Rubber Discs for Shock Strut

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Lucky Dog

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Here is one I am doing for nose gear. Zenith has similar for 701. Donut I made by pouring 50 duro shore A urethane. 3D printed the mold.
This is an example of the best application of the concept. I'd suggest using more elements if possible. Travel is usually 25% of the stack before preloading.
 

PTAirco

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This might be worth doing some tests on. The flat discs or cylinders are very hard to compress after the initial load; as mentioned before, the spring rate goes way up beyond a certain load.

Compression spring
 

Stuffengineer

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You can mix and match durometer to create a variable rate. Aluminum disks between elements allow rubber to move. Nice thing with rubber is that it provides dampening.
 

karmarepair

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You can mix and match durometer to create a variable rate. Aluminum disks between elements allow rubber to move. Nice thing with rubber is that it provides dampening.
The friction between the rubber and the separator disks ALSO provides damping. Rubber has SOME damping of its own due to hysteresis, but frankly not much. Some gear designs of this type use "cup" separators to confine the rubber, while others, including the earliest, used FLAT separator elements, NOT bonded to the rubber. I think the flat separators make more sense, me, but they should be larger in diameter than the rubber elements. Pazmany has drawings of several examples.
 

cluttonfred

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What about something like this rubber shock bump stop? They will fit over a 5/8" diameter tube and are 3" long. There are many other sizes and hardness ratings available.

bump stop.jpg
 

bronkk

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Could something here work:
 

Rob de Bie

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The friction between the rubber and the separator disks ALSO provides damping. Rubber has SOME damping of its own due to hysteresis, but frankly not much. Some gear designs of this type use "cup" separators to confine the rubber, while others, including the earliest, used FLAT separator elements, NOT bonded to the rubber. I think the flat separators make more sense, me, but they should be larger in diameter than the rubber elements. Pazmany has drawings of several examples.
I seem to remember that the friction between the rubber discs and the stationary outer tube created most of the damping. I think this is how the DH Mosquito landing gear worked, among others.

Rob
 

Lendo

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Locally and I assume would be available anywhere, we have Urethane in a Plastic tube of many and various shore densities and Diameters. The plastic tube holds the Urethane rigid and it's cut in a Metal Lathe with a very sharp bit, the inner hole diameter is done the same manner. Could be the cheapest and easiest method. I have some off-cuts/ remnants and cutting bits given to me to play with.
George
 

karmarepair

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Locally and I assume would be available anywhere, we have Urethane in a Plastic tube of many and various shore densities and Diameters. The plastic tube holds the Urethane rigid and it's cut in a Metal Lathe with a very sharp bit, the inner hole diameter is done the same manner.
Polyurethane Rod Stock | Custom Sizes | Online Store | Fast Delivery - Universal Urethane 40A shore MIGHT work. I think any harder than that would be too stiff.

Back to neoprene, limited sizes, but don't have to chew them out of sheet or rod McMaster-Carr
 
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Geraldc

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These are sold as rubber bungs for carboys for brewing.
No idea of suitability or specifications.
1631236458622.png
 

Mad MAC

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Last i need something similar for a project, we made a mold from mdf & dowel, and got the local rubber supply to do a pour of silicone with it.
 

Rob de Bie

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Another thing I remember from studying rubber properties: it was advised to load and unload the rubber product a few times. The properties change over the first few loadings, until it settles to more or less constant properties.

Rob
 
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