Differences in old vs new Barnett plates

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I have a set of Barnett plates I have had with my Commando for the last thirty years.

Differences in old vs new Barnett plates


Have always run it the old school way with 3 bronze and 2 Barnetts in the stack. The old Barnetts showed negligible wear when measuring the stack vs the new ones I put in several years ago after my rebuild. No issues, other than the bronze plates completely ate up the clutch centre.

Differences in old vs new Barnett plates


The old plates are this style

Differences in old vs new Barnett plates


New Barnett plates are this style

Differences in old vs new Barnett plates


Does anyone know if there is any difference in the friction material vis a vis the old style plates?
 
I don't think you would want to lick the old ones.

The new ones are little different to the Surflex plates in beveldrive Ducati's with the band narrowed to reduce surface speed from the inner to outer, less material made for less slippage, the NZ peso's give a good size comparison.
It would not surprise me if the 30 year old ones have asbestos content ?
 
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I don't think you would want to lick the old ones.

The new ones are little different to the Surflex plates in beveldrive Ducati's with the band narrowed to reduce surface speed from the inner to outer, less material made for less slippage, the NZ peso's give a good size comparison.
It would not surprise me if the 30 year old ones have asbestos content ?
Yeah, I can understand the slippage thing and had thought of that.

I wouldn't lick the new ones either.
 
I don’t know the answer to your question Gortnipper, but FWIW I have only ever used the newer type and they’ve been perfect.
I have never had a slip problem with this setup. Nor a sticking problem. I have been very happy with it.

Other threads got me to wondering about the materials.

And other things may change...
 
No idea what the materials are. It seems that Kevlar is a popular material now.

http://www.tribco.com/wetclutch.php

The article below states that adding grooves [or adding more of them] aids in allowing the lubricant to carry away more heat.

https://link.springer.com/referenceworkentry/10.1007/978-0-387-92897-5_811

Edit
Two more interesting articles on wet clutch design & materials

https://www.protecfriction.com/wet-friction-plates

https://www.stle.org/files/TLTArchives/2020/08_August/Lubrication_Fundamentals.aspx
 
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I've have the same Barnett clutch (old style) in my 73 Mk1 since 1985 , not a problem with it.
 
The Barnett plates I have had in my MK3 for over 10 years have been faultless, they never gum up and they always release and hook up with no slip. I have some tricks to set them up.

They are the same as what I get from them now. No problem in wet or belt drive set ups.

The OEM "bronze" plates were always gumming up and needing cleaning.
 
I have a set of Barnett plates I have had with my Commando for the last thirty years.

View attachment 79464

Have always run it the old school way with 3 bronze and 2 Barnetts in the stack. The old Barnetts showed negligible wear when measuring the stack vs the new ones I put in several years ago after my rebuild. No issues, other than the bronze plates completely ate up the clutch centre.

View attachment 79465

The old plates are this style

View attachment 79466

New Barnett plates are this style

View attachment 91137

Does anyone know if there is any difference in the friction material vis a vis the old style plates?
So you have owned your Commando for 30 years and in 2016 you removed the clutch stack for the first time....hmmm
Bill gave you the answer ...you know YOUR old school way ?
Am I missing something.....or what ?
 

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Narrow band of friction material has nothing to do with reducing speed from the inner to outer, the outer dia of the friction material is the same dia as an original plate and this will travel at the same speed. If you placed the ban of friction material nearer to the centre it would then have less speed. I'm sure those who work in the helicopter industry will explain more about it.
 
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