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Catto prop

C

capav8

Registered User
Lee's Summit, MO
Do any of you know how the Catto prop did at Valdeze this year? I was talking to Craig Catto a couple of weeks ago and he told me that his prop won last year and expected to win this year also. Just curious as I want one of those props!


Jim
 
1st, 3rd, 4th, and 5th for Catto. As far as I know, 2nd was a Whirlwind.

Craig's 90 inch pulled the hardest during testing in the days before the contest.
 
The two shortest take offs were a tie between the catto 90 inch and the whirlwind 200g with a distance of 36 feet. Also, Dave is right, the 90 inch pulled harder than anything else that day. Close to 900 pounds of thrust. I recommend it not only because it is somewhere around 14 pounds but also because it, depending on the pitch, can still pull 35s through the air at 100mph at 2200rpm for the 9040 "cruise prop" and 88mph at 2450rpm for the 9034 climb prop. The shorter props have also been out pulling and going faster than their metal counterparts.
 
Ummm.

Bobby. The 90x35 McCauley pulled 920 pounds last year during our pulls....far above the other stuff. FYI:)
 
Since we did not test the props side by side it is difficult to say which pulled harder due to different scales, engine, humidity, etc...

Josh Pepperd's producer pulled some 60 or 70 pounds less than last year when he had not made a single change to his engine. It was a very humid low pressure day so i speculate that is the reason for the variation.

Ideally we would test say ten different props all on the same engine on the same day to get an honest comparison. All i have to say is that the Catto is somewhere around 14 pounds whereas the McCauley is 45+ pounds. Thats a big difference in weight hanging all the way out front.
 
I've read all the three-blade Catto comments here and elsewhere and wonder if they're being used in the boonies on floats because of water erosion and wariness of hand-propping.
 
Bobby, Dave is telling us something here..........I would like to try a fresh McCauley 9035,34,33 to see what happens! Both in flight and in pull tests....Dad

King Brown, I was quite leary of hand propping the 14 pound 2 blade Catto bolted to a high compression O-375 with electronic ignition with variable high advance...... but when necessity required it, despite less "flywheel" mass it was possible to pull it through, and when it fired hard on the first starting pull, the second blade didn't come around so fast that it got my fingers......

Bob
 
My 84" catto with crush plate, adapter, and prop weigh 20.6lbs, my 90" McCauley is 43lbs both without bolts. craig catto told me that his 90" would only weigh 1lb more then the 84".
 
Anyone listening.......I'm all for advancement in design, lightness, etc.

..my comment was to make sure ALL the data was present.
 
I took a moment to look at the test sheet that Josh had prepared for last year. I was wrong about the 90x35 McCauley....it pulled 955lbs. The next best thing pulled 895lbs. I was surprised to see that the sheet showed a temperature of around 50 deg. F for the testing period but no mention of RH or Baro. Press.
 
I'm wondering if anyone is concerned about crankshaft torsional vibration with these light weight and low moment of inertia props. Props are seen by the engine as part of the flywheel. The lighter props are as though the flywheel were cut down. Changing prop mass somehow alters the balance of the mass-elastic system. I am no expert on this subject but I have seen some heavy duty shafting come apart as a result of torsional vibration. Does anyone know if a study of this issue is part of the certification for significantly lower (or higher) inertia props? I'm thinking of potential crankshaft fatigue near the front bearing/flange.
Darrel
 
Yeah re Darrel's comment. I'd think that by increasing moment of inertia, direct pulse stresses could be a problem (closer to hammering against a "fixed mass"). Also that gyroscopic and p-factor induced bending moments would increase with increased moment of inertia and length. And by decreasing moment of inertia, resonance could become a problem. Lots of variables that can interplay, so I too would want to know that analysis and testing have taken place.
 
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Of course, the certified props we run ('Borer props', thank you to Roger Borer) have had vibration surveys done.

Others??????? I dunno. I know we are on the fringe with the 90inch metal props on 4 cylinder Lycomings.
 
Gotta say Craig Catto has provided both excellent service and the best pulling prop we have tested to date! He is willing to help get things right. :lol:
 
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This discussion of props is very interesting to me. Is this discussion all using the big HP stroked 360's? I'd sure like to know which of these pull best on the stroked 320's (340), which is what I have. Has anyone got a catto on the stroked 320? If so what's the best pulling size for that engine. I think that is the engine CubCrafters is using on some of their new Cubs so has anyone done pull tests with different props on this engine? I'm running a Sensenich 80 42 right now on mine. Would be interesting for me to find some "data" on that.
 
I have three Catto three blades two 90" bi-camber Felix P-235 84" 90" Mc Caulys 82"borer 90" prince the best pulling prop is the 90" Mc Cauly the best performing prop is the Catto three blade I've tried every prop know to man Catto ranks #1 in my book mikeo
 
gdafoe said:
...I'd sure like to know which of these pull best on the stroked 320's (340), which is what I have. Has anyone got a catto on the stroked 320? If so what's the best pulling size for that engine. I think that is the engine CubCrafters is using on some of their new Cubs...
Click to expand...

I spoke with Craig Catto regarding the 0-340 at the Alaska Airman's show. He stated that on the Carbon Cub they use his 78 x 54 or 55 pitch prop. I'm planning to use the 340 on my Bearhawk project.

Mark J
 
From my thread on Building a Smithcub


Props

I put my new Catto prop on today. I don't have all the data yet but this is what I do have.

My engine is a moderately hopped up narrow deck 0-320. 9 to 1 pistons, ported, flowed, matched, centercarb sump, etc.

With a 74-56 prop I was getting 2600 static RPM. I am at 850' MSL and the temp was about 60 degrees. At 60 mph climb I was getting 2600 RPM and at 80MPH climb I was seeing 2700 RPM. Max speed and RPM in level flight was 2820 RPM and 124 MPH(I am sure of the RPM but not really sure of the speed I can't find my notes)

Then I tried a 82-42 Borer. I got 2500 static and 2600 RPM gave me 50MPH climb and 2700RPM gave me 70MPH. Much smoother prop than the 74-56

I now have a Catto 82-41 and I am getting 2450 Static. At 80 MPH in the climb I am seeing 2700RPM. It was quite bumpy during my test so I am not real confident of the climb number. Max level RPM is over 3000. I chickened out at 3220. I'll try again when it is smoother. Again the prop is much smoother than the 74-56. The 74-56 weighed 27.2 pounds. The Catto weighs 14.2 pounds. A savings of 13 pounds even.
So far I am very pleased with the Catto

I did a bunch of T.O. test with the 74-56 and will post all that data after I get a chance to test the T.O. performance of the Catto. Perhaps next week. Here are a couple of photos.

Cato_prop_and_gap_seals_013.jpg


Cato_prop_and_gap_seals_001.jpg


Hope this helps

Bill​
 
Irishfield - that was a one time test. Trust me I don't run the engine at those RPMs. Any low pitched prop will overspeed the engine if you let it. I let it, in that case, just to see how far it would go. I keep it below 2700 RPM but I don't think there is any real danger if you momentarily exceed that. I'd bet every Borer is over reved pretty regularly.

Bill
 
SC fitting nicely in a hangar, beauty abounds. Great sight, Bill! How did you rationalize erosion and handpropping issues re Catto? The handpropping is a turn-off for me. Two-blades no problem; I'd be a chicken with three.
 
We have been running composit props on airboats for years... tough on them with the brush and sand in the air.

They last very well, until some idiot mechanic leaves bolts unsaftied.
 
I have never seen an airboat prop around here safety wired. I also know someone that hand propped his 5 blade prop on his airboat. He had just enough beer to be brave enough and not too many to succeed.
 
Buy the way, with wood in them, how do these props hold there tracking and what kind of a hub do they have so when that the bolts are torqued down to proper specs does it crack things?
 
Bill Rusk said:
Irishfield - that was a one time test. Trust me I don't run the engine at those RPMs. Any low pitched prop will overspeed the engine if you let it. I let it, in that case, just to see how far it would go. I keep it below 2700 RPM but I don't think there is any real danger if you momentarily exceed that. I'd bet every Borer is over reved pretty regularly.

Bill
Click to expand...

I know this is old but I stumbled across it recently. It is NOT ok to momentarilly exceed 2700 RPM with any of the engines in the O-320 family (quite a large family I might add!)

Per Lycoming's Mandatory SB369J any overspeed requires certain inspections. Any overspeed exceeding 10% (in the case of an 0-320, 2970 RPM) you are required to remove the engine, inspect all components, replace all dynamic counter weight bushings, overhaul the magnetos unless SLicks, throw them away... anyway, you get the picture. I am not picking on anyone, just making sure that everyone realizes you can't be cavalier with prop selection that allows static RPM to run away like that!


Here's a link to Service Bulletin 369J if anyone wants to read it.

http://www.lycoming.textron.com/support/publications/service-bulletins/pdfs/SB369J.pdf
 
What's going on at Catto? After all the discussions of Valdez and Catto props over the years, I gave in and ordered an 82/41 last January. I was excited about the performance gains, the good looks and getting rid of some weight on the nose. So, order submitted. With Spring coming, I called in March and was told my prop was all done but the leading edges and that I'd have my prop in three weeks. I was pumped. No prop or contact. Oh well, stuff happens. So, I waited until June And I go through the same routine--call, was told my prop was half done and that I'd have it in three weeks max. No prop to date so I finally gave up.
 
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