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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).
Calculations for Spectre Matrix heat dissipation and critical air temperature based on test bed figures.

Identifier  ExFiles\Box 149a\2\  scan0261
Date  6th November 1935
  
(Appendix - Sheet 1)
HS{Lord Ernest Hives - Chair}/Std.14/KW.6.11.35.

Calculations for SpectreCodename for Phantom III Matrix.

From test bed figures, heat to be dissipated at 85 m.p.h. full throttle = 8100 B.T.U's/min.

From test figures, at 85 m.p.h., dissipation of Mark V 84 m.m. matrix block (taking untinned block figures as most reliable)= 66.5 B.T.U's/min/°C. diff. temp. between air and water inlet temps. for a 2 sq.' block.

If H = heat dissipated/min.
& Δt = °C. temp. difference between inlet air and water
A = frontal area of SpectreCodename for Phantom III matrix in sq.'.

∴ H/Δt = 66.5A/2
H = 8100
A = 601/144

∴ Δt = (2 x 8100 x 144) / (66.5 x 601) = 58.5°C.

∴ In limiting case where water inlet = 100°C.
air inlet = critical air temp. = 100 - 58.5
= 41.5°C.

(Note: Critical air temp. = "air temp. to boil").
  
  


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