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 Aircraft Company 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 Biplane.
 
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 Blackburn 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 Blackburn Beagle did not undergo official trials at  Aeroplane and Armament Experimental Establishment (A&AEE) at Martlesham Heath until July 1929. However, and it was found that neither the Blackburn Beagle, nor its competitors, met the required performance and the company was asked to fit a geared and supercharged 590 hp Bristol 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 Blackburn Beagle was returned to Martlesham for further trials from 19th March 1931, where it joined the Vickers Vildebeest and Vickers Hare. The Vickers Vildebeest was eventually chosen to meet the RAF requirement which by now included torpedo bombing.
 
Little use was made of the Blackburn 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 remained in use until October 1933, whereafter it is believed to have been scrapped.
 

Variants & Numbers Built


A single prototype (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