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).
Suggestions for improving aero engine electrical systems to fulfill Air Ministry obligations for radio installations.
| Identifier | ExFiles\Box 163\2\ img015 | |
| Date | 18th November 1932 | |
| -2- Hs{Lord Ernest Hives - Chair}/Wst.2/MA.18.11.32. Contd. wrong because, the presence of these earthed cables and earthed fittings in close proximity to the high tension terminals would produce considerable ionisation inside the hood producing flash overs. A much better scheme is to take the cables in separately and secure the braiding of each cable to the distributor screen by the union and nut method as in aero practice. Ventilation should also be provided in this distributor screen by means of copper gauze covered windows. It is also observed that the low tension terminal has not been screened on the distributor. This should be screened and also the ignition feed wire from the battery. To make a satisfactory job of this ignition distributor screening it would be preferable to cast lugs on the distributor aluminium base and secure the screen by means of screws to the lugs. on the present arrangement it is possible for the screen and wires to move relative to the distributor action of engine vibration etc. (3) Wiring Tubes. It should be instructed that the inside of the tube be cleaned from enamel and also where the clips make contact on the tube and on the cylinder head. (4) H.T. Terminals. The existing terminals to R.31181 have now been superseded in aero work by the more recently designed screw on terminal to DES.1552 - this is a distinct advantage over the other. (5) Dynamo. we think it will also be found necessary to prevent disturbance from the dynamo commutator E.M.F. ripples transmitted from the dynamo terminals along the wires. On most cars where screening has been fitted such as the Flying Squad cars at Scotland Yard and Kaye Don's 20/25, it has been found necessary to introduce a choke in the dynamo circuit and a condenser across the main brushes or terminals. From the point of view of fire risk it is essential that the external bonding of the screens and the cables be effectively carried out. These suggestions are representative of the problems which have had to be tackled on our aero engines in the past to fulfill Air Ministry obligations as a result of prolonged experience in flight with radio installations. Howst | ||