337s for Tailwheels?

[Orion]

I'm contemplating seeking Field Approval, (Yes...I know.), for the Aircraft Products Inc. tailwheel on the M7-260C. On this my 3rd Maule, I've tried every possible tailwheel maintenance tip and trick that over 6 A&Ps, myself included, could conceive. No help. Still significant shimmy that scrubs the tire down.

I've had one of these cool dual fork solid 6in tailwheels on both Pitts and Eagles and they do quite well. The weight is less than either Maule's or Scott's. BTW, these are the ones in the Spruce Catalog. Anyone successful with a 337/Fld Appr. for a tailwheel?

Jud

[a64pilot]

I've seen one for a Scott 3200. I'm sure you know that finally there is an STC available for a Maule for the Alaska Bushweel. I feel sure that the standard tailwheel is very similar to the Scott 3200.
If you want to try for a field approval, I have a number for someone down in Moultrie that may be able to help.
Ive given up on the Maule tailwheel myself. I can stop it from shimmying, but it's a temporary fix. In a few landings it's back.

[MauleWacko]

[maules.com]

Airplanes used to have skids at the back to keep the rudder from scraping on the ground.
If anybody tries the excuse that a tailwheel shimmy caused an accident then that person is not properly trained or not properly handling the plane. The tailwheel can break off and you as pilot still have control.
Many owners complain of their tailwheel shimmy, however most of the time it is ithe wrong maintenance and lack of understanding the system.
How is it that I can bash around on rough terrain and not have shimmy problems.
There is a drawing in the maint. manual showing the parts.
The friction dept. should be bone dry of grease but I see the majority with grease in there. The wrong grease with the advent of warmer days will allow that wrong grease to migrate from the bearing dept. to the anti shimmy friction dept. There should be drag on the swivel so that when the rudder is moved, the tailwheel lags somewhat.
All attach bolts should be tight along with the rudder horn bolts.
The preload on the bearings is a distinctly different adjustment from the friction adjustment.
Tyre pressure should be 50psi
The tailwheel does not cause an accident any more than "the aircraft ran out of fuel" Truth is, the pilot did it .

Sorry, but another pet peeve.

[Kirk]

Jeremy,

What grease would you recommend for warm weather? Now that I read your last post, I realize I am seeing more shimmy in the summer. Getting ready to annual mine in a few weeks and it will be pulled apart then.

I printed out a copy of one of your posts on tailwheel tuning from way back and mine has been pretty good since adhering to it.

Thanks very much for the info!

Kirk

[a64pilot]

What has worked for mine is use very little grease, The bearings don't move much, except when it shimmys and I believe the grease is there more for corrosion protection than lubrication, so a little is all it takes. A little bird told me that high temperature automotive grease meant for disk brake vehicles is the ticket, but of course that's for cars and not airplanes. Crank the friction up by removing a shim if necessary. I've heard it said that old man Maule built his tailwheel upside down. Although that makes perfect sense, I don't know how to turn it right-side up. Check ALL bolts that have anything to do with either the tail wheel or tail wheel spring, rudder control horn etc. That shimmying will loosen things. Keep the tail wheel tire pressure up high. If mine get's to the point it even looks a little low, then it's way too low.
When everythings perfect then mine will only shimmy if it's set off by something like an expasion crack in asphalt or a similar bump, but it will subside on it's on fairly quickly. If everything is not perfect, then once it starts, it must hit a resonance frequency, because away it goes and the only thing that usually will stop it is to lighten the tail, something that I'm not entirely comfortable doing especially in a strong crosswind.
Now mine is an 83 model with apparently a past history of off airport landings that may have over time decreased the tail spring arc, so part of my problem may not be the tailwheel, but it is manifested there.
It seems however that whenever you get around other Maule drivers that the issue of tailwheel shimmy is brought up, and invarably there is someone that had that problem until they put a Scott on it.
I have also heard, but not verified myself that the Scott is hard to "break" out and annoying for that. (this is called rumor mongering)

[Lowflybye]

Between my father-in-law and myself we have put almost 200 hours on our Maule in the last 9 months and shimmy has not been a problem. We have the original Maule tailwheel. A few things that we do to maintain our tailwheel...

- 1) 60lbs or better tire pressure
- 2) Friction area is free of grease
- 3) Steering springs and chains are free of slack and in good shape
- 4) Castor Axle centerline is 15 - 20 degrees positive angle ***This is important*** The axle angle must not be vertical; it must be forward of vertical and never aft of vertical.

Corrected from the previous photo...this is a more accurate picture and description


As Jeremy noted, the tailwheel is not a reason for a bent aircraft...for those who have never landed with only one steering spring attached let me tell you that it feels as though the tail is ripping itself off the aircraft. It will get your attention very quickly and the tailwheel will shimmy worse than you can ever imagine, but the aircraft is still very much controllable.

Be easy on the tailwheel, it is basically there to keep the aircraft from dragging its ass on the ground. They are not designed to take the punishment of hard landings like the mains are designed to do. They are tough, but they have their limits.

[Green Hornet]

I installed the Alaskan Bush Tailwheel and shimmy is a thing of the past. Undoubtedly the best decision I have made in connection with shimmy and I tried many suggestions at some expense.

[Rocketman]

...for those who have never landed with only one steering spring attached let me tell you that it feels as though the tail is ripping itself off the aircraft. It will get your attention very quickly and the tailwheel will shimmy worse than you can ever imagine, but the aircraft is still very much controllable.

Be easy on the tailwheel, it is basically there to keep the aircraft from dragging its ass on the ground. They are not designed to take the punishment of hard landings like the mains are designed to do. They are tough, but they have their limits.

Down here in the South we'd say "Das a fak jack"

[taildragger]

When I bought my M5 the previous owner was having the shimmy problem also. It is the Maule tailwheel. He installed new tire. new leaf springs and steering springs and still had it. I followed Jeremy's advice from previous posts. Just needs a good cleaning and reassembly and keep the grease out of the friction area. 70 hours later it will only start a little shimmy once in a great while if you hit some cracks on asphalt. Spare the grease on the reassembly.

Scott

[UP-M5]

i have a scott 3200 and it has been shimmy free- except for occations when loaded heavily WITH my tailwheel ski installed (landing on pavement). the ski seemed to add just the right weight to induce a shimmy every now and then.
but after installing a new heavy duty tailwheel spring from ABW it is completely shimmy free. the angle of my t/w head was incorrect due to a sagging old spring and i was getting the "shopping cart effect".

[YELLOWMAULE]

I'll have to second what Ryan said to a certain degree.
I too went to a Scott (Long story) The Maule TW had shimmy (Sometimes violently) as has the Scott. They would both caster 360 degrees on TD.
I still run the Scott and once in a while it will shimmy. I too changed to the ABW tail spring which is huge help and find that if the shimmy shows, it needs to be cleaned. This is a major component of your landing gear and one that gets the bulk of the abuse. It only takes 2-3 hours to strip it down, clean, lube and reassemble. Never a shimmy after that. I usually have to do it every 50-60 hours, several times a year. If it shows, get the tail up, unload the TW and let it down again. I have flown other A/C with thet TW shimmy too. It's not exclusive to Maule but does seem more predominant no matter what the TW used.

[a64pilot]

The unusual thing is that different aircraft will either have or not have a shimmy problem. Different aircraft of the same model, that is.

[UP-M5]

after a violent shimmy session you should check your t/w tire. there is a very good chance that it did some damage to the chords which may only be visible by looking at the inside of the tire.
sometimes the tire will have a "pregnant" spot bulging out of it, other times it is invisible. but the chords come loose and chafe thru the tube on your next landing.
just something to watch out for.
it's never happened on my maule, but it happens every time on our 185's.

[maules.com]

The narrow Maule tailspring on a relatively heavy plane has a tendency to become weakened after a time and it can 'roll' in it's fastenings, which will lead to oscillations of the spring and thus a reactionary oscillation in the swivelling tailwheel. If all is tight and the spring is the correct angle and the friction set correctly and grease FREE---no shimmy.