Bristol Types 142, 143, 149 and 160

Including Blenheim, Bolingbroke & Bisley

For a description of the format and data included in Production Tables, see here.

Contents

Type Description - UK Variants

• Type 142 'Britain First'
• A six passenger, two crew, low wing high speed transport, the Type 142 was a development of Barnwell's earlier Type 135 project, in order to meet requirements outlined by Lord Rothermere. It was of all-metal stressed-skin construction, and featured a near-fully enclosed main landing gear that retracted backwards into the engine nacelles, with a fixed, spatted, tailwheel. The cockpit area was extensively glazed, giving the pilot excellent forward and side vision. The passenger cabin featured four large windows to starboard, three to port, with a cabin access door at the aft end of the port side. Flying controls were all fabric covered and fitted with trim tabs, the elevators and rudder being aerodynamically balanced. Split flaps were also fitted. Two 650 h.p. Bristol Mercury VIS2 powerplants, initially driving four bladed, wooden, propellers, though these were later replaced by three bladed, variable pitch type.

Type 142 'Britain First' Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
56 ft 4 in	40 ft 9 in	13 ft 10 in	469 sq ft	6828 lb	9365 lb		307 mph/ 267 kn	1000 mi
17.17 m	12.42 m	4.22 m	43.57 m2	3097 kg	4248 kg		494 kph	1609 km

• Type 142M Blenheim Mk.I
• Three crew light bomber development of the Type 142 to Specification 28/35 to meet the requirements of OR.26, with the wing moved from a low-wing to a mid-wing position, allowing room under the main spar for a bomb bay, a dorsal gun position and a new nose design with a stepless cockpit transparency. The fuselage of the Blenheim employed a light-alloy monocoque structure using open-section stringers, and was constructed in three sections. The wing was also built in three sections, the centre-section of which is bolted and rivetted to the fuselage. The outer wing sections were tapered in chord and thickness. Extensive use of Alclad sheeting was made in elements such as the ribs, skin, flaps, and web reinforcement of the spars, while the spar flanges were of high tensile steel. Bristol-Frise mass balanced ailerons and split trailing edge flaps were fitted. The all-metal tailplane was raised from the mid fuselage position of the Type 142 to near the top of the fuselage; the fin was also all metal while the aerodynamically-balanced rudder and elevators used a metal frame covered with fabric. The undercarriage was hydraulically-retracted, with an auxiliary hand-pump for emergency actuation; medium-pressure tyres were used, complete with pneumatically-actuated differentially-control brakes. The aircraft typically carried a crew of three – pilot, navigator/bombardier and wireless operator/air gunner. The navigator/bombardier was seated alongside the pilot, and made use of a sliding/folding seat whilst performing the bomb aiming role. The wireless operator/air gunner was housed aft of the wing alongside the aircraft's dorsal gun turret. Armament comprised a single forward-firing .303 in Browning machine gun outboard of the port engine and a .303 in Lewis Gun in a semi-retracting Bristol B.I. Mk I dorsal turret, firing to the rear. From 1939 onwards, this was replaced by the more modern B.I. Mk.III turret fitted with a .303 in Vickers 'K' gas operated machine gun. A 1,000 lb bomb load could be carried in the internal bomb bay set into the centre section of the fuselage. Two 840 h.p. Bristol Mercury VIII powerplants.
  Production was also undertaken by A.V. Roe to Specification 2/37 and Rootes Securities Ltd to Specification 33/36.

• Type 142M Blenheim Mk.IF
• Long range fighter development of the Mk.I featuring an under fuselage pack containing four forward firing .303 in Browning machine guns. Most were equipped with an AI Mk III or Mk IV airborne interceptor radar for the night fighting role.

• Type 142M Blenheim II
• As Blenheim Mk.I but featuring the additional outer wing tanks of the Mk.IV.

• Type 143
• Eight passenger, two crew, low wing high speed transport, featuring 70% commonality of components with the Type 142, but with reduced performance. Compared to the Type 142, it featured a deeper fuselage and a more pointed, streamlined nose. Later proposed to the Air Council under Specification 14/37. Two 500 h.p. Bristol Aquilla I powerplants, initially driving two bladed wooden propellers.

Type 143 Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
56 ft 4 in	43 ft 2 in	12 ft 3 in	469 sq ft	7000 lb	11000 lb		250 mph/ 217 kn	1250 mi
17.17 m	13.16 m	3.73 m	43.57 m2	3175 kg	4990 kg		402 kph	2012 km

• Type 149 Bolingbroke Mk.I
• General reconnaissance and coastal bomber, initially to Specification G.24/35 to meet the requirements of OR.25, and later to Specification 11/36 to meet the requirements of OR.39, it was a minimal change from the Type 142M Blenheim Mk.I but featuring a 3ft extended nose and extra fuel tanks in the outer wings. Two 840 h.p. Bristol Mercury VIII powerplants. Production of the Bolingbroke was also proposed for Australia to Specification 10/37, but this was cancelled and replaced by the Beaufort.

• Type 149 Blenheim Mk.IV
• Light bomber development of the Type 149 Bolingbroke Mk.I featuring the same extra fuel tanks in the outer wings, along with fuel jettison pipes, and the same increased fuselage length, but with the pilots position moved back to that of the Mk.I, giving a more traditional stepped cockpit. Various dorsal turrets were fitted: Bristol B.I. Mk I or Mk.II, with a single .303 Lewis machine gun, B.I. Mk.III with one .303 Vickers 'K' gas operated machine gun, The Mk.IIIA with two Vickers or Mk.IV with two .303 in Browning machine guns. Many aircraft were fitted with a single rearward firing .303 in Browning machine gun in a ventral cupola below the nose, while some aircraft of Bomber Command had a Frazer-Nash F.N.54 turret with twin Browning machine guns in the same location. Two 920 h.p. Bristol Mercury XV powerplants.
  Production also undertaken by Rootes Securities Ltd to Specification 34/36.

Type 149 Blenheim Mk.IV Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
56 ft 4 in	42 ft 7 in	9 ft 10 in	469 sq ft	9790 lb	14400 lb	198 mph/ 172 kn	266 mph/ 231 kn	1460 mi	27260 ft
17.17 m	12.98 m	3 m	43.57 m2	4441 kg	6532 kg	319 kph	428 kph	2350 km	8309 m

• Type 149 Blenheim Mk.IVF
• Long range fighter development of the Mk.IV featuring an under fuselage pack containing four forward firing .303 in Browning machine guns. Most were equipped with an AI Mk III or Mk IV airborne interceptor radar for the night fighting role.

• Type 149CS Bisley Mk.I
• Iniial designation of Type 160 Blenheim V in close support configuration.

• Type 149HA Bisley Mk.I
• Iniial designation of Type 160 Blenheim in medium to high level bomber configuration.

• Type 160 Bisley Mk.I
• Ground support variant of the Bristol Blenheim IV, it was initially designed with a solid nose section with four forward-firing .303 in Browning machine guns. Enhanced armour protection was fitted and the up-armoured dorsal turret was modified to fit two Browning guns and to allow firing through a full 360-degree arc.

• Type 160 Blenheim Mk.V
• Originally named Bisley and proposed in two versions: a medium to high level bomber, or low altitude close support machine, both to Specification B.6/40 to meet the requirements of OR.83. Based on the Type 149 Mk.IV featuring either a a glazed nose or a solid nose with four .303 machine guns and extensive armour plating. Two 950 h.p. Bristol Mercury XXV or Mercury XXX powerplants, except first 254 aircraft, fitted with 920 h.p. Bristol Mercury XV [7, scan 1307].

Type Description - Canadian Variants

• Bolingbroke Mk.I
• As Blenheim Mk.IV with two 840 h.p. Bristol Mercury XIII powerplants.

• Bolingbroke Mk.II
• As Bolingbroke Mk.I with American equipment and instruments.

• Bolingbroke Mk.III
• Bolingbroke Mk.I converted to floatplane. Two 920 h.p. Bristol Mercury XV powerplants (later machines fitted with Mercury XX).

• Bolingbroke Mk.IV
• Bolingbroke Mk.II fitted with two 920 h.p. Bristol Mercury XV powerplants.

• Bolingbroke Mk.IV-C
• Bolingbroke Mk.IV fitted with two 850 h.p. Wright Cyclone G3B powerplants.

• Bolingbroke Mk.IV-T
• Navigation and Gunnery training version of Bolingbroke Mk.IV, with a Boulton Paul dorsal turret replacing the standard Bristol one.

• Bolingbroke Mk.IV-W
• Bolingbroke Mk.IV fitted with two 825 h.p. Pratt and Whitney SB4-G Twin Wasp Junior powerplants.

Projected Variants

• Type 143F
• A convertible version of the Type 143 with interchangeable nose and rear fuselage sections enabling it to perform a variety of roles, to meet a Finnish government requirement Two Bristol Mercury VI powerplants.

• Type 149
• General reconnaissance and coastal bomber to Specification G.24/35 to meet the requirements of OR.25, featuring a wider fuselage. Two Bristol Aquilla powerplants. Eventually developed into the Type 152 Beaufort.

• Type 149 Blenheim Mk.III
• As Blenheim Mk.IV but without the additional outer wing tanks.

Production Tables Index

Type 142
Type 143
Types 142M, 149 and 160 Blenheim, Bolingbroke and Bisley - UK Built
Type 142M Blenheim - UK Built Exports
Type 142M Blenheim - Finnish Built
Type 142M Blenheim - Yugoslav Built
Bolingbroke - Canadian Built
Type 142M Blenheim With Foreign Air Forces, Not Directly Exported From UK

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Production Summary

Notes

1. K7072 (c/n 8025) was converted to the prototype Bolingbroke Mk.I, later Blenheim Mk.IV. Shipped to Canada late in 1940 as a pattern aircraft for the Bolingbroke. RCAF serial 701 reserved but apparently never carried.
2. Although diverted from an RAF contract and already possessing c/n's, these apparently received new c/n's for export.
3. One aircraft, L1348, was rebuilt into a Blenheim PR.I reconnaissance aircraft at the beginning of 1940. To improve performance, the gunner's turret was removed, and the nose received special re-profiled in metal. The PR.I had a crew of two, the pilot and the navigator/camera operator. New Rotol constant speed propellers were also fitted.
4. In March 1937 Australia placed a formal order, Air Board Overseas Indent 550 [11,12, 13], for 40 Bolingbroke General Reconnaissance aircraft from Bristol, along with Indent 551 for spares, with serials A9-1 to A9-40 allotted; 10 more ordered in November (Indent 591). The design was cancelled in December 1937 and in February 1938 the order was changed to Beaufort.
5. There is some confusion over this Contract Number. It is mostly shown as 588371/36, which is what is given on the Contract Delivery Summary ([7], scan 1045). However, Contract Cards [7] for serials L6804 - L6843 and N3522 - N3631 give the Contract as 599371/36, albeit corrected on the cards for L6804 - L6818 and N3612 - N3631. Similarly, A.M. Form 78 [9] for serials L6817 - L6843, N3522, N3535 - N3593 also give the contract as 599371/36.

Production References

1. Bristol Aircraft Since 1910, C.H. Barnes (Putnam, 1964, 1970 and 1988)
2. Bristol Blenheim, Chaz Bowyer (Ian Allan, 1984)
3. Air Britain RAF Aircraft Register Series, Various Volumes (Air-Britain Publications)
4. Air Enthusiast Quarterly No 16
5. Air Enthusiast Quarterly No 54
6. RAF Contracts - Air Britain Aeromilitaria, various issues
7. RAF Air Historical Branch: Contract Delivery Cards (Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MFC-78-8-1)
8. RAF Air Historical Branch: Delivery Serial Ledger (A.M. Form 622)(Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MF-1 thru 5)
9. RAF Air Historical Branch: RAF Aircraft Movement Card (A.M. Form 78) (Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MFC-77-15-17 through -22)
10. Bristol Air Ministry Contracts Ledger via The Bristol Aero Collection Trust Library
11. National Archives of Australia Series Number A705, Control symbol 9/18/15 Overseas Indents 550 and 591 - Bristol Beaufort aircraft and taurus engines
12. National Archives of Australia Series Number A1196, Control symbol 1/501/213 - Purchase of (Beaufort) Aircraft for RAAF Policy file
13. National Archives of Australia Series Number A14487 11/AB/1997 Air Board Agenda 1997 (RAAF) - Supply of Bristol type 149 General Reconnaissance aircraft with Mercury engines - Air Board Order No. 550
14. Hungarian Eagles the Hungarian Air Forces 1920-1945, Gyula Sarhidai; Viktor Kozlik; Gyorgy Punka (Hikoki Publications / Howell Press, 1999)
15. Greek serials from http://forum.12oclockhigh.net/archive/index.php?t-8738.html
16. Blenheim in Portuguese service, from http://altimagem.blogspot.com/2013/01/57-bristol-blenheim.html

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