Strange rudder/nosewheel behavior

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injb

Pre-takeoff checklist
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jb
Today I had something odd with the rudder in the 172 I'm training in. The wind was blowing from the south, around 10 kts. We were taxiing east, and I kept drifting off the line to the right (into the wind). It took pretty much full left rudder to get back and stay on the line. I told my instructor and he took over. He experienced the same thing. The rudder itself appeared to be deflecting normally.

Neither of us had any idea what caused this. We took off and flew normally with no issues (although it's hard to say for certain that the rudder was normal in flight because it was very bumpy anyway. )

Anyone ever experience something like this? Any idea what caused it?
 
Was the wind from the right pushing the tail to left, and therefore the nose to the right? (Weathervaning)
 
Sounds like weathervaning but it's not usually so severe with only 10 knots of wind. Perhaps the nose strut was pumped up with air making it more difficult to turn the nosewheel. Less likely, nosewheel steering mechanism/bungee(s) broken. Try turning the nosewheel with the towbar and see if the rudder moves.
 
Was it cold? I had a similar issue with a brake dragging on one wheel from older brake fluid that had absorbed a lot of water which froze. Dragging the brake a bit to heat it up while taxing cleared it up.
 
I bet it's weathervaning. With my plane (free-castoring nose wheel), the winds typical at my airport necessitate a little right brake on taxi back to the hangar, so the right brakes get more of a workout and need to be re-lined sooner.
 
It shouldn't take full rudder deflection to combat a 10-kt crosswind.
Probably a high-time 172 with worn-out steering bungees. Those are the two tubes that extend out of the belly and attach to the nose strut steering collar. They have springs in them that get tired and soft. Those springs are being worked constantly in flight, since the nosewheel's centering cam engages on liftoff and holds the nosewheel straight ahead while the rudder system still moves against those springs.

Or the whole rudder system is misrigged. Lost count a long time ago of the airplanes I find with that system way out of rig. Another common failure is a broken rudder bar spring that results in the other spring pulling the rudder off-center, making the pilot have to hold constant pressure on one pedal to keep the ball centered.
 
Release the parking brake.

Did it do the same thing after landing..??
 
After landing, I thought the problem was the other way around, i.e. we were still being pushed into the wind and the right rudder seemed weaker. My instructor had a quick look and he didn't think it was as bad. I'm guessing that the weathervaing thing is what was happening, and that the wind report was just wrong. It was extremely windy at pattern altitude (definitely more than 10 kts) and I assumed that was just different because of the altitude, but the whole thing makes more sense if they were just wrong about the wind.
 
Don't forget that Cessna utilizes the highly-sophisticated bungee cord steering mechanism. Its strength is often over-estimated. A 10-kt direct x-wind will take a lot of pedal to correct on the ground.
If your pedals are not enough, you gotta employ differential brakes to help with steering.
 
I've always hated taxiing Cessnas, maybe the ones I've rented have been old and abused, but it seems any type of wind pretty much requires full rudder and then some brakes. And this isn't just one crappy plane I rented once, I think all the 172s I've ever rented were crap to taxi and had a monster shimmy on the nose after landing

The PA-28 line is an absolute dream to taxi compared to the Skyhawks.. it's like you are on train tracks, so much more solid through and through. The free castoring nose wheels, like Cirrus has, seems to track nice once you have around 10-12 knots GS. It's really just the Skyhawks that seem to dance around while taxiing

^sorry @injb not much help but that seems pretty typical to all the Skyhawks I've rented
 
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