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Tailwheel steering springs

Scott Hersha

Well Known Member
Anybody have a good idea about how to install the tail steering springs/chains using those wire clips? I had a difficult time installing them a few months ago, and yesterday I had to remove them while removing my rudder for painting the airplane. The clips are hard to pry open, and I know I’ll end up scratching my new paint job. There must be a right way to do that, but I haven’t figured it out yet. I’m afraid if I pry the clip open wide enough, it won’t spring back. Plus they rust pretty quickly. Trying to find some sort of chain link (like the threaded ones) that will fit.

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I may end going with a steering link if it can be modified. My tail stinger is a cut off original bent tail spring type original to RV4&6 that I modified for a full swivel unit, so it is a little shorter than minimum steering link size. I prefer the way the two springs handle though. If anyone has a good way of installing those clips, please share.
Thanks
 
Anybody have a good idea about how to install the tail steering springs/chains using those wire clips? I had a difficult time installing them a few months ago, and yesterday I had to remove them while removing my rudder for painting the airplane. The clips are hard to pry open, and I know I’ll end up scratching my new paint job. There must be a right way to do that, but I haven’t figured it out yet. I’m afraid if I pry the clip open wide enough, it won’t spring back. Plus they rust pretty quickly. Trying to find some sort of chain link (like the threaded ones) that will fit.

View attachment 35272

I may end going with a steering link if it can be modified. My tail stinger is a cut off original bent tail spring type original to RV4&6 that I modified for a full swivel unit, so it is a little shorter than minimum steering link size. I prefer the way the two springs handle though. If anyone has a good way of installing those clips, please share.
Thanks

IF we were based close to each other, I would show you.

It is difficult for me to type up the procedure but I could do it in a few minutes.

I used AN42B eye bolt on the spring. The compression spring come apart easy and can be slid on one of the spring parts that make it a compression spring. (I forget the name and cannot find the name of the parts right now.) Slide the 'retainer' through the spring and slip the AN42B on the 'retainer' then slide both parts back through the spring.

Maybe the above words will 'click' and give you an idea on how to make the compression spring work with the least number of parts. Tomorrow I can walk out to the hangar and take / post a photo. Ready for bed and do not want to walk out to the hangar right now.
 
Thanks Gary, a picture would tell me what I think you are saying. I know what you are saying about the compression springs coming apart, and was able to do that while trying to figure this out. In my picture above, there are two different sets of springs. The ones on the right are the ones that I have been using. The springs on the left are just some extras that I’ve had laying around for a while, and they are slightly bigger. On the smaller ones, the retainer clips will not fit down through the center of the spring. On the larger - and stronger - springs, the retainer will fit. And I’m guessing the AN42B fastens to the tailwheel control arm on the aft end, and also another AN42B on the rudder bottom horn on the forward end - with a nut and washer. A picture would say 1000 words.
Thanks
 
How I did mine

Scott, here is mine showing how they should be orientated . i made small angled tabs that are loosely bolted to the tailwheel and to the rudder arm giving the chains a better angle to operate. It is IMPERATIVE that you safetywire the loops at the small end of the clip to the spring and chain. This will keep them from slipping sideways and spreading open, which leaves you without steering, and dragging a chain..(ask me how I know).I have the original non-full swivel tailwheel which in my opinion gives the best control of any tailwheel set-up, but unfortunately you cant push the plane backwards.
 

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Vans RV-7 Transition Trainer Installation

Here is a photo I took of the Vans RV-7 trainer setup during my transition training last November with Mike Seager.
 

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Or give the clips a flotation test in the nearest body of water.
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Thanks for the pictures gentlemen. I like the metal tabs and also the AN42B bolt will work too. Trying to get those chain clips on the thicker tailwheel control arm or the rudder arm without scratching the new paint on them, or spreading them apart so far that they don’t spring back isn’t going to work. A thin tab will be easy to install. How did you keep those chain clips from rusting? The galvanized sash chain didn’t rust and neither did the spring, but those clips rusted before I was through phase 1. I might try 1/8” SS quick links from HD:

https://www.homedepot.com/p/Everbilt-1-8-in-Stainless-Steel-Quick-Link-3-Pack-44384/205882906

480# working load limit.
 
Or give the clips a flotation test in the nearest body of water.
.

Wow - I like that idea even better. I might have to buy a $45 crimper from HD for the cable, but maybe worth it. The bottom of the river is a good place for those nasty clips…..
 
Spring Breaking?

I know the "form" of the generally used tailwheel spring is to foster safety, but they look like (and are) boat anchors, so -

My question to this august body is: Anybody ever had one break, thereby relying on the overrunning attach clips to maintain control through rollout, until a replacement is fitted.

Not asking about the linkage on the ends - but the body of the spring itself. It might happen in the harsh world of bush/sea plane ops., but just wondering in the "soft" world of EAB, whether or not this ever happens?

Thanks in advance for any relative feedback.

HFS
 
Not the spring but the clip breakage

I had one of the spring clips (not safetied) turn sideways and spread, which made it come off while I was taxiing onto the runway..felt a little bobble, but took off rather normally. My wingman (we were going formation), saw my chain/spring in trail behind my tailwheel so I returned to field for uneventful landing and I could hardly tell, but if it was a windy day, I might have needed the TW authority.
 
The compression spring part is by far the most robust part of that system. Weakest link is those clips, followed by the slightly stronger sash chain (design load limit about 106 lbs). Like others have said, if it comes off, you should still be able to land safely, unless some part of the broken chain gets tangled up in something - unlikely. I’ve had two of the steering links break, one FlyBoys Rocket link, and of of JD’s. My landings actually improved for a while, until I replaced them. If you were to use cables, quick links, and bolted ends, like in Dan’s picture, I think you would end up with the strongest system we have available.
 
Thanks Gary, a picture would tell me what I think you are saying. I know what you are saying about the compression springs coming apart, and was able to do that while trying to figure this out. In my picture above, there are two different sets of springs. The ones on the right are the ones that I have been using. The springs on the left are just some extras that I’ve had laying around for a while, and they are slightly bigger. On the smaller ones, the retainer clips will not fit down through the center of the spring. On the larger - and stronger - springs, the retainer will fit. And I’m guessing the AN42B fastens to the tailwheel control arm on the aft end, and also another AN42B on the rudder bottom horn on the forward end - with a nut and washer. A picture would say 1000 words.
Thanks

Scott:

Here are the photos without a lot of words.

I had chains like you but found that after 300-hours, they would stretch and need a link removed. Removing a link, they are too short for my liking. After replacing the chain twice, I copied another guys setup and used cables. The cables will last at least a couple thousand hours before they need replaced. The 30-year old compression springs from Van's worked best. The new ones that Aircraft Spruce had were shorter and more difficult to get the hardware through the coils.

My setup as replaced last year.
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Following is a show with little tell on how to get the AN42B installed on the compression spring.

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Hope this helps and gives you some ideas along with what others have posted. There is more than one way to accomplish this. I tried to have parts that wear that could be replaced before they became unsafe.
 
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I had chains like you but found that after 300-hours, they would stretch and need a link removed. Removing a link, they are too short for my liking. After replacing the chain twice, I copied another guys setup and used cables. The cables will last at least a couple thousand hours before they need replaced. The 30-year old compression springs from Van's worked best. The new ones that Aircraft Spruce had were shorter and more difficult to get the hardware through the coils.

Hope this helps and gives you some ideas along with what others have posted. There is more than one way to accomplish this. I tried to have parts that wear that could be replaced before they became unsafe.

Only difference I use is to put the "I" bolts on top of the tailwheel belcrank to lessen to angle of the springs.
 
Only difference I use is to put the "I" bolts on top of the tailwheel belcrank to lessen to angle of the springs.

I tried that first and the springs would hit the fiberglass rudder bottom on my RV so move them to the way they are shown in the photo.
 
I ran those crappy clips for a while. They started cutting into the soft aluminum rudder horn. Almost anything is better.
 
Or give the clips a flotation test in the nearest body of water.
.

Dan,
Does that aft cable shackle, AN515-21 for assembly I assume, fit through the center of the tail steering spring? Or is it something else?
 
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Compression Spring adjustment

For those that are particular about the length of the compression spring/chain/cable assembly here is a tip just provided by an A&P buddy: Take the compression spring apart and insert spark plug gaskets at one or both ends. I haven't tried it yet, but it sounds like a good idea.
 
Dan,
Does that aft cable shackle, AN515-21 for assembly I assume, fit through the center of the tail steering spring? Or is it something else?

I think it just slips over the loop without taking the spring apart. I don't remember. It went together 12 years ago. That's kinda the point...don't have to overhaul it very often ;)
 
Thanks Dan - that’s what I sort of figured out last night in my almost sleep. And I miss-typed, it’s an AN115-21 (3/16” hole for the bolt).
 
dans right, they are best installed by throwing them away. i had one open up on landing with someone in the back seat of the 4. interesting landing. i went with the shackles from the airplane parts isle of HD.

bob burns
RV-4 N2RB
 
I found these swageless fittings for 1/8” cable used for rigging sailboats. They are stainless with a working load limit of 400 lbs which makes them a lot stronger than the chains.
 

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Great article and thanks for the education.

Do you know what the failure force is for the original setup?
 
Great article and thanks for the education.

Do you know what the failure force is for the original setup?

Not really. It's easy to know the rated capacity of the cable, eyes, and shackle. I vaguely recall the cable as being 3/32".

Here the wildcards would be the capacity of the screw link, as well as rudder horn bending because of the cantilevered eyebolt. The little 1/8" hardware store quick link has a labeled "safe working load" of 220 lbs, but I'll bet breaking strength is somewhat more. Dunno about the rudder horn.
 
This is a timely thread as I'm about to hook up my tailwheel controls "for real". I like the idea of using cable shackles, but as I went to order myself a pair I realized that there is a wrinkle if you have a Flyboy Accessories steering arm like I do.

I measure the thickness of my steering arm at roughly 0.2", which would be right for an AN115-32 (0.203" opening), but those are only available with 1/4" bolt holes and the holes in my steering arm are 3/16". Conversely, an AN115-21 with the correct 3/16" holes only has a 0.156" opening.

I figure my options are:

1. Use AN115-32s and drill the steering arm up to 1/4" (don't really want to do this due to the edge distance that would result)
2. Use AN115-32s with bushings to adapt to 3/16" bolts (also seems kind of iffy)
3. Use AN115-21s and deform them to fit over the thicker steering arm (also also iffy)
4. Switch to Van's standard steering arm so I can use AN115-21s (I assume it's thinner but I haven't checked)
5. Forget the cable shackle idea and do something else...
 
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I measure the thickness of my steering arm at roughly 0.2", which would be right for an AN115-32 (0.203" opening)....an AN115-21 with the correct 3/16" holes only has a 0.156" opening.

Matt, I really don't remember what I did, but I would not hesitate to rework an AN115-21. AN hardware is typically malleable.
 
Another variation on the theme, is using Dyneema instead of steel cable. Lighter, and as strong or stonger than same diameter cable. No need for crimps or swages, just a locking brummel splice on each end.

Used this stuff on my boat a lot. Many modern higher end yachts are now leaving the factory with all standing rigging in Dyneema.
 
Wondering how well the dyneema rope will wear on the metal tailwheel spring or rudder horn component when in constant load/use in flight. I can’t see how it would wear as well as a steel thimble in a SS cable.
 
Wondering how well the dyneema rope will wear on the metal tailwheel spring or rudder horn component when in constant load/use in flight. I can’t see how it would wear as well as a steel thimble in a SS cable.


Yeah Dyneema or Spectra would be more susceptible to chaffe but easily resolved with periodic inspections. You could also use either a SS or plastic thimble in the eye if desired, or use a rounded shackle.
 
Matt, I really don't remember what I did, but I would not hesitate to rework an AN115-21. AN hardware is typically malleable.

I received my AN115-21 shackles, and the AN42B eye bolts from Wicks yesterday (less expensive that Spruce). Dan is right, the shackles are malleable. I spread the opening easily with a long screw driver. Then took a spare tail wheel lever, inserted between the opened up shackle and squeezed it down to a correct parallel gap in my vise - easy. I also had to open up the hole in the AN42B bolt to get the quick link inserted. There’s a slight lip on the end of the threads on the quick link so the nut has a stop. I used a #6 drill bit to enlarge the hole by about .010. You could go up to a 7/32 drill bit if that’s what you have. It’s still only 1/32 larger. In the picture below, I still have the sash chains until I get the plane home from the paint shop to work on a cable and get it right. The chain is the weak link (he, he) in this setup, but I think it is still strong enough and easy to adjust to the right length for now.
I assume I’ll want the shackle and the eye bolt to be able to rotate slightly, so planning on using a castle nut/cotter pin.

35A36202-A3B4-428C-998D-3E40B501CC15.jpeg
 
Just thinking…..what if you eliminate the shackle?

Use 1/16” cable (exceeds 400lbs) and corresponding size thimble. Eye on flange bolt is 3/16”.

Bevel the edges of the flange bolt hole and loop the cable and thimble through the hole and then crimp.
 
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Would a thimble for a 1/16” cable fit through a 3/16” hole? I don’t think the ones I saw at Home Depot would fit, although I haven’t tried it. The shackles work pretty good and I can remove it with a socket wrench - no cutting the cable.

I’ve wondered if there is some sort of quality industrial strength bungee material that would have the same resistance as the compression springs we use and have an ultimate pull limit where it wouldn’t stretch anymore, like the cable. Something like that would be simple, streamlined, and maybe lighter……. guess I’ll do a little research…..
 
Something like this is what I was thinking:

https://superbungee.com/collections...ucts/24-inch-marine-superbungee-up-to-12-feet

Except that it would need to be about 8-10 inches long, not including the carabiners, and have a max stretch of about 2”. Something that short that only stretches 2” would be way too stiff probably. I’m going to ask anyway. I understand that this would be an extension load verses a compression load like we have now. I’m not sure what difference that would make. There are plenty of taildraggers with extension springs, although there is always some load on the springs, I think.
 
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Would a thimble for a 1/16” cable fit through a 3/16” hole? I don’t think the ones I saw at Home Depot would fit, although I haven’t tried it. The shackles work pretty good and I can remove it with a socket wrench - no cutting the cable.

I’ve wondered if there is some sort of quality industrial strength bungee material that would have the same resistance as the compression springs we use and have an ultimate pull limit where it wouldn’t stretch anymore, like the cable. Something like that would be simple, streamlined, and maybe lighter……. guess I’ll do a little research…..

I’ll let you know. For 8 hogs, you can get 1/16” stainless cable and thimbles on Amazon. I’ve ordered. Goodness knows I’ve spent more for a scotch out at dinner. Now I’ve got to order the flange bolts. $24 plus shipping for 4. Even if you have to open the holes a smidge, they will still be stronger than the cable.

More to come.
 
The thimble easily goes through a #12 drill hole. Have to open it a bit to get it through. I think the thimble will also handle 3/32” cable. I suspect a 1/8” cable could be used if the hole was enlarged a “smidge”.

No shackle needed if you bevel the hole’s edge.
 

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The thimble easily goes through a #12 drill hole. Have to open it a bit to get it through. I think the thimble will also handle 3/32” cable. I suspect a 1/8” cable could be used if the hole was enlarged a “smidge”.

No shackle needed if you bevel the hole’s edge.

That’s good, but the thimble/cable assembly will need to rotate in the hole with tailwheel movement. Not sure what the wear pattern on these parts mean over time. It seems like the shackle would have better wear characteristics, and it can be easily changed. You’ll need to cut the cable/thimble and install a new one if the thimble, or more likely the tailwheel steering arm wears out. Time will tell. Either option is superior to the rusting clips - mine are laying on the bottom of the nearest lake….
 
I’m going to use flange bolts (AN42B) and run the thimble thru them. Not the rudder arm made of aluminum. I do think the hole in the bolt should be beveled so there is a round shoulder that mirrors the thimble.

No sharp edges which should minimize wear of a stainless thimble and the steel bolt. And as Dan said, won’t need overhauling for a long time.
 
Or give the clips a flotation test in the nearest body of water.
.

Dan - a question. You’ve drilled a hole in your rudder arm closer to the rudder for your rudder steering cable mount. It seems like that would allow more rudder deflection relative to tailwheel deflection. Seemingly preferable in a crosswind? Or is it because of torque? Tailwheel steering during taxi should be less sensitive. Just wondering the reason and what result you have found.
 
Matt, I really don't remember what I did, but I would not hesitate to rework an AN115-21. AN hardware is typically malleable.

Closing the loop on this for the benefit of future readers... Dan is of course right, a pair of AN115-21s worked fine for me after I opened them up a bit. The best way I found to do this with minimum mangling was to take a large tapered punch and gently tap it through the space between the ears until they would easily fit over the steering arm, then use a nut and bolt to squash them back flat.

For the forward end, I bought some of these quick links to attach the chains to eyebolts on the rudder horn. They look like they will do the job, and I will be happy to avoid the cheesy little clips that have caused me trouble on other aircraft.
 
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Looking for Tailwheel lightweight springs

My hangar mate has lighter and slimmer tailwheel steering springs/cables on his -6, and am trying to locate who sells these. ( Not the old style typical large compression springs)
Does anyone know where I could find them ?
Cheers
 
This thread was a great help - here's how my installation ended up. I used AN42B-4A eye bolts and AN115-21 cable shackles as described previously. The removable links at the forward end are Maillon Rapide Links, manufacturer's part number 7350SF-1/8. These are rated for a 440 lb working load and a breaking limit much higher than that, plenty for this application. I put a bit of blue Loctite on the threads to keep them closed.

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20230208_chain2.jpg
 
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This thread was a great help - here's how my installation ended up. I used AN42B-4A eye bolts and AN115-21 cable shackles as described previously. The removable links at the forward end are Maillon Rapide Links, manufacturer's part number 7350SF-1/8. These are rated for a 440 lb working load and a breaking limit much higher than that, plenty for this application. I put a bit of blue Loctite on the threads to keep them closed.

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20230208_chain2.jpg

I’m concerned about the torque/twisting loads on the rudder arm from the AN42B eye bolts. Why not use those cable shackles that are on the Tailwheel arm, and use them on both ends of the chain?
 
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I’m concerned about the torque/twisting loads on the rudder arm from the AN42B eye bolts. Why not use those cable shackles that are on the Tailwheel arm, and use them on both ends of the chain?

In my case - the success of the many builders who have already used eye bolts here with satisfactory results.
 
Matt, place the rudder against a stop, and see if the tailwheel fork is still locked to its arm. It should be necessary to stretch the spring to put the tailwheel into swivel. In service we do that with a brake tap.
 
Matt, place the rudder against a stop, and see if the tailwheel fork is still locked to its arm. It should be necessary to stretch the spring to put the tailwheel into swivel. In service we do that with a brake tap.

Yes, it's just short of unlocking with the rudder on the stop. I knew to check for this based on your previous posts on the subject, so thanks for that!
 
Tailwheel chain

For a even cleaner look and to prevent chain marks against bottom of the rudder I put a piece of shrink wrap around the length of the chain.
 
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