Catto 3 blade vs. 2
 

I'm building a day vfr RV4 with a fixed pitch carbed 0360. I've pretty much settled on a Catto prop and wanted to hear pros and cons regarding the number of blades. I figure 1 blade is out, but should I go 2 or 3?

i've talked to craig about this, and if i go with a XX-360, i'm gonna use a two blade from him. two blades equal less drag, and more speed. three blades will get you better climb with the additional thrust from the third blade. craig can pitch the prop to your needs...want more climb with a two blade? no problem...more speed, no problem. three blades LOOK cooler, but make mine a two paddle.

I have the two-blad catto prop. No matter which way you go I'd suggest Landoll's harmonic dampener. Give the prop a little inertia. One pro on the two blade prop is that you can prop it if your battery goes dead out in the boonies. I'd be afraid to prop a 3 blade.

I've flown behind both and would recommend the two bladed if clearance is not a problem. The 3 blade was smoother but did not outperform the 2 blade
in top end or climb.
Tom
RV3 2000+

I don't know about the performance, but I saw a three blade Catto on an RV-6 at Sun N Fun and it looked COOL!

I talked with Craig before I ordered my prop from him, and I directly questioned him about the performance I might expect with my engine (TMX-IO360 + EI) and his 3-blade prop.

He replied:

From the performance that you are expecting, you should easily achieve. The
360 RV-7's are getting close to 1800 feet a minute and top ends of over 210
TAS.
Short field operations usually isn't to much of a concern with the RV's as
their takeoff performance is quite good anyway, especially if your running a
360.

My reasons for going 3-blade were for smoothness and extra ground clearance. And since he is confident of my getting the performance he says I can with his 3-blade prop, that's how I went.

So, 6 years later. Are you getting the performance expected?

The RV-6 (and -7 and -9) definitely looks very cool with a 3-blade prop. In my personal opinion a -4 looks better with a 2-blade prop. I'm in the process of buying a -6 with 2-blade Aymar-Demuth prop, and one of the first upgrades I'll seriously consider after my bank account recovers from the purchase is a prop upgrade...mostly to get a metal leading edge on it, and will probably go for a 2-blade Catto when funds allow. Mostly because it's significantly less cost than the 3-bade , but also because the 3-blade makes it more difficult to remove the cowl with the prop still installed.

I've been running a 3-blade on my -4 (O-320) since '03 and do not have any degradation of performance...I'm right on Van's numbers.

My opinion is the performance is affected more by design and weight of the prop. The 3-blade metal props are obviously heavier and absorb some power compared to a 2-blade but also due to design costs, harmonics and weight the metal props can be at a slight disadvantage to the composites.

My 3-blade Catto weighs approx. 15lbs and the blade design is optimized for my plane, it's power and it's speed so it has no 3-blade performance problem.

That's my story and I'm stickin' to it.


Glenn Wilkinson


P.S. For those of you with the 3 blade, I have worked out a removal method I can do myself that works well for me.
Turn your prop with one blade straight up to give most possible clearance between the other blades. Now get your creaper positioned in front of the lower cowl and after removing the pins as the firewall. Try to make sure the cowl will hang on the hinges.
Now on the lower cowl ring just behind the spinner I wrap a shop rap with small spring clamps holding each end of the rag so as to scratch the paint..
Run around the front and get on the creaper and roll under lower cowl.
Then carefully wiggly out the lower cowl likes the way it likes to come out.

Then reverse order to re-install, I won't claim it's easy by with a little practice you will be able to handle it with as much ease as possible.

Two for you, Three for me...
 

Steve,
I tested Craig's first 2 blade RV prop on my RV4 in the late 90's. Since then he has amassed alot of RV data on the various engines and refined his props to an art form.
My experience from delivering and inspecting many RV's has shown that the 0-360 Catto prop of choice is the 3-blade.
For the 0-320, the 2 blade is preferred. My current RVX has an 0-320A 150HP with Craig's newest 2 blade. Excellent performance!

Just ask several 200HP C/S RV drivers I have flown alongside...:)

V/R
Smokey


New Catto 2 Blade on "The X"