Which Catto on RV-4?

Hello and sorry again for my multiple questions.
The good news is I am at the end of the ordering process. So no more questions... ;-)

I ordered an IO-320 160 HP new from Van's.
I will install a fixed pitch. I will go with a Catto.

I will operate occasionaly from relative short grass strips (1400'), mainly from longer strips and airport, I would like to have a lot of fun with it (i.e.: acro), I will mount a full Raven. I have inverted fuel system. I am planning to build it as light as possibile (Dynon SkyView, one VHF, one GPS, no lighting, Aerovoltz battery, minimal upholstery). I will 99% fly solo and for sunday short runs.

I received an email from Craig Catto and he suggested me to go with a 69 pitch propeller. 3 or 2 blade my choice. He stated that with a 3 blade 67diameter and 69 pitch I will have 2.300 static and 2.750 on top 193 mph.

I am not familiar with fixed pitch propellers and maybe I do not have the big picture. Why should I go with a 3 blade or rather opt for a 2 blade? Better brake on descent while doing acro? Much smoother? Better pull on take-off?

Will a 69 pitch give me enough cruise speed?

Will rather a 70 pitch ruin my take-off run?

Thanks.
Camillo

Camillo,

You'll get a bunch of replies to this no doubt!

Craig's recommendations tend to be on the money, and he'll tweak the prop (if required) after you've tested it.

A three-blade will generally give slightly better initial takeoff/climb performance and may cost a bit at the top end (a two-blade is more efficient in cruise), but it's really a matter of static RPM. The 3-blade will be smoother and, well, they look really nice! Light weight, fixed pitch props tend to be "pinwheels" and don't provide much drag--combined with the low drag characteristics of the RV-4, this will make for a very good glide ratio. You'll learn to modulate power as required to prevent an over-speed during maneuvering and once you get used to the glide characteristics, no issues there either. Either prop Craig recommends will likely do the trick, so it's a matter of choice.

I'm a happy Catto customer (light nose RV-4: 160 HP O-320, 2-blade Catto). All of the flight test data for our installation is here:

https://docs.google.com/file/d/0B8EIT6g2n8o_aXhENlczZXhpQWs/edit

Unfortunately, I don't have measured takeoff and landing performance data although there is discussion in the performance section you might find helpful.

You won't go wrong with a Catto prop.

Ciao,

Vac

I flew one of the early 3-blade props on my 160hp -4 for 10 years.

I was very happy with the performance and it was the smoothest and quietest prop I have ever had.

They say that you give up some speed with a 3-blade but I did not see it.

All of my performance numbers were an exact match of what Van has published for the -4 with 160 hp.

The only slight challenge was removing and installing the lower cowl and with some time and practice I was able to do it alone.

Once I got my system perfected I think it was also easier alone.

Besides I think the 3-blade looks better too.

Good Luck,

Glenn Wilkinson

Thank-you.
How far are pitched your propellers?
Glenn, where you say that you match Van's figure you also talk about take-off distance?

I've found the performance difference between 2 and 3-blade to be too similar matter. The only points I will add to those already mentioned is that the 2-blade will be significantly cheaper. It is also easier to pack up and transport if you need to send it back to Craig for some reason. If you're into acro, the 3-blade will make less noise if that's a consideration for you. Of course, noise is a function of RPM. If you don't exceed RPM redline, then this probably won't matter. If you ever think you might need to hand prop your airplane, I would much prefer to handprop a 2-blade.

I race, so top end is important to me. I've had 4 props over the life of my plane, 3 of them Catto's. The two fastest were two blade Catto. The three blade is 2 knots slower on my plane, but does have noticably better acceleration and climb. If you fly in weather at all, the three blade is much better for tip erosion because the tip speed is much lower due to the smaller diameter. The three blade is also a little smoother.

I have three blade I would consider selling for the right money... send me a pm if interested.

All I know is if your really want a Catto Prop, plan for years in advance. Ask me how I know.

Camillo,

I never measured my takeoff distance.....but considering how well the performance matched all the other parameters I believe the distance would be about the same.


Glenn Wilkinson

I'm running a Catto 68X70, 150hp O-320 A1A. Up in about 600ft give or take, jumps upto 195mph at 2800rpm. Luv the Catto. Crankshaft luvs a light prop like that, and throttle response is a lot better. Makes small throttle inputs on landings a lot more pleasant and manageable. Dealing with Catto was an absolute pleasure, and if you're not happy with the pitch you can always send it back and he will repitch it. And that's my two cents? I hope it helps

Prop me up...

Camillo said:

Hello and sorry again for my multiple questions.
The good news is I am at the end of the ordering process. So no more questions... ;-)

I ordered an IO-320 160 HP new from Van's.
I will install a fixed pitch. I will go with a Catto.

I received an email from Craig Catto and he suggested me to go with a 69 pitch propeller. 3 or 2 blade my choice. He stated that with a 3 blade 67diameter and 69 pitch I will have 2.300 static and 2.750 on top 193 mph.

I am not familiar with fixed pitch propellers and maybe I do not have the big picture. Why should I go with a 3 blade or rather opt for a 2 blade? Better brake on descent while doing acro? Much smoother? Better pull on take-off?

Will a 69 pitch give me enough cruise speed?

Will rather a 70 pitch ruin my take-off run?

Thanks.
Camillo

Click to expand...

Camillo,
Having been Craig's first RV4 customer back in 98', he has perfected the pitch/length equation through trail and error and lots of testing. (by me and others)
I found on my RV4 operating from my home strip and many short (less than 1000'/350m) strips in hot. muggy conditions the 2 Blade Catto 69/69 was perfect for my 150HP RV4. WOT at Sea Level was 2850/ 2700 at 12,000', perfect for both STOL and XC trips where I normally ran WOT above 10,000' anyway.
My current RVX has a Narrow Deck 0-360J2A and I use a 70/74, a match made in Heaven. I wouldn't go with a 3 blade if you do back country flying as they are more difficult to hand-prop. Also, three blades are slightly slower in cruise despite claims to the contrary and more expensive...

Bellisimo...
V/R
Smokey

Cant get a quote...

Like another poster has said, plan for a year...I have been sending E-mails to Catto for almost that long, with a quote request and my current Sterba performance statistics. I have seen and heard all I can stand about Craig's great props, but feel like you need an insider to make actual contact. Glad to hear others are getting through, and have some good feedback, but I have given up.

Catto Prop contact

Not having tried to contact Catto props until this past week, I sent them an e-mail with some specs from my RV-4 and the time frame I was looking at to buy a prop. Having gone to their website I included all the email addresses on the "contact us" page.

It was less than a week later I got a message back with a request for more specific information and we were off to the races.
I sure hope others are successful.

AL