Sunbeam 350HP

Sunbeam 350HP
Overview
Manufacturer Sunbeam of Wolverhampton
Production one
Designer Louis Coatalen
Body and chassis
Body style Open wheel racing car
Powertrain
Engine 18.3-litre V12 Sunbeam Manitou of 350 hp (260 kW)
Transmission 4-speed pre-selector,
final drive ratio 1.5:1
Dimensions
Wheelbase 10 ft 7 in (3.2 m), track 4 ft 6 in (1.4 m)
Length 16 ft (4.9 m)
Curb weight 1,550 kg (3,417 lb)

The Sunbeam 350HP is an aero-engined car built by the Sunbeam company in 1922, the first of several land speed record breaking cars with aircraft engines.

Design

The car was fitted with a purpose built 18.3-litre V12 engine based on a hybrid of the Sunbeam Manitou and Sunbeam Arab aero engines. This engine had four blocks of three cylinders arranged in two banks set at 60 degrees (unlike the Arab which were set at 90 degrees). Each cylinder had one inlet and two exhaust valves actuated by a single overhead camshaft. The two camshafts were driven by a complex set of 16 gears from the front of the crankshaft - a very similar arrangement to that used on the Maori engine which had two OHC per bank of cylinders. A 4-speed transmission initially drove a back axle with differential with a shaft drive rather than the hazardous chains of other cars. Harry Hawker drove the car in 1920 at Brooklands and had initial problems controlling the car - spinning off the circuit. The Differential was replaced with a simple crown wheel and pinion so that the rear wheels were locked together and it was more successful in the hands of Kenelm Lee Guinness. Brakes were crude, as was usual in the period, with a foot brake acting on the transmission and a hand brake on the rear drums. Suspension was also typical, with half-elliptic springs all round damped by Andre Hartford friction shock absorbers.[1][2][3]

Racing career

The 350HP was first raced at Brooklands in 1920 by Harry Hawker. In October Rene Thomas set a new record at the Gaillon hill climb.

In May 1922 Kenelm Lee Guinness set three records with it: the Brooklands lap record at 123.30 mph (198.43 km/h), then the land speed record over a mile at 129.17 mph (207.88 km/h) and over a kilometre at 133.75 mph (215.25 km/h) – this was the last land speed record to be set on the Brooklands track.

Blue Bird

Malcolm Campbell drove the borrowed car at the Saltburn Speed Trials on 17 June 1922 and broke his first speed record at 138.08 mph (222.22 km/h). However the manual stopwatch timing system was not accepted for an official record.[1][4]

Campbell persuaded Coatalen to sell the Sunbeam to him, painted it blue and renamed it 'Blue Bird', already the fourth Blue Bird.[4] 23 June 1923 saw Campbell at Fanø, Denmark, recording another record-breaking speed of 137.72 mph (221.64 km/h) over the flying kilometre. This time the record was not officially accepted as the timing equipment was not of the approved type.[1][4]

Over the winter of 1923–1924 the car was sent to the aircraft maker Boulton Paul at Norwich, for wind tunnel tests. They streamlined the car with a narrow radiator cowl at the nose and a long tapered tail. The rear wheels were also fitted with disk covers. Engine compression was raised by new pistons.[2][5]

Campbell returned to Fanø in the summer, but the beach was in poor condition and crowd control of the spectators was poor. On the first run both rear tyres were ripped off Blue Bird and narrowly missed the crowd. Campbell protested to the officials about safety standards and declined to take any responsibility for anything else. Sadly, this time a front tyre came off and killed a boy in the crowd.[4]

The car was taken to Pendine Sands in South Wales and saw a more successful result with the first of Campbell's nine records. The record was achieved on 24 September 1924, with a speed of 146.16 mph (235.23 km/h) and an officially sanctioned time. After this he put the car up for sale for £1,500, but decided to keep it for a further attempt on hearing that Parry-Thomas was also planning a record attempt with 'Babs'. Blue Bird returned to Pendine in 1925, and on 21 July it raised this record to 150.766 mph (242.628 km/h), the first time a car had exceeded 150 mph (240 km/h). The best run over the mile had reached 152.833 mph (245.961 km/h), a figure that appeared in contemporary motoring adverts for oil and sparkplugs.[6] To commemorate this achievement Campbell had commemorative models of Blue Bird made.[7]

Survival today

After Campbell, the Sunbeam appears to have returned to circuit racing with wider tyres and a return to the short tail with green paintwork. As late as 1936, bandleader Billy Cotton recorded 121.57 mph (195.65 km/h) over a kilometre on the beach at Southport.[8] The car may have stayed in Lancashire afterwards, turning up there during World War 2 and then being sold to the Beaulieu collection in 1958.

It is on show today at the National Motor Museum at Beaulieu, Hampshire. The engine has undergone extensive restoration after suffering severe damage in the 1990s and was run for the first time in 20 years in January 2014.[9]

References

  1. ↑ 1.0 1.1 1.2 Holthusen, Peter J. R. (1986). The Land Speed Record. ISBN 0-85429-499-6.
  2. ↑ 2.0 2.1 "Sunbeam 350HP". The Racing Campbells.
  3. ↑ "1920 350 HP Sunbeam – ‘Blue Bird’".
  4. ↑ 4.0 4.1 4.2 4.3 "Campbell at Fanoe, 1924".
  5. ↑ Brew, Alec (1998). Sunbeam Aero-engines. Airlife. ISBN 1-84037-023-8.
  6. ↑ "Lodge sparkplug advert". The Motor. 9 March 1926.
  7. ↑ "Sunbeam Manitou". Wolverhampton Museum of Industry.
  8. ↑ Guidebook. National Motor Museum, Beaulieu.
  9. ↑ Cropley, Steve. "Cropley on Cars: Sunbeam Land Speed Record car runs again". Autocar. Retrieved 30 January 2014.

External links