Thornycroft

In 1896, naval engineer John Isaac Thornycroft formed the Thornycroft Steam Carriage and Van Company, and built a steam van that was exhibited at that year’s Crystal Palace Show. Steam-powered lorries were a logical step for a company that was heavily involved in steam-powered boat design and construction.

The first Thornycroft van could carry a load of one ton and was powered by a Thornycroft marine steam-launch-sized boiler. The engine was a twin-cylinder ‘compound’ engine arranged so that used high-pressure steam could be admitted at lower pressure to a larger cylinder, to give extra power.

A modified version of the steam wagon with a six-cubic-yard tipper body was developed for Chiswick Vestry and went into service as a self-propelled dust-cart. While the original 1896 wagon had front-wheel drive with rear-wheel steering, the tipper dust-cart had rear-wheel drive and front-wheel steering. The Thornycroft tipper was built by the Bristol Wagon & Carriage Works, although engineered by Thornycroft.

In 1898 a Thornycroft steam-powered articulated vehicle won the Premier Award at the Liverpool Self-propelled Traffic Association’s Trials. 

A passenger carrying version of the company’s ‘under-type’ steam chassis was exported to Bruma in 1900 and in 1902 a double-deck model went on trial in London.

Thornycroft’s first petrol vehicle was built in 1902 and the company transferred motive power to internal combustion engines in 1907. The early engines ran on paraffin and proved popular in British Colonies.

After 1908 Thornycroft had a range of trucks with payloads ranging from one to four tons that were also available as passenger-carrying versions.

In 1913 the J-Type three-tonner, with T-head petrol engine was released. This truck was designed by Thornycroft to meet a 1911 War Office specification for a three-ton ‘Subsidy Scheme’ cargo truck. (The Scheme provided a grant of £110 to civilian companies towards the purchase price of a truck suitable for military service, but included a provision that the military could requisition the vehicles if they required them.)

Initially the War Office purchased H-, J- and K-Type chassis from Thornycroft, with further deliveries of all three types to follow, but in August 1914 the War Office settled on the J-Type chassis. Over 5000 were delivered to the British military during the war; some were supplied to Imperial forces and the vehicles remained in British Army service until 1930. Thornycroft also provided different-sized engines to the Admiralty, War Office and other government departments at the beginning of the War and for the next two years. 

Development was slowed by War surplus trucks arriving on the market, but in 1922 the new 24-seat Boadicea and 34-seat Patrician buses were launched. In 1924 the A1 chassis was launched, with 11/2-ton or 20-passenger payload rating and a unitised engine, clutch housing and transmission. Also, Thornycroft developed the X-Type three-ton chassis from the J-Type.

The ‘Hathi’ – named after the elephant character in Rudyad Kipling’s Jungle Book – was released in 1924. This vehicle was a specialised four-wheel drive artillery tractor.

Although capable in its day, the Hathi was a complex and expensive vehicle that required regular maintenance if the front axle was to remain reliable. For most purposes it was soon replaced by 6×4 trucks with just as many driven wheels, but without the need for the complex combined driving and steering axle. Even half-tracks, were more popular in this period.

Bodywork of the Hathi was typical for the time with a wide bench-seated open cab, no windscreen and the only weather protection being a folding canvas roof. Although the lack of cab was typical for the time, it had also been part of the requirement to maintain a low profile.

The engine was a Thornycroft GB6 11.3-litre, straight-six petrol engine, with the cylinders cast in two blocks of three. Thee engine had overhead inlet valves and side-valves for the exhaust. Dry sump lubrication was used, to avoid problems when tilted off-road.

Four wheel drive for heavy vehicles in this period was difficult and the Hathi used a complex arrangement of bevel gears to transmit drive through the steering joints of the front axle. The constant velocity joint used to make modern articulated drive shafts was unheard of and even the simpler Hooke-type universal joint wasn’t yet in common use. Thornycroft’s usual practice for prop shafts at the time was to use a flexible leather disc joint. To save weight, the axle casings were cast in aluminium.

The BC 32-seat bus appeared in 1929, along with the HC six-wheeler that could be had with a drop-frame chassis for double-deck bodywork. The JC 10-ton six-wheel truck chassis was another 1929 release.

From 1931, Thornycroft used names for its vehicle range and started to introduce diesel engines. By 1932 Thornycroft had more than 40 commercial vehicle and bus chassis and many of the bonneted designs gave way to COEs.

The Handy two-tonner, Dandy three-tonner and Sturdy four-tonner were released; followed by heavier variants: Strenuous, Mastiff, Iron Duke and Taurus. The 6×4 Amazon was aimed at on-off-road work.

The lightweight Stag COE six-wheeler had a choice of six-cylinder petrol or diesel power, with an eight-speed transmission. The Trusty eight-tonner was powered by a four-cylinder diesel engine.

Thornycroft’s Bullfinch three-tonner was the first truck to have a proprietary engine: a Dorman-Ricardo diesel and a Gardner 6LW option was available on some other models.

In 1935 Thornycroft launched the a new Sturdy model, with 62hp petrol power and a bus version was later launched.

During World War II the company designed several war-related vehicles, including thousands of Nubian 4x4s, military Amazons and Sturdy army trucks. The Tartar three-ton 6×4 was also developed for civilian and military tasks. Thornycroft built nearly 4000 of them between 1938 and 1945.

One military version was the Bison armoured vehicle, based on a Tartar three-ton, 6×4. Military Tartars had single rear wheels while civilian trucks had duals on the drive axles.

Post-War models were mainly Nippy, Sturdy and Trusty, including a petrol-injection, eight-wheeler version of the Trusty. The Sturdy Star was powered by a 4.2-litre, direct-injection diesel.

In 1948, the company name was changed to Transport Equipment (Thornycroft) Ltd to prevent confusion with the shipbuilding Thornycroft company. 

Launches in 1950 included the Trident, an export-market, six-wheeler 12-tonner and the Mighty Antar.

The Mighty Antar 6×4 was designed in the late 1940s for oilfield work, transporting pipes over rough ground. The name ‘Antar’ was based on that of an Arab poet-warrior, thus clearly marking the truck’s intended customers.

The original engine, the Meteorite, was a cut-down, 18-litre, V8 version of the V12 Rolls-Royce Meteor used in tanks and that engine had its beginnings as the famous WW2 Merlin aero-engine. Early Antars used the petrol version made by Rover, but by the early 1950s, in-line Rolls-Royce diesel engines were used. The transmission was a main four-speed, with a three-speed auxiliary box.

Early Mighty Antars had wide bonnets to cover the V8 engine, but six-cylinder ones had narrower bonnets.

In 1951 the first Antars entered British Army service. These were fixed-body ballast prime movers to pull Centurion tank low loaders.

By the late 1960s, it was clear that the Antar, even when re-engined, was an old design and replacement would be needed. There was also concern over the spares situation, as they were out of production and Thornycroft had been absorbed, via AEC, into the Leyland morass. The Antar was replaced by the Scammell Commander in 1986.

In the meantime, Antar prime-movers were imported into Australia in 1953 for the construction of the Snowy Mountains hydro-electric scheme. Originally designed for long desert hauls, the Antars needed modifications for their job in the steep, rugged Snowy Mountains, including axle oil distribution.

The Antars also experienced problems with the original Rover engines and, in 1960, they were replaced by Rolls Royce C6TFL units which produced 300hp at 2100rpm, compared with the Meteorite’s 250hp at 2000 rpm.

During 20 years of service the Antars hauled more than 20,000 tons of plant and equipment to dam and power sites, working as single prime movers, or in double-headed rigs.

In 1952 Thornycroft released the Sturdy Star and Nippy Star four-tonner 

Thornycroft was well known for providing fire engine chassis, with multi-axle drive for uses such as airports. A limited number of 4×4 chassis were also provided to Worcester-based fire engine manufacturer, Carmichael, for sale to civilian brigades in the 1950s.

Thornycroft’s Big Ben was released in 1953. This six-wheeled prime mover was powered by an 11.3-litre, direct-injection diesel engine, rated at 155hp at 1900rpm, with and 508 lb-ft of torque at 1000rpm. The main transmission was a four-speed gearbox, similar to the Antar’s, with a two-speed auxiliary box behind it.

Big Ben was designed to haul trailer loads of up to 40 tons GCM. It was sold with a fifth-wheel attachment for operation with a semi-trailer, or with an unsprung coupling for four- or six-wheeled four- or six-wheeled drawbar trailers. Clayton Dewandre compressed-air braking equipment was standard and the chassis had a mean wheelbase length of 13ft. 6in.

In 1957-58 the Nippy Star and Sturdy Star were replaced by the Swift and Swiftsure and the FRP-cab Mastiff arrived. The Trusty was made available with a bonnet or COE cab and the Antar and Big Ben trucks could be ordered in desert-service Sandmaster specification.

Thornycroft was taken over on 1 March 1961 by AEC parent Associated Commercial Vehicles (ACV), with production limited to Antars, Big Bens and Nubians, although the Thornycroft-designed six-speed constant mesh gearbox was used in AEC and later medium weight Albion and Leyland trucks. ACV was taken over by Leyland in 1962. 

The last Thornycroft-branded trucks built were 1964 Nubian 6×6 fire crash tenders. 

Leyland already had a specialist vehicle unit in Scammell, so vehicle production at Basingstoke ceased in 1969 and was transferred to Scammell at Watford. The factory continued to manufacture gearboxes, but was sold in 1972 to the Eaton Corporation. 

Thornycoft’s bus models ran like this: Type J; Beautyride; Boadicea; Cygnet (Single Deck); Daring (Double Deck); Lightning (first six-cylinder model); Nippy and Patrician.

The truck line-up was: Type-J 40hp, 1913; Type-K 30 hp, 1913; Hathi, 1924; A1 RSW / A3 RSW  (off-road capable rigid six-wheeler military specification, 1926; QC / Dreadnought, 1930 (12-ton rigid six-wheel chassis); Hardy; Dandy; Sturdy (5/6 tonner); Trusty (eight-ton forward control four-wheeler); Bullfinch; Strenuous; Mastiff; Tartar three-ton 6×4; Taurus; Iron Duke; Amazon; Stag; Bulldog; Jupiter (6.5-ton); Nubian; Big Ben; Antar (85-ton capacity, 6×4 pipeline and tank transporter); Swift and Trident.