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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Proposed changes to the track width for the 40/50 'X' series chassis.

Identifier  ExFiles\Box 66a\4\  scan0188
Date  12th May 1925
  
To CJ. from R.{Sir Henry Royce}
c. to BJ. Wor.{Arthur Wormald - General Works Manager}
c. to RG.{Mr Rowledge} LHS.{Lord Herbert Scott}
c. to Hs.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer}
c. to DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer}
c. to PN.{Mr Northey}

Y8250

R2/M12.5.25.

RE. 40/50 AT 'X' SERIES. X. 8770
X. 8250
Y8350

Thank you for your memo. CJ10/E11.5.25.

The track we propose will be no detriment to Colonial cars because if the ruts are measured it will be found that we should be safer by being rather greater than the present 40/50 standard. Most farm carts are considerably over this gauge. The fault with automobiles is that the track is generally too narrow, never too wide. In this respect we are following the practice of other makers, who are generally in their big cars slightly wider than we are, as will be seen from the following :-

Daimler 60" Delage 59"
Renault 57" Panhard 58"
Hispano 57 1/2" Hudson 58" There are many others.

Regarding the quantity of new parts the list looks rather formidable because of the many advantages to be derived from the change of the back axle.

It will be remembered that we have made a considerable move towards improving the water boiling situation because the new engine heats less water per HP. the radiator has grown (and is still growing) in height say altogether 10%, and the fan is much more efficient in size, easier to drive owing to its increased efficiency, and therefore the situation is considerably improved, and personally I do not think the increased width of the radiator so great a necessity as the back axle advantages specified, and if the alteration to the track is not adopted there will be considerably less work because we should not change the front axle forging at 'X' series, but leave it until a later move.

The advantage to the heating system with the increased width would probably be in the neighbourhood of 7 1/2%, the actual dimensions being only 4%. It would not be worth while delaying the improvements to the chassis past the 'X' series for this change in width.

The track would therefore be made 57" parallel, and consist of frame, cross members, springs, and back axle, and propeller shaf.t

R.{Sir Henry Royce}
  
  


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