April 12, 1935 – The First Flight of the Bristol Blenheim

Today is the 72nd anniversary of the first flight of the Bristol Blenheim, a high-speed civilian aircraft that was later used as light bomber and heavy fighter during the Battle of Britain. Built by the Bristol Aeroplane Company, the Blenheim completed its maiden flight on April 12, 1935, when the Britain First sped across the skies over Filton, a South Gloucestershire town that forms the heart of the British aerospace industry. Although the plane was originally designed for civilian use, Britain's Air Ministry was so impressed by its speed that the Royal Air Force (RAF) ordered a Blenheim bomber prototype called the Type 142M. Ironically, the first civilian Blenheim (then known as the Bolingbroke) had been ordered by Lord Rothermere, a proponent of British aviation who would later use his ownership of the Daily Mail to advocate the appeasement of Nazi Germany.

The Bristol Blenheim was designed by Frank Barnwell, a Scottish engineer who had worked as a shipbuilder before joining his brother's company near Stirling, where they built gliders and powered airplanes. In March 1911, Barnwell headed south to Filton to join the Bristol Aeroplane Company as chief engineer. After serving his country as a fighter pilot during World War I, Barnwell returned to Bristol and became one of the first aeronautical engineers in Britain to use stress-skin designs, structures which localize their compression-taking elements and distribute their tension-taking elements. The Bristol Blenheim was also one of the first aircraft to use retractable landing gear, flaps, powered gun turrets, and variable-pitch propellers. Before his death in a plane crash in 1938, Frank Barnwell modified the aircraft's civilian design to allow more room under the spar for a bomb bay.

The Bristol Aeroplane Company delivered the first of 4,422 Bristol Blenheims to the RAF in March of 1937. With a maximum speed of 285 mph at 15,000 ft., each aircraft featured two 840-hp Bristol Mercury VIII nine-cylinder air-cooled engines. When viewed from the side, these wing-mounted engines nearly hid the cockpit and its asymmetric instrument panel. The pilot, who sat forward of essential controls such as the propeller pitch, was joined onboard by an air gunner, whose station was located on the upper fuselage. Four .303-in Browning machine guns were mounted in a ventral fairing, one in a hydraulically-operated, semi-retractable dorsal turret. Although the Bristol Blenheim was ill-equipped for daytime combat, its role as a night fighter was legendary. During the Nazi bombing raid on London on June 18, 1940, Blenheims destroyed five German bombers.

Resources:

https://en.wikipedia.org/wiki/Bristol_Blenheim

http://www.battleofbritain.net/

https://en.wikipedia.org/wiki/Filton

https://en.wikipedia.org/wiki/Harold_Harmsworth

http://www.aviationarchive.org.uk/stories/pages.php?enum=GE130&pnum=2&maxp=2