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Tailwheel castering issues after restoration

gravytime

Registered User
Just finished up the restoration on our L18-C a few months ago and I am having issues with the Scott tailwheel castering. I did the grove brake conversion and the brakes are better (but still not the best) but I can’t seem to get the tailwheel to caster while taxiing. The restoration project was over 10 years so it has sat….considering just getting a new tailwheel assembly. Looking for any information or help before I order a new assembly. Thanks for any info.
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Did someone with knowledge disassemble/clean/inspect/lube/reassemble it before you put it on? Steve has some excellent videos on the topic, also check castor angle hard to do with the picture angle.
DENNY
 
When you say castor are you referring to the steering or just the tailwheel centering behind the plane when you’re going straight ahead? I’m assuming steering but it’s not clear. More detail as to the exact problem would be helpful in troubleshooting.

I will say that the steering arm is bent pretty badly on both sides of the tailwheel. At a minimum a new steering arm is recommended.
 
When you say castor are you referring to the steering or just the tailwheel centering behind the plane when you’re going straight ahead? I’m assuming steering but it’s not clear. More detail as to the exact problem would be helpful in troubleshooting.

I will say that the steering arm is bent pretty badly on both sides of the tailwheel. At a minimum a new steering arm is recommended.


The steering actually works fine it’s the breakaway swivel when you are trying to make a tight turn that is hard to make happen. I can make it break away when I’m pushing it around but not while taxing.
 
Did someone with knowledge disassemble/clean/inspect/lube/reassemble it before you put it on? Steve has some excellent videos on the topic, also check castor angle hard to do with the picture angle.
DENNY
I’m not sure they did anything with it but put it back on. I’ll take a look in the logs.
 
The only thing that lies worse than a pilot is the logs!! Take it off and go through it, also send a picture of that from a direct side view at tailwheel level. Several things can cause that issue, I agree with Gabe, steering arms are bent but send a picture/look at steve's videos/pull it off and get hands dirty.
DENNY
 
The tailwheel hitting a "stop" and not breaking into full castor is normally the steering pawl binding against the compression spring. There's a flat piece of spring steel in a roughly "U" shape inside with legs left and right that fall into notches on the steering arm. The ends of those legs interact with the pawl to compress them out of the notches to unlock the tailwheel. The pawl can dig up burrs and create a groove in the end of the compression spring where they ride over one another that causes them to jam. Knocking burrs off and smoothing the mating faces of both with light emery cloth or a buffing wheel fixes that. You can replace both parts as well if you're feeling ambitious.
 
And, while you have it apart, have them replace that steering arm with a “bent steering arm” from Airframes Alaska. That’ll also require a different dust seal. Will steer much better and much less susceptible to bending, like the one you have. The Scott designation was a 3214 T steering arm.

But as Steve says, have someone who knows tailwheels take it apart and properly service it.

MTV

MTV
 
.... replace that steering arm with a “bent steering arm” from Airframes Alaska. That’ll also require a different dust seal......

The 3214T steering arm is kinda spendy at $275 but worth it.
But you can save about $70 by notching out the standard dust covers to fit the beefier steering arm,
instead of buying new ones.
 
While it’s apart you can change the shim with the pawl to help get you the right angle/clearance. You can also bend that pawl slightly if one side isn’t doing the same as the other. I did not these things, replaced parts with the airframes kit, and put on the airframes 18 spring. Went from poor steering and bad shimmy to trouble free.
 
And then buy a two bolt head, an acme stinger, 10:1s, an outlaw prop, p stol flaps, 35s, some carbon fiber and titanium, alum. struts…..wait, wrong thread!

You get it though. It’s a slippery slope. A bent steering arm can turn into a 100k “while your at it.”
 
And then buy a two bolt head, an acme stinger, 10:1s, an outlaw prop, p stol flaps, 35s, some carbon fiber and titanium, alum. struts…..wait, wrong thread!

You get it though. It’s a slippery slope. A bent steering arm can turn into a 100k “while your at it.”

And, it can also prevent that "tweaked" steering arm from failing at just the wrong moment, thus contributing to a 100K complete airplane rebuild.

There are many things that are "niceties", but at the point where your stock steering arm is bent that bad, it's time to upgrade. And, that's a once in the life of the airplane deal....those 3214T steering arms just don't get tweaked.

Steering effectiveness is also significantly improved.

MTV
 
And then buy a two bolt head, an acme stinger, 10:1s, an outlaw prop, p stol flaps, 35s, some carbon fiber and titanium, alum. struts…..wait, wrong thread!

You get it though. It’s a slippery slope. A bent steering arm can turn into a 100k “while your at it.”

it’s already a 100k+ project! 😂. Thanks for the motivation though…trying to keep it somewhat close to the way it was born minus my DDay flare.
 
And, while you have it apart, have them replace that steering arm with a “bent steering arm” from Airframes Alaska. That’ll also require a different dust seal. Will steer much better and much less susceptible to bending, like the one you have. The Scott designation was a 3214 T steering arm.

But as Steve says, have someone who knows tailwheels take it apart and properly service it.

MTV

MTV
Thanks for the info, at this point the rest of the plane is pretty much “new” it probably wouldn’t hurt to just get a new tailwheel assembly and sell the old one. By the time I spend labor on an overhaul I’m close to half way there…
 
Before you bail out of this tailwheel, it looks like an original Scott 3200 and you would only be able to replace it with a "aftermarket" one.

I am an enthusiastic amateur but armed with Steve Pierce's video and all the other good stuff on this site, I took my "serviceable" tailwheel apart and it was a mess in here. I am sure you would be well advised to stick with what you have and rebuild it, you will have an "as new" original Scott 3200 back there which would fit your rebuild objective.

Apart from the steering arm, you will need new dust covers, pawl, springs/shims and certainly the copper washers. It is almost certain that you will find that the peg that stops the copper plate washers rotating will be worn flush.

I successfully rebuild mine and one other and now it is not a black art thanks to Steve Pierce & Co on this site.

Kind regards

Stew
 
The steering arms don't bother me. Hard to tell from the pictures. A lot of time it is just dirt and grit, cleaning and new grease can do wonders. $1200 for a new one. Just dropped one to Florida where he is installing the new one and disassembling and inspecting the old one to learn how it works IRAN 9inspect and repair as necessary) so then he will have a spare. Time, money and knowledge.
 
.......Apart from the steering arm, you will need new dust covers, pawl, springs/shims and certainly the copper washers.......

Thoughts on long pawl vs short pawl?
I installed a short pawl in my 180's t/w & didn't like it,
went back to the long one.
 
Most tailwheels I work on have the long pawl. Had an engineer get very upset over the long pawl and I sent him a short pawl. Found out later he blamed the long pawl for getting his Cub off the runway on landing. I also got a call from Airframes a few years ago about this issue. Seems Dan of Dan's Aircraft was blaming the long pawl for several accidents and petitioned the FAA. Don't know what ever happened with that. I like the long pawl because it unlocks with less movement of the tail and allows me to steer around things easier. I installed a long pawl in my Dad's Clipper and he did not like it, he reinstalled the short pawl. He also likes 5 spring (more tension) between the head and the fork where I prefer it to move more freely. Everyone is different and likes the tailwheel to behave differently.
 
Thoughts on long pawl vs short pawl?
I installed a short pawl in my 180's t/w & didn't like it,
went back to the long one.

My uncle is thinking of trying the short pawl. It seems not worth a try. He might ordered one already, I'll visit him later after I finished installing the shocks from 4Wheelonline onto the Wrangler tomorrow. We'll see.
 
I found it was not as easy to kick the tailwheel into free-swivel mode when you wanted it with the short pawl.
"If it ain't broke, don't fix it".
 
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