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Blackburn
BT1 Beagle

A short-lived long range bomber / reconnaissance / torpedo biplane prototype that failed to enter production.
Blackburn BT1 Beagle N236 initial configuration The BT1 Beagle N236 in its initial configuration, with large rudder aerodynamic balance.
 
The Blackburn BT1 Beagle was a single engine biplane that competed for Air Ministry Specification 23/25 against other prototypes including the Gloster Goring, Handley Page Hare, Westland Witch and the Hawker Harrier.
 
In the event, none of these aircraft received a production contract.
 
The requirement sought a single-engine day bomber that could also be used for long-range reconnaissance and as a torpedo carrier.
 
The single prototype of the Beagle (N236) was a single-bay biplane of mixed wood and metal construction, resembling a radial-engine Blackburn Ripon in general appearance. Power was initially provided by a 460hp Bristol Jupiter VIIIF engine.
 
The aircraft carried two crew in separate cockpits, these being a Pilot and a Gunner / Bomb-aimer.
 
For bomb or torpedo dropping, the Bomb-aimer could access a prone 'aiming position' beneath the pilot’s cockpit. The gunner however was provided with a Lewis gun for defensive purposes, supplementing a fixed forward-firing Vickers gun which was operated by the pilot.
 
A crutch was provided between the undercarriage legs to carry either a 185 gallon long-range tank or an 18 inch naval torpedo. The tank was intended for use on extended reconnaissance missions, supplementing the standard fuel capacity of two 62 gallon tanks in the upper wing, delivering a maximum endurance of 8.5 hours in this role.
 
Blackburn BT1 Beagle N236 underslung tank The Blackburn BT1 Beagle with revised rudder and long-range fuel tank.
 
The prototype (K236) made its first flight at Brough on 18th February 1928 where it found that the rudder was evidently over-balanced in its original form and its upper portion was cut back, giving a stepped appearance to the fin and rudder combination.
 
The Beagle did not undergo official trials at Martlesham Heath until July 1929 however and it was found that neither the Beagle, nor its competitors, met the required performance and the company was asked to fit a geared and supercharged 590 hp Jupiter XF radial engine.
 
Blackburn BT1 Beagle Jupiter XF The BT1 Beagle showing the revised nose shape when fitted with the Jupiter XF engine.
 
After this change, which also resulted in modified cowling lines, the Beagle was returned to Martlesham for further trials from 19th March 1931 where it joined the Vickers Vildebeest and Vicker Hare.
 
The Vildebeest was eventually chosen to meet the RAF requirement which by now included torpedo bombing.
 
Little use was made of the type thereafter although it is known that it visited the Development Squadron at Gosport as well as the Royal Aircraft Establishment (RAE) at Farnborough.
 
On 6th June 1932 it was subject to a test flight at Brough and thereafter it was last reported as visiting De Havilland at Stag Lane on 3rd October 1932.  Records show that it remain in use until October 1933 whereafter it is believed to have been scrapped.
 

Variants & Numbers Built

A single prototype, serial N236.

Specification (with Jupiter VIIIF)

  Bomber Torpedo
Powerplant One 460 hp Bristol Jupiter VIIIF radial engine
Span 45 ft 6 in
Maximum Weight 6,120 lb  7,500 lb (max allowed 7,750 lb)
Capacity & Armament Two crew; one fixed Vickers gun and one defensive Lewis gun. Provision for carriage of one 18 in torpedo, or 185 gallon long-range fuel tank. 
Maximum Speed 140 mph at 5,000 ft 133 mph at 5,000 ft
Endurance 3.5 hours (8.5 with long-range tank) 3.5 hours

Survivors

None. First flown in February 1928 and believed withdrawn from use by late 1933.