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Breakout force adjustment

Plummit

Plummit

Well Known Member
Since I am now the owner of a -10, can someone tell me how to adjust the nose wheel breakout force?

thanks

-Marc
 
Marc, I use a socket with an extension on the axle nut. Then I use a bathroom scale to push, so there's no damage to the wheelpant. Of course, it needs to be in the air.

Best,
 
Thanks Mike, I ordered the CD, but I still would like to know how to check the breakout force. A search of the web appears to indicate a fish scale attached to the axle. Do you measure the force to just start the caster action or move it to the stop?

Thanks

~Marc
 
Hi Pierre, the problem I have is that my -10 has non-standard wheel pants, so I have to remove at least the front half and maybe the back half too. There is no cut out to reach the axle nut,

regards

~Marc


pierre smith said:
Marc, I use a socket with an extension on the axle nut. Then I use a bathroom scale to push, so there's no damage to the wheelpant. Of course, it needs to be in the air.

Best,
Click to expand...
 
Plummit said:
Hi Pierre, the problem I have is that my -10 has non-standard wheel pants, so I have to remove at least the front half and maybe the back half too. There is no cut out to reach the axle nut,

regards

~Marc
Click to expand...

How do you tow the plane?
To answer your question:
To measure, you apply a specified torque (my memory is 25 pounds applied to the axle in the side to side direction). The nose wheel assembly should not move with less, but should move with more, than 25 lbs (again, going by memory). Obviously the nose wheel has to be off the ground for this measurement.
To adjust, remove the cotter pin from the large nut above the pivot axis, tighten (usually) or loosen as needed, replace the cotter pin.
 
I see the issue. Pierre meant that he applies the force to the large Allen head bolt used for the tow bar, not the axle nut.
 
Measure it just until it starts moving.
You do need to take the wheelpants off. Not a big deal, just take off the front half, then remove the two towbar blocks and just slide off the back half.
Here's what the manual says:

breakout_force.jpg


Plummit said:
Thanks Mike, I ordered the CD, but I still would like to know how to check the breakout force. A search of the web appears to indicate a fish scale attached to the axle. Do you measure the force to just start the caster action or move it to the stop?

Thanks

~Marc
Click to expand...
 
BobTurner said:
How do you tow the plane?
Click to expand...

Very carefully! Actually, I did get a Bogo bar with the plane but it connects to the two allen bolts that secure the wheel pant bracket to the fork. I assume this is the stock setup.

The wheel pant is a bear to remove and re-install. I pulled it off to see what I needed to do to attach my Power Tow. Of course I checked the tire pressure which was low, so I brought it up to 45psi.

I've read that having a low tire makes shimmy less likely but I've also read the opposite! I have felt a little shimmy on occasion so I felt I should check the nose gear pivot for proper tightness while I have the wheel pant off.

I still need to work out the raising of the nose and the fish scale, but I think I have it figured out now -with help from you guys!

regards

~Marc
 
The nose wheel fairing should be fairly easy to remove - you pull out the two large allen screws, and the ten or so #6 screws that hold the two halves together. The nose half comes free, and the rear half slides off the axle assembly. The metal bracket is permanently attached to the fairing. If this takes more than a couple of minutes, something isn't right.
 
aturner said:
The nose wheel fairing should be fairly easy to remove - you pull out the two large allen screws, and the ten or so #6 screws that hold the two halves together. The nose half comes free, and the rear half slides off the axle assembly. The metal bracket is permanently attached to the fairing. If this takes more than a couple of minutes, something isn't right.
Click to expand...

Yup, I took the front part off then removed all of the screws from the back of the fairing and then fought to remove it over the bracket! It will be much easier now, thanks! ;-(

~Marc
 
If you do need to tighten it, you will likely be between the cutouts on the castellated nut and the cotter pin won't work. Long story short, you might have to drill a new hole to allow passage of the cotter pin while maintaining the correct breakout force.

David
 
The other tell tale sign is having somebody look at the wheel pant while flying. If it isn't straight, it's too loose.

Many have set it up to be a couple pounds higher than the plans. The downside is that you may have to use a bit more braking to turn.

As previously mentioned, Murphy's Law will dictate that you'll have to drill new holes when you tighten the nut to the appropriate setting.

Also, don't assume the shimmy is the nose wheel. Some also experience a shimmy in the mains that sometimes occurs around 30kts. Several folks have taken video of the gear to determine which gear is the root cause of the shimmy.

I've been fortunate in the I've only had to tighten up the nose wheel after a year of flying, which is normal. I've not experiences any shimmy caused by the mains.
 
my experience

for what it's worth, I find the 'breakout' to be uneven. ( 9a )

if even a drop of oil leaves the engine room, it seems to run down the fork and lubricate the washer, thus reducing the friction.

if you want to 'check' the breakout, you can lift the nose wheel ( ballast the tail, or whatever works) and throw a strap around the pant in line with the axle.
pull on the strap ( 2" webbing works well) and you can check if your breakout has changed, without full disassembly of the pant.
No fish scale? put a block of wood across a bathroom scale, and push or pull on that. it's gonna be within a pound or two.

mine tends to be 28 lbs to starboard, and 25 to port for some reason....consistently.

just one reason that it's not that great a damper.
as others mentioned, it may not be the only source of shimmy; many seem to be fans of improving the bearing, tire balance etc.
 
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