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Thread: Slack or no slack in the tail wheel chain?

  1. #1

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    Slack or no slack in the tail wheel chain?

    I've seen tail wheel chains setup so that they sag down a bit (just slightly loose on the spring) and I've seen them put just a slight pressure on the springs (no slack, but minimum tension on the springs). Which is the preferred length of chain? A bit of slack, or no slack?

  2. #2
    algonquin's Avatar
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    Just one word , I’ve seen tight chains cause the rudder yoke to break off. Steve Pierce has a video on setting up tail wheels that will give you all the answers you need.
    Last edited by algonquin; 12-09-2019 at 10:18 PM.
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  3. #3

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    I doubt that anyone would dispute that tight chains will give the most rapid and direct response to steering inputs but that can and will get very expensive in bent and broken parts. Several years ago I had purchased a used Light Sport aircraft that had several steering issues. Previous owners (or maybe the factory) had the spring set up very tight and it was obvious that the steering arm on the rudder (control horn) was being over stressed, to the point of eventual failure by excessive bending or possible fracture. I also was never happy with very rigid tail (shock, not steering) springs so I added a T-3 (love it) tail spring setup. After T-3 installation, I set up the compression chain springs as shown in Steve's video. The result was being excessive slack and resultant "river dance" on the pedals to keep it in line. Point taken that the components were NOT the same components that Steve was using in his vid. I have no issue in using my feet but it can and did cause issues when taking off or landing with a cross wind where all steering was rudder and practically no tail wheel steering at all. If I tightened up a link then the compression spring would put excessive force on the control horn before the wheel would breakaway and go free caster. Matco does have tailwheel control arms that reduce the angle the wheel must pass through before the wheel goes into caster. I purchased those arms and reduced the breakaway angle from 45* to 25*. That did help and is something to look into but didn't make things "perfect". The T-3 also introduced some new parameters. As weight is applied to the T-3 (may be exclusive of the geometry of my plane only) it introduced more slack to the steering chains. After trying every combination of chain length, I gave up on compression chain springs. IMO, they do not give enough..."give" before applying stress to the control horn. If anyone knows of a source of lighter and longer compression springs, I would entertain revisiting them. In the mean time I ordered tension springs from Spruce. Turns out that they were just as strong and just as limited in tension length as the compression springs. I then went through over dozen or more combinations of tension springs (I'm E-LSA) before I found some that will keep the chains somewhat taught but with a light enough force to not overstress the control horn at any position of the tail wheel while still providing positive and immediate response to rudder input. I'm now happy with the combination. I feel sorry for you certified folks who don't have hardware store type options.

  4. #4
    www.SkupTech.com mike mcs repair's Avatar
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    Slightly slack


    Sent from my iPhone using SuperCub.Org

  5. #5
    mvivion's Avatar
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    Quote Originally Posted by mike mcs repair View Post
    Slightly slack


    Sent from my iPhone using SuperCub.Org
    What he said^^^

  6. #6
    Steve Pierce's Avatar
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    Jack the tail up and go full rudder to steering arm break. There are some instances where the tension will bend the arm (light duty arm) prior to kicking out to free castering. My chains have a hint of tension and have very positive steering and the pawl kicks out steering prior to maxing out the travel. I run the long pawl so it breaks out with less travel. I like it that way but my Dad and one other customer did not. They like the short pawl so you have more range of steering.
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    Long pawl compared to the short pawl.
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    Short pawl gives you 45 degrees of travel before the steering arm breaks out and free casters.
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    The long pawl breaks out at 30 degrees.
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    Dan of Dan's Aircraft in Anchorage called the FAA and complained about Airframes/Bushwheel installing long pawls in their tail wheels. he claimed it was causing people to ground loop their airplanes. Scott used both pawls but the short ones were more prevalent. I can't see an issue if you see how far over a tailwheel is at 30 degrees vs 45 but it was an issue. Airframes uses long pawls unless otherwise requested otherwise.
    Last edited by Steve Pierce; 12-10-2019 at 02:10 PM.
    Steve Pierce

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  7. #7
    Steve Pierce's Avatar
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    I edited my previous post. Airframes is shipping new tailwheels with the long pawl and 5 springs in the head unless you request otherwise. Cub Crafters prefers the short pawl and 3 springs in the head which is how Scott did it. I prefer 3 springs because it takes it takes less pressure to pivot the tailwheel and the long pawl so it breaks over sooner. I like it that way because maneuvering around rocks, sink holes, logs etc is easier with the tailwheel breaking out to free caster sooner. Some people take the steering parts out and have a free castering tailwheel so they must use breaks to steer when slow. I could not get use to that and like my set up for what I do with my airplane.
    Steve Pierce

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  8. #8

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    I use a little slack. The small J3- type Scott may actually need tension - I don't know, since I don't use them. I hear they are excellent tail wheels.

  9. #9
    skukum12's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    I edited my previous post. Airframes is shipping new tailwheels with the long pawl and 5 springs in the head unless you request otherwise. Cub Crafters prefers the short pawl and 3 springs in the head which is how Scott did it. I prefer 3 springs because it takes it takes less pressure to pivot the tailwheel and the long pawl so it breaks over sooner. I like it that way because maneuvering around rocks, sink holes, logs etc is easier with the tailwheel breaking out to free caster sooner. Some people take the steering parts out and have a free castering tailwheel so they must use breaks to steer when slow. I could not get use to that and like my set up for what I do with my airplane.
    So 3 springs and a long pawl should make turning around in tight areas on straight skis a more successful operation?
    "Always looking up"
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  10. #10

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    That is what I use. Sometimes you have to do a double kick of the rudders to lock it back up when it's cold. I prefer no slack in my chains but will take a little vs tight.
    DENNY

  11. #11
    Steve Pierce's Avatar
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    Quote Originally Posted by skukum12 View Post
    So 3 springs and a long pawl should make turning around in tight areas on straight skis a more successful operation?
    Yes, swivels and unlocks with the least amount of effort in my opinion. Never flown skis but works great on tight gravel bars with lots of obstacles.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

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