Scott 3200 high speed shimmy

[8474]

Any comments on this....

https://www.aircraftspruce.com/catalog/ ... ey=1234807

Not approved for the Scott, and, when the spring bottoms out it'll bend your rudder bellcrank.

And yet there is a guy who posted on the reviews that it stopped the shimmy on his 3200.....

[8474]

So if you enter Scott springs in ACS, it comes up with this:
https://www.aircraftspruce.com/catalog/ ... ey=5036176

But if you look at the installation specs they call for 25-30 lbs tension, but everything I have read is no tension on a 3200.....confused.

[8451]

I'm catching up on the rest of the posts here but in the meantime, here are the pictures I took of my installation.

My 8000 series serial number I believe should have a straight spring; currently installed is a single bend. My IA also had a double bend. The spring we replaced was a very fatigued single bend. There may have (are?) 170 springs mixed in, not entirely sure of the difference other than thickness. At the time and based on what was available we elected to use the good condition single bend as it appeared to put the king pin at the correct angle.

I should note that when I had my first severe shimmy incident (that cost me a tire and tube) with the old spring, when I jacked the plane it was discovered that there was a lot of rotational play around the bolt holding the tailwheel assembly to the spring. On the new spring we used an additional shim plate to hold it in and torqued it down; I admit I haven't jacked the plane to check if it held yet.

[8451]

One more picture:

[2356]

Not that it would affect the shimmy but the springs should attach directly to the rudder.

[6643]

So if you enter Scott springs in ACS, it comes up with this:
https://www.aircraftspruce.com/catalog/ ... ey=5036176

But if you look at the installation specs they call for 25-30 lbs tension, but everything I have read is no tension on a 3200.....confused.

Those springs are for the 2000, not the 3200. the 2000 relies on tension to lock the steering arms. The 3200 springs are much bigger in diameter.
https://www.univair.com/cessna/cessna-1 ... ts-cessna/

The eyebolts are not called for on the tailwheel end.

The kingpin looks like it is still tilted forward at the top. The weight of the plane tends to push the tailwheel to the side.

Are the rudder pedals, rudder, and tailwheel all centered at the same time?

The scrubbing on the tire is probably due to the shimmy.

[8474]

Hi John,

So ACS does not sell the correct springs for the 3200, is that correct?

[8451]

The eyebolts are not called for on the tailwheel end.

The kingpin looks like it is still tilted forward at the top. The weight of the plane tends to push the tailwheel to the side.

Are the rudder pedals, rudder, and tailwheel all centered at the same time?

The scrubbing on the tire is probably due to the shimmy.

The eye bolts are an easy fix; I’ll admit the tailwheel came with them installed and I didn’t really have reason to question it.

As far as tilt, is forward or rearward tilt proper? The Alaska bushwheel article lists rearward but Neal’s article lists forward. If rearward is proper do you think trying out the double bend spring is worth a shot despite the serial number mismatch?

I’ll check on the rigging next time I’m out there.

[6597]

If rearward is proper do you think trying out the double bend spring is worth a shot despite the serial number mismatch?

I would suggest against putting double bend springs on an early serial number frame, that was an issue when I got my plane. Poor previous maintenance. I dropped the tail a full 3" by installing the proper single bend spring. I couldn't make a decent 3-point landing either (well, still can't but my odds have improved immensely).

[7698]

If rearward is proper do you think trying out the double bend spring is worth a shot despite the serial number mismatch?

I would suggest against putting double bend springs on an early serial number frame, that was an issue when I got my plane. Poor previous maintenance. I dropped the tail a full 3" by installing the proper single bend spring. I couldn't make a decent 3-point landing either (well, still can't but my odds have improved immensely).

I'm interested in the spring dilema... The double bend spring is correct for the Scott 3200 wheel, however even though the tailwheel is in the correct position as documented by Scott, its not pretty.. So im interested in your thoughts about fitting the single bend spring set...

Yes; the aircraft sits in a much better position, but the tailwheel is leaning slightly forward. To me that would assist with holding the wheel straight.

When I bought VM she had a single bend spring and 3200, but the wheel had been fixed with a steel wedge slid in-between the wheel and spring in order to pull the wheel more upright. (The bolt was bent when I took this out!)

Personally I would prefer to refit a single bend spring, but Im interested in if you have found any issues with your set up.