Stuart Turner (engineer)

Sidney Marmaduke Stuart Turner was an English engineer born in Shepherds Bush, London in 1869. Little is known about his childhood or adolescence although we do know that his family's ambitions for him did not include becoming an engineer. After a series of other jobs including an apprenticeship on the Clyde building marine engines, a period at sea and working as an engineer in Jersey (where he installed electricity generating plant), he gained employment in 1897 looking after the steam generating plant at Shiplake Court near Henley-on-Thames, England.^[1][2] In those days mains electricity was rare and therefore most large houses had their own electricity generating plants.

It was while working at Shiplake that Turner designed his No.1 Model Steam Engine. He drew up the patterns which he then sent away to be cast. On their return he machined and assembled them and soon showed the finished model at a local exhibition. He then approached Percival Marshall the editor of Model Engineer magazine who wrote an article about the engine. This coverage brought an immediate response and orders for sets of castings flooded in, and a business was established in 1898. He was joined in the business by Alexander Frederick (Alec) Plint in 1903, who he had worked with in Jersey and was trained in electrical engineering.^[1] This business produced an unusual mixture of small mainly 2-stroke engines used in boats, generators, as well as model engines and castings aimed at the model engineering market. They also briefy made a motorcycle and the Stuart lathe, and latterly a range of centrifugal pumps. The name Stuart Turner is eponymous with small quality models, and many of the steam models and rarer internal combustion models are much sought after by collectors.

Stuart Turner left the firm in 1920 and went to South Africa. He returned to Southend to retire and died in April 1938.^[3]

Stuart Turner Ltd before the First World War

Stuart Turner Ltd was incorporated in 1906^[4] and started to produce model steam engines, gas engines for domestic electricity, lathes, etc. Stuart Turner went on to produce further model steam designs, and in 1906 there were nine models in the range. By 1907 more space was needed so premises were rented at Market Place, Henley-On-Thames where the company remained for many years.

The 2-stroke engine with crankcase compression had been invented by Joseph Day in the mid 1890s. This made possible lightweight engines and new applications. Stuart Turner were exploring making small 2-strokes for motorcycles and generators. They secured the contract to make engines for the Dayton motorised bicycle made by Charles Day Manufacturing Co in Shoreditch, London, who were until then purely a bicycle manufacturer.^[2] This went on sale in late 1913. The engine has a one-piece cylinder and head with a rear facing spark plug, and was of 162cc, rated at 1.5HP. The bore was 57mm and the stroke 63.5mm, and it had a U.H. magneto and Amac carburettor. Both single speed and two speed versions were available, and prices in July 1914 were 20 to 28 guineas according to specification.

Two employees, Alec Plint and W.G. Ayling, rode the Dayton bikes in motor cycle endurance events run by the Auto-Cycle Union (ACU), such as the six days trial. Weighing only 148 lbs these were usually the smallest motorcycles competing. These events included riding between and taking part in various tests, such as hill starts, acceleration and braking, cold starts, and climbing steep rough hills. Total distance for the 1914 event was 674 miles.^[5] The Daytons did well given they were considered rather lacking in power as revealed by this excerpt from the Motor Cycle magazine of July 1914 – 'Ayling (Dayton) footed vigorously, but got his lilliputian engine to the top'.^[6] Production of engines for the Dayton was 20 engines per week, but production of the Dayton motorcycle ceased in 1915 due to the first World War.^[7]

In 1911 Stuart were working on building a complete motorcycle, and they exhibited a single cylinder motorcycle at the 1911 Olympia show (on the stand of R.G.Nye and Co of London).^[8] The engine was 299cc with internal flywheels. In 1912 and 1913 they marketed the Stuart Stellar (some early references use 'Stella') motorcycle,^[9] this used an in-line two-cylinder water-cooled two-stroke engine complete with shaft drive. Engine capacity is variously quoted as 743cc and 786cc. This would be comparable with the Scott motorcycle of the time which had a transverse water cooled two-stroke twin cylinder engine of 532cc. However, in-spite of the innovative design, the Stellar was not a success and only 26 examples were built.

Many of the technical developments during this period appear to be down to Alec Plint, who is named as applicant on 5 Stuart Turner patents which include sealing crankcases,^[10] padding crankcases to improve compression,^[11] variable speed gears,^[12][13] and decompression devices.^[14] The 1911 patent diagrams show the current 2-stroke to be '2-port', i.e. with the inlet being by non-return valve into the transfer port, with ball races for the main bearings and deflector type piston. The inlet non-return valve is the subject of another Stuart Turner patent in 1911, naming Ernest Masters as co-applicant.^[15]

In 1914, the company manufactured a generating plant for the Antarctic explorer Ernest Shackleton's ship, the Endurance.^[2] It was used in the ill-fated Imperial Trans-Antarctic Expedition.

Stuart Turner Ltd during the First World War

During World War I (1914–18), the company produced nuts and bolts, gas valves and a Klaxon horn for gas attack warnings. The workforce expanded to over 300 men and 100 women. In 1917, Stuart Turner acquired Broadgates Inn in Market Place, Henley-on-Thames, and has used this as a base ever since.

Stuart Turner Ltd in the inter-war years

Shortly after the war Stuart introduced the P3 single cylinder 2-stroke engine, designed by Alec Plint to drive lighting and pumping plants. This engine was to form the basis of a range of engines used for small power applications, particularly as marine engines and to drive generators, though also to drive equipment and pumps. Casting were produced in Stuart Turner's own foundry. The P4 superseded the P3 in 1928, and in 1930 the marine variant was introduced, and was sold in considerable number for fitment in small yachts and other pleasure boats. In around 1935/1936 the P4 was joined by the larger bore P5 (268cc) and twin cylinder P55 (535cc). While the P4 was made until the war, the P5 and P55 continued in production for over 30 years. For the marine engines Stuart produced a reversing gearbox and optional final drive reduction gear, and everything else up to and including the propellor was available. The many variations of the engines (marine and otherwise) were indicated by suffixes to the engine number, so for example a P55ME would be a marine P55 with electric start (Lucas Dynamotor, Siba Dynastart, or separate dynamo and starter).

Between 1932 and 1935 Stuart produced the small (1/2 HP) type N engine, which had an overhung crank. This model seems to have been superseded by the type R 2-stroke engine, which was introduced in 1934 with a full width crank. The R2 being 84cc, and the R3 having a larger bore size and hence 123cc. These small engines were used for general utility, but also the R3M for pleasure boats, hire boats. The R3 was to continue in production until 1977.

The model engineering range was extensive throughout the inter-war years, with a lot of production sold as kits of castings, though some complete engines were also sold. Most of the models were designed to be representative of a class of engine, mainly steam driven, rather than an accurate scale recreation of a specific engine. Internal combustion engines were also available as kits, including the 'lighweight' 2-stroke petrol engine. From 1935 Stuart Turner were also UK agents for the American 'Brown Junior' 10cc engine^[16] for which they developed an aluminium (elektron) airscrew. Some of the engines were intended to do a job of work rather than for the entertainment of a model engineer, for example the 1935 Sandhurst horizontal 2/3 bhp engine, which was described thus:^[17] 'This engine will run on gas or petrol and is designed for continuous work such as dynamo, workshop or pump driving. It is supplied only as castings for the amateur to machine up.'. The larger steam engines, for example the model 6A, are capable of 4 bhp and powering steam launches, thereby blurring the distinction between whether they were model engines, or designed to do a job of work, or both.

Many ancillaries were sold to illustrate the power from the model engines, such as the Avery Multipolar dynamo. In the 1906 catalogue this dynamo (output of 20volts, 4amps at 1200rpm) was said to have been "designed for use with a Stuart No2 engine". A variety of dynamos were sold over the years allowing them to be matched to the power of the model engine.

Stuart Turner also produced a wide range of boilers to power their steam engines, and sold matched boiler and steam engine as complete 'steam plants'. The most common boilers are the small 501 and 504 copper horizontal types used to drive the model steam engines, but they also produced a range of riveted steel vertical boilers up to 20inches diameter, and 36inches high, either with central flue or with multiple tubes. They also offered brazing services for customers' boilers.

They also produced two complete model steam boats. The 24" Henley was produced from 1925, and had a single cylinder S.T. oscillating steam engine, and the 39" Isis was launched the next year with a model 495 boiler and the twin cylinder Star steam engine.^[18] These boats were produced until at least 1936, probably until the war disrupted matters. There was a version of the Henley steam boat powered by a Stuart electric motor, this boat was sold as the 'Magician'. The 4 volt electric motor was also sold separately.^[17]

In 1923 the War Office invited Stuart Turner (and other firms) to design a very light air-cooled engine and generator for wireless. It was to be carried on a pack mule. The whole plant must not weigh more than 84 lbs, it had to run in any temperature from freezing to 60 °C; it must not be affected by being carried upside down or in any position; it must govern within 5% and there were various other conditions. The result was that five firms produced engines but the Stuart was the only one which fulfilled the requirements and passed the tests. This was the W.D. engine, which was a 4-stroke side-valve flat twin, and continued in production for 20 years.^[2] Two of these engines were taken on the 1933 Everest expedition to power the wireless sets.

From 1928 until the war the company issued 9 patents (again naming Alec Plint) for milking machines, and developed a diaphragm pulsatory milking machine which was marketed by Gascoine of Reading who later took over the rights. They also developed pumps, and in the 1933 Bond's catalogue^[19] a complete Stuart electric motor and centrifugal pump on a baseplate with 180, 800, or 1120 gallons per hour was advertised. This evolved into the current product line of centrifugal pumps.

In 1932 Stuart produced the model K 4-stroke engine, which was a single cylinder overhead valve engine designed to power refrigeration units. Only 64 were made, the last in 1938.

In 1934 Stuart introduced the S type steam engine. This was not a model but a fully enclosed single cylinder commercial power unit of 1 to 1.5HP designed to drive generators or fans or pumps. It stood 22" tall with a 10" flywheel and weighed about 120 lbs. Preston Services ^[20] have stated that there were both slide valve and piston valve versions, only 247 were made between 1934 and 1962.^[21]

In 1938 Stuart developed a single cylinder 2-stroke diesel with crankcase compression, the model H. At the time this was the smallest commercial diesel engine in the world.^[1] These engines were sold mainly to the RNLI for charging batteries.^[22]

Stuart Turner Ltd during World War II (1939–1945)

The company produced a number of products for the military including combined boiler, steam engine and generator plants, designed to be used by resistance fighters or troops operating covertly behind enemy lines to power radio transmitters. The first of these modest-sized steam generator plants was called the Firefly, and was based around the Stuart Sirius engine,^[23] later ones named Mk814 had a bespoke single cylinder piston valve engine.^[24][25]

Stuart also produced many internal combustion generators with uses such as charging aircraft batteries, and providing dummy runway lights on fake airfields. Stuart engines were built into the back of AEC fuel bowser trucks to drive a Zwicky Ltd pump to transfer fuel to aircraft.^[2] These P5XC engines were referred to in-house as the Zwicky engines.

Stuart Turner Ltd after World War II

Stuart Turner continued to make engines (especially marine engines), pumps, generators, and model kits throughout the post-war years, though several of the pre-war model internal combustion engines did not reappear.

The pre-war single-cylinder diesel engine was joined by a new twin cylinder 2-stroke diesel in 1953,^[26] the H2/H2M/H2MR. Whereas the single had used crankcase compression to scavenge the cylinder, the twin cylinder had two air pumps. Rated at 9HP, the capacity was 780cc, and weight 240 kg. The single cylinder diesel was phased out in 1960 and the twin in 1968, with only about 400 of each model produced.

A four-stroke twin cylinder petrol engine (the 12HP ST4/ST4M/ST4MR/ST4RE) was introduced in May 1968. Rated at 12HP, it was the most powerful engine in the range. This side-valve engine was 955cc capacity and weighed 155 kg.^[22] Both hand start and electric start versions were produced, but production was only about 150 engines and it was phased out in 1975.

In 1969 the P5 and the P55 twin, were replaced by the more powerful 5HP P6 and 10HP P66 (both at the higher speed of 1650rpm). There were a number of detailed differences including a change to the ignition system, but the bore and stroke remained the same.

Stuart Turner marketed some small marine diesels from the Spanish marine engine company Solé as the Stuart Solé. Solé convert engines from a wide variety of manufacturers for marine use. From a 1977 Stuart Solé operators manual it is known that Stuart Solé engines were available in 6 hp and 9 hp variants, which seem identical in appearance to the Solé Mini-1 and Mini-2 engines, based on Lombardini engines and made by Solé between 1974 and 1986.^[27] These were a common fitment in vessels made by the Cornish Crabbers boat-building company in the late 70s and probably into the early 1980s, one 1981 example being listed for sale with a 11 hp Stuart Solé engine.

Stuart Turner ceased their marine engine production in 1978, and the spares and support were transferred to another company. In 1987, Stuart Turner Ltd acquired Morewood Model Engineers and the Stuart Model range moved to Cheddar in Somerset. Still branded as Stuart Models, it was a wholly owned subsidiary of Stuart Turner Ltd. Cheddar Models Ltd was formed as an offshoot from Stuart Models in the late 1980s. In 1991, the brand and range was sold to David Jones of Jones and Bradburn and it moved to Guernsey. When Cheddar Models went bankrupt in 2005 models and plans were absorbed back into the Stuart Model range. At some point, possibly as part of this reorganisation, Stuart Models had acquired the rights to the Plastow Traction Engine model range, which they sold in October 2006 to Bridport foundry of Dorset, who had been responsible for the castings. In July 2012 Stuart Models was bought by Bridport Foundry.

Stuart Turner Ltd. continued making domestic water pumps pumps staying at Henley-on-Thames, Oxfordshire, England.

List of Stuart Steam Models

No.1 

The original vertical single cylinder steam engine, bore 2", stroke 2", standing 13" high. With single sided support casting and slipper guide this form of engine is designed to run predominantly in one direction. Still available.^[28]

No.2 

A short stroke high speed version of the No 1 single cylinder steam engine withdrawn in the 1920s.

No.3 

A compound twin cylinder vertical engine, bores 1.25" and 2.25", stroke 1.5". Also available as non-compound. This has single sided support casting and slipper guide as common in marine engines^[29]

No.4 

A vertical single cylinder steam engine, bore 1.5", stroke 1.5", standing 10" high. With A-frame castings and trunk guide.^[30]

No.5 

With a 2" bore and 2" stroke, a heavy 7" flywheel, it stands 14.5" tall which is higher than the number 1. engine. It also runs at a higher speed and produces more power that the number 1. engine.

No.5A (Cygnet) 

A vertical single cylinder steam engine popular for steam boats, bore 2.25", stroke 2", standing 15" high. With A-frame castings and trunk guide.^[31]

Swan 

A vertical twin cylinder steam engine comprising two 5A engines on a common baseplate, popular for steam launches, bore 2.25", stroke 2", standing 15" high.^[32]

No.6A 

A 4HP compound twin cylinder vertical engine, bores 2.25" and 4", stroke 3", standing 20" high. A favourite for larger steam launches.

No.7A 

A vertical single cylinder steam engine, bore 1", stroke 1", standing 7.5" high. With A-frame castings and trunk guide.^[33]

No.8 

A horizontal single cylinder steam engine, bore 1", stroke 1", 8.5" long, with slipper type crosshead guide, so designed for single direction of rotation.^[34]

No.9 

A larger horizontal single cylinder steam engine, bore 1.5", stroke 1.5", 11" long, with a slipper crosshead guide, so designed for single direction of rotation.^[35]

10V 

A small vertical single cylinder steam engine, bore 0.75", stroke 0.75", standing 6.5" high. The earliest versions of this engine had a single sided support casting and slipper guide like the No.1,^[36] however this was changed to an A-frame casting and trunk guide allowing equal crosshead support when running in either direction (also easier to make on a lathe).^[37]

10H 

A small horizontal single cylinder steam engine, bore 0.75", stroke 0.75", length 6.5". This has a trunk guide so the crosshead is equally supported for either direction of rotation.^[38]

D10 

A small twin cylinder vertical steam engine (based on 10V), bore 0.75", stroke 0.75", standing 6.5" high.^[39]

Score 

A small twin cylinder horizontal engine, bore 0.75", stroke 0.75", length 6.5".^[40]

S50 

A small horizontal single cylinder steam engine, bore 0.625", stroke 1.25", length 8.5".^[41]

Beam 

Central column style beam engine with Watt's parallel linkage, bore 1", stroke 2".^[42][43]

Half Beam 

Grasshopper style beam engine. Bore 1", stroke 2".^[44]

Major Beam 

A larger beam engine based on a model published in Model Engineering magazine in 1914. Bore 1.75", stroke 3.75", 18.25" high.^[45]

Victoria 

Typical of low pressure horizontal Victorian factory engine, 1" bore, 2" stroke, 15.5" long.^[46]

Twin victoria 

Two Victoria engines driving a common flywheel.^[47]

James Coombes 

Based on a table engine that ran at a Bristol colliery, from 1970s, 1" bore, 2" stroke, 14.5" high.^[48]

Real 

Another 1970s introduction based on a colliery engine. Overhead crank engine, 1" bore, 2" stroke, 15.5" high^[49]

Williamson 

A model based on an engine made by Williamson of Kendal. This model was researched and designed by Tom Walshaw (pen name Tubal Cain) in 1976. Bore 0.625", stroke 1.125", 11" tall.^[50]

Oscillator 

Also listed as the "S.T." engine. The cylinder pivots thereby alternately uncovering inlet and exhaust ports (see Oscillating cylinder steam engine). Bore and stroke 7/16".^[51]

Twin Oscillator 

Twin oscillating cylinders set in a 90-degree V to drive a common crank. Introduced c1930.

Puffin 

Twin oscillating cylinders set in-line. A model sold as a complete steam plant with boiler as part of the Cheddar Models range in the 1990s, and absorbed into the Stuart Models range where it was made available as a ready-made stand alone engine, or a complete plant with boiler. It has 7/16" bore and stroke.

Pintail 

Twin oscillating cylinders set in-line. Like the Puffin, this was a model sold as a complete steam plant with boiler as part of the Cheddar Models range in the 1990s, and absorbed into the Stuart Models range where it was made available as a ready-made stand alone engine. It has 5/16" bore and 7/16" stroke.

Progress 

This was actually a range of engine kits designed for the owner of only a small lathe, with the cylinder already bored and faced. These were produced in the 1920s and 1930s. There was the vertical oscillating (OV), horizontal oscillating (OH), the vertical slide valve (SV) the horizontal slide valve (SH), and the horizontal mill (HM). The horizontal oscillating engine has been recently re-introduced by Stuart Models.^[52]

Meteor 

A small vertical single cylinder marine engine designed for 30" boats. 7/16" bore and stroke, table style engine supported on 4 columns with trunk crosshead guide and piston valve. Listed through 1930s.

Simplex 

A small vertical single cylinder engine made in the 1920s, maybe a precursor to the Meteor, with slide valve. Bore and stroke 0.625".^[53]

BB 

5" tall enclosed vertical steam engine with single sided ball bearing crankshaft and aluminium crankcase available in 1930s for model boats, e.g. hydroplanes. Bore 0.75", stroke 0.625".^[54]

Twin Launch 

Twin cylinder vertical launch engine, bore 1", stroke 0.875". The cylinders are supported on 5 steel columns, and there is single sided crosshead support.^[55]

Compound Launch 

Twin cylinder vertical launch engine but with compound cylinders, bore 0.75" and 1.25", stroke 0.875".^[56]

Triple Expansion 

As in best marine practice, three vertical cylinders 0.75", 1.25", 1.75" all 1" stroke.^[57]

MTB engines 

These were a range of twin cylinder enclosed engines first introduced in 1906–1909 and resembling the Westinghouse full scale engines (link to sectioned view). The design was aimed at small high speed boat models, of which the motor torpedo boat was in vogue. Ray Nightingale produced a review of the history of these engines.^[58]

No.1 MTB 

0.75" bore and stroke, with cam driven slide valve gear. Available as a complete engine or a set of castings. Weight 2 lbs.

No.1a MTB 

0.6875" bore and 0.625" stroke but all aluminium body with brass cylinder liners. Slide valve driven by bevel gear and scotch crank. Available into the 1920s either as a complete engine or a set of castings. Weight 14.5oz.

No.1b MTB (180) 

As the No1 engine but with bevel gear and scotch crank to drive the slide valve. Many have casting number '180' visible. Introduced between 1910 and 1923.

No.2 MTB 

As No1 engine but with two geared together contra-rotatory crankshafts. Slide-valve. Ideal for driving twin prop model boats with no torque reaction. Dropped sometime prior to 1924.

No.3 MTB (255) 

A larger version of the engine, with 1.25" bore and 1" stroke. The bevel drive valve gear is enclosed. Casting number 255 on the crankcase. These appeared in about 1924 and were available for 10 years. They were also sold as stationary engines and would drive 120 to 150W output.

Star 

The aluminium bodied Star was introduced in 1926 (as was the Isis steam launch she powered). Although similar in design it was a completely new engine, and was only available as a finished item. It had 0.625" bore and stroke. It used the bevel drive, but this time enclosed within the crankcase. For the valve gear it used a banjo drive to a close fitting piston valve. This having significant advantages for 'flash' steam plant which could be very high pressure. This engine was produced until the 2nd World War.

Sun 

The Sun was launched in 1927 as a direct replacement for the 1b MTB engine. Like the Star, the bevel drive was moved inside the crankcase, and banjo drive was used with a choice of either piston valve or slide valve. Bore and stroke were 0.75". While the slide valve variant was only available as a kit, the piston valve version was available as a complete engine or kit. The Sun continued after the war as a piston valve kit only and last appeared in the Stuart catalogue in 1989/1990.

Sirius 

The Sirius was introduced in 1938 as a more powerful version of the Star, with 1" bore and stroke. The Sirius was to be the driving force in the Firefly generator set during the war, and is still available (2014). At over 6.5 lbs, it was three times heavier than the No1 MTB from which it was descended. It is rated at 1/3 hp at 2800rpm and 80psi.^[59]

Steam Hammer 

This is 1" bore and 2" stroke, and is a scale model of Rigby's Patent steam hammer made with the co-operation of its manufacturer at the time, R.G.Ross & Son Ltd. It stand 10.5" tall, and weighs 9 lb.^[60]

Steam Boiler Feed Pump 

This is 0.5" bore and 0.75" stroke, and has a conventional slide valve cylinder actuated by the pump rod.^[61]

H.U. Horizontal Undertype 

This combined horizontal boiler with engine below dates back to a design for a compound undertype engine by Henry Greenly in c1901.^[62] It is in the Stuart catalogue for 1928, but was dropped by 1940.^[63] After a redesign by H.A.Taylor a larger version of the undertype was re-released onto the market by Stuart Turner in 1973. This later model had an aluminium baseplate 25" long, whereas the original model had a smaller cast iron baseplate.

Gas/Petrol Engine Kits

400 

A horizontal single cylinder open-crank gas engine with hot tube or spark ignition^[64][65]

600 

A substantial horizontal single cylinder open-crank gas (0.75HP) or petrol (1.0HP) engine. 2.5" bore, 4.5" stroke. From ST's 1930 catalogue "Its very efficient governor renders it particularly adaptable for lathe driving, and other variable loads".^[66]

800 

A smaller horizontal single cylinder open-crank gas (0.25HP) or petrol (0.5HP) engine based on the 600, but better suited to being made with a small lathe. 1.5" bore, 2.75" stroke.^[67][68]

Sandhurst 

A horizontal single cylinder open-crank gas (0.66HP at 900rpm) or petrol engine. 2" bore, 3" stroke, 150cc, c1935, but also listed in the 1969 Stuart catalogue.

AE 

A 60cc four stroke flat twin supplied only as castings, air or water cooled. Could also be supplied as a single cylinder model, which was a useful capacity for 30cc tethered boat and hydroplane class. 34.5mm bore, 32mm stroke. Made from around 1910–1912, these early version had an automatic inlet valve.^[69]

New AE 

A 60cc four stroke flat twin supplied only as castings, air or water cooled. The 'new' version was introduced in c1930 and produced until the war. It had both crankshaft and camshaft running in ball bearings, duralumin connecting rods, aluminium piston, and valves all mechanically operated. There was also a single cylinder version. The twin produced 3/4bhp at 3000rpm, and 1.3bhp at 4200rpm, weight 7.5 lbs including the flywheel. The single weighed 4.25 lbs and produced 0.6bhp at 4500rpm. In the 1938/1939 Stuart catalogue the air cooled version of the twin cylinder engine was also available with 1.5in bore and 1.75in stroke, giving 74cc. The advertising suggests the main market for these engines was 'record breaking model boats and hydroplanes', and the single's 30cc capacity was stated in 1931 to 'conform(s) to the rules of International Power Boat racing'.^[70]

Lightweight 

With the same bore and stroke as the AE, the lightweight single cylinder 2-stroke is 29cc, 1/8 bhp, revs to 3500rpm, and weighs 3 lb 12oz, 5 lb 12oz with flywheel. Like many Stuart engines the Lighweight had iron pistons. It was water cooled, and was available either as a finished engine or as a set of castings. Advertised in the 1931 catalogue as 'completely redesigned' making it 'easier to machine and lighter', it was probably introduced in the late 1920s, and was for sale through the 1930s, advertised sitting in the palm of your hand.^[71] It also appeared in the 1969 catalogue as a kit either water or air cooled, this time with an aluminium piston. An Amal carburettor was available as an optional extra.

W2 

Three 147cc engines were listed as new in the 1931 Stuart Turner catalogue all rated at 1/2 HP at 1000rpm. With 53mm bore and stroke the W2 was a 2-stroke, and water cooled. The engine featured a cast iron piston and steel H section connecting rod. The steel crankshaft could be supported in either plain or ball bearings. The kit did not include a carburettor, stating that 'any good carburetor of the correct size may be used', though a range of extras listed included a Villiers carburetor. Likewise the magneto wasn't included, stating that 'any standard single cylinder magneto of 35mm centre-height may be used', though an English magneto of unspecified make was listed among the extras available.

A2 

The air cooled version of the W2, identical in every other respect. In this kit only the cylinder was provided ready machined and ground. In the other kits this could be requested as an option.

W4 

A water cooled 4-stroke overhead valve version of the W2. Separate inlet and exhaust camshafts ran in bronze bearings. The gear wheels to drive them were supplied ready-made. The four stroke crankshaft could only use ball bearings.

Other casting kits

Compressor 

A compact twin cylinder air compressor, 2200cu in air per minute at 1400rpm.^[72]

Oil Field Pump 

Known colloquially as the Nodding Donkey, this class of pump is used in onshore oil fields around the world. Height 12".

Manual Boiler Feed Pump 

Hand cranked, 3/8" bore, 5/8" stroke, 4.5" long.

Pillar Drill 

9" high miniature pillar drill for the model workshop.

Lathe 

8.5" long miniature lathe for the model workshop.

Shaper 

6.5" high miniature shaper for the model workshop.

References

See Also

• Whitney (City Road, London) who made lighting plant, generators, small steam models and centrifugal pumps

External links

• Stuart Models website
• Summary of many Stuart models