Tail Wheel Assembly?

I have the Bell fork and am assembling it with the tire, spring, etc. I have a couple questions:

1) What torque is used for the large nut that holds the yoke to the assembly?
2) On the bolt that goes through the wheel, is it OK to have 3 washers on one side of the wheel and 2 on the other side? Three will not fit on both sides without springing the yoke out. I tightened the castle nut and the yoke clamps the washers without them spinning.
3) Related to #2, how freely should the wheel spin? It rolls when I spin it by hand but only about one revolution before it stops. Want to make sure the nut isn't too tight or too loose.

Thanks,

Hi John,

I don't have a Bell tailwheel (I have a JD air parts setup), however I noticed that no one had responded to you, so I thought I should have a crack at it. When dealing with situations where a rotating part is encapsulated within a structure, generally it is important to have the retaining bolt/nut tensioned in accordance with guidelines specified in AC_43.13-1B (table 7-1, pg 7-9) which is available free from the FAA site. The only time you would use a lesser torque is in a low loaded application that does not have a bearing, like a cable connection to a heater valve control arm or something similar, where the bolt is designed to spin in the hole. In addition to of course the diameter and thread pitch of the bolt, the torque needs to be applied according to what nut is provided with the assembly. If you are unsure, just go onto aircraftpsruce.com and type "nut" in the search bar, then look through the resulting images until you have found one that looks the same. Generally thinner nuts are the "shear" type, as they are only designed to take load in shear, and these will have lower torquing values than the thicker regular type nuts. If you tighten the nut to the specified torque and you are getting binding, it means that your axle spacing is not correct. This is also a common issue on control surfaces. You do not want to alleviate this by reducing the torque value, as this may lead to the bolt spinning in the hole, when what you want the wheel assembly spinning on the bearing. Thus the way to rectify this is to adjust your spacing. This can be done by adding shims of the required diameter and thickness. If an entire washer is too much, then shims of the lesser thickness can be purchased from McMaster Carr.
I hope this helps.
Tom.

Thanks for the info Tom; an extra thin shim may be the way to go here.

John,
As far as the washers are concerned, have you tried using two thin (-L) washers in place of one of the regular thicker washers?
If you are using three regular washers on one side, and two regular washers on the other side (such as AN960-416), you could try two regular -416 washers on each side, and one -416L ON on each side and you would have the same thickness you had before. You've probably already done this but that wasn't clear.

TW

I have a Bell TW fork also and its a little wider than Vans the reason I went with Bell is it gives more clearance for pot holes as my airport has lots of them with tie downs .I think mine came with brass bushings to make up for it being wider than Vans I ran the Vans wheel for two years and went through two sets of bearings the Vans rubber tire is great with long wear but the bearings are shopping cart and not many shopping carts are rated at 60mph.At OSH this year I purchased Flyboys TW with sealed bearings and installed and the difference was night and day do yourself a favor try one.
Bob

John, see my answers embedded next to your questions.

No offense to Tom, but just tighten that top nut all the way down. When it bottoms out, stop wrenching. It's not necessary to torque this nut (gasp!). Same for the axle nut. It is by clearance, not torque. You'll understand when you assemble the parts.

Vince

pilot28906 said:

I have the Bell fork and am assembling it with the tire, spring, etc. I have a couple questions:

1) What torque is used for the large nut that holds the yoke to the assembly?

SNUG that nut all the way down onto the fork. If anything binds, then something is wrong with the fit. Investigate and correct it.

2) On the bolt that goes through the wheel, is it OK to have 3 washers on one side of the wheel and 2 on the other side? Three will not fit on both sides without springing the yoke out. I tightened the castle nut and the yoke clamps the washers without them spinning.

Yes, that is OK. Or find some 960-616L washers (thin washers) if it bothers you.


3) Related to #2, how freely should the wheel spin? It rolls when I spin it by hand but only about one revolution before it stops. Want to make sure the nut isn't too tight or too loose.

Are you using the stock Van's tire? If so, it may have too much preload.
Loosen the axle nut a bit. Other tires are similar, but some have bushings to prevent overloading the wheel bearings. Regardless, it is OK to tighten the axle nut by hand, or by wrench until the slack is just barely removed, and even back off .001" or so to the loose side. Loose is better than too tight. A torque wrench is not required, or even desired here, either.

Thanks,

Click to expand...

No worries Vince. As I pointed out, I don't actually have a Bell tail-wheel assembly. I was just providing info on a general rule when it comes to bearing installations, and suspected there may be some intricacies for this specific application. I just wanted to get the ball rolling on a response to the OP's queries, and was hoping you guys with a little more experience in this area would chime in.
Tom.

Thanks All

Thanks all for the great info. I will loosen the wheel bolt some and will put a thin washer in.

Also, I noticed the grease fitting on the Van's wheel has no spring loaded ball in it. Was this left out on purpose? Do you just squirt some grease in?

Thanks again.

pilot28906 said:

Also, I noticed the grease fitting on the Van's wheel has no spring loaded ball in it. Was this left out on purpose? Do you just squirt some grease in?

Thanks again.

Click to expand...

Don't use the grease fitting, it will only result in a mess. Replace the bearings when they get noisy, they are inexpensive.

Thanks Sam.

Sam Buchanan said:

Don't use the grease fitting, it will only result in a mess. Replace the bearings when they get noisy, they are inexpensive.

Click to expand...

Even better, just install a better tire with sealed bearings, better tread, and lighter weight. No more mess and reasonably priced!

Here's the options:

http://www.flyboyaccessories.com/category-s/23.htm

Either of the 6" tires are a great upgrade for most RVs. The 4" is an option for lighter aircraft.