Beware the T3 tailwheel shock

He did share his experience. Which is considerably more than most.

It's nice to have the ability to use/test 'new' ideas. But in rough conditions sometimes tried and true may be the best answer.

Web

This whole thread makes Acmes product more appealing to those wanting a modern tail suspension. Like said prior, I’m sure it too can be broke if you try hard enough. I still lean towards the simple stupid spring set up as it works for my mission and I am uber cautious about protecting the tail.

I can see the appeal to the tail suspension set up for guys flying heavy or those that three point more. It’s a ying and yang deal. If you keep the tail up you’re wearing out brake pads and rotors. If you leave the tail down you’re wearing out tail wheel components but probably saving brakes. Pick your poison.

Most here are sharing information on our findings with various T3 versions in this thread. Tried and true is not what we are discussing here.

motosix said:

Most here are sharing information on our findings with various T3 versions in this thread. Tried and true is not what we are discussing here.

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I agree with sharing the information. It's precisely why I'm on here. But the baseline for comparison with new designs is, 'is it better than the old design?' Judging from what I've read about the T-3, my opinion is that it is better under some circumstances and maybe not so tough in the rough going. Your opinion is obviously different. I can live with that.

Web

wireweinie said:

I agree with sharing the information. It's precisely why I'm on here. But the baseline for comparison with new designs is, 'is it better than the old design?' Judging from what I've read about the T-3, my opinion is that it is better under some circumstances and maybe not so tough in the rough going. Your opinion is obviously different. I can live with that.

Web

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I don't disagree with you, and in fact, enjoy supplemental information regarding the T3.

There is nothing supplemental in saying "...50 year old technology is better than <this widget> I have no direct experience with. I don't like it, and you shouldn't either."

Motosix said "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."

That was rude and uncalled for.

This is starting to feel a lot like the “legacy gear” thread.

I like my T3 and will look at it close to see if mine is holding up. If it needs some attention I'll order some parts. In the 4600+ cub hrs that I have I have broken 2 stock tail springs, one on my 11 and one on my J4. I think anything that gets side loaded has a limited life span. My opinion is that the T3 absorbs most of the stress that a stock spring transfers to the back section of the fuse. When the T3 is in contact with the ground every part of it is in motion absorbing stress. Is it as strong as a pawnee spring? Maybe in straight line stress but not side loaded. Pawnee spring is strong enough that it will bend the back half of your airplane when side loaded. Life is full of choices.
By the way, reliableflyer has 20k+ Alaska Cub hrs and a lot of us valve his hard earned opinion

Glenn

cubdriver2 said:

Life is full of choices.
By the way, reliableflyer has 20k+ Alaska Cub hrs and a lot of us valve his hard earned opinion

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The sad truth is that the guys who have the most to contribute to threads like this one have been taught to not bother. Why would anyone want to constantly defend their decision to run one part over another on their experimental airplane?

Don't like it? Don't run it.

Every thread that gets derailed because someone with 10 million hours in Alaska doesn't like a product limits the usefulness of the forum and the contributions from people who have pertinent information to share.

I apologize to any of you folks that I offended. Not trying to tell anyone what they should do. I would just encourage you all to be safe. And try not to raise my insurance rates.

motosix said:

The sad truth is that the guys who have the most to contribute to threads like this one have been taught to not bother. Why would anyone want to constantly defend their decision to run one part over another on their experimental airplane?

Don't like it? Don't run it.

Every thread that gets derailed because someone with 10 million hours in Alaska doesn't like a product limits the usefulness of the forum and the contributions from people who have pertinent information to share.

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I don't call different opinions as derailing a thread. I call it learning something useful.

Glenn

Hey Jake,

Even though no one was injured (thankfully), the wing repair isn’t going to be cheap. A polite letter to the manufacturer inquiring about who you should contact regarding their Products Liability Insurance Policy might quickly net you your out-of-pocket losses.

motosix said:

The sad truth is that the guys who have the most to contribute to threads like this one have been taught to not bother. Why would anyone want to constantly defend their decision to run one part over another on their experimental airplane?

Don't like it? Don't run it.

Every thread that gets derailed because someone with 10 million hours in Alaska doesn't like a product limits the usefulness of the forum and the contributions from people who have pertinent information to share.

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Not sure that disagreeing with an install is enough to turn people away from use. Isn't the design and use of new items all about being better (and proving that there is a better way)? If I don't like your tail wheel set up, then prove me wrong. Show me that your idea is better. Tell me the concept behind the design. If I don't like it, I'll tell you why and show my evidence to back up my case.

Example from my experience; ELT antennas. I've pissed off more than a few people with my advice on ELT antenna installation. I have very specific ways to orient the antenna, fabricating the ground plane for it, and the specific location on the aircraft. Every time it comes up, a bunch of people will tell me I'm full of excreted digestive material. They argue one way and I argue another. I always hope that I can persuade as many as I can of what I consider the 'right way'. In the end the guys are going to install it as they see fit. If a guy comes on the forum and states that all ELT antennas need to be painted blue, I like to think that I will ask 'why'. I may not like the answer but what if he has a point? I expect the 'newer' guys to do the same with me; ask 'why'. I've been surprised many times, in the past, by asking only to learn that an idea had already been tried and abandoned because of X, Y, or Z.

I'm glad the T3 works for you. Sounds like the upgrade was an improvement.

Web

Ok everybody take a deep breath and relax....

sj

I checked my log book; I installed the LSA version of the T-3 in March of 2020, on the 780 lb. S-7S, and now have right at 190 hrs. on it now, with just 9 pavement landings, the rest off airport, plus the ski ops. I checked it last night after reading this post, it's tight as a drum, no slop whatsoever, though I did take up about a quarter to half a turn on the AN5 nuts, to achieve what felt like "just right" torque.

9 hrs. after the install, I was trolling a 8400' ridge I have landed a half dozen times in the last few years, though each time the rocks seem to be re-arranged from my last visit just a bit. The end result being on one of my passes as I was finding a clear/clearer path for touchdown, and while flying upslope, I got into a situation where I smacked a rock with the mains off the ground but the tail low, while ALMOST having enough climb to clear it. It wasn't a vertical force, but a big sideways (straight back) hit. It bent the main AN7 bolt, blew the tire, broke the wheel, and trashed the 8" Matco tailwheel enough to make it cheaper to just buy a new one, which I immediately did as I have gotten good service out of them in the past, this was a out of the ordinary event. I thought at the time that I may have done airframe damage, it was a BIG hit, and I did tweak the bushing the AN 7 bolt goes through, and the bent bolt is still in there as to get it out will probably require a skinny wheel grinder. I did effect a "temporary" fix, that upon further reflection was deemed good enough to serve as a safe repair until I run out of other projects.

Point being, the T-3 survived this event unscathed, in addition to the other 181 hrs. afterwards. I'm not saying it's bulletproof, but after carefully reading all the posts on the subject here, I have no plans to change it. In my previous S-7 time, I broke 2 of the original RANS single leaf springs, and then went to a 3 leaf J-3 spring, breaking one leaf of it twice, before deciding to pre-emptively replace them at 1000 hrs., as the breakage seemed to occur at a bit less than that time. I can see how it MAY have a bit less tolerance in a sideload situation, but am willing to pay that price for the super cush action it provides. My big takeaway from this thread is the stated lube issue, I guess I will take that into consideration, certainly can't hurt, also the checking of the torque on the side plate nuts.

Weight on the tail would seem important too, I assume Your rans has a lighter tail than most experimental cubs, but I might be wrong about that assumption.

sj

Mine is also the LSA version

Glenn

Sorry Dad :lol:

Web

damn, after reading all this I was pumped up to go buy one Wednesday when I get home, but they are out of stock at airframes.

Just checked mine, had some play, half a turn on the cross bolt and most of it stopped. Mine is the old style with the strap.

Glenn

SJ said:

Weight on the tail would seem important too, I assume Your rans has a lighter tail than most experimental cubs, but I might be wrong about that assumption.

sj

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Probably, guesstimating about.... wait a minute, I have a new digital scale, I'll run out to the hangar, you got me curious.

If my scale can be believed, 118 pounds, more than I thought. What's a Cub's? First time I've weighed the RANS's.

In the 3-point position & with 31” tires, my PA-12 tail weighs 120 lbs. It’s pretty heavy.


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I just realized, I stupidly put the digital scale on my usual pick points for when I lift the tail up in the hangar. A couple feet or so in front of the tail wheel, duh. Just checked W&B sheet, 47 lbs. In flight attitude.

courierguy said:

I just realized, I stupidly put the digital scale on my usual pick points for when I lift the tail up in the hangar. A couple feet or so in front of the tail wheel, duh. Just checked W&B sheet, 47 lbs. In flight attitude.

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When on the ground it's not in flight attitude?

Glenn

cubdriver2 said:

When on the ground it's not in flight attitude?

Glenn

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No, the tail has to be raised to flight attitude to get the right weight, however, for the purposes of this discussion, the weight on the ground is likely more important than the weight in level flight attitude.

sj

windy said:

In the 3-point position & with 31” tires, my PA-12 tail weighs 120 lbs. It’s pretty heavy.


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120 lbs on a tailwheel in a cub of any kind is a red flag for me. I would check the weight and the CG limits and your CG paper work. in an effort to soften my statement after my stepping on toes the other day I’ll say maybe I’m mistaken. I suggest you do some checking in case I’m not.

Empty for weighing my planes’ tails weigh essentially 1/9 of the total when in 3-point. Loaded to gross within the CG envelope the tail weight is 1/5. It may be coincidental but it’s a good way to estimate weights for my loads.

reliableflyer said:

120 lbs on a tailwheel in a cub of any kind is a red flag for me. I would check the weight and the CG limits and your CG paper work. in an effort to soften my statement after my stepping on toes the other day I’ll say maybe I’m mistaken. I suggest you do some checking in case I’m not.

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Windy has a PA12, almost a Super Cub but not quite. Don't 12s seem to be heavier on the the tail? Don't confuse tail weight on the ground with tail weight when weighing.

I've always been curious if a tapered rod tail spring could save some bent fuselages. Anybody tried that in Alaska?

Tail shock vs Spring seems like a simple list of pros and cons/priorities depending on your mission. Great to have options.

I don't use the tailwheel for directional control (no steering) so I'm not as worried about a scenario like Jake's causing a loss of control.



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I have seen side loads from people taxiing into a hole but wouldn't the tailwheel swivel in most other cases?