Shock mounts - help!

[Marty_d]

Hi all, 

 

Would love to get some advice and possibly leads on where to source these parts.

 

I'm designing the engine mount that connects to the Rotax ring mount.  At the point where the EM is bolted to the RM, it requires rubber shock mounts to isolate engine vibration from the frame.

 

Rotax installation manual shows Lord J-3608 rubber shock mounts used, with cup washers -

 

 

This seems similar to the original 701 setup which you can purchase from Zenith (unfortunately at quite a high price) - pictures of someone's setup below, which is what I'm trying to duplicate:

 

 

Trouble is I can't find any mention anywhere of the dimensions of the Lord J-3608 shock mounts, or how much thickness you need in the internal ring which separates the two, or what size / where to source the cup washers that are needed either end, or how long the internal tube needs to be (ie how much shorter than the entire assembly so the rubber has room to compress), or what torque to put on those bolts, etc etc.  

 

Anyone got any ideas???

 

Alternatively, does anyone know of a crashed aircraft (any type) which has the 4 rubber/cup/steel mount fittings, which I could buy and weld into my own mount?

 

Thanks!

 

Cheers, Marty

 

 

 

[djpacro]

Seems like a common mount https://www.aircraftspruce.com/catalog/eppages/lordenginemountscessna_07-01131.php

 

You could email Lord for the dimensions.

 

 

[trike1]

Have a look online at the Mackay rubber products catalogue.133 pages———gotta be something that will do the job

 

 

[Yenn]

I have looked quickly at Aircraft Spruce catalogue and didn’t see that number. Why not try Lord themselves? Failing that any manufacturer who uses Rotax engines.

 

 

[Marty_d]

I have looked quickly at Aircraft Spruce catalogue and didn’t see that number. 

Yeah they're not that easy to find.

 

While looking at that, this came up too... https://www.aircraftspruce.com/catalog/eppages/lycbushing.php?recfer=14540 - at US $42.80 for a set of 8 it's about a quarter of the price of the Lord ones at $20.60 each.  Size is about the same at 39.7mm diameter on the big end.   I've asked Aircraft Spruce if they stock the 25mm cup washers for the small ends - if they do then I might order a set.

 

Have a look online at the Mackay rubber products catalogue.133 pages———gotta be something that will do the job

 

Thanks Trike - I'll have a look.

 

 

[Blueadventures]

Hi Marty May be worth a look at 'AMC  Mecanocaucho' product range.  It's a site that I saved their pdf.  Cheers Mike