Жагуар XK120: Жылдамдық пен инновацияның тарихы

The XK120 was launched in open two seater or (US) roadster form at the 1948 London Motor Show as a testbed and show car for the new Jaguar XK engine designed by Jaguar Chief Engineer William Heynes. The display car was the first prototype, chassis number 660001. It looked almost identical to the production cars except that the straight outer pillars of its windscreen were curved on the production version. The sports car caused a sensation, which persuaded Jaguar founder and Chairman William Lyons to put it into production. Beginning in 1948, the first 242 cars were wood framed open 2 seater bodies with aluminium panels. Production switched to the 1cwt or heavier all steel in early 1950. The "120" in the name referred to the aluminium car's 120 mph (193 km/h) top speed (faster with the windscreen removed), which made it the world's fastest production car at the time of its launch. In 1949 the first production car, chassis number 670003, was delivered to Clark Gable. The XK120 was ultimately available in three body styles, all two seaters and available either as Left (LHD) or Right Hand Drive (RHD): an open 2 seater described in the US market as a roadster (OTS); a fixed head coupé (FHC) from 1951; and a drophead coupé (DHC) from 1953. Certain Special Equipment roadster and fixed head coupe cars were produced were sold between 1948 and 1949 as an early production build for enthusiasts, denoted by an 'S' preceding the chassis number. A version with a smaller engine (2 litre 4 cylinder) designated the XK100 and intended for the UK market was cancelled prior to production. On 30 May 1949, on the empty Ostend Jabbeke motorway in Belgium, a prototype XK120 timed by the officials of the Royal Automobile Club of Belgium achieved an average of runs in opposing directions of 132.6 mph with the windscreen replaced by just one small aero screen and a catalogued alternative top gear ratio, and 135 mph with a passenger side tonneau cover in place. In 1950 and 1951, at Autodrome de Linas Montlhéry, a banked oval track in France, open XK120s averaged over 100 mph for 24 hours and over 130 mph for an hour. In 1952 a fixed head coupé took numerous world records for speed and distance when it averaged 100 mph for a week. XK120s were also highly successful in racing and rallying.

The first 242 production XK120s, hand built with aluminium bodies on ash framing, were constructed between late 1948 and early 1950. To meet demand, and beginning with the 1950 model year, all subsequent XK120s were mass produced with pressed steel bodies. Aluminium doors, bonnet, and boot lid were retained. The DHC and FHC versions, more luxuriously appointed than the constantly exposed open cars, had wind up windows and wood veneers on the dashboard and interior door caps. The XK120’s steel chassis was mostly copied from the Jaguar Mark V, using many of the same parts. The dual overhead cam 3.4 L straight 6 XK engine was highly advanced for a mass produced unit of the time, featuring a high temperature, high strength aluminum alloy cylinder head, hemispherical combustion chambers, inclined valves, and twin side draft SU carburetors. Using 80 octane fuel a standard 8:1 compression ratio developed The XK engine's basic design by William Heynes, later modified into 3.8 and 4.2 litre versions, survived until 1992. All XK120s had independent Heynes designed torsion bar front suspension, semi elliptic leaf springs at the rear, recirculating ball steering, telescopically adjustable steering column, and all round 12 inch drum brakes which were prone to fade. Some cars were fitted with Alfin (ALuminium FINned) brake drums to help overcome the fade. The open two seater provided little weather protection. Its lightweight folding canvas top and detachable sidescreens stowed out of sight behind the seats. The doors had no external handles; they were opened by an interior pull cord, accessed through a flap in the sidescreens when the weather equipment was in place. The windscreen could be removed for aeroscreens to be fitted. The drophead coupé (DHC) had a padded, lined canvas top, which folded onto the rear deck behind the seats when retracted, and roll up windows with opening quarter lights. The flat glass two piece windscreen was set in a steel frame that was integrated with the body and painted the same colour. Dashboards and door caps in both the DHC and the closed coupé (FHC) were wood veneered, whereas the open cars were leather trimmed. All models had removable spats ("fender skirts" in America) covering the rear wheel arches, which enhanced the streamlined look. On cars fitted with optional centre lock wire wheels (available from 1951), the spats were omitted as they gave insufficient clearance for the chromed, two eared Rudge Whitworth knockoff hubs. Chromium plated wire wheels were optional from 1953. Factory standard 6.00 × 16 inch cross ply tyres were fitted on 16 × 5K solid wheels (Pre–1951), with 185VR16 Pirelli Cinturato radial tyres available as a later option. In addition to wire wheels, upgrades on the Special Equipment (SE) version (called the M version for Modified in the United States) included increased power, stiffer suspension and dual exhaust system.

+ XK 120 ENGINES Model Years Displacement Configuration Bore x stroke Carburetor Power XK 120 3.4 1948–1954 DOHC Straight 6 Double SU H6 @ 5000 rpm XK 120 3.4 SE for Special Equipment (unofficially called the "M" for Modified in the USA) higher lift camshafts and twin exhaust pipes offered as a factory option beginning mid 1951 per Service Bulletin #95 dated June 1951 @ 5300 rpm XK 120 3.4 modified by agent/dealer or owner (C Type Head and larger SU carbs) racing parts made available through agents/dealers beginning in 1953 per Service Bulletin #95A dated April 1953 Double SU H8 @ 5750 rpm XK 120 3.4 modified by agent/dealer or owner for racing (C Type Head and Weber carbs) racing carbs and manifold not supplied by the factory Double DCO3 40mm Weber

The Motor magazine road tested an XK120 in November 1949. This pre production car, chassis number 660001, road registered as HKV 455, was the first prototype built. It was also the 1948 London Motor Show display model, and had been driven by Prince Bira in the 1949 Silverstone Production Car Race. When tested, it had the 8:1 compression ratio, was fitted with an aerodynamic undertray, and ran with hood and sidescreens in place. The magazine reported a top speed of , acceleration from 0– in 10.0 seconds and fuel consumption of The car as tested cost £1263 including taxes. The XK120 M for US market accelerated from 0– in 8.7 seconds, top speed was by the speedometer, but actual top speed was about .

First race victory: In the Daily Express sponsored One Hour Production Car Race held on 30 August 1949 at Silverstone Circuit, England, Leslie Johnson drove the Jabbeke car to the XK120's first ever race victory (despite an early collision with a spinning Jowett Javelin which dropped the Jaguar to fifth). Haines, with co driver Peter Clark, finished 12th, and Walker's car, driven by Peter Whitehead and John Marshall, was 15th. Targa Florio: Biondetti's car, the first XK120 to contest the Targa Florio, lay second to Alberto Ascari's Ferrari when a connecting rod broke, ending the Jaguar's run. Mille Miglia: Johnson took fifth place in the Mille Miglia, with John Lea as his riding mechanic, while Biondetti and co driver Gino Bronzoni finished eighth. Fifth was an outstanding achievement for a production car, with Johnson's Jaguar beaten only by Fangio's works Alfa Romeo and the works Ferraris of Serafini, Bracco and winner Marzotto. It was Jaguar's best ever finish in the Mille Miglia; also the best by a British car and driver combination, a feat that only Reg Parnell ever equalled, driving an Aston Martin DB3 in 1953. Silverstone Production Car Race: Five XK120s entered the race, which Peter Walker won from Tony Rolt, with Johnson recovering to eighth after spinning on oil. Jaguar won the team prize. Tourist Trophy: XK120s also achieved a 1–2–3 victory in the TT, held at Dundrod in heavy rain. On the eve of his 21st birthday Stirling Moss drove Tom Wisdom's car to a brilliant win ahead of Whitehead and Johnson, and Jaguar once again took the team prize. won the first Grand National road race, held at Linden Airport, New Jersey, on 13 June 1954. Foreign made cars were banned from this series after this race.

through the flying mile: in May, Jaguar demonstrated an XK120 to the press on the high speed autoroute between Jabbeke and Aalter in Belgium. The road was closed for the occasion. The white left hand drive car, chassis number 670002, was the second XK120 built. Jaguar's development engineer Walter Hassan was to have driven but fell ill, so Jaguar test driver Ron "Soapy" Sutton substituted. With hood and sidescreens erected, and the airflow under the car improved by the addition of a full length aluminium undertray, the Jaguar was timed through the flying mile by the Royal Automobile Club of Belgium at With hood, sidescreens and windscreen removed, a metal airflow deflector fitted in front of the driver, and a tonneau cover fastened over the passenger side of the cockpit the speed improved to The Observer's Book of Automobiles said it was the fastest production car in the world. The Special Equipment 'S' series cars made in 1948 1949 had better compression ratios and were capable of top speeds of 128 mph.

for 24 hours (including stops for fuel and tyres): Leslie Johnson sharing his XK120 JWK 651 with Stirling Moss at the Autodrome de Montlhéry, a steeply banked oval track near Paris. The first time a production car had averaged over for 24 hours. Changing drivers every three hours, the Jaguar covered 2579.16 miles, with a best lap of .

131.83 mile (212 km) for one hour: Johnson solo in JWK 651 at Montlhéry. "No mean feat driving at almost twice today's maximum (UK) speed limit into a steep turn, assaulted by the G Force induced by 30 degree banking twice every minute, using Forties technology, leaf spring" (rear) "suspension and narrow cross ply tyres Johnson remarked that the car felt so good it could have gone on for another week, an off the cuff comment that sowed the seed for another idea. Flat out for a week "

A 2 litre four cylinder version of the twin cam XK engine was to have powered an XK100 variant of the XK120 for the UK market. Details of the model were included in an "Advance Particulars" brochure for the XK but Jaguar's managers were dissatisfied with the engine and the project was cancelled prior to production.