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).
Power checks and performance tests on different engine nozzle configurations.
| Identifier | ExFiles\Box 179b\3\ img210 | |
| Date | 1st February 1933 | |
| -20- A power check (4e) was now taken and the power was found to have increased to 95.6 lbs/sq.in. A new R.R-Bosch nozzle in ball race steel and K.E.8 was made and heat treated by a new method and found to be free from cracks. The nozzle and needle when completed functioned well on the hand pump and in the engine gave a power figure of 94.8 lbs/sq.in. (test 4f). A standard Bosch nozzle had its spray holes lapped out with a wire and in a power check (test 4g) gave 95.6 lbs/sq.in. B.M.E.P. A standard R.R-Bosch nozzle in S/2NCR was tested in the engine (test 4j) and gave 86.8 lbs/sq.in. The holes were then cleaned out with a .010" dia. drill and the power measured (test 4j) was now 93.3 lbs/sq.in. These tests show very definitely that with clean nozzle holes, the power is of the order of 95 lbs/sq.in. and may be maintained without power drop if the injector system is in order. Since the power fell off from approximately 95 lbs/sq.in. to 90 lbs/sq.in. when the nozzle holes became reduced in diameter by a carbon deposit, it appeared possible that an increase in power might result if a nozzle was tested having holes larger than the standard .010" dia. Hence a nozzle was made having .0115" dia. holes. On test the power 92.7 lbs/sq.in. (test 4k) and specific consumption .506 lbs/BHP/Hr. Hence a nozzle hole either greater or less than .010" dia. gave a reduced power figure. At the conclusion of these tests the motoring losses were again measured and were plotted against speed in Fig.20. On the same diagram are plotted the motoring losses in C.I.1. It will be seen that at 3000 R.P.M. the losses are about 3 lbs/sq.in. M.E.P. greater in C.I.2 than in C.I.1. The tests concluded at this stage and hence the final power figure for C.I.2 is 95 lbs/sq.in. B.M.E.P. and specific consumption .480 lbs/BHP/Hr. Provided the nozzle holes are clear and the injector is properly cooled, this power is maintained. Allowing for the increase in the motoring losses in C.I.2 this is equivalent to 98 lbs/sq.in. B.M.E.P. in C.I.1 and is therefore between 3 & 4 lbs/sq.in. below the C.I.1 figure. | ||