Comparison table of engine data for different rotor diameters and supercharger types.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan025 | |
| Date | 15th December 1930 guessed | |
| - 2 - | Engine Data. | 10.25" Diameter Rotor. | 9.5" Diameter Rotor. | Existing Standard | |---|---|---|---|---|---|---| | | "H" F.S. | "H" F.S. | "H" M.S. | "H" F.S. | "H" M.S. | "H". M.S. | | Comp Ratio. | 5.5/1 | 5.5/1 | 5.5/1 | 5.5/1 | 5.5/1 | 5.5/1 | | Rated Power | 750 H.P. | 750 H.P. | 835 H.P. | 750 H.P. | 816 H.P. | 825 H.P. | | Rated Altitude | 10,000 ft. | 8,500 ft | - | 9,000 ft. | - | - | | Rated Boost | + .68"Hg. | + .68" Hg. | - | + 1.00"Hg. | - | - | | "Take Off" Boost. | + 1.75 lbs/sq.in. | + 1.75 lbs/sq.in. | - | + 1.75 lbs/sq.in. | - | - | | "Take Off" R.P.M. | 1720 | 1745 | - | 1750 | - | - | | "Take Off" BHP. | 675 | 685 | - | 680 | - | + | | Normal R.P.M. | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | | Camshafts. | E.33096 | E.33096 | E.33096 | E.33096 | E.33096 | E.31788 | | S/C. Gear Ratio. | 8.8/1 | 8.3/1. | 5.5/1 | 9.5/1 | 5.5/1 | 5.5/1. | | S/C. Choke Dia. | 2.95" | 2.95" | 2.95" | 2.95" | 2.95" | 2.70" | | Ground L.P. | 676 | 680 | 835 | 683 | 816 | 825. | | Enc. BHP. | 608 | 612 | 752 | 614 | 733 | 742. | | Rotor Tip Speed. | 762 ft/sec. | 742 ft/sec. | 476 ft/sec. | 761 ft/sec. | 442 ft/sec. | 476 ft/sec. | | Throttle Move | 68º | 68º | 68º | 68º | 68º | 58º | | Detonation. | O.K. | O.K. | O.K. | O.K. | O.K. | More than other "H" M.S. column 3 & 5. contd. | | ||
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).