Always carry a spare if you have one

[Bruce Fenstermacher]

What's missing in the picture on the right?

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Here is a closer shot.

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No the ground is not so soft the tail wheel sunk in though it was pretty soft. Seems that after landing and taxiing into the fly-in at the Golden Age Air Museum today I noticed something missing.

The king pin in the bracket assembly on my 3200 failed on lift of from my home base but was unbeknownst to me. We eventually found it there when we returned home.

The pin broke clean where it tapers to start the thread which holds the nut that keeps everything together. There is no evidence present of an old crack. I can't say for sure but total time on this tail wheel might have been about 60 years.

The good news is that when this pin breaks there is nothing to hold the tailwheel to the airplane and it won't beat the rudder and elevators up. And what is left makes a pretty darn good tail skid specially if you land in some soft grass. Even though I drug it through about 500ft of grass and dirt there is no damage to the steering lever and bushings in the pack.

BTW I'm lucky enough to have an entire extra Scott 3200 which along with a main spring and bolt is carried in the airplane all the time. Borrowed a few wrenches and some extra hands to lift the tail and we had it fixed in no time.

Anyone have a spare bracket assembly they'd like to get rid of cheap so I can rebuild my now spare Scott 3200?

[15A]

Bruce,
You carry a spare tailwheel and spring?

I had the unfortunate experience of snapping my leaf spring at the housing during a grass taxi to take off. Luckily I was at a friends field and he had one for a 170! It didn't fit! But I made it fit to get me home. Went to the local leaf spring shop with my broken one and matched up the thickness, width, and arc. Cut it to size and bored 2 holes in it and FIXED .
It's a Bolins conversion and he must have made his own.

[GAHorn]

I hope there's an article coming soon!
(Good one, Bruce! let's see that kingpin and zoom in on the break.)

[W.J.Langholz]

I love the expression on your face Bruce!!!!!! I think I'll bring it up again tomorrow for another chuckle...

W.

[Bruce Fenstermacher]

W that is a look of concentration. Holding the piece just right while looking at the computer monitor to frame it.

Here is a better shot. Can't really see evidence of a crack that grew or any fault that might cause the failure.

Can't think of a story to tell unless the story is to carry a spare. BTW you should have seen the shock and amazement from all my airplane friends when I pulled the extra tailwheel out of the back of the plane.

Or maybe the story is that in less than a year I've had the AN-7 bolt that holds the tailwheel to the main spring break will taxiing. 2 months later while sitting in the tie down, not in motion, the main spring broke. And now, the last "weak", the tailwheel king pin let go. I had spares in hand for all of the failures.

Hey we should be good to go for another 60 years.

[4-Shipp]

My initial thought looking at the picture is crack propagation from both the left and the right as shown by the shiny, clam shell type surface leading to the narrow grainy area just left of center. The shiny areas are where it was cracked. The grainy area is what failed instantaneously. Hard to tell for sure from that picture resolution. The only thing that would make me doubt this theory is the small size of the grainy area. I would think the bolt would have failed long before it got to such a small area still holding it together. Hmmmm....

[MoonlightVFR]

I am simply amazed that you would have an entire Scott tailwheel on hand when yours broke after nearly sixty years service.

What other unique "SPARES " do you keep in the airplane while traveling?


Are we to be suspect of the steel used in the kingpin of the tailwheel?



Regards

[jrenwick]

Tail wheels carry some heavy loads, and tires and tubes fail often. You can carry a spare tire and tube, but repair in the field is easier if you have it on a wheel already inflated. And if you've got an extra wheel, maybe you've got a complete spare tail wheel assembly, so why not throw the whole thing in the baggage compartment? I certainly see the logic of it.

[Bruce Fenstermacher]

John I think your catching on to my logic. And the extra main spring and AN7 nut and bolt don't do you any good on your shelf at home when you break away from home. These are the only spares I carry all the time. They sit in the back in the baggage and make my plane faster because the CG is further back.

Bruce Shipp you may be right about the crack propagation. Maybe someone with training in that area would know. A local machinist looked at it an he didn't see anything obvious pointing to why the failure. I've heard of other tailwheel pins breaking. I think they broke along the drilled grease channel down the center of the pin then out to the side. This is not where this on broke. That grease hole is higher.

I'm not worried (much) about the other tailwheel that I put on with unknown hours on the pin. But my partner and I will probably splurge and by another new bracket assembly with pin for $208. And repair this one for a spare just in case. My partner of course wants to just get a new pin but they are not available by themselves. I thought he would suggest we make a new one but he hasn't yet. He's either feeling rich this week or thinking poorly of his lathe skills I'm not sure which.

[Harold Holiman]

Many years ago, I broke the tailwheel axle on my Maul tailwheel while landing at a very rural airport at night. The Maul axle is only supported on one end and I don't think anyone is still flying 170,s with Maul tailwheels. Anyhow, the next morning we found my tailwheel along the runway. Nothing had been damaged except the broken axle which released the tailwheel clean. We then looked around and found a old tailwheel assembly hanging on the wall in an old cropduster shed, which was one with the very small solid tire, probably off a Champ, J3, or such. The mounting bracket was the right width for my tail spring so I bolted it on and flew with the small solid wheel mounted for a couple of weeks untill my new Maul axle arrived. This was in the early 1970's.

[GAHorn]

I used to always carry a spare tailwheel tire, tube, foot-pump, and inner-tube-patch-kit. I carried it for ten years. I did this subsequent to landing at Galveston during an airshow with Jamie, Wendell Wyborny, and Cleo Bickford aboard...and my tailwheel went flat. I've told that story elsewhere...but that experience prompted me to always carry those spares (and a few other things as well.)

About 2 or 3 months ago I removed my baggage bulkhead to inspect the tailcone and failed to place my "spares" back into the bag compartment when I finished. This weekend, while flying without the spares.... of course.... it "happened".

Fellow Member Bob Lavery ("HawkerCFI") brought a foreign (from India) co-worker of ours, "RanJan", to the ranch for a short visit, and we all piled into N146YS to fly them back to Ft Worth Hicks Airport.
It was a spectacular, smooth, sunset-flight which departed at 1730 and landed just as it became dark about 1900. While taxying in to the fuel pumps, the tailwheel went FLAT.
We got the tail up onto a short stepladder and removed the wheel and found a puncture, but we had no repair-kit, my having left it in my hangar back home. So we went to WalMart. Would you believe they no longer sell decent inner-tube repair kits? They have PLUGS for tubeless tires....and they have liquid aerosol tire-fillers (NO-NO-BAD-BAD)...and in the bicycle section they sell a cheap repair kit which has quarter/coin sized clear cellophane "patches" which are pre-glued (like postage stamps). The material looks like heavy-duty "Scotch-Tape". AutoZone, O'Reillys and other autoparts stores in the area also no longer carry genuine, quality tube-repair patch kits/materials.... so we used the bycycle kit. (After all.... I only needed to make one flight to get home where I have proper repair materials and also have a NEW tire and innertube in my hangar.)

The flight home was uneventful....until I landed. The tailwheel tire was again FLAT! (That cheap bycycle repair kit is pure JUNK!)

Now the problem is that taxying around on a flat tailwheel tire poses several issues:
1- It will destroy the tire in short order.
2- It will cut/destroy the inner-tube. IF it was repairable...taxying around on it while flat will finish its destruction.
3-That expensive/rare wheel-hub is subject to severe damage, especially on pavement.
4- Manuevering/turning is almost impossible. (If you've never tried it you will have to before you will believe how un-cooperative the airplane is with a flat tailwheel.)
Fortunately most of my taxi-in to my hangar was on grass, because I had no suitable "dolly" to get the airplane the 3,000' or so to the hangar. Once there, I had no way to get the airplane rolled into the hangar and onto it's concrete floor without risking additional damage to the wheel assy. I was contemplating just leaving the airplane out on the grass for the night and deal with it in the morning because it was now 1 AM and I"m a bit fed-up with this tailwheel situation tonight.

Then it HIT me! About two years ago I bought a couple of casters w/pneumatic tires from Pep Boys (bluEldrs favorite airplane parts-house). They had decided to divest themselves of handling cheap chineese junk and sold them for $3 each. (Yep...that's THREE DOLLARS, U.S. money.) I've been keeping them on a shelf in the hangar.
I walked over and measured and ....couldn't believe it! The hub is 3.25" wide...same as the Scott tailwheel..and the tire is a 2.80/2.50 X 4" ....similar to the Scott. All that was necessary was to pull the axle, drop the Scott wheel...and... In about 3 minutes I had that chineese wheel perfectly skewered by the Scott axle. I wheeled the airplane into the hangar and closed the door.

Next day...I returned to the hangar and properly repaired my Scott (by installing a brand new tire/tube.).

But that chineese wheel shore does look convincing don't it, bluEldr? D'ya think it might pass for an "emergency replacement" up in Alaska (where you can almost SEE china?)

Anyways....here's some pics. Northern Tool handles this part but they get full price for it (about $24).

Here's how it is sold as a caster in chineese tool stores like Northern Tool, etc.

Camera angle is misleading: Both wheels are same height, although China wheel is slightly more narrow.

Don't miss this: Scott axle-bolt-head is "locked" by this special washer w/tab which fits into the hole in the fork.

TIP: Use valve-stem cap which doubles as core-removal tool. Carry extension onboard to ease inflation of tire (standard hose chucks will not fit inside wheel rim.)

Finished repair! (Just so everyone can relax in the knowledge that the genuine article got re-installed for operation.) LOL

[170C]

Yep George, been there, done that! I carry a spare tire, tube, pump and repair kit after incurring that problem several times. I don't have a spare wheel which would simplify the situation. I recently had to replace the innertube in my airplane tug. I found exactly what was needed for under $8.00 at Tractor Supply. Next time I am in one I am going to check to see if they have the correct size for our tail wheel tires. The tubes are made "over there", but so are the ones I have purchased from suppliers listed in Trade-A-Plane. The only thing I don't carry is a small jack, due to the weight. Not sure one person could manage lifting our plane's tail and placing something under the aft area in order to change a tire.

[blueldr]

Some years ago I went through the grief of a flat tail wheel and the accompanying PITA to get home.
I found a pneumatic small equipment or caster wheel at Harbor Freight that would do the job using a fist full of large washers on the axle to center the wheel. Carried it around for years just dareing my tail wheel to try to strand me again. It didn't.
I did install it and flew around the pattern some at my home base just to make sure it would work. It did.
The last flyer I received from Harbor Freight had that wheel with installed tire and tube on sale for less than $4.00.

P.S. Please be avised that should you be interested in this emergency spare wheel, it requires a 5/8"
diameter axle. I carried an axle length piece of 1/2" copper pipe (5/8" OD and 1/2" ID) used to shim the Scott 1/2" axle, and the large washers to center the offset wheel hub.

[GAHorn]

Frank, the last time I was in TSC the only tube which was even-close was a 3:50/4:10 X 4 ...and that is too large. While it may fit inside the tire if you "stuff it" in... you won't be happy with it.

bluEldr is correct...the chineese caster wheel has a 5/8" axle, so a bushing is probably a good idea. Making one out of 1/2" copper tubing is a good idea. (This is only for "ground movement" purposes, of course!)

I was in Northern Tool today and discovered they sell the wheel alone for a reasonable price. Anyone contemplating such a purchase would be well-advised to "spin" the wheel before purchase to check the bearings and to check the hub for true-ness. (Some of them have a distinct "wobble".) The tires/tubes are the similar size 2:50 X 4. Oddly, if the inner tube is any good (and the ones in my hangar have held air for two years) it's cheaper to buy the Northern Tool wheel just to get the tube!

Here's what I found in Ft Worth's Northern Tool today...and the posted price. It is the same as the one I posted above and has a similar width as the Scott and would not require washers, but it would be best if accompanied by a bushing/copper tubing:

[Kyle Wolfe]

Rminds me of my last flat tailwheel....... After landing back home and realizing I had a flat, I got the bright idea to simply set the tail on the creeper from my hangar and taxi back on the ramp to the hangar.

Becky kindly walked back to the hangar, picked up the creeper and returned to the a/c. We lifted the tail, set it on the creeper and away I went slowly taxiing back. Was able to make turns and everthing!

Thought I was pretty smart.... till I found out my cheap creeper from the local parts house did not have wheels with bearings but only the cheap plastic ones! The wheels melted from the heat just as I got back to the hangar.

Won't do that again!