Introduced at the Scottish Show in November 1938, the Nippy 3 tonner (3,048kg) was a four-wheeler of pleasing, modern appearance, available with two alternative wheelbases. Also, normal and forward control versions were offered, as the GF/TC4 and HF/TC4, respectively. The Nippy was one of two new lorries listed for 1939, the other being the Dreadnought twin steering-axle RSW, and both these vehicles followed the usual lorry design layout of a separate body mounted on a chassis frame. The makers offered a drop-sided body as standard for the Nippy. Power came from a relatively small four-cylinder TC4 engine of 3.865 litres, giving 60bhp at a lively 2,400rpm. An Autovac vacuum device was fitted as standard equipment for raising fuel to the carburettor from the petrol tank. The latter was fixed externally to the left side of the chassis frame, just behind the cab.
Following normal Thornycroft practice, the Nippy’s engine was in unit with the gearbox, a four-speed unit, from which a propeller shaft transferred power to the rear axle. The latter incorporated a spiral-bevel final drive instead of Thornycroft’s much-used worm gear. Standard equipment included Girling hydraulic drum brakes on all four wheels, electric direction indicators (known as trafficators) and a windscreen wiper for the driver only. Surprisingly, an electric starter was not included in the standard specification, although one was available at extra cost. By 1939 customers expected electric starters to be fitted as standard on modern medium-weight lorries.
TC4 engine comments: this petrol engine appeared in 1936 when it was used in the Sturdy of 4 tons to 5 tons (4,064kg to 5,080kg) capacity. The TC4 was a side-valve engine, despite Thornycroft’s use of more modern overhead valves in other petrol engines at the time of the TC4’s introduction. However, Thornycroft was not alone among vehicle manufacturers in using side-valve engines. The TC4 replaced the 3.625 litre GD4 55bhp four-cylinder engine, which was withdrawn in 1935, the year before the TC4’s introduction. Thornycroft’s other ‘small’ petrol engine, the 50bhp 3.625 litre FB4/1, was in production when the TC4 appeared, and was finally dropped in 1938, leaving the TC4 to represent Thornycroft in the small petrol engine class.
“Nippy” Class 3 ton (3,048kg) chassis, petrol-engined forward-control type “HF/TC4” long-wheelbase
In-line cylinders. A single casting of iron is used for the cylinder block and crankcase, with side valves housed in the cylinder block. Renewable exhaust valve seatings, dry cylinder liners and Thornycroft-made aluminium-alloy pistons are fitted. The cast-iron cylinder head is of the Ricardo-type.
The camshaft operates the valves through inverted-mushroom type tappets, and is driven by a triple-roller chain.
Crankpin and main-journal diameters are 2¼ins (5.72cm).
Forced feed system from a pump.
By carburettor. The inlet manifold has an exhaust-heated hot spot.
By centrifugal water pump (incorporates a carbon gland).
Borg and Beck dry plate clutch of 12ins (30.5cm) diameter and 140sq ins (903.2sq cm) frictional area.
Unit with engine and clutch, and providing four forward speeds and a reverse speed.
The overall gear ratios are as follows (including final drive)
Layrub two-piece type with universal couplings.
One piece type.
Incorporates fully floating half-shafts, spiral-bevel final drive and differential.
Leaf type. Distance between rear spring eye centres is 4ft (1.22m).
Girling drum brakes on all four wheels, pedal operated through a Lockheed hydraulic system. The diameter of the front and rear brake drums is 14ins (35.6cm) Front drums are 1.75ins (4.45cm) wide. Rear drums are 3ins (7.62cm) wide. Total frictional area is 232sq ins (1496.8sq cm).
Operates on the rear wheels by mechanical means.
The turning circle is 48ft (14.6m) on both locks.
Pressed steel. Maximum depth of side members is 7ins (17.8cm).
A 15-gallon (68.2 litres) fuel tank is carried on the nearside of the chassis frame. An Autovac vacuum device, fixed in front of the passenger’s seat, draws the fuel from the main tank and delivers it by gravity to the carburettor.
Wheels and Tyres
Tyres are 32ins x 6ins (81.3cm x 15.2cm) on pressed steel wheels, single front, twins at rear. The standard position for carrying the spare wheel and tyre is at the rear underneath the frame.
Equipment. An electric lighting set combined tail and “stop” light, instrument panel, driver’s electric windscreen wiper, trafficator (i.e. turn indicator), dynamo, battery, spare wheel, tyre and carrier, Lockheed brake fluid container with hexagonal filler cap, etc. An electric starter is available at extra cost.
Information for these pages comes from contemporary Thornycroft technical and other data, as well as contemporary copies of The Commercial Motor.
Nippy outline diagram 54kb pdf