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).
Failures in Goshawk ignition condenser connections due to high-frequency currents and manufacturing tolerances.
| Identifier | WestWitteringFiles\J\May1923\ Scan70 | |
| Date | 26th May 1923 | |
| To R.{Sir Henry Royce} from EFC. c.c. EY. E.{Mr Elliott - Chief Engineer} EFCB/T26.5.23. X.443D - RE GOSHAWK CONDENSER. ---------------------------- The present design of Goshawk ignition condenser connections requires great care in manufacture to ensure that these pressure connections shall remain sound enough to accommodate the apparently intense instantaneous local heating which occurs with high frequency currents at pressure connections, (the actual high frequency current may be 2 or 3 amperes momentarily) an effect which we sometimes call "splashing" at the contact. It appears that a contact which is good enough for direct or low frequency alternating current is not necessarily good enough for high frequency currents of the same value, this probably having some connection with the electronic constitution of the atoms. You will remember that as in the 4C/50 case, our recommendations were for definite metallic continuity as far as possible, from condenser foils to contact points. We have had cases of failure (burning of points) which in most recent instance has been unquestionably due to this phenomenon. We do not assert that the design is defective, if one could rely on it being perfectly correctly carried out every time, and in this case our demands might be considered too exacting, but in view of the particular failure above, we feel there is insufficient margin for slightly incorrect production. Contd. | ||