Catto Prop

[Steve Fisher]

Has anyone got some flight experience/data they are willing to share on using a Catto prop on a O-360 (180 HP) patrol?

Craig Catto is suggesting a 82X48 or 80X50 prop. While I was at Oshkosh talking with Bob Barrows, I believe he suggested maybe 82X50 or 82X52 for a Catto prop.

Thanks,
Steve

[Mark Goldberg]

Hi Steve. The Catto has worked very well on my LSA. And there are a couple O360 powered Patrols that have Catto props as well but they are not flying yet. Pretty soon though. Sorry, I am not much help. Mark

[m.mooney]

I have a Sensenich 76 58 on my 0360 powered Patrol. A friend has a Catto 84 45 on his experimental Super Cub and is doing some ignition upgrades. He graciously suggested that I give it a try while it’s off his airplane. Why not. The Catto weighs 13lb 10 oz and my Sensenich is 35lbs 2 oz. I’m happy with the Sensenich’s performance but I had to investigate the Catto. Losing 21.5 pounds off the front end had me intrigued.

Empty CG moves aft from 10.9 to 11.2. At first glance, this 84 45 is not what I would choose for my Patrol so I wasn’t overly critical of the performance. Static rpm was low at 2200 and came up to 2310 by liftoff. Takeoff and climb performance was better than my Sensenich. 2300 rpm resulted in only 18” manifold pressure where the Sensenich runs approximately 20” there. Generally, it took about 150-200 rpm more to get the same MP and a comparable cruise speed.

The part that Got my attention was the lighter nose, which was quite noticeable on approach and landing. It felt more stable and was comfortably slower on landing. I can’t really explain it properly; but, this alone has me wanting to find the proper pitch for a Catto prop to replace my Sensenich. If I can find the pitch that will result in the Catto performing similar to my 76 58 Sensenich, I’m all in. That weight loss off the front end obviously helps with useful load but the real treat is the effect it has on CG and pitch authority when slow.

I know there are some Catto props on 0360 Patrols and am curious what kind of performance folks are getting with a certain prop (length/pitch). Personally, I really don’t want to give up my respectable cruise speed that the 76 58 gives me. Patrols with a Catto?

Mike

[svyolo]

Supercuts cruise a lot slower than a Patrol. That sounds like a good prop for a Supercub. It would be interesting to see a properly pitched prop on a Patrol.
I sent Catto a couple of emails requesting information with some particular performance parameters. They never responded.

[marcusofcotton]

Catto props tend to have a slightly lower pitch number than others for similar performance. The difference between Craig's numbers and Bob's numbers would seem about right, going with the Catto, I would go with Craig's numbers.
​​​​Even though Mike's experiment was a 84x45, I think his low static and take off RPMs back this up.

[zkelley2]

I have a Sensenich 76 58 on my 0360 powered Patrol. A friend has a Catto 84 45 on his experimental Super Cub and is doing some ignition upgrades. He graciously suggested that I give it a try while it’s off his airplane. Why not. The Catto weighs 13lb 10 oz and my Sensenich is 35lbs 2 oz. I’m happy with the Sensenich’s performance but I had to investigate the Catto. Losing 21.5 pounds off the front end had me intrigued.

Empty CG moves aft from 10.9 to 11.2. At first glance, this 84 45 is not what I would choose for my Patrol so I wasn’t overly critical of the performance. Static rpm was low at 2200 and came up to 2310 by liftoff. Takeoff and climb performance was better than my Sensenich. 2300 rpm resulted in only 18” manifold pressure where the Sensenich runs approximately 20” there. Generally, it took about 150-200 rpm more to get the same MP and a comparable cruise speed.

The part that Got my attention was the lighter nose, which was quite noticeable on approach and landing. It felt more stable and was comfortably slower on landing. I can’t really explain it properly; but, this alone has me wanting to find the proper pitch for a Catto prop to replace my Sensenich. If I can find the pitch that will result in the Catto performing similar to my 76 58 Sensenich, I’m all in. That weight loss off the front end obviously helps with useful load but the real treat is the effect it has on CG and pitch authority when slow.

I know there are some Catto props on 0360 Patrols and am curious what kind of performance folks are getting with a certain prop (length/pitch). Personally, I really don’t want to give up my respectable cruise speed that the 76 58 gives me. Patrols with a Catto?

Mike

Why not just add 4lbs and do a composite constant speed ?
you'll pick up a ton of performance on both ends for little weight gain over your sensenich.

[svyolo]

I think on a very fast plane a CS prop is almost a requirement. On a BH? Not sure. I am buying one. But I wonder if I wouldt get pretty close with a good fixed pitch.

[zkelley2]

I think on a very fast plane a CS prop is almost a requirement. On a BH? Not sure. I am buying one. But I wonder if I wouldt get pretty close with a good fixed pitch.

You wont. That's like saying I wonder if I can win the tour de France on a single speed.

Cubs benefit greatly from them. Now that composite constant speed and fixed aluminum are close in weight.
There is no way to turn 2700rpm on takeoff and have any cruise speed.
You need all your hp for short field stuff. But an 80kt cruise speed as a result is terrible.

Everything else is a compromise between the two.

[m.mooney]

While I won’t disagree with the benefits of a CS prop, it’s not for me. I have a solid crank and actually like my performance with the Sensenich fixed pitch. On Desser 31s and unfaired shock struts I get 139 mph ias at 1500’ and 2700 rpm, which is respectable in my opinion. I’m not saying that this is my cruise configuration, it’s just a data point.
My primary focus is to LOSE weight in search of that wonderfully light nose and improved performance on landing. I spoke with Nicole at Catto and she was quite helpful. To replicate my metal Sensenich 76 58 performance (on both ends) and get 139 ias at 2700 she comes up with a Catto 78 54. A 78 55 will bring 141 ias, according to the calculator, at the expense of low end performance of course.
Worth mentioning, is another option that I’m gravitating towards. When I built my Rans S7 I put on a Whirlwind 3 blade 75” Ground adjustable prop. It was very lightweight and was a phenomenal performer. The ground adjustability is extremely valuable and is very easy to do, as in 15 minutes. For the 0360, whirlwind makes the GA-200L-stol, a ground adjustable 2 blade in lengths from 76 to 82”. It is heavier than the Catto by 4 pounds at 18 pounds. This is still almost 18 pounds lighter than the Sensenich. I’m intrigued.

[WyoDave]

m.mooney, did you ever get a Catto or Whirlwind for your plane? I believe Sensenich makes a GA for your application, too.

[m.mooney]

I’m still running my sensenich but think that I’ll probably go with a whirlwind or sensenich ground adjustable if I do make a change.