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Catto 3 blade Pireps ??

Larry DeCamp

Well Known Member
I am finishing -4 with 180HP 0360. Nicole advises their latest recommendation is a 68 X 75 for 3 blade with 2650 RPM at 8,000DA. Does anyone have experience with this combination to use for reference. I know Craig is fantastic, just looking for data points that might apply to me to discuss before ordering.
 
I don't think you can beat Nicole/Craig's recommendations. They know what they are doing.
I've been flying behind their props since 2003 and couldn't be happier. I'm set up for 2750 @ WOT/8000'DA because of my short strip.
 
Catto prop

Very happy with the 3 Blade Catto on my 4.
Changed from Whirlwind GA prop.
Happy to discuss on the phone my experience.
I sent my phone number via PM.
 
Every customer for which I installed one is very happy. Better cruise and climb performance, and very smooth.

Vic
 
+ 1 for Mel.

I agree with Mel on this one. We don't run a Cato but if you look at the numbers Put out by Lycon and most of the old prop charts, 2750-2800 is a good medal road figure to try and get WOT down low. I think the number that I have heard down through the years is 105% of max. rated RPM at WOT down low and 100% up at 7500' D.Alt. or for the 320 and 360 2700 RPM's. This is what we have and are very happy with the take off and cruse medium.
I would think you will be mostly on the top end of the cruse with 2650, WOT, down low, But yes Cato knows these RV's.
Hope this helps. Yours, R.E.A. III #80888
 
My 160 hp -6 with a nle 3 blade 67x70 catto will turn 2660rpms at 8000ft da doing 182.5 mph from a 4 way gps run. Static rpm is 2160.
 
Yep

If I didn't have a constant speed prop already, I would definitely go with a Catto three blade prop. I had a three blade on my -6a and it was very smooth and was a climber. Getting the cowl off was a little bit tricky.
 
power-off glide ratio

The 3-blade Catto props offer great cruise performance and less vibration. I only had two complaints: I only got 2,100 RPM on takeoff so my performance sucked until I build up some airspeed. The second thing is that with three blades out front, your power-off glide ratio will be MUCH worse than with a two-blade prop.
 
The 3-blade Catto props offer great cruise performance and less vibration. I only had two complaints: I only got 2,100 RPM on takeoff so my performance sucked until I build up some airspeed.

That of course depends on the prop pitch you select. Craig can build anything.

The second thing is that with three blades out front, your power-off glide ratio will be MUCH worse than with a two-blade prop.

That's an interesting observation, and I'm curious how the RV platform would differ so much from my experience and extensive testing between running a 2-blade metal Sensenich and four different 3-blade Cattos on my Pitts S-1S. I did not notice any increase in drag associated with the 3-blade. In fact, it seems my glide ratio shallowed very slightly only because with such a lightweight prop, you must bump your idle speed up slightly compared to what can be achieved with a metal prop. And even at that, I have my idle set with the Catto that I sometimes must be careful to blip the throttle to keep the engine running during spins. My glide ratio definitely did not steepen with the 3-blade Catto. RVs are floaters compared to the Pitts, and the only prop change I can imagine significantly affecting the glide ratio in an RV would be going from a FP to a CS prop.
 
My Catto observations

I went from a two blade Sterba wood on my O360 RV6A to the 3 blade Catto 75" pitch. I'm within one or two knots of my original speed.

Two observations: I second the comment above about glide ratio. With my Sterba when I pulled the throttle back it was like the plane was on ice. To reach flap speed I would have to pull the plane up to slow down. With the three blade, the speed is very linear to the throttle settings. Pull the throttle to idle and it's like putting brakes on. I actually find it much more controllable in the pattern.

Also there is much more P factor. Lots of right rudder on climb and lots of left rudder on descent, something I've never experienced before.
 
data point

On my Lancair 235 with the two-blade Aymar-Demuth prop, my best glide in the clean configuration is at 85KTs - 680 FPM - 13:1 - 2.40 sm/1,000'. I'll have to go back through my archives to see what it was with the 3-blade Catto.

OK, I found the data on three-blade Catto. Best glide = 90 Kts, 741 FPM, 12.3:1 glide ratio, 2.3 sm/1,000'.

It was a 62x76 and worked perfectly at 2,800 RPM in cruise. Like I posted earlier, the takeoff performance pretty much sucked but that was my fault - I ordered a "cruise" prop and that's what I got. At Denver on an 8,000' DA day, it took me 4,000' to break ground with the 3-blade. The reason I ordered the three-blade was to reduce vibration, and it did that. Although the 3-blade looked sexy, I will probably order a 2-blade if I order another Catto.
 
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The only down-side I have found is the installation and removal of the lower cowling. Put some protection on the prop blades until you can do it without touching.
 
Catto, the "Great-O..."

Back in the 90's I tested Craig's first 2-Blade and later an early 3-blade on my RV4.
I compared the two and three blades directly with my original Sterba 2 blade and a later a pair of Warnke (both Margie and Bernie)"almost constant speed" props as well as a Sensenich metal, Hertzler, MT fixed pitch and 3 other Catto test props. Many years later I would test one of the first Catto Gen-II 2-blades on my RVX. My data is nearly 20 years old but still relevant inasmuch as the Theodorsen theories are timeless.
Observations:
1. Two blades are faster than three, every time. I tested at low and high altitude and the results always favored the 2 blade. (original design)
2. Three blades cost more than two. $$$ (Nuff said)
3. Hand propping a three blade with a dead battery is more challenging than two.
4. Three blade props climb better and are smoother and a bit more quiet.
5. The 3 blade had higher coefficient of drag throttled back. (glide and in the traffic pattern) than 2.

Overall winners for my 170HP 0-320 powered RV4.
Flat out speed (WOT): Margie Warnke "Claw" Hands down.(great prop, sadly, She is retired)
Climb, cruise efficiency, second fastest. Gary Hertzler "Silver Bullet" (special order on a case by case basis).
Climb, Aerobatics: Catto 3 Blade. (original blade design)

*Best overall compromise prop for speed, utility, climb, STOL, aerobatics, rain,
cost and longevity: Catto Two Blade with LEP

Recommendations: Craig Catto is an awesome guy and good friend. You can't go wrong with his product. On a tighter budget? Ed Sterba is hard to beat and a great guy as well. If you want a technically better prop that requires care in rain, buy a Hertzler Silver Bullet.
For me, I'd go with a 2 blade Catto every time.
V/R
Smokey

Notes: A. *Worst prop I tested: Sensenich Metal FP 2 blade. Heavy, noticeable flywheel effect, not aerobatic approved (By Sensenich) and RPM limited at 2600.
B. Axel and many others are flying Craig's latest 3 blade on their RV's with excellent performance matching or exceeding the 2 blade from what I've read.
 
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