Getting ready to pull the trigger on a Catto prop just wondering if anybody had an opinion/experience on the 2 vs 3 Blade prop. 2 blade is cheaper but the 3 blade is really a good looking prop. RV8, O360
thanks
I talked with Craig when I ordered mine. I liked the looks of the three blade and the additional ground clearance. However I knew that the three blade would be less efficient and I did not want to loose any speed. Craig convinced me there would be very little difference in performance so I opted for the three.
Glad I did.
The Catto 3-blade looks really sexy and the vibration will be less with a 4-cylinder engine. The downside is that your glide ratio will be MUCH worse with the 3-blade.
There are rumors of a Catto constant speed prop coming out. If this is true, may add complexity to my 2 vs 3 blade decision.
I am vindicated....more of a braking affect when you pull the power...
Back in late 2013/early 2014 I did much of the testing for Craig on the gen 3 Catto Carbon Fiber three blade design for the side by side Rvs equipped with the 180 hp Lycoming--I think Axel was simultaneously testing the pitch/design options for the tandem RVs. After the testing was complete and Craig went into production I decided that the optimum prop for my RV9a/180 (James long cowl) to be a gen 3 with 74 1/2" pitch by 68" diameter 3 blade. If you would like to see the test results do a search for "2005 Catto 3 Blade vs. 2014 Catto 3 Blade".
Based on the performance I was getting with the 3 blade, a friend with an RV9a/180 also ordered a 74 1/2 pitch but he got a 2 blade. The point of all this is that eventually my friend opted to go constant speed and I tested his 2 blade on my plane back to back with my identically pitched 3 blade. The differences I noted where as follows:
The 3 blade was noticeably smoother in cruise
The 3 blade was quieter in cruise-due to the slower tip speed at same rpm
The 3 blade climb out was better--I recall around 150-200 fpm better climb
The 2 blade was 2 knots faster in my typical cruise-60-65% lop 8k+DA
I did not detect much difference in "braking action" at power down
On my plane, the 3 blade just looked great IMO.
Bottom cowl removal was more difficult with the 3 blade
I thought this info may be of value since the two props were tested on the same airframe in as near to identical conditions as possible.
Cheers,
db
Hi Dave,
Thanks for the fast response and details. I'm already sold on a Catto for my RV-7A, the only question is how to pitch it. Do you have any suggestions here? Stock IO-360 parallel valve engine and cowl, and the only exterior options I have planned so far are the extended rail for the sliding canopy and the step to help shorter people get on and off the wing.
Could somebody who has tried both a 2 blade and 3 blade on their plane please chime in. Lots of post saying how the 3 blade makes it more difficult to remove the lower cowl. How difficult is it compared with a 2 blade, really difficult, just a bit more difficult? Just trying to get a good idea so I can make an educated decision.
Thx
Back in late 2013/early 2014 I did much of the testing for Craig on the gen 3 Catto Carbon Fiber three blade design for the side by side Rvs equipped with the 180 hp Lycoming--I think Axel was simultaneously testing the pitch/design options for the tandem RVs. After the testing was complete and Craig went into production I decided that the optimum prop for my RV9a/180 (James long cowl) to be a gen 3 with 74 1/2" pitch by 68" diameter 3 blade. If you would like to see the test results do a search for "2005 Catto 3 Blade vs. 2014 Catto 3 Blade".
Based on the performance I was getting with the 3 blade, a friend with an RV9a/180 also ordered a 74 1/2 pitch but he got a 2 blade. The point of all this is that eventually my friend opted to go constant speed and I tested his 2 blade on my plane back to back with my identically pitched 3 blade. The differences I noted where as follows:
The 3 blade was noticeably smoother in cruise
The 3 blade was quieter in cruise-due to the slower tip speed at same rpm
The 3 blade climb out was better--I recall around 150-200 fpm better climb
The 2 blade was 2 knots faster in my typical cruise-60-65% lop 8k+DA
I did not detect much difference in "braking action" at power down
On my plane, the 3 blade just looked great IMO.
Bottom cowl removal was more difficult with the 3 blade
I thought this info may be of value since the two props were tested on the same airframe in as near to identical conditions as possible.
Cheers,
db
We have a 3 bladed Catto on our -4. Removing the lower cowling is a bit of a pain, as you want to slide it forward to clear the gear legs, yet run into at least one prop blade then. Best is to have the prop with one blade pointing up. The cowling WILL clear the lower blades, but not by a big margin.
Having said that, I wouldn't want to swap the prop for a two blade. It is ultra smooth and seems to be very efficient. We're getting ridiculous performance from our 160 hp engine with it. Highly recommended!
(and how often do you remove your lower cowling, really?)