Scott 3200 steering arm bent

[BES]

After a rather firm landing in a stiff crosswind requiring full left rudder, the steering arm on my Scott 3200 tailwheel is bent upwards. It used to be bent a bit on the starboard side, but now the port side has been bent enough to render the tailwheel steering slack to non-existant.

I'll bet I am not the only one to have experienced this particular problem, so what have you done to fix it? I can shorten the port side chain a link or two and accept the bent steering arm, but could I straighten it if I would? Or would it break?

I have been looking for the Steve Pierce video on adjusting the tailwheel chain length on YouTube but cannot seem to find it. Does anyone have a link for it?

Thanks,
Bent

 

[bob turner]

There is a much heavier part, with ears that are up 90 degrees.

For some reason some Cubs have a "pull" angle that tends to bend them - I am not sure, but I think compression style springs may add to the problem.

 

[BES]

I am not sure, but I think compression style springs may add to the problem.

Makes sense. I have compression springs on mine.

 

[mvivion]

There is a much heavier part, with ears that are up 90 degrees.

For some reason some Cubs have a "pull" angle that tends to bend them - I am not sure, but I think compression style springs may add to the problem.

It's called a 3214 T steering arm. It'll fit on a 3200 tailwheel, but you'll need the grease seals as well as the arm. Here's a link with photos: https://www.google.com/search?q=321...ka.com%2FABI-3214T-p%2Fabi-3214t.htm;1200;610

Had one on a Cub, couple Huskys and on my Cessna 170. Work great, and much stronger, and better geometry.

MTV

 

[BES]

Mike, did you have tension or compression springs on your tail wheels?

 

[irishfield]

Get rid of the "door closer" springs and put the spec'd tension springs on for the Scott 3200 and the problem will go away.

 

[mike mcs repair]

Bushwheels sells replacement parts http://www.airframesalaska.com

http://www.airframesalaska.com/ABI-Replacement-Scott-3200-Scott-3400-Tailwheel-Parts-s/1849.htm

 

[mvivion]

Mike, did you have tension or compression springs on your tail wheels?

Tension.

MTV

 

[Darrel Starr]

I had the normal tension springs on my SC when the narrow straight arm bent. Installed the one with bent up ears like folks are recommending to you - problem solved. When you look at the two arms side-by-side, it is obvious that the one with bent up ears has about twice the cross section.

 

[TirolCub]

... maybe you are looking for this one?

www.youtube.com/watch?v=QtokU8mIDQk

Anthony

 

[Steve Pierce]

That is Steve Davidson formerly of AK Bushwheel and now works at Ultima Thule. If correct springs, chain length and tailwheel geometry I have had no problem with those steering arms bending. The other arm is way beefier.

 

[hotrod180]

It's called a 3214 T steering arm. It'll fit on a 3200 tailwheel, but you'll need the grease seals as well as the arm. ....

Better geometry with the chains attaching higher, so won't be as prone to bending. And beefier, so won't bend as easy. If you wanna save yourself about sixty bucks (!!), your standard dust covers can be trimmed with a sharp pair of snips to fit the wider steering arms.

 

[Crash]

Remember.... "Heavy Duty" is usually heavier. 99% of the time it's not needed if you're plane is set up right, taken care of, and flown right.

Take care,

Crash

 

[mvivion]

Crash, take a look at the tailwheel steering geometry on a 52 Cessna 170. Or a number of other aircraft, for that matter.

On that plane, the tailwheel steering arms are well below the aircraft steering arms. So when you apply rudder, you're actually pulling UP on that tailwheel steering arm. Put in a bit of steering input and have the misfortune to hit a rock, etc at the same time, and it'll bend that lightweight arm upward. And you just lost a good bit of steering effectiveness.

Bend the arm back and you've weakened it......

Install the 3214 T arm and you get better, more effective steering effectiveness, plus a much stronger steering arm. Those upturned ears really improve the geometry.

Would I replace a perfectly good standard arm with a 3214 T arm? Nope. But if I bent one, I'd upgrade......actually, I did.

Good steering is a real novelty in some aircraft......and welcome.

MTV

 

[bob turner]

That's what we have - bent almost vertical. Half due to compression springs, probably. Tanks for the tip on the dust cover - I have a cutoff disc that will be better than tin snips.

 

[Crash]

Mike mine is a general statement on "heavy duty" parts. With the proper springs and tension this would not have happened. Been around Cubs since 1962 and actually own one with a few hours on it.

Take care,

Crash

 

[BES]

... maybe you are looking for this one?

www.youtube.com/watch?v=QtokU8mIDQk

Anthony

Yes, that's the one I was looking for. Thanks! (and sorry for mis-remembering it as your movie, Steve )

 

[RCharles]

Take a look at your tail wheel leaf spring ..if it is weak and too springy it can tend to stretch and lose it's arch on a heavy three point landing .that will make the entire tail wheel Assy move in such a manner as to make the spring tabs rotate toward a more vertical position making it easy for heavy rudder inputs to bend them when the wheel is in contact with the ground....that is what is being referred to when tail wheel geometry is mentioned...

 

[Steve Pierce]

That is why Bushwheel started making the tailsprings for Aviat. The springs were losing their arch and bending the steering arms.

 

[Darrel Starr]

Also the Huskys and many of our Super Cubs are a lot heavier than Piper or Scott probably ever envisioned. When loaded near gross of 2000 lbs, a SC has 200 lbs + on the tailwheel; actually more like 250 lbs. I always, on my mind, think of the tailwheel load as being 60-65 lbs, but that is when the plane is level during an empty weight W&B check. The real world is near gross and 3 point. Takes some pull on those chains to move the tailwheel especially if it is a bit underinflated.

 

[TirolCub]

Take a look at your tail wheel leaf spring ..if it is weak and too springy it can tend to stretch and lose it's arch on a heavy three point landing .that will make the entire tail wheel Assy move in such a manner as to make the spring tabs rotate toward a more vertical position making it easy for heavy rudder inputs to bend them when the wheel is in contact with the ground....that is what is being referred to when tail wheel geometry is mentioned...

... thats a good view for alignment ...

 

[mvivion]

That is why Bushwheel started making the tailsprings for Aviat. The springs were losing their arch and bending the steering arms.

And, all new Huskkys come with the 3214 T steering arm, if I'm not mistaken.

it only takes one shimmy event to bend your steering arm (or airframe). But to me, the upturned ears on the 3214T steering arm provide more positive steering in most applications. That's generally a good thing.

I was told for years that Cessna 170s had lousy steering. Mine didn't, and folks that flew it were always impressed. It had other mods but the bigger steering arm was a significant improvement.

And, yes, I know, you can go for years and not have a problem.....but if you're replacing a steering arm anyway, why not upgrade?

MTV

 

[BES]

And, yes, I know, you can go for years and not have a problem.....but if you're replacing a steering arm anyway, why not upgrade?

MTV

Another way to look at it: If you can buy a $230 part that might save your bacon and a $100,000+ aircraft, why wouldn't you?
I have taken your good advice and ordered one from Airframes Alaska.
Thanks Mike

 

[BES]

Thursday afternoon fun in the hangar:


Quite a difference!
Thank you very much to all who helped solve the issue. Also, I would like to mention how nice Airframes Alaska were to do business with.
;-)
Bent

 

[TirolCub]

... looks great, congrats. But also check the correct torque for the single bolt attaching the spring. If it is to stiff, the spring is not able the work properly...

 

[Steve Pierce]

My Dad was having steering issues. You can see the notch for the lock has been filed before. He got a new steering arm from Airframe and it now steers better than it ever did.

 

[N86250]

My Dad was having steering issues. You can see the notch for the lock has been filed before. He got a new steering arm from Airframe and it now steers better than it ever did.
View attachment 20412
View attachment 20413

A question about fine tuning these parts. How does moving the spacer P/N 3258 ahead or behind the spring P/N 3222 affect the operation? Does that affect how easy it unlatches? Can it be set too loose or too tight? jrh

 

[Steve Pierce]

A question about fine tuning these parts. How does moving the spacer P/N 3258 ahead or behind the spring P/N 3222 affect the operation? Does that affect how easy it unlatches? Can it be set too loose or too tight? jrh

Yes. If you set it too tight it won't allow the 3222 compression spring to move when the pawl (3219) tries to unlock it. Too loose and there is a lot of movement in the steering arm prior to moving the fork and premature wear in my opinion.

 

[hotrod180]

Also make sure that p/n 3222 spring has a nice smooth burr-free finish on the ends, else it will chew up the notches in that expensive steering arm.