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Prop pitch selection for a 9A

J

jimbo

Well Known Member
Patron
With a O-320 160 HP engine and Sensenich FP metal prop Van's recommends a 79" pitch on the prop for the best combination of Takeoff performance and cruise.

What have others found with this engine/prop combination for the 9A? Are you satisfied with this pitch or have you selected to re-pitch? I know a lot depends on what type of flying you do and what T.O. performance you need for your gross weight, runway surface, elevation and density altitude at the airports you normally fly to among other things.

Trying to get some opinions out there before I make an order. Lastly, can a metal prop get re-pitched for less pitch or only for more pitch?

Thanks,
Jim
 
Jim,

Slightly different setup (I have IO-360) and I use the 85" prop. Not as good as others on takeoff, especially at Reno, but works great in cruise. Takeoff performance is still MUCH better than the typical spam can - certainly more than adequate for me. I chose more pitch because I spend a lot more time in cruise than in takeoff/landing. And I believe you are correct that pitch can be made higher but not lower.

cheers,
greg
 
Jim
The 79" prop works great on a 160hp engine. I flew out of Willow Run for 200 hours, it worked well there. This morning I flew to Big Bear with a density of 8200 feet. With two people and full of fuel, I wouldn't have wanted more pitch.

Cameron
 
Since engines run most efficiently with the throttle full open, choose a pitch that will give you the RPM you want at full open throttle at 9000 ft. & above.

As to how you get to the "RPM you want" it's a matter of finding where your engine/prop combination is most efficient and/or where it just "feels" smooth and happy.

It would be nice if you could try out a few props before committing to one, but in lieu of that I would suggest you'll be happier erring on the side of more pitch as opposed to less. As someone said earlier, you spend very little time taking off compared to all the time you'll spend in cruise.
 
I have the Vans recommended 79" prop w/IO-320 engine on my RV-9A. I think Vans made a great choice on this metal prop/ engine combination. The airplane accelerates rapidly on take off, climbs well at 110-120 kias, and cruise is 150 ktas range. Redline is 2600 RPM. Best of all, it is basically "no maintenance". No overhauls, no wory about flying thru rain, and will eat a resonable amount of sand and gravel from the airport environment without substaining major damage.
 
It isn't only metal props that can be repitched. Catto will repitch his props, so you might consider a Catto two-or three-blade. I am very happy with my Catto three blade and consider it a very good combo on my 160 hp 9A. It should give a little less noise and vibration than metal props, and it offers a weight savings. I have not flown out of very high DAs, but Craig Catto can take that into account.

Bob Kelly
 
Be aware of composite props and rain. I have a refinished factory Prince for sale for this very reason. I know Craig sells leading edge tape but it you talk to Mr. Lipps you'll find that isn't an optimum solution. If you're never going to fly in rain, no problem. Wonderful props. (Although it's become apparent in the case of the P-tip the "P-tip" does nothing except cause drag and perhaps reduce noise a tad.)
 
MikeS said:
Be aware of composite props and rain. I have a refinished factory Prince for sale for this very reason. I know Craig sells leading edge tape but it you talk to Mr. Lipps you'll find that isn't an optimum solution. If you're never going to fly in rain, no problem. Wonderful props. (Although it's become apparent in the case of the P-tip the "P-tip" does nothing except cause drag and perhaps reduce noise a tad.)
Click to expand...

Craig now has nickel leading edges for his props, so there is no restriction when flying in the rain.
 
81" pitch

I use an 81 inch pitch. 2240 static. Still short takeoff, great climb (still at 2300 at low altitude), but at 7500 ft or higher full throttle and still not more than 2600; great cruise at high altitudes.

Doug Dahl
finish on the RV-12
 
my numbers

just to flesh out the averages, I have an old 7:0 - 1 compressoin 0-320 150 hp.
with the -79 prop, I can only get 2150 static, and maybe 2200 on takeoff, which means I am only making 80 hp by rough estimate.
still climbs at 1000 fpm solo, 85 kts.
sounds like too much pitch, right?
cruises at 130 kts IAS, WOT, 5000' on a roughly standard day. Hard to get up to the 2600 rpm redline unless in a descent.

yMMv.
 
flyboy1963 said:
just to flesh out the averages, I have an old 7:0 - 1 compressoin 0-320 150 hp.
with the -79 prop, I can only get 2150 static, and maybe 2200 on takeoff, which means I am only making 80 hp by rough estimate.
still climbs at 1000 fpm solo, 85 kts.
sounds like too much pitch, right?
cruises at 130 kts IAS, WOT, 5000' on a roughly standard day. Hard to get up to the 2600 rpm redline unless in a descent.

yMMv.
Click to expand...

Perry....For the 150 HP Vans recommend the -77 pitch prop.

Jim
 
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