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).
Modifications for the India 3 crankshaft damper and timing gear spring drive.
| Identifier | WestWitteringFiles\Q\July1927-September1927\ Scan101 | |
| Date | 7th September 1927 | |
| ORIGINAL FROM E.{Mr Elliott - Chief Engineer} C. to HS.{Lord Ernest Hives - Chair} INDIA 3. CRANKSHAFT DAMPER AND TIMING GEAR SPRING DRIVE. We send you herewith drawing LeC. 2457. shewing the above. This is to be used for India 3. in conjunction with the larger crankshaft, written instructions for which latter have already been sent. To accommodate LeC. 2457. it is necessary to move the fan drive .250 further forward than India 2. This appears to be quite possible from an inspection of the 20HP chassis here, both the distances between the fan and radiator, and the fan and fan belt, being capable of reduction. The driving springs in this design give the same torque as India 2. but the damping is somewhat less, in the ratio of 6 to 5., since although the same number of damping springs and the same load is employed, the radius of the friction discs is somewhat less. For the friction discs Mr. Royce prefers fibre in preference to bakelite or substances of a gummy nature. It is realised that fibre is hygrostatic, and changes its thickness to a surprising extent with the absorption of water. This design however allows of considerable expansion, and moreover the fibre runs in a bath of oil instead of having the oil centrifugally flung off it, and therefore stands a better chance of protection against moisture when the engine is standing for a long periods. We propose to incorporate in India 3. alterations to the mounting of the idler gear, and should be glad to hear of any further features in connection with making the timing gear more silent, which it is considered should receive attention. E.{Mr Elliott - Chief Engineer} | ||