Introduced in March 1937, the Bristol Blenheim was a British light bomber aircraft designed and built by the Bristol Aeroplane Company and used extensively in the first two years and in some cases, throughout the Second World War.
The Blenheim was one of the first British aircraft with an all-metal stressed-skin construction, retractable landing gear, flaps, a powered gun turret and variable-pitch propellers. The Mk I was faster than most fighters in the late 1930s but the advance in development of monoplane fighters made all bombers more vulnerable particularly if flown in daylight.
Constructed in three sections, the fuselage of the Blenheim combined a light-alloy monocoque structure using open-section stringers with the wings also being built in three sections and the center-section of which is bolted and riveted to the fuselage. Its pair of Bristol Mercury VIII air-cooled radial engines, each capable of 860 hp drove three-bladed controllable-pitch giving the light bomber a reasonably fast airspeed of 266 mph which in the mid to late 1930s was considerably faster than most fighters of the era.
Unfortunately for the Blenheim and many other aircraft developed during this period, the frantic lead up to the Second World War saw massive technological advances in aircraft design, engines and Armament and like many of its contemporaries, within a year of the conflict commencing, it found itself struggling against the more advanced German fighters.
Carrying a crew of three consisting of - pilot, navigator/bombardier and wireless operator/air gunner the Blenheim owed also owed much of its airspeed to its small fuselage cross-section, with its upper front glazing all at one angle in the form of a “step-less cockpit” that used no separate windscreen panels for the pilot. Even so, the pilot’s cockpit was incredibly compact with the control yoke obscuring most of the main flight instruments with the secondary instruments having to be arranged down the left hand side of the cockpit. Other critical instruments such as the propeller pitch controls were located behind the pilot who had to reach back and adjust them by feel.
For armament, the aircraft carried a single forward firing .303 Vickers VGO machine gun in the port wing while the rear gunner sat behind 2 x .303 Browning machine guns in the dorsal turret with another Browning fixed in a rear firing position under the nose blister. Like most contemporary aircraft, the Blenhiem’s bomb bay doors were secured closed by bungee cords - relying on the weight of its 1000lb bomb load to force the doors apart when they were released. With no way of knowing how long it would take the bombs to force the doors open, bombing accuracy was extremely poor.
With the fall of France and the evacuation at Dunkirk, the remaining Blenheims flew harassing missions over the beaches to provide air-cover for the retreating forces but were hopelessly outclassed by the German fighters.
Blenheim units continued to operate throughout the Battle of Britain, often taking heavy casualties and were also involved in missions that resulted in a 100% casualty rate. One such operation was mounted on 13 August 1940 against a Luftwaffe airfield near Aalborgin north-western Denmark by twelve aircraft of 82 Squadron. One Blenheim returned early (the pilot was later charged and due to appear before a court martial, but was killed on another operation); the other eleven, which reached Denmark, were shot down, five by flak and six by Bf 109s.
With numbers rapidly depleting, the Blenheim’s role was switched to coastal patrol and that of night fighter defence above the British cities under attack from the Luftwaffe's bombing campaign.
The original Bristol Blenheim Mk 1, introduced to the RAF in 1935 featured the 'short nose' but with its increased role as a coastal reconnaissance/light bomber, the nose section was extended to accommodate additional crew and radar equipment. The Mk IV's were also fitted with the more powerful Mercury XV or Mercury 25 engines together with nose gun blister packs for low level straffing of enemy shipping.
Equipped with some of the first radar sets of the war, the Mk IVs were highly successful in locating the German bombers in the darkness - managing to shoot down a Dornier Do 17 on their first mission with many other successes following. From mid 1940 to the end of 1941, the Bristol Blenheim had proved itself invaluable as a night fighter only being replaced when the faster and more heavier armed Bristol Beaufighters came into service.
By late 1941 and with many of their roles being taken over by the faster Beaufighter, Blenhiems were despatched to the Middle East and later, South East Asia where they were used as fighter bombers against ground forces and enemy shipping. They continued to suffer heavy losses and were gradually phased out of service by the Beaufighter and the USAAF Douglas A-20 Havoc.
All Bristol Blenheim instruments listed below come complete with a detailed, custom-built Scale Model of the Bristol Blenheim Aircraft on its Magnetic Display Arm; Mango Wood Display Stand & Plaque, plus Printed Fact Sheet featuring photo of instrument in aircraft cockpit - as shown in this Bristol Beaufort example opposite:
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