To Catto or not to Catto

Discussion in 'Hangar Talk' started by cwspilot, Dec 16, 2017.

  1. Dec 16, 2017 #1

    cwspilot

    cwspilot

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    Thoughts on going from a metal fixed Sensenich to a Catto prop on a Pitts S2. Advantage or disadvantage?
     
  2. Dec 16, 2017 #2

    pittss1flyer

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    We did this on an S2E a couple years ago. Definitely need to recalculate the CG and W&B. We moved the battery (an Oddessy at the time) to the firewall from behind the rear seat to compensate. Worked out great and lost quite a few pounds of heavy wire and prop weight. Performance was however not so much improved that we noticed (we were not serious acro guys though--just some gentlemen's acro), though one did feel the loss of weight as helpful. Sold this plane about a year and a half ago. A really nice flying Pitts, but neither of us (it was co-owed) flew it much, so couldn't justify keeping it.

    Catto Prop.jpg
     
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  3. Dec 16, 2017 #3

    Chris McMillin

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    If one uses a Catto, a Wolf Pitts cowling and gear you go from 172 to 195 mph, I did that with mine. It had a drilled flange HO so that was my main motivation.
    Chris...
     
  4. Dec 16, 2017 #4

    grassroots

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    Are seriously considering or is this hangar talk along the lines of the VG thread? ;)
     
  5. Dec 16, 2017 #5

    Morphewb

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    At least we now have some good options. Wasn't the case when I started. Some wood props were available but they were hit and miss unless you wanted to get a nice Hoffmann from Germany. Problem was you could buy two metal Sensenich props for the price of one fixed pitch Hoffmann. MT wasn't in business, Mulbauer was working for Hoffmann at the time.

    It's pretty obvious now after years of going through this topic that the best is still the fixed pitch Sensenich prop. Totally understand the lightening hole situation though. I'd rather take a mild drop in performance and use a wood/composite prop than risk losing a flange/prop/airplane/my ass.

    I've owned two Cattos over the years and they both performed as advertised. Quality was first class and had no issues with either application. The fixed pitch Sensenich is approaching $5 grand from what I've been told. Sensenich does make a wood/composite prop with a metal leading edge bonded on. Way more durable than the urethane leading edge wood prop they sell. If you ordered one painted gray it would almost be impossible to tell it from their metal prop until you picked it up.

    Unless I had a ''holey'' flange I'd rather have a 76EM8-0-56 to 61 inch pitch metal if I was running a 180 with an akro flange. Of course I'm partial to constant speed props but if that option was ruled out I'm going aluminum. I've had a lot of trouble free hours behind that particular propeller and I wasn't very kind to it or the engine. They never let me down...ever....and I never had to worry about rain erosion either.
     
    Last edited: Dec 16, 2017
  6. Dec 16, 2017 #6

    Bond007

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    It's hard to beat a metal Sensenich.
    You get that sucker wound to 3100,and it's not stopping any time soon on a vertical up line.
    Low end Performance is also better,climb,and slow speed acceration off the top of slow figgures.
    U may gain some cruise from the catto,but who cares about that,I want Aerobatic Performance.
    Also you can readily get your hands on any pitch Sensenich u want,don't know how many months leed time on a Catto
    Danny 007
     
  7. Dec 16, 2017 #7

    Bond007

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    Eric it's winter time no one can fly so we have to talk about it
    Danny 007
     
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  8. Dec 16, 2017 #8

    jrs14855

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    3100?? Why not full throttle??
     
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  9. Dec 16, 2017 #9

    jrs14855

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    One of the options in the era of the Anderson props was to start with a prop that was no longer airworthy. I think I can get the profiles of the Anderson prop, thinking about modifying a stock Sensenich myself. If I can find a cheap un airworthy core.
     
  10. Dec 16, 2017 #10

    cwspilot

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    Grassroots, I've been kicking the Catto idea around and for awhile.
    Bond007, you don't fly in the winter? I just went up today here in winter wonderland Michigan
     
  11. Dec 16, 2017 #11

    Bond007

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    Good point Jim ,I just never look in the cockpit ,its probably more RPMs then 31
    Danny 007
     
  12. Dec 16, 2017 #12

    Bond007

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    I would love to try one of those things
    Danny 007
     
  13. Dec 16, 2017 #13

    Bond007

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    I do fly all winter ,just don't fly my boat or my open cockpit stuff
    Danny 007
     
  14. Dec 17, 2017 #14

    EAABipe40FF

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    I have a "EXP" prop on the Tu-holer that's in fine shape except too thin. Probably nowhere near as refined as a Anderson but it does do better than a like airworthy propeller.
     
  15. Dec 17, 2017 #15

    smizo

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    All I know is if you get a catto, for God’s sake have it painted to match your airplane or you’ll never hear the end of it.......:rolleyes:
     
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  16. Dec 17, 2017 #16

    airplanegeek

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    Just placed my order with Nichole Catto. She is nice to deal with. My 3 blade prop with metal edges, spacer, 14 inch carbon fiber spinner, and shipping is right around 5k. Certainly not cheap, but everyone that has them loves them. You will not find many on the used market. That alone speaks volumes. The metal edges add 750 but they are worth it I think.
     
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  17. Dec 17, 2017 #17

    Beej

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    hahaha
     
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  18. Dec 17, 2017 #18

    Larry Lyons

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    For what it's worth Chris, ( in case you didn't know) I don't like your prop tips! :D


    PS: By the way if we can't give you the devil who will we give it to: Doc?
     
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  19. Dec 17, 2017 #19

    Bond007

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    Chris ,I saw your plane at oskosh, everything looked great to me.No wierd prop thing going on
    Danny 007
     
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  20. Dec 17, 2017 #20

    grassroots

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    What are your goals for the new prop? I've done careful testing with four different Cattos on my airplane and can tell you that the Catto will not quite match the performance of a metal Sensenich across the entire speed range, assuming both are optimally pitched for your flying style. The difference is not huge but is noticeable. It's not a matter of the Catto being an insufficient design, it's just the rigidity of the metal prop. The Catto is very nicely built. But most Pitts pilots don't need (or are able to utilize) every ounce of performance the airplane has to offer, so the performance issue is an individual one. In my opinion, unless you have a light flange and/or hollow crank AND are doing a whole lot of snaps and gyro/tumble/3D type maneuvers that really rotate the prop disc quickly, then a Catto is not worthwhile. And even then, it's largely peace of mind. Actual failures are very rare, but have happened. My 1976 light crank flange (solid crank) has seen a whole lot of basic snaps with a metal Sensenich and is fine. For me it's mostly peace of mind when doing fun stuff like tumbles, shoulder rolls, flat spins, spiraling towers, etc. If you just do basic loops, rolls, spins, and hammers, then the Catto is hard to justify. And the small weight reduction of the Catto is more than offset by the performance loss.

    Those are the raw performance issues. There are some niceties associated wight the Catto though. It greatly reduces the gyroscopic resistance to pitch, which makes the airplane a little lighter to handle. At first I was unsure if this was a result of the aft CG shift, but after moving my battery forward after changing to the Catto, my CG is back where it was with the metal prop, and there was a negligible change in control feel. Hammers didn't really get any easier with the Catto, but I can fly Humptys slower over the top at zero indicated without torquing off.

    The Catto gets rid of any harmonic (red arc) RPM range. But there's little reason to hang out in this range anyway. The Catto runs very smooth and significantly reduces vibration. This is most noticeable on your first flight after switching. But....you forget about 10 seconds or so later and just fly the airplane. Same with switching back to metal, you notice the increased vibration at first, and then immediately forget about it. It's more of a passing "aha" moment than anything that affects the long-term enjoyability of the airplane.

    A 3-blade Catto makes less noise for those on the ground when you're turning 3,000+ RPM if that's any consideration at all. It has a distinctive growl.

    Unless you add the metal leading edges, you'll need to throttle back to around 2,000 RPM when flying through even light drizzle to avoid chewing up your prop tips. Obviously not an issue with the metal prop. Ask Danny 007 what his prop tips looked like after flying a single vertical line at 3,300 RPM through virga.

    The Catto is much more difficult to hand prop than a metal prop, if needed. I've done it a few times with both the metal prop and Catto.

    The Catto also looks pretty cool when you first put it on, but you'll get over that. So again, it all comes down to how much you value your money and what you're trying to accomplish. May be worthwhile for some and not for others.
     
    Last edited: Dec 18, 2017

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