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prkaye

Well Known Member
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?
 
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!
 
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.
 
190 kts... sigh, that sounds awesome. I'm typical cruising at only 150 kts :( Sometimes I really regret not building an -8!
 
rv8bldr said:
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.
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prkaye said:
190 kts... sigh, that sounds awesome. I'm typical cruising at only 150 kts :( Sometimes I really regret not building an -8!
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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?
 
Mark has an -8, not a -9A, hence my comment that "Sometimes I really regret not building an -8!"
 
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.
 
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?
 
prkaye said:
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?
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Lots of variables, just look at the different blade shapes etc.

Catto knows exactly what his props will do, trust their numbers.
 
prkaye said:
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?
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What you're missing is his constant research into design improvements that have created record setting props for all sorts of different aircraft. It all ends up in the newest props.

If you read the write up in Kitplanes or followed the comments on the recent fly in to his facility you'd know what I'm describing. The little tweaks he continues to find in different areas are amazing. It's almost like electronics getting better all the time!

I'm waiting for his latest stuff in a new prop and know full well it will be better. Always has been. When that changes you'll hear about it!
 
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pitch varies

Pitch varies from one manufacturer to another and is more of a relative number not necessarily comparable . Catto props deliver.
 
Huh?

I have a -9A with Catto prop. With no requests or other input he sent me a two blade 70x70. Only 5 hrs so far so just a few glances at airspeed and RPM and it's pretty easy to redline the engine at 2700 rpm at 6500' (so far) and GS of 165 kts. Can't wait to get to 8500' and see what WOT yields,
 
Ok, it was explained to me by a local builder. A prop has a twist and so the pitch varies along its length. The value for pitch is usually given at some specific datum point on hte blade. So even at the same pitch value, two different props can have very different characteristics because of their shape and the way in which the pitch varies along the blade.

I'm in the queue for a new Catto prop with nickel edges! Going to stick with the 70 inches. Can't wait to get it :)
 
If you specify the engine and the aircraft type Craig Catto will cut the prop for "total performance" just like the RV design objective.

I've had 2 Catto 3 blade units, both turned up about 2200 for take off and max out at 2750 @ 75% power at 8500'.

Cruise at the 8-10,000' level burning 8 or 10 gph shows 2500-2600 rpm.

Not sure what you are asking for by wanting a.cruise prop. The RV is a relatively fast airplane with a wide speed range. I believe Catto cuts the prop quite well to satisfy that need. I don't see how it could be improved.

PS As of an early flight to beat the heat, 38.4.hours, 97 landings and no bent metal so far. The 8 is one fine flying machine. :)
 
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