Thornycroft SG/NR6

Thornycroft SG/NR6

Can anyone tell me the registrations of the 5 Thornycroft SG/NR6 coaches new to Bristol Coop Society coaches with Longwell Green bodies new in 1948

Geoff Clayton


04/12/15 - 10:04

This article in Commercial Motor of 7th May 1948 may help. http://archive.commercialmotor.com/article/

Stephen Howarth


05/12/15 - 14:30

I've attached a link, showing one of these coaches at Wembley in 1952. From this, you'll see that the Fleet No. was 27 and the Reg'n No. LAE 293, which is a start! http://www.na3t.org/road/photo/Hu03253

Chris Hebbron

P.S. Two points to add to above

1) That another photo, at the same event, shows another one of these with registration No. LAE 296, but fleet number is illegible.
2) Bristol Co-op seem to have used the trade name, "Queen of the Road".


06/12/15 - 06:23

The Thornycroft SG/NR6 has an interesting history. In 1937 Sydney Dack joined Thornycroft from AEC, where he had been Assistant Experimental Engineer. He designed a new double deck chassis with a Gardner 5LW engine that was given the entirely logical type name DD/5LW. Progress was impeded by war production commitments, but the prototype chassis, no. 35131, was completed by January 1940, when it was bodied as a works lorry for testing.
With the end of the war, Thornycroft pursued its determination to re-enter the heavyweight psv market, and it was duly included in the Labour government's list of authorised manufacturers. All material supplies were then strictly controlled by the government and such authority was essential. The DD/5LW design then reappeared, though now with the firm's own NR6 7.88 litre direct injection engine developing 100 bhp at 1800 rpm. The chassis then became the DG/NR6. Consultations with prospective customers had indicated that the Gardner power plant was much preferred, but Thornycroft did not offer a Gardner option, probably because the strong demand set against the modest production output of the Patricroft factory severely limited the supplies. Double and single deck versions of the new chassis were offered, DG/NR6 and SG/NR6. Two double deck chassis were completed in 1946, and these had a basically conventional gearbox that was intended to operate in a rather complicated manner. This 'self shifting' transmission consisted of a fluid flywheel and preselective system for second, third and fourth gears, but also included a single plate clutch and synchromesh arrangement with conventional left hand located gear lever for the selection of first, second and reverse. The preselective gears were selected by a lever on the right hand side of the steering column, but for these to work, the conventional lever had to be set in a 'locked' position. Presumably, it was anticipated that the vehicle would normally be driven in the second, third and top gears of the preselective range. Unsurprisingly, the whole thing defied all attempts to make it work properly, and it was abandoned, a standard gearbox being fitted instead. After a prolonged period of testing, the first DD/NR6 chassis, no. 48064, ultimately received a Thurgood B35F body in July 1952, and was used for staff transport at Thornycroft's shipyard at Woolston, Southampton. What happened to the other double deck prototype, no. 48065, is unclear; it was probably not bodied, and no others were manufactured.
The single deck version, SG/NR6 was barely more successful. The Bristol Co-operative Society took five with Longwell Green C33F bodies in the spring of 1948, and, notwithstanding the Commercial Motor article, it is believed that these had conventional gearboxes from new.
Finally, two bonneted, left hand drive, 8ft wide, 18ft 6in wheelbase examples were built in 1948. One of these, chassis no. 51718, was bodied by Thurgood and shown in the demonstration park at the 1948 Commercial Motor Show. It was then sent to Kuwait, but soon returned, after which it was used by Thornycroft for staff transport. No record exists of the other example, no. 51717 entering service; again, it probably did not receive a body.
It is curious that, after expending much effort on what was fundamentally a sound chassis design, Thornycroft quickly seemed to lose interest in the DG/SG project. In part this may have been due to the departure of Sydney Dack in 1947, when he moved to the White Motor Company in the USA.
I must acknowledge the valuable source of these comments - Alan Townsin's comprehensive volume on Thernycroft in the Ian Allen Transport Library.

Roger Cox


07/12/15 - 06:31

Thx, Roger, for the background info on a vehicle I'd never heard of. Sydney Dack, as an experimental engineer (once an experimenter, always an experimenter!), might not have been the ideal man for the job, expending years on inventing a gearbox so complex and unlikely to appeal to any buyers, when there was a desperate need for simplicity and reliability in double-quick time. How the production d/d chassis was finished in 1946, yet not shown to the public, with body, until 1952, is beggars belief! By then, distress purchases were virtually a thing of the past and passenger numbers were beginning to fall!

Chris Hebbron


28/12/15 - 06:24

The five examples for Bristol Co-op were LAE 292-6, chassis numbers 49682-6, fleet numbers 26-30.

David Williamson

 


 

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