SECTION 1

Development of the Comet

In the final months of the second world war Leyland Motors started to actively plan its post-war range of vehicles. Before considering the proposed catalogue and development of their new Leyland Comet models it is worth reviewing briefly the position then held by the company as a commercial vehicle maker.

Leyland Motors had grown continuously and steadily in the period up to 1939 to become the leading heavy commercial vehicle builder in Great Britain. The company produced a range of high quality passenger chassis and lorries which achieved envied reputations at home and overseas for reliability, longevity, and durability. Leyland was recognised as a formidable competitor in world markets with its buses and lorries being the equal of, and in many instances superior to, those of competitors. The company was innovative and regularly updated its designs resulting in continuous developments and rapid progress.

Leyland Motors' philosophy was to manufacture as much as possible itself and the main production and assembly facilities were concentrated in and around the small Lancashire town which gave its name to the company. Other nearby factories included the spares and service headquarters at Chorley, and the foundry at Farington. There was also a large assembly plant at Kingston-upon-Thames and a smaller works at Lincoln. Of the other premium quality British Commercial vehicle makers only AEC at Southall could rival Leyland, although in terms of annual sales Leyland was the bigger concern. This was partly achieved by them selling a wider model range including successful light and medium weight vehicles such as the Cub and Lynx.

During the 1939-45 world war all of Leyland's considerable manufacturing capacity was switched to the war effort. Over 10,000 complete lorries were built and a similar number of other chassis were bodied for the forces, mainly at Kingston Works. In Lancashire Leyland built around 3,000 tanks and some 10,000 tank engines. In addition they machined approximately 8,000 high explosive bomb casings. There was still spare capacity and the Farington foundry cast over 10,000 tons of aluminium aero engine components. Also for aeroplane makers, Leyland produced over 7,000 engine mountings and nacelles. Such statistics provide some idea of the size of Leyland Motors and during the war years over 11,000 men and women were employed.

With an allied forces' victory assured, in 1945 Leyland Motors announced its plans for the following period. The company had not made any passenger vehicles since 1940 and despite some other manufacturers having made double deck buses to a 'Utility' design, by 1945 there was a desperate shortage. Hence, Leyland's PSV sales catalogue comprised just two chassis; the single deck PS1 and double deck PD1. Both were basically pre-war designs, but planned for a new engine of 9.8 litres to be fitted. This power unit could be fuelled by either petrol(P.600) or diesel (0.600). The Leyland heavy lorry range was restricted to three models; the 12 tons gross weight Beaver four wheeler, the 18 tons gross weight Hippo six wheeler; and the 22 tons gross weight Octopus eight wheeler. These were the maximum solo permissible gross weights in the respective categories although each type was suitable for pulling a drawbar trailer. These lorries were also scheduled to have the 0.600 diesel engine fitted and a new all metal, Leyland built cab. In reality the first Beavers to be built after the war had the pre-war designed cab and earlier 7.4 litre engine, which was also used for some of the contemporary passenger chassis. This heavy lorry range was supplemented a couple of years later, in 1947, by the 15 tons gross weight Steer, a twin steering front axle (Chinese-Six) six wheeler.

Although not announced in 1945, a completely new medium weight chassis, which although primarily a lorry was suitable for bodying as a passenger vehicle, was being designed. This was to be the replacement for the famous Leyland Lynx. When it was introduced in 1936 the Lynx was specifically engineered to weigh less than 2½ tons unladen and complete with a standard body. This enabled the lorry to be exempt from the 20mph heavy lorry speed limit. It was a semi-forward control design and had a legal payload of 5 tons. Power was from a six cylinder petrol or diesel fuelled 4.73 litre engine. With powerful vacuum-servo brakes the Lynx was a relatively fast and safe lorry. It set the standards for other designers and makers to match and sold very well. The Lynx remained in production at Kingston-upon-Thames until 1944 with much of the wartime output going to Army transport units. Many Lynxs were also supplied to the Pool Petroleum Board, established in 1939, for tanker duties. Any remaining available chassis were allocated to selected hauliers under the Ministry of War Transport allocation scheme.

By 1945 it was the opinion of Leyland Motors' sales management that the successful Lynx should be replaced by a similar top quality medium weight lorry. By then the Lynx chassis was considered old fashioned and not really suitable for upgrading to higher gross weights. Also, a new engine design was required. In the 1930s Leyland, along with other manufacturers had used aluminium alloy for engine crankcases and other castings. During the war all available aluminium supplies were directed to aero engine and airframe makers. This forced Leyland, and others, to change to ferrous metal castings and it was decided to continue this policy even when aluminium became available again. In any case iron and steel was cheaper.

Whilst Leyland had developed a new heavy chassis engine, the 9.8 litre 600 type, they had no immediate plans for a new smaller unit. However, Napier of Liverpool who made industrial and railway locomotive engines, had designed an in-line six cylinder unit of 4.92 litres capacity. This had been developed as a multi-fuel general purpose engine for a variety of military applications. With the war ending Napier no longer had an outlet for this power unit so they entered into negotiations with Leyland Motors. By chance the Napier design had a capacity of half Leyland's largest automotive engine so it was an ideal size for the proposed medium weight chassis. Leyland's engineers were sufficiently impressed with Napier's design and after agreeing suitable modifications an arrangement between the two companies was reached. Leyland bought the rights to the engine but Napier were to assemble it at Liverpool with many of the components and castings supplied by Leyland. At that time there was simply insufficient capacity available at Leyland's own engine plant.

It is worth pausing for a few moments to describe the situation faced by manufacturing industry in 1946, and the conditions which were to prevail for the next few years. Even though the war had ended it was still a period of severe shortages and rationing. This state of affairs had adverse effects on companies such as Leyland Motors and resulted in serious delays to production schedules and development programmes. Leyland had a full order book for months ahead. In particular passenger vehicle orders were plentiful as municipal and private operators replaced obsolete and worn-out buses. These would normally have been scrapped years before but for the intervention of war. A similar situation existed with lorry sales although there was a considerable uncertainty amongst hauliers because of impending nationalisation of road transport. Coupled to this the government had decreed that at least 50% of industrial output must be exported to provide valuable foreign exchange for a virtually bankrupt country. Another legacy of the years of conflict. Whilst the desire to produce goods in companies such as Leyland Motors was definitely there, the means of doing so were fraught with difficulties. In the winter of 1947 arctic weather conditions virtually brought the nation to a halt as supplies of coal and oil could not get through to the power stations. Then, electricity generation was much more localised than today with most sizeable towns boasting a municipally owned power station. There were regionally based producers such as the Lancashire Electric Power Company who supplied Leyland Motors, but with the national grid distribution network nowhere near completed then, localities were much more dependent on the nearest generating station.

Leyland Motors was a sales and marketing led company and the sales force desperately needed a new medium weight lorry. Because of production difficulties coupled to an already full order book, development of the new chassis was inevitably delayed. Leyland built many of the bodies for its buses and coaches and was also committed to a new cab for the heavy weight lorry range. With no capacity available at their own body works a proprietary cab was needed for the Comet. (At this stage in 1946 the chassis had not been given a model name). Briggs Motor Bodies of Dagenham were contracted to build a suitable cab. Similarly there was insufficient rear axle manufacturing capacity available within the company. Negotiations commenced with the Moss Gear Company of Birmingham for them to make rear axles to a Leyland design and specification. The new 5 speed gearbox was able to be built by Leyland, albeit at Kingston-upon-Thames works.

In the early part of 1946 development of a new medium weight Leyland and its components commenced. By February Briggs Motor Bodies had made a full size clay mock-up of the cab. It was a bonneted design for a normal control chassis and Leyland approved it. In this month bench testing of the...