Full Swivel!

With just one more hour to go before Tsam reaches 500 on the clock, her Silver bullet tailwheel steering arm decided it had seen one too many cracks in the various taxiways we had visited.



Well actually, it wasn?t the Silver bullet the failed ? it was the Heim Bearing that screws into the Bullet that fractured. This left me with no tailwheel steering, and from the cockpit, this manifested itself as not being able to get the tailwheel to lock in to the rudder ? effectively, it felt like a full-swivel tailwheel. When I got out to have look, the steering arm was all the way up against the tailwheel spring on the left side ? I think this is why I had a full swivel instead of one that was locked in place.

I discovered this after landing at our home airpark. I had made a long back-taxi at the neighboring field where we are working on our Dream Tundra project ? a runway known for some fairly large transverse cracks that are filled with sealer, but known to give a good ?bang!? every time you cross one with a small tailwheel. For those of you who have taxied any distance at Reno Stead?same thing! When I turned around at the end of the field, it didn?t want to turn left very well, but I choked up on the brake pedal and she came around ? I chalked it up to getting used to the pedal position again after being out of the cockpit for two weeks after a hip injury. Directional control was fine on take-off and the subsequent landing at home ? had a little difficulty straightening back out after turning off the runway, and it felt like I had a weak brake ? but the pedal was firm.

We have a little uphill turn onto our twelve-foot-wide private taxiway, and because I felt something odd, I took time to line up carefully so as not to fall off the side ? and it all went fine. I did a quick run-up brake check and found that both brakes held just fine. It wasn?t until I climbed out that I saw the problem. So?.easy fix, just needs a new Heim bearing (I think I have one in a drawer). The lesson is that even with NO connection to the tailwheel, steering on the runway with rudder alone was more than adequate under today?s light wind conditions. I know some have gone to full-swiveling as a matter of course to reduce hardware count and maintenance requirements, and as long as precise taxiing in close quarters isn?t required, I think that would be just fine. I missed the precision of steering on tight corners that the link gives me however ? so I think I?ll stick with the steerable wheel for now.

We have those rod end bearings if you need them.

Not trying to sell more tailwheel parts, we're plenty busy, but I always wonder about the guys who intentionally disconnect the tailwheel steering. What do they do if they lose a brake?

vfrazier said:

We have those rod end bearings if you need them.

Not trying to sell more tailwheel parts, we're plenty busy, but I always wonder about the guys who intentionally disconnect the tailwheel steering. What do they do if they lose a brake?

Click to expand...

Found one in my drawer Vince - thanks! But I'll probably need to replenish my spares and will get in touch.

I guess with no tailwheel steering and no brakes, you're back to the good old days of barnstorming....

Paul,
All of us have our own way of thinking not sure if you thought about it. I would replace both of those bearings. it would be cheap enough, not take long and it will be peace of mind. If one failed is the other one about to fail?

A similar failure to the forward bearing could result in a more difficult situation if the rod digs into the runway or a crack.

When a part fails, I always like to try to figure out exactly why. I wouldn't think a straight load on a Heim bearing would cause it to break.

Is there some kind of bending load due to the geometry?

PCHunt said:

When a part fails, I always like to try to figure out exactly why. I wouldn't think a straight load on a Heim bearing would cause it to break.

Is there some kind of bending load due to the geometry?

Click to expand...

It is actually fairly rough duty for a little AN3 Heim joint stem I think - and it has seen a lot of bouncing around in 500 hours. Actually, if I recall correctly this Silver bullet we got used from someone - so it might be more than that. We'll probably rebuild both ends when I get a few spares in hand Alex.

I think you've had enough excitement for the month. Tailwheel link, mountain bike incident,
Take a break!
Tom

What are the odds?

Strange, my Rocket steering arm failed this morning, too!
The arm broke internally, I felt it let go as I taxied in.
Would have to check on when exactly I installed it but it has around 900 hours on it.
New arm on order from JDAir.


Scott A. Jordan
N733JJ

I knew I picked a nose dragger for a reason. Deathtraps!

Just kidding. I have had some serious tailwheel withdrawal recently.

Mine broke this year at Osh

After 1065 hours I found myself at OSH this year in the big Thursday morning departure line. Tail wheel control was fine.

I was on the brakes fighting with a hot surging engine like everyone else (except the lucky sucker who was following a long EZ pusher - basically having his own personal cooling fan!

I taxied past the unlucky guy (Steve ?? - I think) who had inadvertent rear end surgery to his rudder.

All was fine. I turned left looking for the gal in the pink shirt and waiting for my turn to blast off. Again, on the rudder, all is well.

"RV line up on left side of runway" came the call. Okie dokie my turn. Step on the rudder, give 'er the gas, line up, all is well.

"RV clear for takeoff" , black knob in, step on rudder to correct for yaw...... WHOA!!! WHOA!!! WHOA!!!! What the ..... My rudder was swinging side to side, I'm dancing on the brakes and thinking that this is NO PLACE TO GROUND LOOP! On the biggest stage of my life.

The link busted right there!

Lucky for us. With a little wind the takeoff roll is short enough, the tail comes up and the rudder is flying.

So I bugger out of OSH. I'm heading to Willmar, MN to meet my friend and have lunch before blazin a trail home to Western Canada.

I still didn't know what was wrong all I knew was that somethin ain't right back there.

I get to Willmar some two hours later. Cross midfield...oh great... Looks like 10 knots, 90 degrees to the runway. I wake my kid up. "Ok son, hang on, this maybe a teenie weenie bit bumpy".

I'll forgo the truth .... I kept the wing low, into the wind, greased it in one wheel at a time, kept the tail off as long as possible... We all belong to VAF so we're pro's. Right! No sweat

Tailwheel touches and ya, not good. Brakes, brakes and more brakes. Ya, not 10 knots cross, felt like 40!

I thought, "dang, I hope I don't burn out these brakes before I shut down"

Anyways, all ended well. I get out. The link looked like Paul's. The main hanger door was open, a couple of 3/8" wrenches and she's off, I slip buddy in the hanger $20, he welds it up while I go have lunch, he threw in a quart of oil for me, bada bing I'm outta there

God smiled on me that day

And I've already installed a new one. Ready for another 1000!!

Darren

Great post, Darren!

Makes me glad I went with the Tail Lynx tail wheel cables sold by Van's.
http://www.vansaircraft.com/cgi-bin/store.cgi?ident=1440786955-448-459&browse=misc&product=tail-lynx

I've had three of them break. All different brands. Never have trusted them, thats why I put two of them on from the start. The reason I keep going back to them is that they clear the rudder and they give a more positive reaction to the tail wheel. The good thing about them is that when they break you don't know it until you do a post flight. What??? you don't do a post flight?? Haha.

Ironflight said:

It is actually fairly rough duty for a little AN3 Heim joint stem I think - and it has seen a lot of bouncing around in 500 hours. Actually, if I recall correctly this Silver bullet we got used from someone - so it might be more than that. We'll probably rebuild both ends when I get a few spares in hand Alex.

Click to expand...

Concur Paul. I've had 5 failures in 1000 hours out of Stead (grand canyon expansion joins here). 3 different brands of link...2 links failed at the weld, and 3 bearings failed at the insertion point. All the bearing failures were at the aft end of the link, just like Paul's photo. Haven't seen a problem at the front, but Axel's point is good.

Its always been very controllable on the landings. Typically I haven't realized the TW steering was gone until turning off the runway, so it hasn't been dicey. I race with no link and a 4" TW too, so its not a horrid controllability concern, IMHO. Of course, the Super Six is docile on the ground...long and tall like a Rocket, and wider as a SBS, so YMMV.

As for root cause analysis?agreed Pete, we want to know why?but since you can hear an RV taxiing a mile away across the field here (sounds like a base drum at every joint), it seems logical. Tough TW duty here, as Paul said.

I know there is a tar flow off the coast of Madagascar, with all the tar we pour in the joints each year here that seems to disappear into the earth's core!

Cheers,
Bob