Catto 3-blade pitch for cruise

[prkaye]

I'm going to be ordering up a new prop from Catto this fall, with the nickel leading edges. I have a -9A with a 160hp O-320. My previous prop has been great, and has a 70" pitch. Since almost all my flying is cruise and since I have more than enough climb performance with my current setup, I thought I might ask Craig to make my replacement prop pitched a bit more for cruise.
Any -9A drivers out there with a Catto 3-blade pitched differently than 70", for optimizing cruise? Recommendations on pitch?

[rockwoodrv9]

I ordered my prop from Craig last month. I am building a 9A and have a O-320D2A engine. I was more interested in climbing since I live in the mountains and will be flying at high altitudes much of the time. He recommended a 67x69 and said he has that on his 6A. He said with the 9A, at 2700-2720 RPM, it will cruise close to 190mph. I am sure that depends on how slick my build is but I would be thrilled with good climb and anything close to that!

If you want more cruise, just give him a call. He will re-pitch it if you want but that would involve going there or shipping so better to get it figured out with him before he builds it.

I can't wait to get mine just to hand it on the engine!

[rv8bldr]

Hi Phil

Just tell Craig what you want and he will figure it out. I told him I wanted more of a cruise prop on my 3 blade for my -8 but still some climb capability. I top out at about 190 kts at 2700RPM but I still get really good climb, so I am VERY happy with my Catto.

I have an IO-360-A3B6B 200hp and the prop is a 66x78.

[prkaye]

190 kts... sigh, that sounds awesome. I'm typical cruising at only 150 kts Sometimes I really regret not building an -8!

[RVbySDI]

Originally Posted by rv8bldr

Hi Phil

Just tell Craig what you want and he will figure it out. I told him I wanted more of a cruise prop on my 3 blade for my -8 but still some climb capability. I top out at about 190 kts at 2700RPM but I still get really good climb, so I am VERY happy with my Catto.

I have an IO-360-A3B6B 200hp and the prop is a 66x78.

Originally Posted by prkaye

190 kts... sigh, that sounds awesome. I'm typical cruising at only 150 kts Sometimes I really regret not building an -8!

I hope Mark comments on this but I bet you that was a miscommunication. 190 KTS = 218.5 MPH. Van's Vne number for the 9A is 210 MPH. I doubt Mark is flying his 9A 18.5 MPH faster than Vne. On the other hand, if he is. . . well ??? Mark are you sure you want to do that?

[prkaye]

Mark has an -8, not a -9A, hence my comment that "Sometimes I really regret not building an -8!"

[RVbySDI]

Thanks for the clarification Phil, I missed that piece of information on Mark's post. I was focused on the questions concerning the Catto prop on the 9A's and missed that he is flying an RV8.

[prkaye]

So Nicole at Catto explained to me that even at 70" (same pitch as I have now) the new prop will be faster at a lower RPM than my current prop. How is this possible? I mean, pitch is pitch, and for a given prop blade-length, the amount of air pushed for a given RPM should be the same, no? What am I missing?

[BCP Boys]

Originally Posted by RVbySDI

Mark are you sure you want to do that?

That's the first thing I thought of when I read that !

[crabandy]

Originally Posted by prkaye

So Nicole at Catto explained to me that even at 70" (same pitch as I have now) the new prop will be faster at a lower RPM than my current prop. How is this possible? I mean, pitch is pitch, and for a given prop blade-length, the amount of air pushed for a given RPM should be the same, no? What am I missing?

Lots of variables, just look at the different blade shapes etc.

Catto knows exactly what his props will do, trust their numbers.