Debut: August 2017



.: Harry Edmond's Resurrected 1930 4.5 Litre Supercharged Bentley





Modelling Time:

60 hrs

PE/Resin Detail:



"Model was built with scratch-built parts & needed a lot of work on the body panels.
Parts were missing, including engine, supercharger & more."

Bentley 4½ Litre

From Wikipedia, the free encyclopedia
Bentley 4½ Litre
1928 Bentley Saloon at Toddington Railway Gala, 0513 8979023957.jpg
Manufacturer Bentley Motors Limited
  • 1927-1931
  • (supercharged model from 1929)
  • 720 produced
Assembly Cricklewood, UK
Designer Walter Owen Bentley
Body and chassis
Class Sports car chassis
Body style as arranged with coachbuilder by customer[1]
Layout FR layout
Related Blower Bentley (supercharged model)
Transmission 4-speed manual
  • Standard: 10 ft 10 in (3,300 mm)[2]
  • SWB (8 made):[2] 117.5 in (2,980 mm)
Length 4,380 mm (172.4 in)
Width 1,740 mm (68.5 in)
Kerb weight
  • 4½ Litre: 1,625 kg (3,583 lb)
  • Blower: 1,727 kg (3,807 lb)
Predecessor Bentley 3 Litre
Successor Bentley 6.5 Litre

The Bentley 4½ Litre was a British car based on a rolling chassis built by Bentley Motors.[1] Walter Owen Bentley replaced the Bentley 3 Litre with a more powerful car by increasing its engine displacement to 4.4 L (270 cu in).

Bentley buyers used their cars for personal transport and arranged for their new chassis to be fitted with various body styles, mostly saloons or tourers.[1] However, the publicity brought by their competition programme was invaluable for marketing Bentley's cars.[citation needed]

At the time, noted car manufacturers such as Bugatti and Lorraine-Dietrich focused on designing cars to compete in the 24 Hours of Le Mans, a popular automotive endurance course established only a few years earlier. A victory in this competition quickly elevated any car maker's reputation.

A total of 720 4½ Litre cars were produced between 1927 and 1931, including 55 cars with a supercharged engine popularly known as the Blower Bentley. A 4½ Litre Bentley won the 24 Hours of Le Mans in 1928. Though the supercharged 4½ Litre Bentley's competitive performance was not outstanding, it set several speed records, most famously the Bentley Blower No.1 Monoposto in 1932 at Brooklands with a recorded speed of 222.03 km/h (138 mph).


Bentley at the 24 Hours of Le Mans

The 24 Hours of Le Mans endurance race is a 24-hour race around the Circuit de la Sarthe. The inaugural race was held 26–27 May 1923, and attracted many drivers, mostly French.[3] There were two foreign competitors in the first race, Frank Clement and Canadian John Duff, the latter winning the 1924 competition in his personal car, a Bentley 3 Litre.

"Made with precision and the finest material,"[4] and with recent success, the luxurious Bentley cars attracted attention. After two years without success, Bentley convened a group of wealthy British men, "united by their love of insouciance, elegant tailoring, and a need for speed," to renew Bentley's success.[5] Both drivers and mechanics, these men, later nicknamed the "Bentley Boys", drove Bentley automobiles to victory in several races between 1927 and 1931, including four consecutive wins at the 24 Hours of Le Mans, and forged the brands reputation.[4][5]

It was within this context that, in 1927, Bentley developed the Bentley 4½ Litre. Two cylinders were removed from the 6½ Litre model, reducing the displacement to 4.4 litres.[6] At the time, the 3 Litre and the 6½ Litre were already available, but the 3 Litre was an outdated, under-powered model and the 6½ Litre's image was tarnished by poor tyre performance.[4][7][8]

Tim Birkin and the Blower Bentley

Main article: Bentley Blower No.1

Sir Henry "Tim" Birkin, described as "the greatest British driver of his day" by W. O. Bentley, was one of the Bentley Boys.[5] He refused to adhere strictly to Bentley's assertion that increasing displacement is always preferable to forced induction. Birkin, aided by a former Bentley mechanic, decided to produce a series of five supercharged models for the competition at the 24 Hours of Le Mans;[9] Mercedes-Benz had been using superchargers for years.[10]

Thus the 4½ litre Blower Bentley was born. The first supercharged Bentley had been a 3-litre FR5189 which had been supercharged at the Cricklewood factory in the winter of 1926/7.[citation needed] The Bentley Blower No.1was officially presented in 1929 at the British International Motor Show at Olympia, London. The 55 copies were built to comply with 24 Hours of Le Mans regulations.[11] Birkin arranged for the construction of the supercharged cars having received approval from Bentley chairman and majority shareholder Woolf Barnato[12][11][13] and financing from wealthy horse racing enthusiast Dorothy Paget.[12][8][14] Development and construction of the supercharged Bentleys was done in a workshop in Welwyn by Amherst Villiers, who also provided the superchargers.[15]

W.O. Bentley was hostile to forced induction and believed that "to supercharge a Bentley engine was to pervert its design and corrupt its performance."[12][14] However, having lost control of the company he founded to Barnato, he could not halt Birkin's project.[12]


Blower Bentley

Front of a "Blower Bentley", showing the supercharger in front of the grille
Intake manifold of a "Blower Bentley"

The essential difference between the Bentley 4½ Litre and the Blower was the addition of a Roots-type supercharger to the Blower engine by engineer Amherst Villiers, who had also produced the supercharger. W. O. Bentley, as chief engineer of the company he had founded, refused to allow the engine to be modified to incorporate the supercharger. As a result, the supercharger was placed at the end of the crankshaft, in front of the radiator. This gave the Blower Bentley an easily recognisable appearance and also increased the car's understeer due to the additional weight at the front.[16] A guard protected the two carburetters located at the compressor intake. Similar protection was used, both in the 4½ Litre and the Blower, for the fuel tank at the rear, because a flying stone punctured the 3 Litre of Frank Clement and John Duff during the first 24 Hours of Le Mans, which contributed to their defeat.[20][21]

The crankshaft, pistons and lubrication system were special to the Blower engine.[10] It produced 175 hp (130 kW) at 3,500 rpm for the touring model[22] and 240 hp (180 kW) at 4,200 rpm for the racing version, which was more power than the Bentley 6½ Litre developed.

4½ Litre supercharged cars

  • Supercharged engine MS3948, a late 1931 replica-bodied car in the Beaulieu National Motor Museum
  • S/c engine MS3948 dashboard
  • S/c engine MS3948 Another view of the grille, supercharger, and inlets
    . Photograph of the dashboard of a Blower Bentley .
  • A Blower Bentley from the collection of Ralph Lauren

    A Blower Bentley from the collection of Ralph Lauren.

Competition performance

Bentley racing car "Mother Gun", built 1927, 4.5 ltr. engine.
Bentley 4½ Litre No. 10 took third at the 1929 24 Hours of Le Mans

Between 1927 and 1931 the Bentley 4½ Litre competed in several competitions, primarily the 24 Hours of Le Mans. The first was the Old Mother Gun at the 1927 24 Hours of Le Mans, driven as a prototype before production.[23]Favored to win, it instead crashed and did not finish. Its performance was sufficient for Bentley to decide to start production and deliver the first models the same year.[10]

Far from being the most powerful in the competitions, the 4½ Litre of Woolf Barnato and Bernard Rubin, raced neck and neck against Charles Weymann's Stutz Blackhawk DV16, setting a new record average speed of 111.12 km/h (69 mph); Tim Birkin and Jean Chassagne finished fifth. The next year, three 4½ Litres finished second, third, and fourth behind another Bentley, the Speed Six, which possessed two more cylinders.[13][23][24]

The naturally aspirated 4½ Litre was noted for its good reliability. The supercharged models were not; the two Blower models entered in the 1930 24 Hours of Le Mans by Dorothy Paget, one of which was co-driven by Tim Birkin, did not complete the race.[24] In 1930, Birkin finished second in the French Grand Prix at the Circuit de Pau behind a Bugatti Type 35.[3][13][24] Ettore Bugatti, annoyed by the performance of Bentley, called the 4½ Litre the "fastest lorry in the world." The Type 35 is much lighter and consumes much less petrol.[9][10] Blower Bentleys consume 4 liters per minute at full speed.[21]

Despite the Blower's record of poor reliability, Mildred Bruce, a British female racer, achieved a 24-hour distance record at Montlhéry in one, attaining an average speed of 89.4 mph (143.89 km/h).[25] In 1930, the Daily Heraldoffered a trophy for the fastest driver at an event at Brooklands. The first year, Tim Birkin and Kaye Don competed and Kaye Don won with a speed of 137.58 mph (221.41 km/h). In 1932, Tim Birkin won driving his red Blower "Monoposto," clocking 137.96 mph (222.03 km/h).[26]

Bentley 4½ Litre at Le Mans
Year Competition Position Drivers Team Model
24 Hours of Le Mans
United Kingdom Woolf Barnato
Australia Bernard Rubin
United Kingdom Bentley Motors Ltd. Bentley 4½ Litre
24 Hours of Le Mans
United Kingdom Jock Lawson Dunfee
United Kingdom Glen Kidston
United Kingdom Bentley Motors Ltd. Bentley 4½ Litre
United Kingdom Dr. Dudley Benjafield
France André d’Erlanger
United Kingdom Bentley Motors Ltd. Bentley 4½ Litre
French Grand Prix
United Kingdom Sir Henry (Tim) Birkin United Kingdom Bentley Motors Ltd. Blower Bentley
500 miles of Brooklands
United Kingdom Dr. Dudley Benjafield
United Kingdom Edward R. Hall
United Kingdom Bentley Motors Ltd. Bentley 4½ Litre

Click on each image for a closer look

Box art:

End of production

Supercharged car GN1767
mounts Kop Hill 22 September 2013

In November 1931, after selling 720 copies of the 4½ Litre - 655 naturally aspirated and 55 supercharged - in three different models (Tourer, Drophead Coupé and Sporting Four Seater[1]), Bentley was forced to sell his company to Rolls-Royce for £125,175, a victim of the recession that hit Europe following the Wall Street Crash of 1929.[10][27]


Thanks Wikipedia!

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