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Investigation into brake fade on a Phantom III (35-EX), detailing pedal movement measurements and their causes.


Identifier  ExFiles\Box 92\4\  scan0113
Date  21th November 1935
  
To E. {Mr Elliott - Chief Engineer}
c. to Wor. {Arthur Wormald - General Works Manager}
c. to GWH. {George W. Hancock - Head Chateauroux}
c. to By. {R.W. Bailey - Chief Engineer}
c. to Mx. {John H Maddocks - Chief Proving Officer}

X30Z

Hs {Lord Ernest Hives - Chair} /AFM. {Anthony F. Martindale} 17/KW.21.11.35.

Phantom III Brake Fade - 35-EX.

We have made a thorough investigation into the above trouble. The following sponge measurements have been made using, where necessary, a pedal load of 200 lbs. without servo, or 52 lbs. with servo, (which is the same thing) as occasion demanded.

| Reason for Pedal Movement | Movement of Pedal Inches |
|---|---|
| Minimum clearance between shoes and drum. | .91 |
| Sponge in rear drums, chiefly due to a drum expansion of .035" on dia. | 1.20 |
| Due to temperature difference of 80°C. between shoes and drum. | 0.75 |
| Total loss in drums - | 2.86 + | 2.86 |
| Slack in cables | .21 |
| Opening of servo | .82 |
| TOTAL LOSSES | 3.89 |

+ Total loss in Ph.II drums is only .98".
  
  
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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