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).
Design, capacity, and material improvements for the R.R. Goshawk Condenser.
| Identifier | ExFiles\Box 180\M1\5\ img011 | |
| Date | 12th December 1921 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Hm.{Capt. W. Hallam - Head Repairs} 2156/13. To EFC. from R.{Sir Henry Royce} Copy to:- CJ. " PN.{Mr Northey} " Hs.{Lord Ernest Hives - Chair} " Wor.{Arthur Wormald - General Works Manager} " Wd.{Mr Wood/Mr Whitehead} REX.4430 R.R. Goshawk Condenser. X. 2512 In reply to your EFC2/T6/12/21., this trouble should never have existed but it has forced us into scheming an improved arrangement so that ample capacity, will be fairly easily obtained. I have written elsewhere that the capacity should be from .3 to .4 micro-farad i.e. slightly more than is required for the maximum length of steady sparking so as to be very certain about protecting the contacts. It is certain that the flat folded condenser is the least expensive. probably aluminium foil would be superior mechanically, and also for electric conductivity: it will not solder, and whether it will make good contact by simple pressure should be tested. You will notice in all cases that we have allowed room for 3 inserts to make contact with the tin foil or aluminium foil; these inserts can be made of copper or any metal found advantageous. American Bosch condenser should fail in use because both earth and the connection to contact arm are very unreliable, and from your own tests quite a good contact is needed. They stuff in a crumpled up piece of foil as a packing. Mica was suggested by me as the only suitable material known to us giving high electro inductive capacity. We now find that Linseed oil film is equal and more easily obtainable. I do not know why you do not try the single oiled paper .0015" thick, and why two thicknesses of this were used for winding enamelled coated secondary. You will notice that both paper and silk are only used (1) | ||