A different Catto prop?

[jasimmons]

Anyone running a Catto other than the standard 80x50? I heard Craig has a 86X? that might offer some enhanced performance...

Thanks!

[Dan L]

I’m on my third Catto. The second one was the 80x50. After going to the trade show in Alaska in 2016 and talking to Craig Catto there I bought his 84x42.5. Craig told me it would reduce take offs but be a little slower in cruise. But he said because the 84x42.5 is flatter it pulls less manifold pressure at the same rpm as the 80x50. So it burns less fuel. But bumping up the rpm by 100 gets the cruise speed and fuel burn back where it was.

So how much shorter does it get off? About a third less. I almost always take off from the sod in front of my hangar parallel to the runway at our airport going the same direction. I’m hangar two so there isn’t a lot of room between my turnaround point and my taxiway. With the 80x50 I was always off about 50’ on the far side. Now I’m always off before the taxiway.

Its a a fooler though. My static rpm is just 2350. When I first put it on they told me I was thinking with a Borer prop mindset and that their props are different. They told me I was getting more thrust and that’s what mattered. They were right. And once the plane is on the roll the rpm comes up quickly.

This prop has also had a vibration survey on the O-340. That’s an important test.

For me it was a win-win.

[Springloaded]

[QUOTE=Dan L;20258]I’m on my third Catto. The second one was the 80x50. After going to the trade show in Alaska in 2016 and talking to Craig Catto there I bought his 84x42.5. Craig told me it would reduce take offs but be a little slower in cruise. But he said because the 84x42.5 is flatter it pulls less manifold pressure at the same rpm as the 80x50. So it burns less fuel. But bumping up the rpm by 100 gets the cruise speed and fuel burn back where it was.

So how much shorter does it get off? About a third less. I almost always take off from the sod in front of my hangar parallel to the runway at our airport going the same direction. I’m hangar two so there isn’t a lot of room between my turnaround point and my taxiway. With the 80x50 I was always off about 50’ on the far side. Now I’m always off before the taxiway[/QUOTE

I've been running a 84-42.5 for about 3-4 years now. It's all I run on my planes. I think Dan explained it perfectly.

[jasimmons]

Thanks so much guys. Great info. Glad to know a vibration study was performed.

My cylinders are at Lycon right now getting the port/flow treatment. Trying to figure out (predict) if a different length/pitch might help optimize the potential gains. Once put back together, will put the 80x50 back on to get some 'after' data to comparer to the 'before' data. Then consider a diff prop. Fun stuff.

Andrew

[Springloaded]

I've done (2) CC SS with 10-1 pistons, port n polish. I redline the 80-50 almost instantly. I just finished one I put a 80-52 on it turns 2680 WOT. level flight. That's another to keep on mind the 84-42.5 can be redlined very easily in level flight. I had friend try the 86" Catto he said it pulled hard but was really just to flat of a pitch for him.

[40m]

I've done (2) CC SS with 10-1 pistons, port n polish. I redline the 80-50 almost instantly. I just finished one I put a 80-52 on it turns 2680 WOT. level flight. That's another to keep on mind the 84-42.5 can be redlined very easily in level flight. I had friend try the 86" Catto he said it pulled hard but was really just to flat of a pitch for him.

You're giving away some of your secrets

[Springloaded]

You're giving away some of your secrets

That's exactly what your suppose to think😀 He never asked about the 90" prop