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 cold starting tests on a Derby Hot Throttle system.
| Identifier | ExFiles\Box 50\3\ Scan252 | |
| Date | 7th December 1922 | |
| Y4305 December 7, 1922. To: Messrs. Belnap Olley Nadin Bagnall Southern Hulley C Mr. Platford From: Mr. Caswell Re Tests of Derby Hot Throttle The following cold starting tests were made with two chassis - one being fitted with the Derby hot throttle and boilers and pilot jet; the other being a standard Springfield Chassis, Mr. Platford witnessing numbers 1, 2 and 4. No. 1 - Derby Hot Throttle and Derby Boiler Car left in yard all night No water in engine Pilot jet unscrewed two complete turns Air temperature 27º F Engine started in 5 seconds and ran on jet alone for few seconds, then slowly opened throttle and partly closed jet. After running 60 seconds, it was possible to close pilot jet and run on carburetter alone, which we did for 15 seconds more. After stopping the engine, wet gas was seen running down exhaust valve stems of 4th and 5th cylinders, and the piston tops and spark plugs were very wet. No. 2 - Derby Hot Throttle and Boiler Car left in yard all night No water in engine Drains to boilers plugged up Pilot jet same setting as No. 1 Air temperature 37º F After running under similar conditions to No. 1 for same length of time valve stems and pistons and plugs were wet with gas. No. 3 - Derby Hot Throttle and Boiler Same conditions, etc., as No. 1 Air temperature 32º F Pilot jet set to 1 1/2 turn - other tests 2 turns After running 1 1/4 minutes, the pistons, plugs and valve stems were found to be dripping with wet gas. | ||