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Full Castoring Tail Wheel-All The Time

M

mbauer

Well Known Member
Hello,

In March 2017 purchased a flying RV-6. Unlike the builders who learn and understand what the systems do, I have to ask questions about issues.

Hopefully someone can help with an on-going problem:

My Tail Wheel is not working properly. It is not working when applying rudder inputs, in other words it is full castoring only.

Can someone give me a clue why from the photos?

Where to buy the parts needed as well?


Photo 1 is the overall type:
TW1_Copy.jpg


Photo 2 closeup of problem I think-looks like this should be sticking out to catch the arm from the rudder connection?
TW2_Copy.jpg


Photo 3 Different angle-shows a small piece that might be jamming it from sticking out?
TW3_Copy.jpg


Thank you for your help with my problem.

Best regards,
Mike Bauer
 
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The small part is almost certainly the "pawl" which is the locking pin. There is a spring which extends the pawl into a groove or notch in the tailwheel fork and locks it. You need to check that the pawl moves freely and that the spring has enough strength to seat the pawl in the locking mechanism. In addit.ion, the pawl can wear or develop a burr, and the detents in the grooved part of the locking mechanism can wear

Based on what I see, the assembly looks really dirty and the pawl isn't extending properly. You'd do well to disassemble it, clean it, lube it, and reassemble. If that doesn't take care of the problem, you're probably due some replacement parts.
 
You are correct. The plunger is stuck in, a common problem.
With the plunger in like it is, you can pull the whole tail wheel assembly down and out of the tube-housing. Just lift the tail and set the tail spring on a block of wood tall enough to drop the wheel. About a 50 pounds lift?
Then give it a good cleaning and free up the plunger. Then remove the plunger, inspect the spring and clean the cavity. Reassemble with a nice coating of clean grease. The plunger should engage the arm for normal steering, but extreme rudder inputs will release the tail wheel (via the cam slot) for full swivel. Once you pull forward and straighten out, a wiggle of the rudder pedals should re-engage the pin into the arm.
The tail wheel should be serviced annually, or more often if flying off a dirt strip.
Your picture shows a tail wheel that needs such service.
Always park the plane with the tail wheel in trail and the plunger engaged. Otherwise it might stick while parked for a prolonged period or in the winter.
 
Wow, that was quick.

Understand it works like I thought.

I've had three mechanics look at it, all greased it and said it was good to go. It would work for a landing or two then go back to free castoring.

Decided today to take it apart and look at it.

Main project today found me washing the whole outside, removing oil from the bottom and then using a car wash brush and car soap/wax cleaner to scrub the bugs away, used rain for the rinse cycle...

Thank you for all of your input!

Thank you for the links, hopefully just needs cleaned and serviced.

Planning to use some of my bicycle chain lube-designed not to attract dirt...Anybody try this or is there a preferred lube other than wheel bearing type grease?

It will be nice to have some steering; been using throttle and brakes to change direction/keep on center line.

Best regards,
Mike Bauer
 
I "lube" mine with anti-seize, found at any automotive parts store. Forget about using the zerk grease fitting. I've found it is basically useless and the added grease goes to where there is least resistance, which is right out of the top making a mess.

Three years now using anti-seize and servicing at the annual condition inspections, it looks and operates as it did the previous cleaning/lube/ condition inspection.
 
I have had the same problem over the years with my -8 and it can be very frustrating and at times dangerous.

A couple additional observations:

In my case, I removed the pawl (the pin) and chamfered the corners some. Both the pawl and the housing are steel and it helps with the ability to move in and out of the housing without getting caught up.

I RARELY use any type of lubrication for the pin itself and after much experimenting with different types of lube have found that this is the best policy for prolonged normal function. Lubrication attracts a lot of dirt back there and the space between the pawl and the housing is tight, not to mention that the spring is not terribly strong. I do lubricate the remainder of the tailwheel assembly, just not the pawl pin.

Finally, I leave the big top bolt holding the tailwheel assembly together snug but NOT tight. That also seems to make a big difference.


Hope this helps.

Jon
RV-8 N898JW 2004
 
Fire all 3 mechanics :D Just kidding

Take the time to take everything apart, clean it, heck put some paint on the parts (where paint is supposed to be) and get it restored to new condition. The one thing you want to make sure you do is to replace the $10 locking pin and the locking nut. You won't regret it. I do my tailwheel maintenance about every 25 hours.
 
Cleaned and Lubed!

Thanks to everyone!

Cleaned and lubed the whole assembly today. Pawl was stuck in the opening by a small piece of metal shaving.

Once cleaned and lubed put it back together, before adding the arm and the nut, decided to rotate the wheel to ensure it was nice and smooth.

Right off the bat, the weight of the wheel was enough to "shear" off a small sliver of the metal, looks like a brass liner or bearing surface.

Guess this is not normal!? Took everything back a part, remove the sliver and put it back together. Added the control arm, top washers and nut. Tightened the nut, but still have some play of the arm.

Guess I'll add the shim to my order; bought a new pawl and spring, plus some additional items, now thinking of getting the control arm with the tie-down loop.

Taxied out for takeoff, interesting to actually have some control with just rudder pedals!

Thanks to all for your help!

Best regards,
Mike Bauer
 
All of the above comments are valid, except:

"Finally, I leave the big top bolt holding the tailwheel assembly together snug but NOT tight. That also seems to make a big difference."

While that might not be a problem as long as the nyloc nut is sound, it isn't correct from the design standpoint.

The units are designed to have the large nut tightened normally, i.e. all the way down. There is clearance built into the parts to allow for normal operations.

If tightening the nut down binds the assembly, then the bottom bushing can be sanded or filed down slightly to give proper clearance. Conversely, if the stack is too loose, a shim washer will eliminate any up and down excess. Up and down play is much less of a problem.

These clearance problems are often the result of mixing different parts from different vendors, including us! Let's just say that there is variation in some of the original parts, plus wear, and dirt to allow for. A slightly loose fit is OK... AK-47 fit, not M-16, eh?

Some sort of lube is required to prevent corrosion of the steel parts. Even with lube, these parts do wear out. Replacement parts are cheap.
 
Lube Type?

vfrazier said:
All of the above comments are valid, except:

"Finally, I leave the big top bolt holding the tailwheel assembly together snug but NOT tight. That also seems to make a big difference."

While that might not be a problem as long as the nyloc nut is sound, it isn't correct from the design standpoint.

The units are designed to have the large nut tightened normally, i.e. all the way down. There is clearance built into the parts to allow for normal operations.

If tightening the nut down binds the assembly, then the bottom bushing can be sanded or filed down slightly to give proper clearance. Conversely, if the stack is too loose, a shim washer will eliminate any up and down excess. Up and down play is much less of a problem.

These clearance problems are often the result of mixing different parts from different vendors, including us! Let's just say that there is variation in some of the original parts, plus wear, and dirt to allow for. A slightly loose fit is OK... AK-47 fit, not M-16, eh?

Some sort of lube is required to prevent corrosion of the steel parts. Even with lube, these parts do wear out. Replacement parts are cheap.
Click to expand...

Hi Vince,

Kind of curious what would be a good lube to use?

I have some "Dry" Lube - Finish Line DRY Teflon Lube. A synthetic lube for bicycle chains. I like it because it is easy to clean, water doesn't wash it away and dirt is not attracted to it like other lubes. Being synthetic it doesn't freeze in the winter when I ride at -20 deg F up in the mountains (I go on snowmachine trails after they freeze).

I bought some parts from the Flyboys Accessories, Blake was very helpful with my purchase today!

Bought a shim as my arm is wobbly once tightened down. New nut, two each of the spring and pawl. Minimum cost to get this working correctly!

Best regards,
Mike Bauer
 
Tire

I purchased a new tailwheel from Flyboys @OSH this year installed it and what a difference that made from Vans tire.
Bob
 
mbauer said:
Hi Vince,

Kind of curious what would be a good lube to use?

I have some "Dry" Lube - Finish Line DRY Teflon Lube. A synthetic lube for bicycle chains. I like it because it is easy to clean, water doesn't wash it away and dirt is not attracted to it like other lubes. Being synthetic it doesn't freeze in the winter when I ride at -20 deg F up in the mountains (I go on snowmachine trails after they freeze).

I bought some parts from the Flyboys Accessories, Blake was very helpful with my purchase today!

Bought a shim as my arm is wobbly once tightened down. New nut, two each of the spring and pawl. Minimum cost to get this working correctly!

Best regards,
Mike Bauer
Click to expand...


Mike,

We've tried all sorts of lubes. All work and all need cleaning and re-lubing periodically because of the dirt they are exposed to.

YMMV.
Vince
 
Thank You!

After several weeks of constant rain and low ceilings, was able to take a test flight yesterday of the new parts from Flyboys.

Pretty sure the spring was the issue, would not pop back at all once inside the housing. New spring is beefier and longer! Old spring looks like it was from an ink pen...

Seems weird to be able to steer with just the rudders!

Thank you to all who helped!

Next is to find some touch up paint to fix a couple of areas.

Best regards,
Mike Bauer
 
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I would steer clear of those three mechanics. If they didn't know and couldn't work out its operation, I wouldn't let them near a perambulator.
 
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