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Beware the T3 tailwheel shock

C130jake

BENEFACTOR
Four Corners Wyoming
Got my wing apart and parts ordered. I was the honorable mention in Steve’s Wednesday tailwheel presentation.

I bought the hype and put a T3 on my EX1 CarbonCub a while back. Last summer while pushing the plane into the hangar, the tail wheel assembly folded under it self. The shock shaft had broke. Called Airframes and they sent me a new one. Said the new shock was built stronger. I installed it and continued flying until last month.

The little red light in my head never went off and said, why did or how did that shock fail. I usually wheel land and keep the tail up as long as it will stay up. When solo, the tail stays up to about a brisk walk.

While returning to Bentonville after flying around NW Arkansas with the management of SC.org, the T3 had enough and despite a good crosswind from the right, when I brought the tail down after a wheel landing, it groundlooped to the left. Eye witness said it looked the the tailwheel assembly laid over like a water skier. Taxied back and started the analysis. I assumed pilot error. Did I tap the left brake? Was the brake dragging, did I ham fist it when transitioning from two point to pinning the tail? It should have wanted to weathervane to the right. Sad, angry and confused, I taxied to park and looked over the damage.

Here is what I found. Not much for lateral stability, thin sheet metal wrapped around a bushing that slowly stretched. The broken shock is the one that was replaced.


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Wow, sorry to see your troubles Jake. That stings in more ways than one.

I have a T3 also on my EX and it has been trouble free so far. In my opinion the tail wheel had too much positive angle as originally installed. It made it hard to get the tail wheel into the trail position. I added a 1/2” thick aluminum spacer between the fuselage and front attach point where the AN7 bolt is.

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That extra half inch made a big difference. Prior to the spacer it took a lot of side load to get it to swing around. If pushing it by hand I could see the assembly torquing as it tried to pivot around.

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This shot shows the spacer too. And that I don’t baby my Baby Bushwheel/T3
 

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I agree with spinner, at full extension and less trail the T3 is vulnerable to side load.
Made worse with the added mass and leverage arm of a bby bush-wheel .
Sorry to hear of your mishap, but until there’s other evidence of T3 failures I would chalk this up to a freak incident, possibly brought on by previous, undetected damage.
I will defiantly be inspecting mine more thoroughly based on your account. like Spinner, I’ve been running a spacer block. But I’m also not a fan of bby bushwheels on Cubs.
 
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Wow, sorry to see your troubles Jake. That stings in more ways than one.

I have a T3 also on my EX and it has been trouble free so far. In my opinion the tail wheel had too much positive angle as originally installed. It made it hard to get the tail wheel into the trail position. I added a 1/2” thick aluminum spacer between the fuselage and front attach point where the AN7 bolt is.

View attachment 55670

That extra half inch made a big difference. Prior to the spacer it took a lot of side load to get it to swing around. If pushing it by hand I could see the assembly torquing as it tried to pivot around.

View attachment 55671

This shot shows the spacer too. And that I don’t baby my Baby Bushwheel/T3

I see you don’t have the bushing lapped by the strap and your rear attachment is machined and not welded like mine. Newer design I guess after problems like mine. I wish I had looked closer at the design and strength of the individual parts on mine. That’s what I get for being an early adopter I guess. Wing parts come Monday according to the trucking company.


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not surprised, something with that many moving parts is destined to fail.

so you gonna go back to the 3200 or stick with the hype?
 
I had the elastic nuts loosen on the side plates . It let it lay over to one side and want to ground loop me to the right. The first time was in a strong cross wind it was wet and on grass so I didn’t ground loop but slid sideways. The second time I knew it wasn’t me and found what was wrong. Maybe I should take it off before it completely fails. I hate to because it is so good on rough ground.


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Yours was an early version. Newer ones are machined aluminum. All the attachment and the arms. https://www.airframesalaska.com/Sin...l-Suspension-Upgrade-Kit-p/t3-upgrade-kit.htm

I’ve got a pile of the welded steel attachments in various broken pieces


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Can you tell by this pics which of the two models is mine? It will go with a Baby Bushwheel. I still have time to not install it!.


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The upgrade kit has been out since 2017 and installed on all models built since that time. Upgrade to the stronger swingarm, mounts, and shock are highly recommended on the old models. On all T3 models it's highly recommended to check it for play as part of a preflight routine as with any suspension component it can wear and have bolt stretch. Has it ever been inspected for wear at annual and tightened/re-lubricated at the pivots?
 
The upgrade kit has been out since 2017 and installed on all models built since that time. Upgrade to the stronger swingarm, mounts, and shock are highly recommended on the old models. On all T3 models it's highly recommended to check it for play as part of a preflight routine as with any suspension component it can wear and have bolt stretch. Has it ever been inspected for wear at annual and tightened/re-lubricated at the pivots?


An email to customers or a SB type notice might be good for anyone running the original. Upgrade Wasn’t mentioned or offered when I called about my broken shock last summer. I would have gladly upgraded if I was told about it. Sounds like I’m not the only one who had part failures. Even a thread on here and Backcountry.org would have hit many of the users I bet. (That’s where I learned about the T3 to begin with) Expensive lesson for me I guess. Any Acme black ops Gen 4 failures out there? I was a fan of the T3 til last month.

it was lubed and bolts checked when I replaced the shock. And again during the annual condition inspection last fall. Seemed ok when I did a thorough preflight before I left Wisconsin to fly around Arkansas. 6 landings later is when it happened. Just glad it didn’t happen at Trigger Gap the landing prior. Rarely have a passenger. Had one for the last three landings including the ground loop. Maybe the extra force on the tailwheel was the last straw. About 350 hours on the T3. The bolts look fine, you can see the obvious stretch on the sheet metal wrapped around the bushing which is a weak link. (Obviously or the design wouldn’t have been changed soon after it came to market)

Jake
 
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For those on early T3s, check them regularly or better yet, upgrade them ASAP. The old bushings are not up to task even on an 800# Cub. Mine came off due to this:

https://youtu.be/HXjfynsfthk

When did this happen to yours? How many hours?

With all the new gizmos, props, ADSB, gear, avionics, starters, wheels and brakes etc, Maybe we need a new thread under maintenance for “what did you break today” The sooner we can get info out on how or why bits get broken or burned up, the sooner we can get things improved.

I have never heard of any problems with the T3 till now. Didn’t know there was an upgrade kit, that would have been good to know especially since it’s been out for 3 years. (Plenty of discussions on Acme vs AOSS vs T1 vs bungies) but not the T3. Is the Acme Stinger ok? Anyone break one of them? If so, how, when, what part failed etc.

I love innovation. I would also like to hear when things don’t go as planned so we can all learn from that. That is what I love about supercub.org. I have learned a ton, got lots of help, got great advise and made some awesome friends. I hope anyone with the old T3 gets the upgrade kit ASAP or trades it in for a new one.

Take care of each other,

Jake



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Saw one installed on an experimental cub like aircraft, was not impressed, it lacks side load capabilities especially off strip.
 
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The upgrade kit has been out since 2017 and installed on all models built since that time. Upgrade to the stronger swingarm, mounts, and shock are highly recommended on the old models. On all T3 models it's highly recommended to check it for play as part of a preflight routine as with any suspension component it can wear and have bolt stretch. Has it ever been inspected for wear at annual and tightened/re-lubricated at the pivots?

Well not quite. I ordered a t3 in 2017 and specifically asked if it had the upgrade kit. It didn’t. But you guys were happy to sell it to me.


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I can tell you from personal experience if you post things that you find in the field that failed or isn't right there are ramifications that sometimes aren't pleasant. Unpleasant phone calls, cold shoulder from the vendor etc. Vendors love SuperCub.org when the website is selling their wares but not so much when it points out some shortcomings.
 
When did this happen to yours? How many hours?

Is the Acme Stinger ok? Anyone break one of them? If so, how, when, what part failed etc.


Roughly 200 hours, all off field but nothing rough by any real standard. While lightweight and offering great rebound control, the basic design is flawed at the connection between the swingarm and the side plates.

The design does not allow for any preload to be applied to the through bolt because there is no roller bearing in the swingarm. What small bearing surface there is inside the side plates can not handle the loads of a lightweight Cub and eventually chip away, allowing the movement shown in my video. I do not suspect it would fold under at my weights, but I do suspect the entire bearing would eventually be wallowed out. Yes, mine was greased and bolt torque checked regularly.

When people start really using a product, weaknesses are always found. It sounds like T3 is aware hence the upgrade path however it is always a risk buying a product early days and being the guinea pig. I fly an experimental airplane and love the freedom that allows, but the responsibility is mine to make sure the thing is mechanically sound and it does suck when you have to pull something off that just isn't up to the task at hand.

I put in an Acme Stinger, and have roughly 20 landings on it so far. It is waaaay heavier and I would like to think it will hold up better, but I won't really know for another few hundred hours.
 
Just to make sure it is clear I don't have an ax to grind -- I really like the T3 product and think the early version is very very close. In fact, I am probably going to design my own swingarm and side plates for it at some point.

I also happen to love Matco products and the support George provides his customers. Even so, I have one tailwheel unit from him that continually wobbles out press fit bearings after low hours making it a bit of hazard. I liked his basic design so much however, it became inspiration for my own tailwheel design. Point being, just because we are able to bring some products to failure doesn't mean the vendor is **** or the product is bad. It might be very very close to perfect and we simply found the fine line between "lightweight" and "sturdy enough".
 
I have the T-3 on my RANS S-7S, and every time I land off airport I think it's broken, because it feels so soft compared to the J-3 leaf spring I used to use. About 250 hours so far, including ski flying. I will keep an eye on things, though I have not lubed anything yet.
 
No doubt I’m not only old but old school and I subscribe to the premise that if it ain’t broke, don’t fix it. There was a reason to go to the Scott 3200 when we did. I suspect that the 3200’s have done more work and seen more rough country than all the baby bush wheels and the different types of tail wheel shock contraptions have seen.

many of us put this stuff on these planes and are just putting lipstick on a pig, sort of like jacking up a pickup. In my opinion you’ve got to go a long way to beet the old 3200 tail wheel or stock bunji system landing gear or a straight light stock cub for that matter. I would recommend that we concentrate on our technique and flying skill.
 
The plane I fly came with the prototype T3 shock from Dan. I used it for a while until it developed a small crack. I've been running a Pawnee spring for the last year because it handles way better in the hangar (I share with 6 other planes) and the hangar help is always moving the planes around. I do think the T3 adds safety in rough stuff. I never got bucked with it. The Pawnee spring bucks and bounces a lot when my tail height isn't right. I go into upslope strips a lot with 2 pax and gear. Trying to hold the tail up can be a challenge. T3 makes that a non issue. It also gets the tail up faster on a loaded takeoff. I was planning to put the T3 back on this week. Interesting thread, thanks for the honest reviews.

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many of us put this stuff on these planes and are just putting lipstick on a pig, sort of like jacking up a pickup. In my opinion you’ve got to go a long way to beet the old 3200 tail wheel or stock bunji system landing gear or a straight light stock cub for that matter. I would recommend that we concentrate on our technique and flying skill.

You are in the Experimental sub of this forum. While you might not understand it, some of us build, test, and share information about new ideas here. So, here is a tip for the day:

We don't care what your opinion is on the equipment we chose to bolt on to our airplanes.

I suggest you concentrate on letting others fly whatever the hell contraption they like, drive whatever pickup truck they like, use whatever tailspring they like. We are going to freely share information on field experience using such parts independent of self righteous dictation on what we should concentrate on.
 
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