It was also a hot day. Re-pitching my prop in part was desirable so that I could see my temps come down. So far, so good for that. I am thrilled with my RV-9. |
Thats great Tony, now show us your nickel leading edge on your prop.
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