Bristol 91 Brownie | BAE Systems | International

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Bristol
91 Brownie

Bristol's entrants in the 1924 and 1926 Light Aircraft Competitions held at Lympne.
Bristol 91 Brownie prototype The Bristol 91 Brownie prototype in its initial configuration.

 

The Bristol Brownie was a light sports two-seat monoplane, designed in accordance with the rules of the Air Council’s 1924 light aircraft competition. These light weight machines with low installed power offered surprisingly good performance.

 

Previously, the competition rules meant that Bristol had not built an aircraft to compete as engines were restricted to below 750 cc, rendering the Bristol Cherub unsuitable.  

 

However, the 1924 regulations saw the maximum capacity increased to 1,000 cc which allowed Bristol Chief Designer Frank Barnwell to explore studies in alternative wood and metal designs which subsequently gained 'Board Approval' for the initial production of 2 aircraft although this was quickly followed by a third.

 

The first aircraft flew in the hands of Cyril Unwins on 6th August 1924 (G-EBJK - nicknamed 'Jack') and was immediately followed by the second aircraft (G-EBJL - nicknamed 'Jill) in September - the third aircraft (G-EBJM - nicknamed 'Jim) also flew soon after.

 

Bristol 91 Brownie second aircraft G-EBJL G-EBJL, the second Bristol Brownie photographed in September 1924.

 

The Brownie had a steel tube fuselage and was flown with both wooden and two types of metal wing of differing span. Trials at Lympne took place in late September and early October 1924, Uwins taking an overall second prize of £1,000 and a further £500 for the best take-off and landing.

 

G-EBJM was flown in single seat configuration with the shorter span metal wing for speed competitions.

 

Bristol 91 Brownie G-EBJM single seat The third Bristol 91 Brownie G-EBJM in single seat configuration with short span wings.

 

G-EBJK was subsequently returned to Filton for modifications in December 1925 where it was fitted with the newly developed 36 hp Cherub III mounted slightly lower in the fuselage.  The top longerons were curved down more to improve the view from the rear cockpit and the fuel tank was enlarged.  It was fitted with new metal wings, giving it a span of 37 ft 7 in (11.45 m) and was designated as the Type 91A.

 

After further trials at Martlesham Heath it was again returned to Filton where the engine mounting was further lowered and it was fitted with a Fairey-Reed propeller. Additionally, a curved decking was added to the rear fuselage and it was fitted with an enlarged horn-balanced rudder plus a new undercarriage.

 

In this form and designated as the Type 91B (or Brownie II) it competed in the 1926 Lympne Trials, taking the third place prize of £500.

 

All-in-all, the Brownie offered excellent performance, handling and economy on its limited power but it was insufficiently robust, lacking in the power-reserves required for a truly practical machine. Like the other entrants in the 1924 competition, the Brownie proved fairly impractical machines for the private owner.

 

What was actually required was subsequently demonstrated by the De Havilland DH60 Moth which was designed purely to meet similar customer needs but without the constaints of these somewhat artificial competitions and their impractical restrictions.

 

Specification

Specification Type 91                                  Type 91A, 91B Brownie II
Powerplant One 32 hp Bristol Cherub I One 36 hp Bristol Cherub III
Span 34ft 7in (wood) G-EBJK 36ft 7in G-EBJL (metal wing version 1), or
30ft 7in G-EBJM (metal wing (version 2), in single seat configuration), or
37ft 7in (new metal wings fitted to G-EBJK when modified to Type 91A and 91B)
Maximum Weight 870 lb, 720 lb single seat 1,010lb (G-EBJK, 91B Brownie II)
Capacity  Pilot and passenger Pilot and passenger, or pilot only (G-EBJM)
Maximum Speed 70 mph 78 mph (125 mph)
Range 100 miles 125 miles

Variants & Numbers built

Three only        
G-EBJK (Type 91, later Type 91B with revised nose shape, new rudder and 36hp Cherub III); G-EBJL (Type 91A); G-EBJM (Type 91A, also flown as single seater with no change in designation)

Survivors

No examples survive.