Bristol B.R.7

Bristol Aeroplane Company

Industry	Aircraft manufacturing
Founded	1910 in United Kingdom
Founder	Sir George White
Headquarters	United Kingdom
Products	Aircraft

The Bristol B.R.7 was a two-seat, single-engine biplane designed by a Romanian engineer and manufactured by Bristol in 1913 to fulfil an order placed by the Spanish government. The aircraft did not satisfy the required specifications, resulting in the cancellation of the contract.

Development

In January 1912, Romanian engineer Henri Coandă assumed the role of chief designer at the Bristol Aeroplane Company. Initially, he developed the series known as Bristol-Coanda Monoplanes. However, following a structural failure in one of these models that prompted the War Office to prohibit monoplane use within the RFC, Coandă shifted his focus toward biplane configurations. His inaugural biplane design was a two-seat, single-engine model which garnered interest from both Spanish and German authorities.

The Spanish government specified the installation of a 70 hp (50 kW) Renault engine, matching that employed in their existing Maurice Farman aircraft. Meanwhile, the German variant was to be assembled by Deutsche Bristol-Werke and powered by a 90 hp (70 kW) Daimler engine. Consequently, Coandă crafted a design adaptable to both power units. The version equipped with the Renault engine was designated B.R.7, whereas the German model appeared without a specific designation.

The initial batch of five B.R.7 aircraft ordered by Spain debuted at the Olympia Aero Show in February 1913, with their maiden flight occurring in March at Larkhill. These aircraft featured two-bay wings without any stagger. The cockpits were arranged in tandem: one positioned beneath the wing and the pilot’s seat located behind the wing’s trailing edge. The fuselage behind the cockpit was slender and supported a nearly semi-circular tailplane outfitted with a single-piece elevator and a balanced rudder lacking a fin. The undercarriage was distinctive, comprising four wheels similar to those used on earlier monoplanes—two large wheels situated under the wing’s trailing edge behind the centre of gravity and two smaller wheels placed forward near the engine—resulting in an appearance akin to a tricycle undercarriage aircraft.

Initial flight tests revealed that the B.R.7’s wings generated insufficient lift due to their low camber, characteristic of monoplane wings. To address this, they were replaced with wings exhibiting increased camber, which enhanced performance but still fell short of meeting official requirements. Attempts to improve thrust using a four-bladed propeller also proved inadequate, leading to cancellation of the Spanish contract. One of these aircraft was destroyed by fire; the remaining four were seldom flown. A seventh B.R.7 was constructed with wings of larger span; however, only the first prototype saw significant operational use, serving as an advanced trainer at Larkhill.

The German-built variant powered by the Daimler engine featured substantially extended upper wingspan—from 38 ft (11.58 m) to 57 ft (17.37 m)—resulting in approximately a 30% increase in wing area. Additionally, it incorporated an enlarged rudder and improved ailerons. This version took its first flight in July 1913.