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).
Tests conducted on a Phantom II semi-expanding carburetter, focusing on intake silencer design and efficiency.
| Identifier | ExFiles\Box 13\4\ 04-page063 | |
| Date | 3rd November 1932 | |
| To Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} " Hc/Lid.{A. J. Lidsey} 3.11.32. TESTS ON P.II. SEMI-EXPANDING CARB. (Cont'd). Continuing our tests on Phantom II semi-expanding carburetter on 19-EX, we fitted a large air intake alongside the induction pipe, with an adjustable tuning chamber, still maintaining the small silencer which was so good on 20-EX. After trying various sizes of tuning chamber we found a position which gave us absolutely 100% silencing efficiency on 19-EX. We then attempted to move the first tuning chamber we made A from its original position, and incorporate it in the new silencer as per sketch - i.e to C [Diagram showing three chambers, A, B, and C] Diagram annotations: - Chamber C: 4", 5.625", TUNING CHAMBER, 30 1/4" HOLES - Chamber A: 2.625", AIR INTAKE - Chamber B: 9.5", 2.431", TUNING CHAMBER, 2 ROWS OF 10 - 1/2" HOLES - Arrow from A to C: THIS CHAMBER TRANSFERRED TO TOP SILENCER IN POSITION C and we finally found a position where we could claim 90% efficiency. We then made another silencer of similar shape but of large capacities, the outer tube being 5 3/4" diameter inside. The first tests were made with an intake pipe 2.513" inside diameter, and we obtained the maximum silencing efficiency with the front tuning chamber 10 1/4" long and the rear chamber 3 1/4" long. The next tests were made with an intake pipe 2.687" inside diameter and the best position was found to be :- Front tuning chamber 8" long and the rear chamber 2 1/4" long. These three silencers now require testing on the Unit bed for power losses. Hs{Lord Ernest Hives - Chair}/G.H. Whyman. [Signature] | ||