Historic Car Brands

Leslie Hounsfield’s Trojan brand has graced the bonnets of cars that range from the company’s 1914 10hp two-stroke plodder to 1970s sports racing and F1 cars. We’re indebted to the Trojan Museum Trust for its assistance in preparing this report.

During the late-1890s Boer War, young British engineer Leslie Hounsfield helped in the development of a steam wagon for gun haulage. This introduction to the fledgling automotive scene inspired him to design a cheap and economical, chain-driven motor car. 

He had the design roughed out by 1910 and, two years later, produced a prototype two-seater, powered by a duplex two-stroke engine that was mounted vertically between the seats. It featured supple, inverted-leaf, cantilevered, semi-elliptic springs that provided sufficient flex to overcome the characteristically harsh ride from its solid-rubber tyres.

In 1914 he registered the Trojan Limited company, in Clapham, London, followed by a move to Croydon, specialising in precision engineering. Trojan produced five pre-production cars, before Word War One intervened, during which the company mainly manufactured gauges.

Britain suffered from an economic slump post-War that particularly affected vehicle manufacturers, because the military sold off what were then surplus cars and trucks. At Trojan, vehicle development continued but general engineering kept the company going. 

An unlikely partnership emerged from this situation, because Leyland was suffering a severe downturn in sales. During the hostilities, Leyland had filled orders for 6000 RFC (later RAF) trucks and many of the post-War surviving ones were sold off to transport firms, which obviously didn’t buy new Leylands or other brands.

Some of these War-surplus vehicles needed refurbishing and re-bodying, so Leyland bought up as many as it could and worked on them at the old Sopwith Aircraft factory. However, once that mission was accomplished, there was still the future to plan for. Further complicating Leyland’s situation was the fact that its Rolls Royce competitor, Leyland Eight, could hardly have arrived at a less auspicious time.

Leyland started looking for a car it could produce for the lower end of the market – just like Henry Ford was doing in the USA – and that product turned out to be Leslie Hounsfield’s Trojan.

In 1922, Trojan and Leyland signed a manufacturing licence deal, under which Leyland would produce Trojan cars and utilities.

By then, the Trojan prototype had morphed into a more conventional looking vehicle, in the Austin ‘Chummy’ style and sported a larger radiator and bonnet, even ‘though there was no engine behind them.

The split-single, two-stroke engine and simple, epicyclic transmission were retained, but now resided under the front seat. Also retained was the little car’s unique ‘punt-shaped’ welded steel tub chassis. Four, inverted-leaf, semi-elliptic leaf springs were attached to the tub, so that their taped ends connected to the front and rear axles, providing supple spring action.

The axles were rigid, with the rear one featuring a sprocket drive at the right-hand end and a single brake drum on the left-hand end.

Maximum power output of the 1529cc engine was only 11bhp, limiting the top speed to a little over 30mph. However, it had a very flat power curve, developing 10bhp at 400rpm, 11bhp at 900rpm and back to 10bhp at 1200rpm. The Trojan could climb almost anything – albeit at a crawling pace.

Trojans soon proved their worth as on-farm tractors and utilities, because their low-engine-speed torque and supple suspension gave the excellent tractive ability on uneven and muddy surfaces.

The 10hp Trojan engine deserves some description, because its design was most likely influenced by a 1905 Lucas patent and a 1912 Garelli patent – both of which covered the design of twin-cylinder, single cylinder head, two-stroke engines. 

In those early days of engine development, two-strokes struggled with the problem of getting rid of exhaust gases (scavenging), without losing some of the incoming air-petrol mixture down the exhaust port as the charge air forced out the exhaust gases.

One solution was the split-single engine, with two cylinder bores and pistons: one of them opening the inlet port and the other, the exhaust port. This design largely solved the scavenging problem and improved fuel consumption.

Where the Lucas patent used two crankshafts, the Garelli one had long pistons with a common gudgeon pin and a single crankshaft. 

Leslie Hounsfield’s design had shorter pistons, with conventionally positioned gudgeons and a forked connecting rod pivoting on one crankshaft. A roller bearing replaced the original plain bearing in 1923.

The combination of shorter pistons than the Garelli engine and Leslie Hounsfield’s desire for a very long stroke, to improve crankcase compression for effective scavenging, as well as promoting high low-speed torque, dictated a very long vee-shaped connecting rod. 

The geometry of rotating big end and oscillating little ends over long piston strokes meant that the two arms of the connecting rod had to flex slightly as they moved, to avoid ‘binding’ the pistons in the bores. This inbuilt flexibility was part of his engine design and Hounsfield was so confident in the durability of the cast conrods that he foresaw no problem with this. 

Amazingly, even after 100 years of bending on every cycle, no Trojan conrods have ever broken! 

Of course, Leslie did know his metals and he later went on to design the Hounsfield Tensometer, among other metal-testing machine designs that are still in use, although now digital. 

Leslie Hounsfield was also committed to making his car as easy to use as it was reliable. In comparison with the sliding mesh and constant mesh transmissions used by most of its competitors, the Trojan’s epicyclic transmission was easy (and quiet) to operate. Also, its indoor-mounted starting lever was more convenient than a front-mounted crank handle.

In 1924, under the Leyland aegis, Trojan developed a van version of the car which became very popular as it was simple to drive and quite economical. The biggest customer was Brooke Bond Tea, who used an exclusive fleet of some 2000 Trojans to deliver tea to the shops around the UK. Other big fleets included the Post Office and Watermans Laundry.

In 1925 Trojan introduced a larger-bodied Trojan car called the Three Door Tourer. This model had greater rear passenger space, accessed via a single rear door on the pavement side. The option of pneumatic tyres was also introduced, to give a more comfortable ride.

A ‘posher’ canvas-bodied saloon car, known as the Achilles, came in 1928, along with with a roll-back roof version, the Apollo. However,  they still were hampered by the Trojan’s top speed of 35mph and sales were disappointing.

The writing was probably on the wall in 1925, for the wind-up of the Leyland-Trojan marriage, when Leyland had got back on its financial feet and released a new passenger vehicle range, powered by the same 40hp petrol engine that the company used in the QH2 truck that succeeded the RAF truck.

In the late 1920s, Trojan ended its relationship with Leyland and began manufacturing its vehicles in the Purley Way factory.

In 1929 a newly-designed Trojan RE was introduced, with the duplex two-stroke engine located in a box at the back, along with a three-speed epicyclic gearbox, with gate gear change. The rigid rear axle was replaced by a unit with a lockable differential and brakes at both ends, but still no front-axle brakes. 

The standard tourer and saloon on this chassis both cost Stg£179, while the deluxe model, for Stg£198, which had such un-Trojan features as an electric starter motor, wire wheels and an electric windscreen wiper.

Also in 1929, Trojan experimented with tracked army vehicles and supplied basic trucks to the RAF. Trojan launched a marine version of the car engine and, in conjunction with the Windermere boat builder Borwicks, produced a launch called The Trojan.

At this time Trojan was producing a large number of products either as contract work or based on its own inventions. Two of the most successful, and both still in production in the 21st century, were the Hounsfield Tensometer and the Hounsfield camp bed.

The Trojan RE was not successful, so, at the 1935 Motor Show. Trojan introduced an entirely new car, called the Mastra, which was streamlined and had a six-cylinder, duplex two-stroke engine at the rear, driving through a conventional three-speed synchromesh gearbox.

The Mastra engine was the standard pre-War four-piston engine used in the earlier cars, but with two extra cylinders, so making it a six-cylinder, with three forked conrods instead of two.

Trojan finally adopted four-wheel brakes on this car, plus the luxuries of inbuilt hydraulic jacks and a heater. However, at a price approaching Stg£400, the Mastra was expensive and orders didn’t flow from its Show debut. After producing three prototypes, Trojan dropped the project entirely.

Trojan now abandoned car manufacture and concentrated on vans, introducing a new larger van, the Trojan Senior. This still had the engine under the floor, but the forward control design gave more internal space.

Throughout WWII Trojan produced highly engineered parts for tanks and planes; a small bomb trolley; an oil bowser for servicing planes and the Trolley Acc, battery pack for starting Spitfires, Hurricanes and Lancasters.

After the War, Trojan released a completely new large van, with a three speed standard gear box and a supercharged version of the pre-War two-stroke engine.

This engine was fitted to their vans from 1946 until the mid-1950s and was based on the principles of the earlier engines, but with two supercharging cylinders and no forked conrods.

Trojan van engine – Powerhouse Collection

The new engine was a V4+2 configuration, in which four of the engine cylinders were split singles – one behind the other – and fired by two spark plugs. The unfuelled two cylinders on the opposite bank were for scavenging purposes only.

As an answer to the post-War need for cheap transport, Trojan introduced the Trojan mini-motor in 1949. This 50cc engine clipped onto a standard push bike and converted it into a moped. More than 50,000 were produced over the next five years.

The standard van was redesigned in 1953 and Trojan fitted it with a Perkins diesel engine, making it the first small van to be diesel powered and solving the fuel consumption issue of their vans.

By the late 1950s Trojan Ltd was in financial trouble and losing over Stg£400,000 per annum. Peter Agg stepped in and bought the company. He had made his fortune through being the sole importer of Lambretta scooters and now combined the two businesses on the Trojan site.

Forward control vans and 13-seater buses replaced existing vans. Peter Agg had seen go-karting in America and, by manufacturing the TroKart, introduced karting to the UK. In 1961 came a garden tractor, called the Toraktor, for which there were various implements, including trailers, rotavators, lawn mowers and snow ploughs.

1963 Trojan 200 – Writegeist

In 1962, Trojan bought the international rights to the Heinkel bubblecar and manufactured it as the Trojan 200, using the Heinkel engine. 

Then Trojan bought the Elva sports car company in 1962 and manufactured the Elva Courier, producing 210 cars between 1962 and 1965. 

In 1968, Trojan struck a deal with Bruce McLaren, to manufacture all of their non Formula One racing cars, including the famous M8s. Trojan also made the first McLaren road car.

1971 McLaren M8E at Laguna Seca – Reilly Hamilton

After Bruce McLaren was  killed in a testing accident, Trojan lost the McLaren contract, but switched to making its own racing cars. Trojan had its own Formula One team in 1974, with Tim Schenken as the driver. Trojan entered eight Grands Prix but scored no championship points.

Trojan T103 F1 car

Trojan continued supplying parts for racing cars through the 1970s, but that effort played second fiddle to the fact that Peter Agg was then the sole importer of Suzuki Motorcycles. The site was gradually sold off and Trojan briefly became a classic car restorer in the 1990s.

Trojan was finally shut down in 2013, following Peter Agg’s death.

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