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).
Letter from Joseph Lucas Limited clarifying the differences between the WT13 and WT11 horns.
| Identifier | ExFiles\Box 166\9\ img137 | |
| Date | 21th September 1937 | |
| HEAD OFFICES & WORKS: GREAT KING ST.{Capt. P. R. Strong}, BIRMINGHAM. CONTRACTORS TO THE ADMIRALTY, WAR OFFICE, AIR MINISTRY, INDIA OFFICE, G.P.O. AND LEADING RAILWAYS. 6066 JOSEPH LUCAS LIMITED GREAT KING STREET BIRMINGHAM 19 TELEPHONE: NORTHERN 5201 (12 LINES) TELEGRAMS & CABLES: 'LUCAS, BIRMINGHAM' SERVICE DEPÔTS BELFAST 3/5, CALVIN STREET, SHANKHILL ROAD BIRMINGHAM, 18 10, GREAT HAMPTON STREET BRIGHTON, 4 85, OLD SHOREHAM RD., HOVE BRISTOL 345, BATH ROAD CARDIFF 54A, PENARTH ROAD COVENTRY PRIORY STREET DUBLIN PORTLAND STREET NORTH, NORTH CIRCULAR ROAD EDINBURGH, 11 60, STEVENSON RD., GORGIE GLASGOW 227/229, ST.{Capt. P. R. Strong} GEORGES ROAD LEEDS 64, ROSEVILLE ROAD 'KING OF THE ROAD' LAMPS, HORNS, CYCLEALITIES, MOTOR-CYCLEALITIES, 'MOTORALITIES' MAGNETOS, BATTERIES, ELECTRIC LIGHTING & STARTING SYSTEMS. Codes: A B C 5th & 6th EDITH & BENTLEY'S 1st & 2nd. LIVERPOOL, 13 450/456, EDGE LANE LONDON DORDRECHT ROAD, ACTON VALE, W.3 LONDON 757/759 HIGH ROAD, LEYTON, E.10 LONDON 319, REGENT ST.{Capt. P. R. Strong}, W.1 SHOWROOMS & OFFICES LONDON 155, ISERTON ROAD, WANDSWORTH, S.W.18 MANCHESTER, 3 291/293, DEANSGATE SUPPLY DEPOT MANCHESTER TALBOT RD. STRETFORD NEWCASTLE-ON-TYNE, 2 84/86, ST.{Capt. P. R. Strong} MARY'S PLACE WHEN REPLYING PLEASE REFER TO Messrs.Rolls-Royce,Limited, D E R B Y. 21st.September,1937. X/LGT9. For the attention of Mr.Childs. Dear Sirs, We will try to make clear the situation regarding the pair of WT13 Horns which were submitted last week for further tests. In the first place these WT13 Horns differ from the WT11 inasmuch as the body casting was altered, and an Elbow fitted at the rear of the casting to which was screwed the Trumpet or Flare. This trumpet or flare still being exactly the same length as the WT11, but when screwed into the Elbow at the back of the casting actually made the overall length of the trumpet to its base, an 1 3/8" longer than the WT11. Although this may sound very disconcerting, actually the WT13 Horn when put alongside the WT11 Horn, is an 1 3/8" shorter from the fact that the trumpet is screwed into an elbow at the rear of the body casting. When we first submitted the WT13, the slots in the flare were in the same position as they are now in the WT11, and it was found that the tone of the horn was not so good as that of the WT11. By experimenting, we found that by moving the slots in the trumpet right forward into the bell mouth, complete with gauze, we improved the tone of the WT13, considerably, and in fact brought it up to the level of the WT11, although it may be just a shade lower in pitch, but in our opinion still as penetrating and as satisfactory a road clearer, as the WT11. The operating element is not altered in any way, it being the same as the WT11X supplied to you regularly. Summing it up, the WT13 only varies from the WT11 | ||