tail spring re-arch

[rdooley79]

I've got a shimmy that was there with my old hard Maule tail wheel. Just replaced with the 8" wide matco single arm and it's a major improvement. Still shimmies though. I've got the dampening springs and the chains aren't tight or loose. I think it's caused by the spring flattening out.
I'm running two leaves and want to get them re-arched the same.

How would a guy re-arch the springs?

[Av8r3400]

Use a press to re-arch them.

I am lucky to have a spring shop in my town. They do it for a couple bucks.

[rdooley79]

I'm not so lucky....

I was thinking of getting new springs made but a couple inches longer to extend the wheel out and provide a little more dampening. Has anyone done this or is it not a good idea?

What about using a thicker single piece of spring steel rather than two thinner ones? Or alternately four thinner pieces sandwiched together with the total thickness the same as stock?

Just curious, I'd just like to find a press to re-arch my springs with for now and go fly!

[cap01]

Funny you should bring this up as I just rearced mine last week. The spring I have on mine isn't a kitfox spring , rather a three piece spring that was for a piper . It required rearcing when I first installed it and worked pretty good for several years until last summer when I developed a shimmy . I only had the shimmy landing on hard surface . I'd don't use had surface very often so it wasn't a urgent problem but this spring I decided I'd better address the issue .
I have been able to use one of those bottle jack hydraulic presses to get the job done . I did have the foresight to trace the spring on paper so I have a referance . I would re arc one spring then match the other two springs to that he first one so they are all the same arc . Kind of a guess about how much to rearc until the spring is reinstalled and the weight of the plane is back on the tailwheel . Since I've rearced mine I've made several landings on hard surface with no problems .

[jrevens]

I'm not so lucky....

I was thinking of getting new springs made but a couple inches longer to extend the wheel out and provide a little more dampening. Has anyone done this or is it not a good idea?

What about using a thicker single piece of spring steel rather than two thinner ones? Or alternately four thinner pieces sandwiched together with the total thickness the same as stock?

Just curious, I'd just like to find a press to re-arch my springs with for now and go fly!
Hi Rhett,
A couple of thoughts - as far as extending the spring length, a lot depends on the spring rate of the assembly itself - material, length, thickness, temper, etc., but I think you can run the risk of adding extra force & stress at the fuselage attach points because of the additional leverage. IMO, a thicker solid single leaf might not be good. Ideally with a tail spring, you want to match the spring rate of the main gear as close as possible - this can potentially improve 3 point landings. I've been intrigued with the solid rod (Whitman style) tailsprings, and curious if Lowell (Highwing) had any luck with his... maybe he will chime in.

[HighWing]

I've been intrigued with the solid rod (Whitman style) tailsprings, and curious if Lowell (Highwing) had any luck with his... maybe he will chime in.

John,
Interesting that you ask. I guess the best answer would be what kind of luck are you referring to. The real answer is that there were issues I was not able to address. When making the receiver for the spring, I could ream to precise internal dimension, but there is nothing out there spring wise that is dimensioned quite so accurately. I found that anything ordered would be guaranteed to be within a certain tolerance and my machine tools were not able to make things work.

I was chatting with this guy, but nothing really hit home.
http://www.irondesign-airparts.com/files/web%20site%20stinger%20and%20tail%20wheel%20page.p df

[Dusty]

We have found over here one of the best tail spring arching tools is a log splitter
I have a grove? alloy tail spring which has no give.It has to go ,I have to hold the tail up in the rough,sooner or later it will end in tears!
A slightly longer three leaf would bo a good idea

[n85ae]

Chuck -

Can you describe how you rearced your spring with a bottle jack? Did
you make some sort of fixture for doing it? I want to rework mine, and
while the spring shop isn't very expensive ... I figure if I can do it myself
for free that's even better.

Thanks,
Jeff


Funny you should bring this up as I just rearced mine last week. The spring I have on mine isn't a kitfox spring , rather a three piece spring that was for a piper . It required rearcing when I first installed it and worked pretty good for several years until last summer when I developed a shimmy . I only had the shimmy landing on hard surface . I'd don't use had surface very often so it wasn't a urgent problem but this spring I decided I'd better address the issue .
I have been able to use one of those bottle jack hydraulic presses to get the job done . I did have the foresight to trace the spring on paper so I have a referance . I would re arc one spring then match the other two springs to that he first one so they are all the same arc . Kind of a guess about how much to rearc until the spring is reinstalled and the weight of the plane is back on the tailwheel . Since I've rearced mine I've made several landings on hard surface with no problems .

[avidflyer]

I think he was referring to a press that uses a bottle jack for the power source. I have a 20 ton press like this from Harbor Freight, and have used it to rearch tail springs. Works great. Jim Chukhttp://www.teamkitfox.com/Forums/data:image/jpeg;base64,/9j/4AAQSkZJRgABAQEAYABgAAD/2wBDAAoHBwkHBgoJCAkLCwoMDxkQDw4ODx4WFxIZJCAmJSMgIy IoLTkwKCo2KyIjMkQyNjs9QEBAJjBGS0U+Sjk/QD3/2wBDAQsLCw8NDx0QEB09KSMpPT09PT09PT09PT09PT09PT09PT 09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT3/wAARCABuAG4DASIAAhEBAxEB/8QAHwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQRBRIhMUEGE1FhByJ xFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3O Dk6Q0RFRkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIW Gh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx 8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEAAwEBAQEBAQEBAQAAAAAAAAECAwQFBgcICQoL/8QAtREAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSExBhJBUQdhcRM iMoEIFEKRobHBCSMzUvAVYnLRChYkNOEl8RcYGRomJygpKjU2N zg5OkNERUZHSElKU1RVVldYWVpjZGVmZ2hpanN0dXZ3eHl6goO EhYaHiImKkpOUlZaXmJmaoqOkpaanqKmqsrO0tba3uLm6wsPEx cbHyMnK0tPU1dbX2Nna4uPk5ebn6Onq8vP09fb3+Pn6/9oADAMBAAIRAxEAPwD2akoooAKKKKACiiigAooooAKKKKACiii gApaSloASiiigAoxRS0AU9VvV0zTLi8ZDIIELlQcE4rl0+JenJ IsVxbzxyt0G9ACeOAWIyeelb/igbvC+pD1t3/lXnOmWWhN4YudW1WN3vIWk8tIpMSMowCFXOCcfzrOUnzJI9HD0 KUsNOrNO6aSOub4kaJHMYpjPG4GSCFbHbnaxwfY03/hZ3h5iRHNPIw7JHnn865HU9F8MP4uhs0acwyKkTNFOG3ljxhs8 BcjNaFv4A8OtY6pc6fLqCvZSyxsryDG+ME45B45o5m0+XcccPS hOHt01GR2nh3xHb+JIbiW2hliWGTyz5mMk4B7H3rYxXC/Cr/kFaj6/av8A2Ra7unTk5RTZhjqMaOIlThshMUUtJVnIFLSUtACUUUUAFL SUtAGb4iGfDmoj/p3f/wBBNcP4a0+XV/hnrNlC6JLcSSortnCkheTgV3WvDOgah/17yf8AoJrlvh1bpd+FLyCXOx7twcMVPRe45rJ/xF6HpUn/ALDU/wASKPjOTSvtMlmlqGuYpopJjHDwI+CQWA4znv61a8E6fPYfD3U TcYxcGe4j9drIOvHXO71qXVfC2mP4r061Ecyx30NzJcFZ33OyG LaSc543HjpW0NFttD8MX1tatOyC3k5mmaQ42n16de1RToum5Pu E8RTnTp043unrcw/hUP8AiT6gf+nv/wBkSu6rhvhX/wAgfUPT7Yf/AEBa7mtKXwIjNP8Ae6nqFJS0laHAFLSUtACUUUUAFLSUtAFHWh nQ78f9O8n/AKCa8v8ADvi6bw9ayWkEVvIryGU+YxByQP8ACvUtXG7R70esEg/8dNcf8OrOzvPDs32m3glKzkfOobA2r61hUTc1ynsYGpThhajqx 5ldaGRN49e41uw1GSxjxaRzRlEm+/5m3nJHGNn61pXfxItbzTbm3awuI3miZAQykAkY9vWtq48O+Gr2 +gYrZqY1k/cRlFWQHALMByduOD2yaqax4K0GHR7u6t7XY8MLyIUlfGQuRxnF DjVS3Kp1sulJfu2n6kPwrH/Ejvz/ANPjf+gLXcVxHwr/AOReu/8Ar8f/ANBWu3q6XwI5Mzd8XU9QpKWkrQ4ApaSloASiiigApaSigClrSP Jot6kQBkaBwoJwM7TXidl4Z1fUbZpLGwmYRvhpIpVjlzjp1Bx7 dK90uV32sygA5Rhg/SvPfBfiC00rRJ4kE11cPN+6gjXLvx7dBx69qxmryR6uCqShQqc qT1WjOIfQdfsJpJRBrcTyDDuYjMSP97Dfzo07UrrR7K8sILy+j +0gvcLKVxJkBTnzF3dMDhq9y0yS6nsIpL+FYbh8lo1OQvPAz9M VW8Sqp8N6iWA4t36jpxTlGVtxU8VS51H2SvfoYPwwGNBu+WI+1 t1GP4Vrs647wDdwwaSbaaWITy3EhWNWGcDHPH+c5rsetVT0ijD MbvEzfmFFFFWcQUtJS0AJRRRQAUGiigDF1dNVv5fsensLWBl/e3LAFvoo/wD1VLofhux0CEpaR5dvvyvyzfj2HA4HFatFKyvc19tLk5Fohrk IpZiAoGST2FcB4l8ZPrHm6J4ct2u5Z1KPKBxtPXb2x/tHj6138sazRNHINyOCrA9wapaZomn6MjJp9pHAHOWKjk/U9aUk3ojXDVaVJuc43a27fM5zwn4Cj0eRL7UXWe/5KhfuRZ649T7n9K7LFIKWnGKirIzr151589R3YUUUUzEKWkpaA EopaKAEopaKAEopaKAEopaKAEopaKAEopaKAEpaKKAP/9k=

[jiott]

So apparently you guys just overbend the spring in a press until it takes a permanent set at the new arch. Do you not heat first and then heat again after and quench, etc.? I didn't know you could cold bend them to a new shape without damage.

[SkyPirate]

Jim the springs used for tail wheels now a days are made from what is called "Blue Tempered Spring Steel" its not the true high carbon spring steel still used in trucks etc ,..don't heat it you will activate the atoms burning off what carbon is in it making it soft,,if you quench it it will become brittle

added: its better to bend a tail wheel spring then break it,..same with most of the light duty trailer springs,..they will bend before they break on most newer applications

[avidflyer]

You bend the spring cold. Unless you know how to retemper spring steel to the right amount. I know the spring shop I talked to bends theirs cold as well. Another point of interest, if you are making up a new spring and need to drill holes, don't drill a pilot hole and then try to drill the right size larger hole. Drilling the spring work hardens it and you probably won't be able to drill the larger second hole. That advice also came from the spring shop. I didn't try to prove them wrong. It's best to use a drill press so you can drill at a slower speed with plenty of pressure, maybe use some cutting oil as well. I would use a new sharp drill bit as well. If you don't make it through in the first attempt, the second try will probably be worse. Jim Chuk

[SkyPirate]

very true Jim, drilling it does the same heats it up work hardening it which will also make it brittle at the sides of the hole , when I use to extend a tractor trailer frame or add a frame rail I used a magnetic drill with a low RPM drive ..it would take 20 minutes to drill a 1/4" thick wall no fluid..just sharp slow turning bit

[n85ae]

I've had no troubles drilling holes in leaf springs, just takes cutting lube, a
sharp bit and pressure. I drilled mine last year with my drill press, no problems
at all. I always drill a pilot hole, and work my way up in sizes until the final
size is achieved.

Jeff

[SkyPirate]

Musta been the new lower carbon Blue Tempered Spring Steel

[jiott]

Is there a good way to tell if its the "Blue tempered spring steel" or the old "Hi carbon spring steel"?

[SkyPirate]

Do a search for a grind chart, usually higher carbon is a white spray of sparks where low carbon it orangeish spray, take a grinder and grind an edge a with it, doesnt take much to determine

[SkyPirate]

http://www.weldguru.com/metal-composition.html

[SkyPirate]

The spark metal composition test is a method of classifying steels and iron according to their composition by observing the sparks formed when the metal is held against a high speed grinding wheel. This test does not replace chemical analysis, but is a very convenient and fast method of sorting mixed steels whose spark characteristics are known. When held lightly against a grinding wheel, the different kinds of iron and steel produce sparks that vary in length, shape, and color. The grinding wheel should be run to give a surface speed of at least 5000 ft (1525 m) per minute to get a good spark stream. Grinding wheels should be hard enough to wear for a reasonable length of time, yet soft enough to keep a free-cutting edge. Spark testing should be done in subdued light, since the color of the spark is important. In all cases, it is best to use standard samples of metal for the purpose of comparing their sparks with that of the test sample.



, you want to see a whiter with few orange sparks on spring steel

[charliehill]

here is the source of spark test from WIKIPEDIA.
https://en.wikipedia.org/wiki/Spark_testing
http://www.ylflux.com/