Bristol M.R.1

Le projet MR 1 de Bristol vu par Wikipedia.EN


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The Bristol M.R.1 was an experimental [Vous devez être inscrit et connecté pour voir ce lien] with an [Vous devez être inscrit et connecté pour voir ce lien] and metal wings produced by Bristol during the [Vous devez être inscrit et connecté pour voir ce lien]. Two were built to government order.


Development

Quite soon into the development of powered flight, some manufactures were beginning to think about the use of metal in airframes to replace wood.

Metal structures, even fabric-covered metal frames offered greater robustness to handling and transportation as well as better resistance to tropical climates, and some designers could see the possibilities of metal skinning, stressed or not, for aerodynamically-clean [Vous devez être inscrit et connecté pour voir ce lien] wings and advanced monocoque fuselages.

There was a realisation, too that mild steel, familiar from bicycle manufacture but with a low strength to weight ratio was not going to be the material of choice once the problems of joining aluminium alloy members together and preventing
their corrosion had been solved.

[Vous devez être inscrit et connecté pour voir ce lien] in the UK were one of the first to make steel-framed and -[Vous devez être inscrit et connecté pour voir ce lien] aircraft that flew, with their series of [Vous devez être inscrit et connecté pour voir ce lien] type [Vous devez être inscrit et connecté pour voir ce lien] produced between 1911 and 1913^{[Vous devez être inscrit et connecté pour voir ce lien]}.

In Germany, Junkers produced the first true all-metal (for years, aircraft with fabric-clad metal frames were described as all-metal, but the Junkers was steel-skinned as well) aircraft, the [Vous devez être inscrit et connecté pour voir ce lien], flown in 1915.

Bristol's first draft designs for metal aircraft date from 1914, but it was not until the increase of aircraft production
during the First World War began to put pressure on the supply of high-grade timber that there was official interest.

During 1916 Bristol's designer, [Vous devez être inscrit et connecté pour voir ce lien] submitted a design for a metal two-seat [Vous devez être inscrit et connecté pour voir ce lien] aircraft, the M.R.1 (M.R. for Metal Reconnaissance) and gained a contract for two evaluation aircraft.

The fuselage construction was quite novel. Barnwell borrowed from marine experience in using varnished [Vous devez être inscrit et connecté pour voir ce lien] sheet to prevent corrosion and used these to make the fuselage in four sections.

The two forward sections were semi-monocoque (i.e. open channels) with braced longitudinal upper members which, bolted together held the engine, a water-cooled inline upright 140 hp (100 kW) [Vous devez être inscrit et connecté pour voir ce lien]) and the pilot's cockpit.

Aft, two more sections, both true monocoques, held the observer and carried the tail unit.

The two cockpits were close together, with the pilot under the wing at mid-[Vous devez être inscrit et connecté pour voir ce lien] and the observer under a trailing edge cut-out; indeed, Barnwell proposed that the short observer's fuselage section should be removable to turn the M.R.1 into a single-seater, though this configuration was not realised.

The monocoque sections were very early examples of double-skinned construction, with a smooth outer skin riveted to a
longitudinally-corrugated inner skin.

The detailed design was by [Vous devez être inscrit et connecté pour voir ce lien].

The complete fuselage was of round-cornered rectangular cross-section and quite slender, mounted between the wings.

The M.R.1 was a two-bay biplane without [Vous devez être inscrit et connecté pour voir ce lien] or [Vous devez être inscrit et connecté pour voir ce lien], with [Vous devez être inscrit et connecté pour voir ce lien] on both planes.

Aluminium wing spars proved difficult to make sufficiently rigid and Bristol outsourced their manufacture to [Vous devez être inscrit et connecté pour voir ce lien] at Gloucester, who had successfully built experimental steel wings for other aircraft.^{[Vous devez être inscrit et connecté pour voir ce lien]}

With the fuselage of the first M.R.1 completed ahead of the wings, Bristol decided to make a set of conventional wooden wings, with ailerons only on the upper planes, for flight trials in mid-1917.

These went well and the aircraft was handed over to the [Vous devez être inscrit et connecté pour voir ce lien] in October 1917.

The second M.R.1 did not fly until late in 1918 when the metal wings were at last ready, powered by a 180 hp (130 kW) [Vous devez être inscrit et connecté pour voir ce lien] engine.

It flew successfully but was damaged beyond repair at the end of its delivery flight to the [Vous devez être inscrit et connecté pour voir ce lien]
in April 1919.

The first M.R.1 was fitted with metal wings by 1918 and continued to provide useful information on metal airframe construction.

In 1923, Bristol's rationalisation of type numbers labelled the M.R.1 as the Type 13.

Specifications

Data from [Vous devez être inscrit et connecté pour voir ce lien], p. 129 Unfortunately Barnes does not say which engine the following specifications apply to, nor if the metal or wooden wings were used.

General characteristics

• Crew: 2
  
• Length: 27 ft 0 in (12.85 m)
  
• Wingspan: 42 ft 2 in (8.23 m)
  
• Height: 10 ft 3 in (3.12 m)
  
• Wing area: 458 ft² (42.6 m²)
  
• Empty weight: 1,700 lb (770 kg)
  
• Gross weight: 2,810 lb (1,275 kg)
  

Bibliography

• Andrews, C.F.; Morgan, E.B. (1988). Vickers Aircraft since 1908. London: Putnam Publishing. [Vous devez être inscrit et connecté pour voir ce lien].
  
• Turner, P. StJ.; Nowarra, Heinz (1971). Junkers: an aircraft album no.3. London: Arco Publishing. [Vous devez être inscrit et connecté pour voir ce lien].
  
• Barnes, C. H. (1964). Bristol Aircraft since 1910. New York: Putnam Publishing. [Vous devez être inscrit et connecté pour voir ce lien].