The Sunbeam Rapier is an automobile produced by Rootes Group from 1955 until 1976, in two different generations, the "Series" cars (which underwent several revisions) and the later (1967–76) fastback shape, part of the "Arrow" range.

The first generation Rapier was the first of the "Audax" range of light cars produced by the Rootes Group, in this instance as part of their Sunbeam marque.

Announced at the London Motor Show in October 1955,[1] it preceded its Hillman Minx and Singer Gazelle counterparts which were not introduced until 1956.

The Rapier's 1,390 cc (85 cu in) engine was essentially the same as that fitted to the Hillman Minx but with a raised compression ratio (8:1 instead of 7:1), a Zenith DIF 36 carburettor and revised inlet and exhaust manifolds.

The capacity increase combined with a higher compression ratio of 8.5:1 and larger inlet and exhaust valves to raise the power output to 73 bhp (54 kW) at 5,200 rpm.

Rootes stylists completely redesigned the seats and interior panels and specified that they be trimmed in single colour vinyl with contrasting piping.

Although the engine's displacement was still 1,494 cc (91.2 cu in), it was fitted with a new eight-port aluminium cylinder head with an increased compression ratio and redesigned valves, and used a new, sportier camshaft.

[citation needed] In addition, the Series IIIA included many detail changes such as an increased diameter front anti-roll bar which greatly improved roadholding, a redesigned clutch bell housing, a revised clutch assembly with nine pressure springs instead of six and a redesigned air cleaner assembly.

[1] All of these changes combined to make the Series IIIA subtly different from its predecessor and to give the Sunbeam Rapier a new lease of life in the showroom.

It was no longer the mainstay of the competitions department because Rootes had directed its motor sport effort towards the Hillman Imp and the Sunbeam Tiger.

In fact a totally new Series IV Rapier had been designed, prototypes built and testing completed, and then the Rootes Group changed its focus.

The proposed 'Series IV' became the Mark I Humber Sceptre and the old Series IIIA Rapier was redesigned, hopefully to give it a new lease of life as a touring saloon rather than a sports coupé.

This meant that the stainless steel wheel trims of earlier Rapiers were replaced by Rootes corporate hub caps and rim finishers.

The traditional Sunbeam grille, already stylised for the Series II, was further modified to give a lower, more square shape with a pronounced convex profile.

New headlamp rims were fitted, in fact Sunbeam Alpine items but chromed for the Rapier, and a new front bumper using the same shape and profile as the rest of the Light Car range.

Finally, small badges fitted at the bottom of each front wing and on the boot lid proclaimed each car to be a "Series IV".

The 1,592 cc (97.1 cu in) engine from the Series IIIA was unchanged but the twin Zenith carburettors finally gave way to a single twin-choke Solex 32PAIA in the interests of serviceability.

In October 1964, along with the rest of the light car range, the Series IV received the new Rootes all synchromesh gearbox, a change which coincided with the introduction of a new computerised chassis numbering system.

[9] Rootes redesigned the Rapier's four-cylinder engine to increase the capacity, with a new five main bearing crankshaft, making the unit stronger and smoother.

As well as the Hillman Hunter, the range also included a new generation of Sunbeam Rapiers, with fastback coupé bodies and a sporty image.

The Arrow Rapier – or Fastback, as it came to be known – launched in October 1967,[11] was a four-seat coupé based on the chassis of the Hillman Hunter Estate.

The Rapier used the Rootes four-cylinder, five-bearing 1,725 cc (105.3 cu in) engine, which was tilted slightly to the right to enable a lower bonnet line, in common with the other Arrow models.

During its lifetime it formed the basis for the more powerful Sunbeam Rapier H120, introduced in October 1968[11] and identifiable by its boot-lid spoiler and polished sill covers: it shared its Holbay Engineering-tuned 110 hp (82 kW; 112 PS) engine (with twin Weber carburettors) with the Hillman Hunter GLS.

The Rapier was also the basis for the slightly cheaper but similarly bodied, single-carburettor Sunbeam Alpine Fastback introduced in October 1969.

[12] The Sunbeam Alpine Fastback, introduced in October 1969, was essentially a Rapier with a simplified specification, developed to fill a gap in the Arrow range above the Singer Vogue.

It used the same 1,725 cc (105.3 cu in) engine as the Hillman Hunter which, fitted with a single Stromberg 150CD carburettor, developed 74 hp (55 kW) at 5500 rpm.

To add to its sporty image, the H120 had wider Rostyle wheels,[6] broad side flashes, polished sill covers, a matt black radiator grille and a new boot lid incorporating a faired-in spoiler.