New donuts ?

[mike28w]

Hi guys,

  

  I did some research and realized that my'63 M20C had new shock discs ( donuts) in 1996,  Probably time to replace,

 

  Will I actually notice a softer ride ( on the ground) ??

 

  Opinions and suggestions appreciated......thanks, mike

[ryoder]

Get new ones and sell me yours. Mine are from 65

[Cruiser]

Simple test for replacement is to jack the aircraft and without waiting too long, 5 minutes or so maximum, grasp the donuts and try to rotate them in place. If they are loose or can be moved (rotated) even a little, they should be replaced. 

[Hank]

I noticed smoother taxiing and softer landings. I also,noticed the blessed silence after raising the gear on my first flight with new pucks in January, on the OH-WV border. Old pucks, in cold weather, often leave one or both wheels dangling a couple of inches or more, and the system squalls something awful. And your plane flies slow . . . Not any more!!

[bradp]

Had my first flight with new pucks on Sunday. I would have otherwise had a less than stellar plant on the runway that felt oh so smooth.

Sent from my iPhone using Tapatalk

[HRM]

Hi guys,

  

  I did some research and realized that my'63 M20C had new shock discs ( donuts) in 1996,  Probably time to replace,

 

  Will I actually notice a softer ride ( on the ground) ??

 

  Opinions and suggestions appreciated......thanks, mike

 

Much depends on how the airplane has been flown, the weather conditions and how long the disks were exposed to the rubber killers: sunlight, heat and ozone.

 

One might argue that hard landings rejuvenate the disks (at least that is my excuse).

 

The very best way to know if you need disks is to have a salty Mooney A&P tell you that "it is time".

 

After the disks are replaced all of your landings will be squeakers and the old farts lined up at the FBO will be nodding and clucking with approval.

 

[ArtVandelay]

After the disks are replaced all of your landings will be squeakers and the old farts lined up at the FBO will be nodding and clucking with approval.

Actually it's the opposite, the old dead disks are like an under inflated basketball where the new disks will have more rebound.

In my case the AP said the undercarriage wasn't fully closing and that was due to the 18 year old disks, so they can be considered a speed mod

[rbridges]

As my donuts get older, I just take more air out of the tires to make the ride smoother.

[ArtVandelay]

As my donuts get older, I just take more air out of the tires to make the ride smoother.

I assume your joking, but in case you're not: old donuts result in a lower ride, as do deflated tires, combo that with a bump or hard landing and you have a recipe for a prop strike.

[rbridges]

I assume your joking, but in case you're not: old donuts result in a lower ride, as do deflated tires, combo that with a bump or hard landing and you have a recipe for a prop strike.

Lol. Good point but I wasn't being serious.

[luv737s]

I not only got a better taxi ride and slightly smoother landings, those pucks are the only stress reducers for our wing tanks and might help prevent a leaky tank.

[Yetti]

Just get a better airport with better surfaced runways and taxi ways

[mike28w]

Just get a better airport with better surfaced runways and taxi ways

  Ouch...that touches a nerve as our local airport is planning to close next June-Oct. to replace our runway ......can't just land on the taxiway.  A summer of flying "shot to h*** " ...................

 

  I know this has nothing to do with donuts....just needed to rant.  

[Hank]

Why will they not let you land on the taxiway???

[Shadrach]

Hi guys,

I did some research and realized that my'63 M20C had new shock discs ( donuts) in 1996, Probably time to replace,

Will I actually notice a softer ride ( on the ground) ??

Opinions and suggestions appreciated......thanks, mike

Yes they will feel smoother in the same way that new close make you feel better looking! The more you spend the smoother you'll convince yourself they are! We're on our second set in 47 years. They still pass the jack test, the ride height test and are very plyable when I pull the nose wheel over the parking chalk. I have little faith that replacing would do anything for the firm ride. They weren't designed for smooth ground handling. They were designed to protect the airframe.

[mike28w]

Why will they not let you land on the taxiway???

  "They would have to fill out more paperwork....and they just can't spare the time"......

[mike28w]

Yes they will feel smoother in the same way that new close make you feel better looking! The more you spend the smoother you'll convince yourself they are! 

 

  Yeah, I've wondered about that....

[RobertGary1]

I believe the official test is to measure them. Replacement is based on how much they are squashed and visual condition of cracking.

 

-Robert

[Guest]

Get new ones and sell me yours. Mine are from 65

When you take out your 1965 shock discs drop them off with the Tampa Bay Lightenings, they need some new hockey pucks.

Clarence

[Shadrach]

There is a lot of original rubber in my airplane. All of the PC cans are as supple as can be at the young age of 47yrs. Our donuts are 25 yrs old. Prop clearence is within specs. The shock discs cannot be turned by hand when the plane is jacked.the gear moves up and rebounds nicely. No sign of cracking or rot. Why would I replace them?

[Andy95W]

Ross- sounds like you don't need to change your shock discs. Mine were similar at 20 years old and passed all the tests. I just finished a major tune up of my landing gear including replacement of all bushings and shock discs. Made a BIG and noticeable difference. More than I had expected. New bushings tightened up all of my linkages and the discs made it more "squishy" while taxiing.

[tony]

  Ouch...that touches a nerve as our local airport is planning to close next June-Oct. to replace our runway ......can't just land on the taxiway.  A summer of flying "shot to h*** " ...................

 

  I know this has nothing to do with donuts....just needed to rant.  

 

The airport I was at for a while closed their runway for a resurfacing project as well.  The airport did get a special permit from the FAA allowing the taxiway to be used as a temporary runway.  Now I realize not all taxiways are created equal but its worth a talk with the airport manager even if its going to require him to fill out ore paperwork. 

[Shadrach]

Ross- sounds like you don't need to change your shock discs. Mine were similar at 20 years old and passed all the tests. I just finished a major tune up of my landing gear including replacement of all bushings and shock discs. Made a BIG and noticeable difference. More than I had expected. New bushings tightened up all of my linkages and the discs made it more "squishy" while taxiing.

 

I am due for a rebuilt nose gear.  Over the last 8 years I've replaced the truss, installed an oversize bushing and replaced bits of linkages. I wish I had just installed a rebuilt unit when I did the truss.

[Hank]

Speaking of donuts, we went to a local mom & pop shop last Sunday. Their new donut is "bacon and maple," and it's delicious!! ☕️

[N601RX]

The airport I was at for a while closed their runway for a resurfacing project as well. The airport did get a special permit from the FAA allowing the taxiway to be used as a temporary runway. Now I realize not all taxiways are created equal but its worth a talk with the airport manager even if its going to require him to fill out ore paperwork.

Two years ago they had to close the north 1000 ft of our runway for some work. They left the south 2000 ft open they placed a row of sandbags and flashing lights at the point it was closed. There was a Notam in effect while the work was ongoing for a couple of months.