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).
Performance graph for the WRAITH unit showing B.HP and B.M.E.P. vs R.P.M. under various test conditions.
| Identifier | ExFiles\Box 6\6\ 06-page263 | |
| Date | 9th August 1937 | |
| WRAITH UNIT W III 2 COMP. RATIO 6:1 CAMSHAFT I.W. SIB. (114°) SPEC NPS/CPI/VD. 2. 7. 37 ① OPEN EXHAUST. WRAITH ROCKERS ② 25/30 EXHAUST. SILENCER COMPLETE. VALVE LIFT .380 ③ AS ① BUT WITH 28/30 ROCKERS ④ AS ② VALVE LIFT .340 VALVE TIMING (-.020 CLEAR) IO 5° AT EO 40° BB IC 43° AB EC 2° BT{Capt. J. S. Burt - Engineer} (a) (.030 CLEAR) IO 11° AT EO 35° BB IC 33° AB EC 4° BT{Capt. J. S. Burt - Engineer} B.H.P. B.M.E.P. LB./SQ. IN. R.P.M 5.22 AUG 9 - 1937 | ||