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Thread: Dang rudders on 2960s are small.

  1. #1
    Alex Clark's Avatar
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    Dang rudders on 2960s are small.

    It has been two years since I have flown 2960s and it was calm the last few times I did.

    I had my souped up C-180 out with a client yesterday morning and the snappy winds would not let us turn with the tiny 2960 rudders. I could figure it out, but it was not a good experience for the other guy's first day on floats. Pulling into my slip area was not a pretty sight.

    I was spoiled by using PKs the last few years with over-sized rudders and extra throw angle. ( I modified the arms.)

    Now I remember why years ago I made trim tab additions to my old EDOs.

    Yes my rudders are going down all the way.
    At least the 2960s accelerate pretty fast on breezy days.....and they are pretty fast in flight. I was doing 110 knots at only 22-23 squared.

  2. #2
    BC12D-4-85's Avatar
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    Open the door and look back at the rudders in a L/R turn. Note if they're going to and staying in full deflection when power is added or speed increases. Maybe trim adds are needed too.

    Gary

  3. #3

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    Make bigger water rudders. I could taxi dead straight in 25mph crosswinds with my big tail 180 on 2960s. I'll never forget how surprised I was the first time I did it.
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  4. #4
    Alex Clark's Avatar
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    These look like they are at full deflection because I was thinking they had snagged a bunch of lake grass. So I was looking....

    Years ago I riveted extra helpers to EDO rudders. see pic. it really helped a lot.
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    mvivion's Avatar
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    Alex,

    You say the water rudders are going all the way down. The question is, are they STAYING all the way down in a turn. As Gary noted, look out the door at them WHILE TURNING.

    Bigger blades are easy to fabricate, and look better than the "additions" you showed in the photo. No one is going to measure your rudders, but a scab patch on the back side??? That could draw attention.

    MTV

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    Make new blades, but take care with the geometry. If you have too much or too little blade forward of the pivot axis you may have an interesting day.

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    a friend of mine had trouble turning as it turned out his rudder springs were to weak to hold the rudders down when he was taxing the wake would push the rudders out of the water

  8. #8
    BC12D-4-85's Avatar
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    Interesting topic. Holding down the rudders = stronger springs? I've seen stronger or more added to do what Mike notes especially in weeds or strong current like the Yukon in spots.

    Bigger area rudders. Might be better than trim adds, but there's some trim pieced riveted on the rear rudder portion of a set of CAP 3000's that helped that pilot he claims. As noted the front to rear area geometry of the pivot line outwards when dropped should be maintained.

    The down angle can be carefully changed by removing some of the down stop metal on the rudder where they contact the float stop bumper. If too much rudder area is in front of the down rudder pivot line they can go their own way and run full stop uncommanded. I had a rudder set on 3420's changed like that but I knew they'd do it and acted accordingly.

    Gary

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    Are your cables crossed? That's what helps the most. (Crossing them )Left rudder horn at air rudder to right horn on right water rudder, and right rudder horn on air rudder to left rudder horn on left rudder and you get max deflection. Balance cable on inboard rudder horns. Seems it shouldnt matter because it's a closed loop but it does.. I think it has to do with the angle which the pulleys approach the bellcrank.(This is as opposed to right and left rudder arm hooked to straight-back rigging which means balance cables are on the outside) Big rudders are nice but if they are not balanced (front to rear vs pivot pt) then hard to get to full deflection. If balanced, then next problem is part forward of pivot digs into beaches when tailed-up. It seems compromise is the art of aviation.
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  10. #10
    skywagon8a's Avatar
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    Quote Originally Posted by Alex Clark View Post
    I had my souped up C-180 out with a client yesterday morning and the snappy winds would not let us turn with the tiny 2960 rudders. I could figure it out, but it was not a good experience for the other guy's first day on floats. Pulling into my slip area was not a pretty sight.
    Alex,
    Are your steering cables attached to the correct holes in the rudder steering arms?
    The steering cables (outboard) are attached to the innermost hole in the steering tiller. The balance cable (inboard) is attached to the outermost hole in the steering tiller.
    In other words the outboard cables go to the inner holes and the inboard cables go to the outer holes. EDO drawing #42500. This provides differential rudder travel for steering tighter turns.

    And are you certain that the Cessna steering springs are the correct ones? The seaplane springs are heavy diameter wire and the land plane version are the light ones. These are the springs inside the tailcone which connect to the rudder bellcranks.
    N1PA
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  11. #11

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    I forgot those things don't steer from the rudder bellcrank! Thanks 8A

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    I agree with the comments above concerning spring strength. I fly a 206 and had the same weathervaning problem at Lake Hood AK taking off Southeast. Almost ended up in the takeoff channel once coming out of the slow canal, had to cut the engine off and drift back out. So many people talking on the radio I couldn't get a word in edge wise that I had a problem. The heavy beaver taking off realized though when he got to me. Too close for comfort.
    The stock springs are too weak. I put on heavier springs to the point I have trouble lifting them sometime because of the downward force. But when I put them down, they are down, and no wind or water load is going the lift them. I have complete control in the worst conditions now.
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  13. #13

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    I also had the bushings in the rudder pivots, I reworked them last year because of excessive free play. If the rudder leans slightly as you are turning this can also lift them out of the water. Grab the top and bottom and see if you can shift it back and forth. The lower bushing sits in the water and will corrode out.
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  14. #14
    Alex Clark's Avatar
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    My interior springs are the heavy ones. I will go out today and see if the rudder is lifting while underway. It was rather windy the last few days. Today is mild.

  15. #15
    skywagon8a's Avatar
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    It's the holes that the cables are attached to on the water rudder steering arms which are more important.
    N1PA
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    while you are taxiing lift the handle. You can feel it if the handle lifts freely and then engage the rudders part way up the lift you don't have enough down force. I went to fire and fastener and got some heavier springs and then made extensions for them to get the down force I wanted. It's a bit of trial and error to get good down pressure without overdoing it. You can look at my plane in spot 100 on lake hood and see how they are set up. They aren't pretty but the do the job well. I've run them for a couple of years now the way the are.

  17. #17
    Alex Clark's Avatar
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    By the way, I have made slightly larger rudder blades before. To scale them up, just set the naked blade on an office copier. Hit 135% or whatever size you want. The copier will then print a slightly larger print on your rudder. The screw or rivet holes will show up and you can use it as a paper template.
    Last edited by Alex Clark; 06-13-2018 at 04:17 PM.

  18. #18
    TurboBeaver's Avatar
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    . I could taxi dead straight in 25mph crosswinds with my big tail 180 on 2960s
    Now that would certainly surprise me too!

  19. #19

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    Sometimes you don't want to turn in more wind than the water rudders will let you..Small floats with big rudders can mean wet passengers..with just enough power..
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  20. #20
    Alex Clark's Avatar
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    The previous owner had the cables connected to the wrong holes on the rudder tiller. . ( I hate it when that happens)
    Skywagon Pete guessed that and photos proved it. So I changed to the correct location per EDO drawings and obtained more rudder deflection.
    The 20 knots winds have died and now it is raining buckets... So I have not seen how much it helps while underway just yet.

    ODDLY ENOUGH... All the other EDO 2960s in town are rigged incorrectly.
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  21. #21
    cubdriver2's Avatar
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    Curious why left side is not moved also?

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"

  22. #22
    skywagon8a's Avatar
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    Quote Originally Posted by cubdriver2 View Post
    Curious why left side is not moved also?

    Glenn
    For the same reason that the wheels on a car turn at different angles. It has to do with the radius of the turn at that point of the circle.
    N1PA
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  23. #23
    Alex Clark's Avatar
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    Cubdriver 2, Look on page 12 at figure 6.

    http://www.kenmoreairharbor.com/uplo...s_airplane.pdf

  24. #24
    mvivion's Avatar
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    Quote Originally Posted by Alex Clark View Post
    The previous owner had the cables connected to the wrong holes on the rudder tiller. . ( I hate it when that happens)
    Skywagon Pete guessed that and photos proved it. So I changed to the correct location per EDO drawings and obtained more rudder deflection.
    The 20 knots winds have died and now it is raining buckets... So I have not seen how much it helps while underway just yet.

    ODDLY ENOUGH... All the other EDO 2960s in town are rigged incorrectly.
    I hate to break this to you, Alex, but there’s nothing odd at all about that. Unfortunately
    MTV
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    IMG_1573.jpgIMG_1575.jpgHere are the attachments on my PK-3500's on my 206. Each side is different? They seem to be rigged correctly? Good control both directions. Been that way for years.

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    The pictures in the previous photos are backwards. The left is on the right and the right is on the left.

  27. #27
    BC12D-4-85's Avatar
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    Don't manufacturers provide installation prints? They did for my EDO 2K's.. How bout a pic of them besides the poor PDF's EDO offers for float models on their page? One phone call might do it too.

    Gary

  28. #28
    skywagon8a's Avatar
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    Gary,
    Yes they do supply a large collection of prints with each set of floats. The PDF which Alex supplied is the parts list for the 2960s which is all that Kenmore has on their web site. The information that I supplied to Alex came directly from one of the installation drawings which came with the 2960 floats. I have a large drawer full of these. Unfortunately I do not have the ability to copy and post them here.

    Ed,
    If I were you I would move that one cable to the inboard hole. It may not make much difference in your case but will be more correct.

    It should be noted that Alex's floats are EDO 2960s. 2960s are the same as 2870s except that they are 22" longer aft of the step. Floats are positioned on all airplanes with the step located within certain parameters in relation to the plane's loaded CG. This places the arc of the circle where the water rudders are located 22" further out from the center of the turning circle. As a result this differential between the rudders is more important, actually more critical than most other models of floats. You can walk to the tails of the 2960s easily reaching out and touching the stabilizer. How many other float/plane combinations can you do this? Not many.

    Mike is absolutely correct. You would be surprised at how many people who have installed floats do not look at the drawings when assembling them. Even when they do they do not look at the details. As a result the drawings go in the trash, the floats change hands a few times, and pretty soon the errors become the norm. That does not make them right.
    N1PA

  29. #29
    mvivion's Avatar
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    As Pete says, 2960s are very long floats. I seem to recall noting at one point that they are longer than 4580 and maybe even 4930 Beaver floats. They are great floats in lots of ways.

    MTV

  30. #30
    Alex Clark's Avatar
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    Speaking of big prints. Pete,. ( Saint Peter around my house for all of his help over the years) sent some photos of the 2960 installation prints. Which are 8 ft long.
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  31. #31
    Alex Clark's Avatar
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    Hmm. my computer is kicking my butt.,
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  32. #32
    skywagon8a's Avatar
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    Alex,
    If there is any detail which you can't make out, I'll try to get a close up for you.
    N1PA

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