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 comparison test report between 'Discol' and 'Petrol' fuels on chassis 49DB.
| Identifier | WestWitteringFiles\L\2July1924-September1924\ Scan120 | |
| Date | 25th July 1924 | |
| CHASSIS No 49DB{Donald Bastow - Suspensions} "DISCOL" FUEL TESTS. CONSUMPTION. (AVERAGE RESULTS GIVEN OF SIX TESTS). TIME TAKEN TO CONSUME 1 PINT AT 20 M.P.H. - DISCOL: 4 MINS. 53 SECS, PETROL: 5 MINS. 9 SECS. MILAGE PER GALLON. - DISCOL: 13., PETROL: 13.8. HILL CLIMBING. ASCENT OF PISTERN HILL ON TOP GEAR WITH 10 M.P.H. START AT RAILINGS. (AVERAGE RESULTS GIVEN OF THREE TESTS). DISCOL: MAXIMUM SPEED 36.3 M.P.H, MINIMUM SPEED 22.3 M.P.H, TIME TAKEN TO ASCEND 1 MIN. 11 SECS. PETROL: MAXIMUM SPEED 36.3 M.P.H, MINIMUM SPEED 22.6 M.P.H, TIME TAKEN TO ASCEND 1 MIN. 10 SECS. ACCELERATION. TIME GIVEN BEING THAT NECESSARY TO ACCELERATE BETWEEN THE SPEEDS ON THE LEFT, THE THROTTLE BEING WIDE OPEN ALL THE TIME. (AVERAGE RESULTS GIVEN OF THREE TESTS). TOP GEAR. ACCELERATION | DISCOL (WEAK/NORMAL/STRONG) | PETROL (WEAK/NORMAL/STRONG) 10 MPH - 20 MPH | 6 SECS / 5 SECS / 5 SECS | 6.8 SECS / 4.8 SECS / 5.2 SECS 20 MPH - 30 MPH | 6 " / 5 " / 5 " | 10.3 " / 5 " / 5 " 30 MPH - 40 MPH | 8 " / 6 " / 6.5 " | 20 " / 6 " / 6.8 " 40 MPH - 50 MPH | 11.5 " / 9 " / 9.5 " | - / 8.5 " / 10.5 " N.B. THE READINGS FOR "WEAK" AND "STRONG" ARE GIVEN TO ILLUSTRATE THE LESSER SUSCEPTIBILITY TO CARBURATION OF DISCOL COMPARED WITH PETROL. SLOW RUNNING. (TOP GEAR) DISCOL = 4 M.P.H. PETROL = 4 M.P.H. MAXIMUM SPEED. DISCOL = 63 M.P.H. PETROL = 65 M.P.H. CARBURATION. SPECIFIC GRAVITY: DISCOL - .84 PETROL (SHELL-MEX) - .75. CARBURETTOR LEVEL: OWING TO THE GREATER DENSITY OF 'DISCOL', THE FLOAT REQUIRES LOADING TO THE EXTENT OF .33oz TO MAINTAIN THE SAME LEVEL IN THE JETS. CARBURETTOR JETS: FOR RUNNING ON "DISCOL" THE JETS OF THE STANDARD 40/50 H.P. CARBURETTOR REQUIRE STRENGTHENING AS FOLLOWS: LOW SPEED = 11 NOTCHES. HIGH SPEED = 11 NOTCHES. STARTING FROM COLD: DISCOL REQUIRES A VERY STRONG MIXTURE FOR STARTING FROM COLD, AND THE PERFORMANCE OF THE CAR IS VERY POOR UNTIL THE ENGINE GETS THOROUGHLY WARMED UP. DETONATION. Discol PREVENTS DETONATION. COACHWORK. Discol IS INJURIOUS TO PAINTWORK. | ||