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Proposal to standardise fixed dummy shutters on Bentley cars and design a new thermostatic by-pass system.


Identifier  ExFiles\Box 87\1\  scan0216
Date  22th February 1937
  
Y 1027

DA. {Bernard Day - Chassis Design} from Rm {William Robotham - Chief Engineer} /Std.
c. to Hs. {Lord Ernest Hives - Chair}

240

Rm {William Robotham - Chief Engineer} /Std2/R.22.2.37.

We think there is a strong possibility that we shall shortly be able to standardise fixed dummy shutters on Bentley cars in place of thermostatically controlled ones. This will effect a considerable saving in cost complication and rattles, but will necessitate a by-pass thermostat in the water system. Such a thermostat was designed, and has been run - LeC 3488 - but suffers from a number of disadvantages, chief of which are:-

(1) Expense - the whole assembly costs £2/10/-.

(2) Difficulty of obtaining consistent thermostat bellows of this size.

We think, therefore, that another design should be produced at once for a thermostatic by-pass system, with reduction of cost as the main objective - also that before such a design is produced the makers of thermostatic bellows, i.e., Messrs. Smith & Sons and the British Thermostatic Co. should be consulted as to the appropriate size and length of bellows to be used for our specified diameter of valve and a temperature range of 75°C to 85°C from full closed to full open.

The thermostat should be bought out as a complete unit (as per samples attached) and not assembled here - this is standard practice with other firms.

Finally, we think that we should try to dispense with any device for cutting off the by-pass flow when the water is not, by means of using the hot spot feed and return to pump as a by-pass line - feeding hotspots from thermostat body.

We should like you to produce a design incorporating these features at the earliest possible moment; if possible, it should be applicable to RR.Sch. 1045 (cheapened fan and water outlet) as we also hope to standardise this shortly.

Rm {William Robotham - Chief Engineer} /Std.
  
  
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).


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