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New Shimmy Dampners

ok. My turn. Experienced a shimmy on roll-out today.

Going after this in this order

- replace the bushings on the nose scissors. Will get the service kit from Jim
- I already have the new shimmy damper - will install this as well. Why wait.


Fair ?
Anything else i am missing ..
 
Moazzam, those two items were all it took for me.
 
alim said:
ok. My turn. Experienced a shimmy on roll-out today.

Going after this in this order

- replace the bushings on the nose scissors. Will get the service kit from Jim
- I already have the new shimmy damper - will install this as well. Why wait.


Fair ?
Anything else i am missing ..
Click to expand...

Confirm proper nose wheel inflation pressure and balance. Although the bushings and inflation should fix it.
 
So during my Annual, Pre 44N trip, the day my IA came over to my hanger to 'Inspect' after I had opened all my panels, we both spotted 5606 on the front of the shimmy damper. Now it was the 1st 82 ^ day since ? 2018 and the plane was 'probably still recovering' from last winter's Polar Vortex Super Freeze. Obviously with the 44N 'Event' coming up I was concerned and ordered a Shimmy Damper kit from Aerodyme along with a new T0-360 air filter.

So once we wrapped up the Annual (having received the Aerodyme pkg) (Kit on the freshly refurbed baggage shelf) and I did my 'Post Maintenance and Pre 44N @ the patch (extended to over the Tree Farm (8NM) test flight. I was particularly focused on the Nose Gear behavior.
No issues with Take Off Roll or Landing.

No issues with Landings at ABE, 44N & HWY return.
Once again supports the theory that 'If you have the repair kit, you won't need it'.
Happy to have it 'Just in Case'!

Moazzam, keep us posted!
 
Sherman said:
So during my Annual, Pre 44N trip, the day my IA came over to my hanger to 'Inspect' after I had opened all my panels, we both spotted 5606 on the front of the shimmy damper. Now it was the 1st 82 ^ day since ? 2018 and the plane was 'probably still recovering' from last winter's Polar Vortex Super Freeze. Obviously with the 44N 'Event' coming up I was concerned and ordered a Shimmy Damper kit from Aerodyme along with a new T0-360 air filter.

So once we wrapped up the Annual (having received the Aerodyme pkg) (Kit on the freshly refurbed baggage shelf) and I did my 'Post Maintenance and Pre 44N @ the patch (extended to over the Tree Farm (8NM) test flight. I was particularly focused on the Nose Gear behavior.
No issues with Take Off Roll or Landing.

No issues with Landings at ABE, 44N & HWY return.
Once again supports the theory that 'If you have the repair kit, you won't need it'.
Happy to have it 'Just in Case'!

Moazzam, keep us posted!
Click to expand...

It was a good flight. Was doing my IPC.

Did 1 x GPS approach on autopilot
Did 1 x ILS approach on autopilot
Did 1 x GPS approach flown by hand.

our backup Vaccuum, gyro failed during the flight. Non-event.

Landing was perfect until plane slowed down to 30 knots and then gave a nose shimmy.

Will call Jim on monday to source parts


good weekend ..
 
I have the first batch of Jim’s shimmy dampeners on 44W. Prior owner got it as a alpha tester. Had shimmy develop last year and did the bushing/bolt kit, all gone. And the shimmy dampener still great. We are so fortunate to have Jim taking care of the fleet! Dan Dawson 4944W
 
Check:

Torque knee bushings.
Drag brace bushings.
Trunnion attach bushings.
Steering cable tensions.
Nose wheel bearings.
Nose wheel condition and inflation.
Steering rigging.

Yes, please install the new damper. Continuing to run an old tired damper "that is still OK" will increase wear at the attach lug on the strut collar. This is non-recoverable without replacing the collar, and diminishes lifetime performance of the new damper when you do install it. There are very few original dampers (even on 114B/TC) that are still operating at more than 30% of spec hydraulic damping.

Jim
 
The shimmy damper is downstream from the torque-link so replacing it will do very little (as long as its serviced properly) if your torque-link bushings are worn out.

The most common problem is the AP not understanding the proper sequence in replacing the torque-link bushings, so after 3 landings they're blown out again and the shimmy is back.
 
carllee said:
The most common problem is the AP not understanding the proper sequence in replacing the torque-link bushings, so after 3 landings they're blown out again and the shimmy is back.
Click to expand...

So Carl. WHAT SEQUENCE DO YOU RECOMMEND if one is replacing the Torque Link Bushings?
 
Most AP's just replace the bushings, pat you on the po-po and send you on your way. 3 landings later the bushings are shot again and you have a shimmy again. The torque link needs to be removed from the airplane, and the center bolt and thrust bushing needs to be replaced first. The thickness of the thrust bushing is critical and can only be properly determined with the entire torque link off of the plane. The inside surfaces of the upper and lower torque links must be perfectly parallel when fully extended and fully compressed. If they're not, they will bind, destroy your brand new bearings, and your shimmy will return. It may be necessary to add a washer, or use a thinner thrust bushing to get the upper and lower perfectly aligned (use a metal bar, or wide steal straight edge). Be sure to re-install the right side up. They are different, top and bottom.
 
Finally got to hangar again.
Didn't get a chance to fly but did get to check a few things



1) hadnt checked nose tire pressure since Feb. Found it sitting around 34. Pumped it back up to 50. That likely did it,


2) i did check play in the torque links.
Real snug at the bottom - not much play at all.
Medium at the knee - couid only get play in the bolts - not the knee itself.
And i could get about 1/8" inch play at the top - horizontal. No twisting motion.

What does good look like ?

Posting video :

https://youtu.be/3ZrEOl8K3cU
 
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Yup 50# in the nose tire probably will remove 1 more possible issue.
Nice video.

Per my Text, Joel & I just had this discussion Tuesday. You want no twisting. (YOU HAVE NONE)

Bolts tight but loose. NO or absolutely minimal ( 1/16") play horizontally. (Obviously we want no binding or friction on Nose wheel vertical action. MAYBE you could get one more super thin washer in there, maybe not. Worth exploring, what I plan to do on a rainy day.

In Jim's AN4 to AN5 Nose Bushing Upgrade kit, He included super thin washers you usually can't find - say in 'Home Depot, Lowes, True Value, Ace' -Aviation Department ailse. Even my Aviation Maintenance shop didn't have that thin. So do have some spares from Jim's kit. Plan to see what thin washers I have in my 'AN hardware Compartments Box drawers. Hope right AN size washers. If not will contact Jim. Know Jim has a kit. Last time new bolts/washers/Nuts was Aug 17 Annual. Joel thought I was fine. His exactly the same. Shimmy Damper Mounting attachment Area also. 91GM same as 2HT. Mental relief as we know Joel really uses his TC.
 
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Come on, give it a real wiggle! When you set the nose of a 3000 lb airplane on the runway at 75 KIAS, it's a bit more than a "two finger wiggle".
Your link is way too loose at the top.
 
jrichards said:
Come on, give it a real wiggle! When you set the nose of a 3000 lb airplane on the runway at 75 KIAS, it's a bit more than a "two finger wiggle".
Your link is way too loose at the top.
Click to expand...

Thanks for confirming.
i'll get the top taken care of and replace the shimmy damper while i am at it ..
 
Stuck in Prescott, got horrible shimmy on roll out and aborted. Then got sever shack just trying to taxi. Jim I’ll need a new dampener overnighted to me if possible. I have the scissor kit of yours as well so I’ll install both. I’m gonna send ya an email.
 
As many above recommended, we began our attempt to solve weak ground steering and a severe shimmy problem by applying Aerodyme's torque link kit and shimmy damper kit. Our torque link was clearly slightly loose - applying the kit squared everything up nicely. We used the bolts, washers and nuts from the shimmy damper kit to tighten up its relation to the nose gear, but we did not actually rebuild the shimmy damper as it was providing a nice smooth resistance. Doing these two things MAGICALLY fixed both our weak steering control and the shimmy went completely away.

Thanks much to Jim and Martine at Aerodyme! The kits are great.
 
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I did a second landing after my initial shimmy - got the same. Didn't magically get better. It didnt matter that the second landing was a greaser.
Shimmy kicked in below 30 kts as before.

I am on the schedule to get the bushings replaced and the dampner replaced this week - shop was all backed up
 
alim said:
I did a second landing after my initial shimmy - got the same. Didn't magically get better. It didnt matter that the second landing was a greaser.
Shimmy kicked in below 30 kts as before.

I am on the schedule to get the bushings replaced and the dampner replaced this week - shop was all backed up
Click to expand...

Landing #3 today - flying to mechanic.

Greased the mains - held off the nosewheel off the runway - till it couldn't.
Didnt use any brakes. No weight on nosewheel. No Shimmy.

Taxied to my mech shop. Handed him Jim's Shimmy Dampner ; and the scissors service kit.

Will see him Friday ..to take plane back to homebase.
 
I'm interested Jim. - Gary Snyder 114TC
 
Gary - you can just call the Aerodyme and get the shimmy dampner. I believe they have them in stock.
 
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