7A Nose Gear swivel "sticks"

[hecilopter]

For some reason while taxiing, my nose wheel seems to "ratchet" around turns rather than being smooth. I took off the front of the wheelpant cover and raised the nose to pull on the wheel from side to side. It still seems to have the correct breakout force, but it is not smooth.

I added grease to the fitting in the front hoping to smooth it out. I put about 15 pumps of grease in and it still didn't come out anywhere? Where is the grease going?

Has anyone else experienced this? Is my breakout force too much?

I have 204 hours on the plane now, I have not had to adjust the breakout force yet. I have also NEVER had any wheel shimmy. My nose wheel tire has 30lb of air in it.

Thanks

 

[kevinh]

I added grease to the fitting in the front hoping to smooth it out. I put about 15 pumps of grease in and it still didn't come out anywhere? Where is the grease going?

There is a a LOT of empty space in that weldament. When I initially built the plane I was really surprised at how many pumps were needed to fill up that area. But when the annual came I only had to add like 1-2 pumps to get fresh grease coming out, so not much leaked out over the year.

 

[dan]

When "initially" greasing something, I don't rely on the grease fitting to circulate grease fully. Usually I'll take it apart, at least enough to grease the mating surfaces completely.

Also, if you're just greasing from the fitting, are you swinging the fork around while you do it to circulate the grease?

 

[Chickenlips]

A correctly adjusted nose wheel should experience some "breakout sticky-ness" in steering rotation as a result of the frictional tension between the belleville washers. This "breakout" could result in what you describe but I would imagine you should check your "breakout" force.

The "sticky-ness" of the belleville washers, when properly adjusted, helps reduce any shimmy tendencies of the nose wheel. However, what you describe seems a little 'excessive'.

You might lubricate the interior surfaces of the belleville washers a bit while your greasing the nose axle and checking the breakout force. They may be rubbing together in a dry condition, particularly if you have been in a lot of rain.

 

[AlexPeterson]

You are just sensing the change between what is called static friction and dynamic friction. Mine has done that for 800 hours. The static friction is a little higher than the dynamic, so it builds up a little force, "breaks" free, moves a little, stops, builds up force again and so on and so forth.

Sounds normal.

 

[hecilopter]

Thanks for replies

It seems to be a little better now that I added A LOT more grease. You are right, that empty space holds a ton. It still does it as Alex described but I guess this is more "normal" since I'm not the only one

Rusty