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CATTO 2 Blade vs 3 Blade

n38139

Well Known Member
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
 
3 Blade

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.
2z4igwh.jpg
 
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When money is not a deciding factor, the look of a 2-blade vs 3-blade will come down to “what looks right” - for example the paint scheme and airframe appearance. I have a classic Navy scheme on my RV-8 and a 3-blade would not have looked “right”. (on the RV-8, ground clearance is a non-issue with either choice)

In my case money was a factor and the 3-blade cost more to manufacture, has the cost of one more nickel edge, and would have cost more to ship.

Ultimately, it’s what makes you happy.

IMG_1493-575x399.jpg
 
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Catto constant speed

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.
 
Prop me up

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 bolted Craig's first 2 blade RV prop on my RV4 in 1998 to assist in testing and getting the word out to other RVers at that time.
Twenty years later my current RVX sports Craig's third iteration 2 blade Gen II. Gen III is a slight improvement on the 2 blade but the 3 blade now easily equals the 2 blade in performance.

I prefer the 2 blade for my own reasons, one of them being hand starts. As a frequenter of the CO/ID/MT/WY back-country, Bahamian islands and remote West TX ranch strips, being able to hand start with a dead battery is a big plus.
Additionally, the dos láminas performs slightly better above 10K WOT in thin air IMHO :).
My 2 cents...

V/R
Smokey


Catto Gen-II lámina negra de dos 70X70 with LEP (0-360J2A)
 
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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.
2z4igwh.jpg

Hey Mark, man, that?s a pretty airplane! I?m building a -7 with that same three blade Catto prop. Granted our airplanes are different with yours being a -9 and that you?re running an IO-320 and I?ll be running an EFI-360, but I was wondering what kind of performance numbers you?re getting? Also, in the picture that you posted it appears as though your transponder antenna is mounted up in the corner by the right landing gear....or is that something else I?m seeing? If that is your transponder antenna, how?s the performance of it being mounted there? I?m planning on mounting my Com antennas under the seat pans at about the same location that you have yours and I?d like to mount my transponder antenna in the middle and as far forward as possible under the fuselage. I?ll be running a 4 pipe Vetterman exhaust so I?d like to keep the antenna in the middle and away from the exhaust blast. I think the more conventional location for the transponder antenna is further back and basically at about where the baggage bulkhead is located or maybe even a little further back from that. From what I understand a proper ground plane is needed along with adequate separation from the Com antennas to achieve good performance, but if I can get away with it I?d love to mount it close to the front so that I can avoid a long transponder coax run.

Sorry for the threat drift!! 😬

Thanks,
Mark
 
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.
 
For me, it was all about maintenance.

The bottom cowl is much easier to get on and off with the two bladed prop!

Since these are all custom made to match the airframe, you don't really lose much, if any performance with either selection.

As noted above, the three bladed prop seems to run smoother than the two bladed prop; however, my two bladed Catto is extremely smooth, when compared to a metal two bladed prop.

The good news is, you can't go wrong with either selection and they are easy enough to change out later.
 
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.

Actually the glide ratio will increase of anything. The drag of a prop is determined by disk area and a 3-blade has a smaller diameter.
The only glide compliant I've heard for the 3-blade is the airplane is more difficult to slow down. Simply a matter of learning your airplane.
 
Went with a three blade to decrease vibration and noise (a tad). The fact that it?s really cool helped as well. Love it.
 
I love my gen 3 catto three blade prop, but i do have a new two blade whirlwind c/s prop on order. The only reason is for the extra dead stop to 1000ft agl climb performance and formation flying. The catto runs smooth and looks great.

zVErvfL.jpg
 
Catto Answer

Here is the answer I got four months ago from Catto when I asked them what the difference is between the 2 and 3 blade prop for an RV7:

"The three bladed propeller is quieter, smoother and has more of a braking affect when you pull the power.

The two bladed is around 2-3 kts faster at WOT."
 
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 in the process of changing my firewall and engine to support this testing.

We ordered the hub last week. Blades wont be ready until dec/jan for test on the first RV. I imagine it will be a while yet before the products is ready for sales.

Break

I have done a lot of test with these props. In my configuration the 3-bladed prop is so much more smoother than the 2-blade. The 3-blade is 4kts slower. Many factors go into these numbers but others RV should be close.

So the choice comes down to your mission.
 
2 Blade Catto vs 3 Blade Catto

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
 
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

Thanks for this and the other write-up Dave (http://www.vansairforce.com/community/showthread.php?t=112057)

I notice that you're now running the 74.5" pitch, vs the 75" and 76" in that post. Did you ever run a head-to-head comparison with 74" and 74.5" that caused you to settle there, and if so is that data posted? Searching hasn't returned any results.
 
74" Pitch vs 74.5"

Hi Alexander,

No, I never did get a chance to run the generation 3-68x74" unit on my plane. I ended up with the 74.5" unit based on the following thought process:

The testing data demonstrated that the 76" was clearly too much pitch for my side by side RV--it is a better match for an RV8/180 that has less flat plate area. The 75" was ALMOST a match but I could only turn around 2680-2690 rpm at 8k density with it--although even at that rpm the plane was performing very well. Over the last 12 years of running Craig's propellers I have learned that the sweet spot for all around performance (good combination of take off, climb, and cruise) on my plane is when I have a Catto that will just hit 2725-2750 rpm at 8k density. I could not quite push the 75" to that in level flight. Craig and I talked about it, he did some calculations, and we settled on the 74.5" for my plane and my common flying configuration. Full disclosure is that 9DB has a James cowl and a lot of small aerodynamic clean up details.

If going with a fixed pitch propeller, it is really hard (maybe impossible) to beat the "bang for the buck" you get with one of Craig and Nicole's propellers.

Cheers,

db
 
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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.
 
I've been curious about what the effect of different propeller diameters is. I have my new 3 blade 67" diameter Catto sitting here for my high compression O320. Can one of you prop. testers describe what a little smaller or larger diameter effects? I would just like a little understanding of this.
 
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.

I have the same setup with SJ cowl. Below is the data from my tag. I can just barely get 2700+ RPM at 5500' alt (haven't tried WOT any higher). Still working to clean up a few things to reduce drag a little more. One P-Mag, one Slick. Super tracks installed and dual steps as well. Planning for a Superior cold air sump later this year, which is said to add 7 HP.

Cruise is 160 KTAS @ 8.2 GPH @ 8500-12.5k DA. 2550-2600 RPM.

This is the prop Catto recommended with my setup. When I first started flying, without gear fairings, she was a lot slower (~20 MPH) and CHTs were difficult to control (have since properly tuned the P-Mag, as well).

Glass/2XCarbon Composite 3-B #09165272
Diameter: 68” Pitch: 75” NLE RV-7A
Engn :I0-360 180HP Dsgn RPM 2750
Red Line RPM max. 3200
Torque: 40 ft lbs. 7” Crush Plate Required
Manufacture Date: October 2016
 
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Catto Pitch and Diameter

"Catto for my RV-7A, the only question is how to pitch it"

Alexander, I would recommend you give Nicole or Craig a call to discuss your typical flying performance needs (take off, cross country, racing, etc) and they can guide you in the right direction reference pitch. Both are incredibly knowledgeable and really want you to be satisfied with the Catto!

"effect of different propeller diameters"

Hey Steve, I think the 67" for the 160hp vs 68" for the 180hp is simply a way of reducing blade area for the slightly lower power engine -- but again, Nicole could give you the technical reason.

You guys have fun and fly safe!

Cheers,
db
 
Cowl removal

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
 
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

Looks like you have a taildragger. The difficulty removing the cowling with a 3-blade prop is directed to the nose gear airplanes. I have no problem removing the cowling on my -6.
 
Quick reply

Thank you for the quick reply. I do have a tail dragged. Years back when I told Craig I had a 150 hp, he suggested a 2 blade. I will check back with him and see if he still suggests a 2 blade with my engine upgraded to 160 hp.

Thx again
 
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?)
 
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

Dave,

Was the 2 blade you tested also 68" diameter, or???
 
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?)


Hans, what numbers are you getting with your 160hp -4? I have one with a 160, but mine has the early style cowl, so it might help with removal. Haven't flown it yet, but has a metal 2-blade at the moment.

Jared
 
Diameter

Hi Charlie,

Sorry, just saw your question on 2 blade diameter.

The 2 blade Catto I tested back to back with the 3 blade was the same blade design and pitch but the 2 blade was a 72" diameter while the 3 blade was 68.

Hope this helps.

Cheers,

db
 
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