Leaf spring deflection

[John Billard 1Participant @johnbillard1]

My 5" Super Claud build continues with the tender complete and the current work includes the driving wheel springs. I propose to use the approach favoured by Doug Hewson using spring steel suitably tempered.

Reference to the works drawings refers to 14 plates that scale to just over 3.6 inches across the hanger brackets. The question is how to arrive at the suitable deflection. I am a long way from weighing the engine!

It would be useful to know the anticipated axle weight of such an engine. The Martin Evans Claud is very much based on a Maid of Kent though I am following the original more closely with scale driving wheels and valves under the cylinders – a GER speciality. So my engine might be slightly heavier.

I used this approach for the tender but found that it was necessary to slot the spring plates to achieve the correct loaded deflection.

Kind regards

John B

[John Billard 1Participant @johnbillard1]

[duncan webster 1Participant @duncanwebster1]

Within the past few years there was an article in ME about loco springing, and I seem to remember it was a 4-4-0. Tubal Cain's book on springs might help with the design/rate etc. **LINK**

as you have found, a strictly scale spring will be far too stiff

[John Billard 1Participant @johnbillard1]

Thank you Duncan. The link shows the publication unavailable though I am sure it will be sold elsewhere e.g. TEE Publishing. I think too that was serialised in MODEL ENGINEER a while ago.

Kind regards

John B

[Harry WilkesParticipant @harrywilkes58467]

Comes up on a different link link   

also ebay

H

Edited By Harry Wilkes on 24/04/2019 11:42:59

[John Billard 1Participant @johnbillard1]

A good friend has put his Maid of Kent on the bathroom scales for me.

It weighs 8 stone 9 lbs.

Best wishes

John B

[Phil H1Participant @philh196021]

That's more than my wife!!! Is that the tender only or the engine and tender?

Phil H

[duncan webster 1Participant @duncanwebster1]

John, I've found the ME article which deals with a 'typical' 5"g 4-4-0. It's in issue 4470 from 2013. As it was interesting I scanned it, so if you pm me your e-mail address I'll send you a copy

[John Billard 1Participant @johnbillard1]

The Tender is an extra 3 st 3 lbs, Phil.

Thank you Duncan. That is very kind of you. I have that in my archive – just couldn't remember where. I must look at the internet index more closely.

While I am on, I believe that I sorted out the valve gear calculation for the Claud, the subject of earlier discussion, but I will put that on another thread.

With kind regards

John B

[John PurdyParticipant @johnpurdy78347]

John

Tubal Cain's series on spring design in ME ran  from issue #3783 vol. 157 1986 to # 3807 vol. 159 1987 for a total of 10 installments.  

John

Edited By John Purdy on 27/04/2019 18:07:38

[John Billard 1Participant @johnbillard1]

That's very helpful, John.

Many thanks

John

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