Catto propeller recommendations

I'm preparing to place an order with Catto for my -4 and wondering if anyone has any input or suggestions on what they would or wouldn't change with their Catto prop? At this point, I'm leaning towards the 67" 3-blade w/nickel leading edges. I understand I may lose a little off the top/cruise speed as compared to a two-blade? While my present Sterba climbs like a raped ape, it just doesn't get the cruise speeds my -4 should be getting. Thanks!

My set-up is an 0320/160hp with tall gear (if that matters).

Depending on what propeller you have now, you save a considerable sum of money going with a 2-blade. (I realize you lose some cool factor). With tall gear, the 2-blade may not be an issue.

The savings comes from three places - shipping is less; one less nickel edge; likely reuse of you spinner and related assemblies.

If you consider going with a 2-blade propeller, let me know what Craig says regarding length and pitch. I'm flying a Catto 70-72 with nickel edges and it's a bit too much propeller for my 150hp. If it's matches what Craig recommends, you can fly down and try it (and perhaps we can make a deal that benefits both of us). If nothing else, it's a free meal and a chance to try the Catto.

I have a 70x70 Catto two blade on a 160hp RV4. Looks cool when you beat the fella with a three blade. That said, my Pitts has the three blade since it's much lighter than the Sensenich 76x70 prop and reduces vibration and noise at 3000 rpm. Also much easier on the crankshaft by reducing the gyroscopic forces the heavy prop induces.

I'm happy with both applications.

Cheers, Hans

Thanks Glen and thanks Han. One would think there are more -4's here flying behind a Catto prop.

Glen, hope you get your maintanence issue straightened out and see ya at Jims tomorrow, and we'll talk props.

Just to add more speculation I'll share what Nichole recommended.

RV-4 O-320 160HP. Currently a 2 blade Sensenich w/ 2600 RPM limit.

They recommended for a cruise prop a 2 blade 70x71 and a 3 blade 67x71. This was as of Early 2016. So I would think this would be the latest rendition of the prop. As I understand there's been changes throughput the years to prop design.

These are my current stats with the current configuration...I haven't officially "verified" my Dynon inputs. But here are the outputs.

7500' OAT: 59F DA: 9200'
2400 RPM. 20.5 MP: 129 Kts IAS. 140 Kts TAS.
2500 RPM. 21.4 MP: 135 Kts IAS. 155 Kts TAS.
2600 RPM. 21.5 MP: 141 Kts IAS. 163 Kts TAS.
2670 RPM. 22.4 MP: 145 Kts IAS. 167 Kts TAS.

No idea how these "speeds" compare to other RV-4's or if they are fast or slow. I haven't purchased another prop.

2-blade 70x70...

...works great on my 160hp RV-4. Don't have the nickel - production time was much longer and it didn't seem a requirement for my VFR mission.
Good luck in your quest for the perfect prop!
Patrick

resources

are there any other books aside from bengalis that may have information regarding propeller design vs application. im sure there is but i dont know as im new to building, not even close to prop selection. i may be getting a 3 blade for a deal, albeit not needed at this time, but the price is right and to aquire it and use it, after its inspected, just to get me going is my plan. after flying try to get a different prop that may fit the bill. after hearing a 2 blade is possibly better im keeping the option open. or heck with it all and go constant speed prop. i will not learn if i dont ask. opinions welcome

Van has a write up about props, while it is in generalizations, it gets to the point. The big difference between two and three blades are drag and tip speed. A three blade has more drag so will not be as fast as a two blade. That being said, the difference is typically only a few mph. The three blade will typically out climb, out accelerate and out decelerate a two blade. I have a three blade prop and when I pull the power off abeam the numbers on downwind, it pushes you into the harness. I can be at 130 kias abeam the numbers, pull the power and do a 180 turn for the runway and put it on the numbers. I have two friends who can outrun me, one flys a Glasair, the other flys an MXS-RH, so I was willing to give up a few miles an hour for the better performance on the low end, everyone else I fly with I am always throttled way back any ways.

I have the 3-blade and don't have any experience with the 2-blade. I also don't have the nickel leading edge, but I'm thinking about selling mine and upgrading. Climb is great until you get over about 15K and then I sometimes have trouble maintaining 500 fpm while still moving forward at a reasonable speed. If you don't fly with O2 you will never even think about it. I have an RV6 with a 180HP IO360 and I get 165-170 KTS TAS.