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 engine cooling performance, heat dissipation, and critical air temperature.
Identifier | ExFiles\Box 149a\2\ scan0263 | |
Date | 6th November 1935 | |
(Appendix - Sheet 3) Since pressure difference ∝ v^1.8 and cooling ∝ v^.8 (both very nearly) if H₂ = cooling under car conditions and H₁ = cooling under rig conditions, H₂ = H₁ x { (2.580)/(2.990) * 1/1.8 }^.8 = .936 H₁ ∴ Actual dissipation figure for car using 84.m.m. Mark V matrix = 66.5 x .936 = 62.2 B.T.U's/min/°C. temp. diff. between inlet water and inlet air. ∴ As before H/Δt = (602 x 62.2) / (144 x 2) = 130.0 ∴ Δt = 8100 / 124.3 = 62.3 °C. ∴ Critical air temperature = 100 - Δ = 37.7°C. NOTE: Boiling has occurred under full throttle conditions in France with an air temperature of approx. 30 - 32°C. | ||