1. 2 seater.
Specification.
Chassis. As per. ‘Mark II’ short chassis, 11’ 6" in length. The assembly of all components on the chassis was done using split-pinned slotted nuts throughout. The front axle and steering gear were finished in polished steel.
Engine.
Bore 69.3 mm, stroke 99 mm, 1495 cc. Fitted with ‘Laystall’ billet crank and domed high compression pistons.
Compression ratio: 9.5:1, using a high compression cylinder head fitted with 1¾" inlet valves, double valve springs and R209 camshaft.
Power: 80 bhp at 5250 rpm.
Torque: approximately 75 lbft at 5250 rpm.
Twin side draught 1⅜" carburettors with aluminium bodies. CV needles in .100" jet.
Magneto ignition by Scintilla PN4.
Twin SU L type fuel pump, mounted on the off side top of the chassis in the engine compartment. Each pump feeds to one carburetor, with link pipe.
‘Autoklean’ oil filter with larger oil pipes with ½" BSP fittings.
Transmission. Aston Martin designed 4 speed crash gearbox, and open propeller shaft, as per ‘Mark II’. Gear ratios: 11.5:1, 7.15:1, 5.22:1, 4.11:1. Special ratios were offered at extra cost.
Steering. ‘Marles’ worm and peg, with a bearing at the top of the steering column.
Wheels and tyres. ‘Rudge Whitworth’ 52 mm 18" well base wire wheels with 60 spokes and 2 ¾" rims fitted with 5.25/5.50 tyres.
Suspension. Semi elliptic leaf springs front and rear. Hartford friction dampers were fitted, being transverse at the front. Two extra rebound spring leaves are fitted at the front on top of the main leaf, making ten leaves in total.
Brakes. 14" diameter steel fabricated drums with cam operated 1½" aluminium shoes, mounted on two pivots. Brakes were actuated by cable and rod. The handbrake worked on all four wheels.
Dimensions.
Wheelbase: 8’ 7".
Track: 4’ 4".
Length: 12’ 8".
Height: 4’ 7" hood raised.
Weight: 18 cwt.
Fuel tank capacity: 15 gallons.
Price: £750
Coachwork. A lightweight ash frame was panelled in aluminium, the dimensions being to International sports car racing regulations as defined by the Association Internationale des Automobile Clubs Reconnus (AIACR), later known as the FIA. The body was a simple, narrow, doorless tub, with the spare wheel mounted horizontally on the chassis, directly behind the rear axle. The shape of the coachwork at the rear was therefore determined by the diameter of the spare wheel. The single fifteen gallon fuel tank was mounted over the rear axle and was fitted with two fillers. Two bucket seats were fitted with deep sides, mounted on two 1" x ¼" steel strips bolted to the top of the front main cross member and onto the bottom of the second main cross member, thereby giving a distinct and ergonomic angle to the seat. A fold flat windscreen with slightly curved top frame was fitted to the flat scuttle, with wind deflectors that doubled up as aero screens. A simple hood attached to the screen by ‘lift the dot’ studs had a single bow. Later cars had lower radiators, as did the later team cars. The outside exhaust had a four branch manifold with ‘Brooklands’ box and ‘fishtail’. The bonnet was heavily vented, with out-dented louvers necessitated by the full length under tray, and was secured with two leather straps with quick release catches. The filler caps were all attached to the body with leather thongs. Simple ‘cycle type’ wings were fitted, secured to the wing stays with bolts and split-pinned slotted nuts (to the outside), with 2" diameter rubber washers and steel cup washers on the wings. The wing stays were mounted on rubber mounts, with rubber insulated washers on the mounting bolts. Two production 2 seater ‘Ulsters’ were fitted with the ‘Mark II’ type helmet wings and at least one car was made with aerodynamic valances as per one or two of the later works team cars.
All the components of the running gear on the ‘Ulster’ were secured by slotted nuts and split-pins. This made the assembly of the chassis rather slow and difficult, each nut needing to be individually pinned.
The ‘Ulster’ was a very carefully thought out and purpose built sports racing car. They were well balanced and were very easy and comfortable cars to drive. This was particularly important for long distance motor racing and it must have been a contributory factor to the great success these cars had in long distance events, including at the TT, Le Mans, the Mille Miglia and the Targa Abruzzo.
2. 2/4 Seater
Three of the production ‘Ulsters’ were fitted with 2/4 seat coachwork and ‘helmet type’ wings from new, making them almost indistinguishable from the short chassis ‘Mark II’. One was fitted with a louvred (but painted) radiator. A fourth car had its two seater body removed after a crash whilst testing at Brooklands and was also fitted with 2/4 seater coachwork.
Specification
As per 2 Seater.