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).
Calculation for total head under a bonnet, with a note regarding pressure tests conducted in France on a Spectre bonnet.
| Identifier | ExFiles\Box 87\1\ scan0177 | |
| Date | 7th November 1935 | |
| (Appendix - Sheet 6) Hs{Lord Ernest Hives - Chair}/Std.14/KW.7.11.35. This sheet not sent out- Total head under bonnet = .40 + .26 = .66 "H₂O NOTE: G.W.H. carried out tests in France to ascertain pressure under SpectreCodename for Phantom III bonnet. We attach a sheet giving his results (Sheet 7) The figure which he obtained at 84 m.p.h. (Marston Mark V 84 m.m. matrix) was .67 "H₂O.{Mr Oldham} | ||