Nose Wheel Snaps Over @ High Speed ?

[steve murray]

Today doing a descent, speed reached about 200 mph and all of a sudden I experienced a large amount of Yaw, took a fair amount of rudder pressure to get the ball centered again. This is the second time this has happened, both times during descent. I suspect the nose wheel is "broken free" over the friction and shifted to one side causing the yaw.


Once I slowed down to about 160 mph, I tried yawing with the rudder both left and right to correct but no joy, in correcting the ball out of center condition.

Landed without incident. ( kept the nose wheel off as long a possible). Tomorrow I will check the nose wheel break out force and adjust as necessary.

Anyone else experienced this?

Any thoughts on how to correct this in the air, kind of annoying to hold the extra rudder pressure until landing.

Steve

[Bill.Peyton]

Common problem. Happened to me also after about 10 hours. This is due to prop wash. Tighten up break out force on nose wheel. It almost can’t be too tight.

[rleffler]

You want to check the break out force periodically. If it gets too loose, the nose wheel will weather vane into the wind and when hit hits the runway, it may start porpoising side to side. The end result will be a huge tear in your wheel pant.

It happened to me a couple years ago, a week before my condition inspection. I had a couple weeks before OSH to order, build, and paint a new nose wheel pant.

The break out force had dropped to 16lbs. Even though it’s been flying for over seven years, I check it a couple times throughout the year. If it’s your firsts year of flying, I would check it quarterly.

[kiwipete]

This also happened on a -10 I was flight testing on a VNE dive. As others have said check the nose wheel breakout force.

[Fenderbean]

Would putting a small L bracket on both sides at the end of nose wheel cover prevent this? slight drag is used to prevent flutter as well.

[rvbuilder2002]

Originally Posted by Fenderbean

Would putting a small L bracket on both sides at the end of nose wheel cover prevent this? slight drag is used to prevent flutter as well.

The thing that prevents it is keeping the nose wheel fork breakout force adjusted to the recommended value.
If that is done, other remedies aren't needed.

[Fenderbean]

Originally Posted by rvbuilder2002

The thing that prevents it is keeping the nose wheel fork breakout force adjusted to the recommended value.
If that is done, other remedies aren't needed.

Understood, I just didnt know if it was a aerodynamic reason for the loosening.

[rvdave]

Although I’ve been adjusting break out force periodically it hasn’t been clear actually where to measure the breakout force from. Is it from the end of the wheel pant, end of the tire or middle of wheel pant? And what method are you using to measure?

[tom_AZ]

Originally Posted by rvbuilder2002

The thing that prevents it is keeping the nose wheel fork breakout force adjusted to the recommended value.
If that is done, other remedies aren't needed.

With apologies for a slight divergence from the OP.

What is the recommendation if the specified break-out force (26 lb) is between cotter pin slots? In one position, I measured break-out force at 19 lb. I don't recall the exact value at the next tighter position, but it was well above 30. I did check to make sure that the "stack" was right, e.g. that I hadn't inverted one of the belleville washers, but all was correct. I considered making a shim of some sort, but didn't want to create a second issue in the process of addressing the first, so I went with the lower value. I feel a bit of shimmy at about 35 KIAS, but not more than I've sensed in others' -10s. If the specified break-out force recommendation can't be set exactly, are there recommendations as to which side to err on, e.g. min/max limits?

[lr172]

Originally Posted by rvdave

Although I’ve been adjusting break out force periodically it hasn’t been clear actually where to measure the breakout force from. Is it from the end of the wheel pant, end of the tire or middle of wheel pant? And what method are you using to measure?

Its in the manual; The axle. I use a fish scale.