Nose Wheel / Rudder alignment

[sfGnome]

I've noticed over the last little while that on both the take-off and landing roll, there's a period of time where the rudder and the nose wheel seem to be fighting for dominance and creating a bit of a shimmy dance. My first thoughts were that the two were out of alignment with each other, but then it occurred to me that under power on the take-off roll, I have to have a fair whack of right boot which is obviously not required on the power-off landing, so there's clearly no single alignment between the two that will suit both situations.

 

Is this a normal thing that I've just been too unobservant to notice before, or is there normally some compromise alignment that works well enough to not be noticeable? Or, more simply, should the rudder and nose wheel just line up visually? (I should note that the aircraft's line maintenance manual merely says how adjustments can be made without specifying what the adjustment should be).

 

 

[AVOCET]

What type of aircraft ?

 

 

[dazza 38]

I have never flown a sierra, but I have a fair bit of time in Tecnams. (Golf, Super echo, and Eaglette) I have never came across those symptoms.

 

 

[alf jessup]

Gnome,

 

Never noticed it on mine mate I usually keep some weight on the nose wheel until about 40 kts taking off until the rudder has good authority when not in a crosswind situation, on landing I keep the nose wheel off for as long as I can except when a decent amount of crosswind is around.

 

Correct about the amount of right boot on take off but easy now as I have about 70hrs in it since getting her and am quite used to it by now.

 

I got no complaints.

 

Alf

 

 

[dazza 38]

Gnome,Never noticed it on mine mate I usually keep some weight on the nose wheel until about 40 kts taking off until the rudder has good authority when not in a crosswind situation, on landing I keep the nose wheel off for as long as I can except when a decent amount of crosswind is around.

 

Correct about the amount of right boot on take off but easy now as I have about 70hrs in it since getting her and am quite used to it by now.

 

I got no complaints.

 

Alf

Alf's post is spot on. Tecnams have been bent before because peeps have raised the nose wheel off to early in the take off role. Even with full right rudder , they will head left unless enough airspeed has been reached to make the rudder effective. A bit off thread but important to mention all the same I think.

 

 

[David Isaac]

Not sure I like that characteristic. If you have enough elevator authority to lift the nose off there should be enough rudder authority to keep her straight at the speed at which the elevator lifts the nose off.

 

 

[Graham Pukallus]

Just a suggestion, but check the nose wheel bearings for correct adjustment/preload.

 

Had similar minor shimmy in my Savannah recently and just had its 100hourly completed which revealed the nose wheel bearings needed a slight adjustment.

 

The shimmy has since disappeared.

 

Graham Puk.

 

 

[dazza 38]

Not sure I like that characteristic. If you have enough elevator authority to lift the nose off there should be enough rudder authority to keep her straight at the speed at which the elevator lifts the nose off.

Hi David, I agree, but it isn't dangerous as long as the pilot is aware of it.IMO

 

 

[sfGnome]

Thanks for the comments. Yep, Avocet, I should have said that it was a Tecnam. I'll be having a closer look at the nosewheel structure I think. I've got about 70 landings in this craft, and I've only noticed it recently, so I guess something has changed. One of us has tapped it a bit hard, perhaps? :(