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).
Results of various experimental tests on the power unit, engine mountings, and chassis features to resolve issues like 'booms' and vibrations.
| Identifier | ExFiles\Box 137\4\ scan0277 | |
| Date | 21th March 1931 guessed | |
| Experimental Tests Carried Out. Power Unit. (1) Various dia. Crankshafts. (2) Various crank dampers. (3) Balance weights. (4) Front flywheel plate only. (5) Complete flywheel with aluminium rear half. (6) Flywheel with tail bearing. (A side note reads: None of these produced any result.) (7) Car towed with push rods removed. None of these produced any result. (8) Pistons and con rods removed. Car towed. Booms 90% cured. (9) As (8) but with balance weights. No appreciable difference. (10) Cast iron crankcase & cyl. block in one on 25 HP. No effect on booms. Engine Mounting. (1) Single point in front. 3 rear feet (Sandwich). Slight improvement, but very little. (2) Single point in rear. 2 front feet (Sandwich). Some bodies a complete cure. Other bodies no difference at all. (3) As (2) but with rubber under rear support. Vibrations reduced. Booms unaffected. (4) 4 Diabolo rubber feet. Complete cure on some bodies, no difference on others. (5) "Diamond" engine mounting. Unit supported solidly fore and aft at single points. Torque taken through very soft rubbers. Complete cure on all cars so far tried. Chassis Features. (1) Dash isolated. In some cases slight improvement. | ||