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Thread: McCauley 7140 vs. 7440

  1. #41

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    Can't really remember but seems like about 2375 with both, but was reading my cub club newsletter and they were talking about having a 65 intake spider on instead of the 75-0-200 and low and behold I had the 65. since then have changed intake, carburetors, and done a few more mods and it really woke up a smart airplane. Love the 7440 so much I haven't even tried the 7144 for a couple of years now but feel like I could use more prop now. turning 2475 -2500 on climb out and have to throttle back to about 1/2 in level flight. getting off in about 150'-170' when light. we'll see if I can finally beat the T-crafts in Greenville this fall. pretty hard when you give them a 40-50 pound pilot advantage and they are some great seaplane pilots.

  2. #42

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    Douten, are you using a Sensenich 7440 or is it a McCauley?

  3. #43

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    It's a McCauley, I have a local seaplane with a sensenich on a 95 hp super cub but have not tried his prop yet and don't know that pitch. I tried a sensenich 7443 against my 7144 and it was about 2-3 seconds longer off the water when on floats. also measured my McCauley against a older one and the prop width in different places were not the same. don't understand why.

  4. #44

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    About a year ago, in a post about 7535 performance, throughout most of the post I typoed '7545' instead of '7535'. Saying

    "No, I'm not saying that I would prefer to run the 7535. There are five classes of overspeed (Categories Ia, Ib, IIa, IIb, and III). Running an O-200, you can easily reach a IIb overspeed with the 7545 (I was careful not to exceed IIa, which has the same inspection requirements as Ib). You can probably reach IIb with a C90 as well. A IIb overspeed would require that you replace the rod bolts and nuts, among a number of other unpleasant and potentially more expensive consequences. I've run a 7441, liked it, think a 7440 would do better than the 41, and that a 39 might be better still (I'm not in a hurry to get anywhere in a cub). Any flatter, and you run a severe risk of hurting the engine. I run a 7142 on a daily basis and think that on an O-200 (and probably a 90) it is a great compromise prop that won't lead a prudent pilot to hurt the engine. Being careless with the 7545 could lead to the need for an overhaul or worse within a very short period of time. That said, the 7545 performance is quite impressive, including a 55 mph climb at full rated rpm (2750 rpm) on a 95 degree day -- the 7545 just comes with a potentially exorbitant penalty".

    Needless to say, I meant to say, "7535" instead of "7545". Nobody commented, so I figure all of you knew what I meant, but I thought I'd take this opportunity to correct it anyway.

    BTW, my 7441 has been repitched to 7440, and I'm looking forward to comparing it against my 7142, but FedEx has been bouncing the package back and forth between Portland and Everett for two weeks now (was supposed to have come to a small town near Memphis). FedEx says it is being mis-scanned (15 scans so far between Portland and Everett), but they also say they can't do anything to stop the bouncing or redirect it toward Memphis.
    Oops & Arrgh,
    JimC

  5. #45

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    Douten, I'm curious about the 95hp SuperCub. Did you do it by STC or 337 ? Though Continental allowed the C90 to develop 95 hp during takeoff, Piper prohibited it; limiting the maximum power to 90.
    JimC

  6. #46
    Steve Pierce's Avatar
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    Piper called it a PA18-95.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  7. #47

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    Interesting.
    The PA-18 Type Certificate (T.C.D.S) 1A2 limits the engine to a maximum of 90 hp, so it isn't allowed to produce 95hp without a 337 or STC.

    Reference, T.C.D.S. 1A2, Page 2, Line 1
    Engine Limits For all operations, 2475 r.p.m. (90 hp.)

    The use of the term PA-18-95 must have been a marketing ploy, since the type certificate didn't allow the engine to actually develop that horsepower under any circumstance.
    JimC

  8. #48
    Steve Pierce's Avatar
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    I know what the TCDS says but I refer to them as PA18-95s as did Piper, so do others.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  9. #49

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    P.S. Much the same is true for the J3 and PA-11,

    where for the J3, T.C.D.S. A-691 Item 311. C. (10) limits the power of the C-90 to 90 hp on takeoff and 80 hp for all other operations.

    And for the PA-11, T.C.D.S. A-691 Item 311. D. (5) limits the power of the C-90 to 90 hp on all operations
    JimC

  10. #50

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    P.S. Much the same is true for the J3 and PA-11,

    where for the J3, T.C.D.S. A-691 Item 311. C. (10) limits the power of the C-90 to 90 hp on takeoff and 80 hp for all other operations.

    And for the PA-11, T.C.D.S. A-691 Item 311. D. (5) limits the power of the C-90 to 90 hp on all operations
    JimC
    P.P.S. Airplanes is strange creatures, and their paperwork is even stranger.

  11. #51

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    maybe you misunderstood my comment I don't own the pa18-95, I have a pa-11, I noticed the other day that I turn 2475 on a steep climb then I throttle back to about 1/2 in level flight cruise about 85 indicated.

  12. #52
    Sideslip's Avatar
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    Sorry to bring up this old thread. I came across a 7535 prop in good condition. It's for a pa11. It sounds like it should be a fun prop for short field/climb performance. My only problem is my pa11 has a c85. Will that be to much prop for stock 85? Also is $1400 a decent price I cant seem to bring up any comparisons. Thanks

  13. #53
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    Sideslip,
    That is a great prop for you, those are scarce as hens teeth, if its got good width out at the tips, $1400 is a very fair price, have heard of them bringing up in $2-500 if minty. A buddy just told me he is getting a new one with 38" pitch for his 90hp PA11, said the quoted him $3300 bucks , so your less than half price! The longer prop will generally get your tail up faster, push you up otta ground effect better, pull you onto the step faster, generally climb out
    Better, usually longer disk is smoother, and your approach will be slower with both props windmilling when one is longer with less pitch.
    Used to run a 74/40 on my 90 Cub and it worked good around 8 secs on 1320s, got a 75/38 and got 7 secs all the time. Great skiplane prop as well, been years but 82 mph cruise at 2300 seams to ring a bell, better grab it if its in good shape!
    Have no idea on legality of it on your application.......

  14. #54

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    Sideslip, As Turbo Beaver said Grab the prop if its not junk, I used that pitch on my pa-11 90 for take off comp. in Greenville, ( Yes Glenn I remember the little girl beating me, I will never live it down ). The prop should do good with the 85 and great if you do the 0200 conversion down the road. I use a 7438 with my Amphibs that works great, last summer I ran my 7144 when going to LockHaven cruised about 85 on the Amphibs but had to be careful as it doesn't perform as good.

  15. #55
    Sideslip's Avatar
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    Douten did you notice a difference from the 7144-7535? I'm currently running a 7140 and it seems to do pretty good(2300 rpm at TO with a c85), but after playing around with a friend who has j3 with a c90 (kicked my ass if you ask me). I guess I'm just asking you guys with experience with these props if it would be more of a parallel move, or is it going to my smile even bigger?

  16. #56
    TurboBeaver's Avatar
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    Sideslip prepare yourself for a grin from ear to ear, however dont compare an 85hp engine to a 90hp engine , one is basically a hotter version of a 65,
    The other is really a different animal, when the Greenville fly in first started and there were alot more"little floatplanes" compeating, there were quite a few J3s and PA11 / 85hp that got "egg in their face" going against 7CCM Champs with 90hp engines , not the same story if the he cubs had a ninety.......... they would usually have the champs by a second, all things being equal............ you needed 7 secs or less ,to be at the banquet later that nite!
    Last edited by TurboBeaver; 02-02-2015 at 08:03 PM.

  17. #57

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    Sideslip, when competing I would change my 7440 for the 7535 fro Willy B and get 2425-2450 vs 2370-2425 now repitched 7438 I get 2475 ( 90 HP ) on T/O and climb then throttle back, I think the speed difference is minimal but the fun/confidence factor has really increased. http://www.flickr.com/photos/aircraf...7629997224608/ This should be the link with a few photos of my plane N5082H.

  18. #58
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    When I was competing in the mid and late 70's at Greenville with my 39 J-3, no one ever beat it. It was powered with a stroked 83 swinging a sensenich 76AK2-38 (74" ag. prop for the 85). It would turn that prop 2575 tied down and 2625 going onto the step. That was good; but remember that the 85 has to turn up handy to 2700 to reach a real 85 HP., and even this one didn't do that! That cub on 1320's from the back seat, would consistently make 5 to 6 sec. takeoffs, and even Kathy Hodgekins PA-11 ( Which was very stiff competition) couldn't quite beat it. My point being; I never had a float plane with too much horsepower; but I've seen plenty that should do better than they are doing; usually not the right prop for takeoff; you can't have it both ways. Fun topic.

  19. #59

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    Nice pics Douten.Don't think Glenn ever beat that girl either

    Sideslip a J-3 with a 90 will kick everyone's ass if flown correctly and $1400 is a great price for a Mac 75/35 if it is any good.

    Bill

    Everyone except the guy who posted before me!
    Last edited by willyb; 02-02-2015 at 10:41 AM.

  20. #60
    cubdriver2's Avatar
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    Quote Originally Posted by willyb View Post
    Nice pics Douten.Don't think Glenn ever beat that girl either


    Bill

    Everyone except the guy who posted before me!
    Who do you think coached her for free.


    Glenn

  21. #61
    TurboBeaver's Avatar
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    While it will always be true the old saying " the only thing that will beat a cub, is another cub" is usually true , However the physics of a 180lb pilot vs a 95lb one is a tough thing to get around................
    I still have some old VHS footage, of her getting off with a puff of wind helpin her, in 3.5 secs one year , straight out of the hole, no over the step planeing involved! Pretty impressive stuff. in the film you can hear someone in the crowd say" did you see that she went straight out " To beat that hundred pound weight advantage, she brough to the boat with the flags in it , you had to
    really be "haulin the mail" as that's quite an advantage....................... she did a great job of keeping a lot of ours egos in check. Down in this low horsepower range , weight is almost always the king. Of course there is exceptions to everything, as she was beat before. Like boxing your only the champion for a while.
    Last edited by TurboBeaver; 02-02-2015 at 07:57 PM.

  22. #62
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    Quote Originally Posted by TurboBeaver View Post
    While it will always be true the old saying " the only thing that will beat a cub, is another cub" is usually true , However the physics of a 180lb pilot vs a 95lb one is a tough thing to get around................
    I still have some old VHS footage, of her getting off with a puff of wind helpin her, in 3.5 secs one year , straight out of the hole, no over the step planeing involved! Pretty impressive stuff. in the film you can hear someone in the crowd say" did you see that she went straight out " To beat that hundred pound weight advantage, she brough to the boat with the flags in it , you had to
    really be "haulin the mail" as that's quite an advantage....................... she did a great job of keeping a lot of ours egos in check. Down in this low horsepower range , weight is almost always the king. Of course there is exceptions to everything, as she was beat before. Like boxing your only the champion for a while.
    She was in a Citabria

    Glenn

  23. #63

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    Continental Sea Level power curves for the C85, C90, O-200, & 9.5:1 O-200

    Note that Continental had a bad data point for the C90 at 2350 rpm. That point was low by 1 hp.

    Ain't nuthin' like climbing out a 9.5 O-200 J3 landplane at 55 mph with only 3 gallons of fuel on board and a 7535 prop turning 2850 rpm for about 113 hp. Big grin while doing that.....
    Caution though -- be careful not to unport the nosetank outlet.
    Attached Images Attached Images
    Last edited by JimC; 08-14-2015 at 10:43 PM.

  24. #64

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    I hate to dig up an old thread but I have a question, what data allows the use of a 74" McCauley prop on a C-85? or was it just done? Thanks Tim

  25. #65
    TurboBeaver's Avatar
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    It was and still is commonly done
    Possibly only legal on a Cessna 150 seaplane or Tcraft 65hp ???
    Would only be an issue if you had. Insurance and there was an accident........... Most folks are just running them.

    Sent from my LG-K450 using Tapatalk
    Likes cubdriver2 liked this post

  26. #66
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    I am running a c90 with 7145 on my -11. It cruises about 85 mph at 2200. At my airport elevation of 3400' static rpm is about 2300.

  27. #67
    Cub Special Ed's Avatar
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    Sorry folks. I told you wrong. Im running a 7345.

  28. #68
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    I have a mac 74-38 with a stock o-200 on a ex cub I get 2500 rpm's on take off at 3300 msl. I am building a o-200 with c-85 pistons and a c-90 like cam. I'm curious if that prop will still work or with the added hp I will need a courser prop can't wait to see.

  29. #69
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    A little late in posting but I flew C90-8 powered 46 Cub for 10 years with a 7146 that performed extremely well. At TO it was just reaching max rpm and would cruise at 75-80 at 2200 and burn 4 1/2GPH. That was on wheels naturally.

    Tom

  30. #70
    Doug Budd's Avatar
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    Anyone have a cub with a 0-200 D using a catto prop? If so what length and pitch and performance are you getting

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