In 1935, the BritishAir Ministry issued Specification G.24/35 to procure a coastalreconnaissance/light bomber to replace theAvro Anson.[1] Bristol proposed the Type 149, based on itsBlenheim Mk I, withBristol Aquila engines to give greater range. While the Air Ministry rejected this proposal, a Blenheim Mk I, retaining itsMercury VIII engines, was converted as a Type 149 (Blenheim Mk III) for the general reconnaissance role.[2] The nose was lengthened to provide more room for the bombardier, with the upper left surface of the nose being scooped out to maintain pilot visibility during takeoff and landing.[1]
The longer range also fulfilled aCanadian requirement for a maritime patrol aircraft. Consequently,Fairchild Aircraft Ltd. (Canada) of Quebec started production of the Blenheim Mk IV as theBolingbroke (the originally intended name for the Blenheim IV). This type was nicknamed the "Bolly". After a small run of aircraft constructed to British specifications, as theBolingbroke Mk I, Fairchild switched production to theBolingbroke Mk IV with Canadian and American instruments and equipment. These versions also included anti-icing boots and adinghy. One of the early Mk IV variants was theBolingbroke Mk IVW which was powered by two 825 hp (615 kW)Pratt & Whitney SB4G Twin Wasp Junior engines.[3] Incapable of maintaining altitude on one engine, the normal bomb load was reduced to 500 pounds on these aircraft to compensate for the low engine power.[4] The most-produced variant was theBolingbroke Mk IVTtrainer, of which 457 were completed.[5] A total of 626 Bolingbrokes were produced.[5]
Most of the 151 Mk IVs built served in their intended role as patrol bombers on the Atlantic and Pacific coasts of Canada between 1940 and 1944. Two squadrons of these aircraft also served in Alaska during theAleutians campaign.[6] The Mk IVT trainers saw extensive use in theBritish Commonwealth Air Training Plan (BCATP).[5]
Twin-engine maritime patrol bomber aircraft, powered by two Bristol Mercury VIII radial piston engines, with British equipment. 18 built.[7]
Bolingbroke Mk II
Conversion of fifth Mk I with US equipment - prototype of Mk IV.[8]
Bolingbroke Mk III
Floatplane conversion of sixteenth Bolingbroke Mk I, with twoEdo floats.[8][9]
Bolingbroke Mk IV
Twin-engine maritime patrol bomber aircraft, equipped with anti-icing boots and a dinghy, also fitted with American and Canadian instruments and equipment, powered by two Bristol Mercury XV radial piston engines, 134 built.[10]
Bolingbroke Mk IVW
Sub-version of Mk IV powered by two 825 hp (615 kW)Pratt & Whitney SB4G Twin Wasp Junior radial piston engines as contingency against possible shortages of Mercury engines. The Mk IVW's performance was below that of the Mk IV and the supply of the British engines was maintained so production returned to the Mk IV after only 15 aircraft were built.[10][11]
Bolingbroke Mk IVC
Version of Mk IV with 900 hp (671 kW)Wright R-1820 Cyclone engines not requiring highoctane fuel. One built.[12]
Bolingbroke Mk IVT
Multi-purpose trainer aircraft. A total of 350 built powered by Mercury XV engines, followed by a further 107 powered by the low-octane fuel Mercury XX* engine, giving a total of 457 built, with a further 51 cancelled.[13] Six Mk IVT were converted to dual controls. A further 89 were converted to Mk IVTT Target Tug with the addition of winching gear in the rear cabin and target drogue storage in the bomb bay.[14]
Bolingbroke IVT in the Commonwealth Air Training Plan Museum, Brandon, ManitobaBolingbroke in a Manitoba junkyard, 2006Part of a Bristol Fairchild Bolingbroke at a car show inSainte-Anne-de-Bellevue, Quebec, 2011
9896 - Mk. IVT partial aircraft in storage and restored nose section on display at theCanadian Museum of Flight inLangley, British Columbia.[30] 9896 was delivered to No. 4 Training Command on 13 July 1942, for use by No. 8 Bombing & Gunnery School at Lethbridge, Alberta. It was pending disposal from 21 November 1944. Transferred to No. 2 Air Command on 1 December 1944, still pending disposal. It was stored by Maintenance Command at No. 1 Reserve Equipment Maintenance Unit until the hulk was acquired by the RAF in 1974, and parts used to rebuild another Bolingbroke (reported as 13308?). Remains to Canadian Museum of Flight. As per the museum's website, "After years of having its useful parts removed and bullet holes being shot into it, RCAF 9896 was eventually provided to the Canadian Museum of Flight on permanent loan by Rudy Yancy, Sr. of Skiff, AB, and the airframe was transported to the museum’s homesite on Crescent Road in 1981.What remains of RCAF 9896 are all of its major components: the fuselage, wings, tail feathers, center-section, and nose section. Most of the major components of RCAF 9896 are in storage awaiting eventual restoration to static condition, while the nose section has been meticulously restored and can be seen on display in our museum’s hangar."[31]
9944 – Mk. IVT on static display with the Commonwealth Air Training Plan Museum in Brandon, Manitoba. This aircraft is displayed next to theTrans-Canada Highway in Brandon.[33][34]
9987 – Mk. IV on static display at the Bomber Command Museum of Canada inNanton, Alberta.[35]
10121 – Mk. IVT under restoration to static display at theCanadian Aviation Heritage Centre inSainte-Anne-de-Bellevue, Quebec.[37] Delivered to stored reserve with No. 4 Training Command, issued from storage on 20 May 1943. Transferred to No. 2 Air Command on 1 December 1944. To stored reserve on 24 January 1945 and pending disposal from 13 October 1945. Stored post war at Paulson, Manitoba. Had 987:05 airframe time when struck off. It was sold to a local farmer and stored outdoors. Sold to T. Kucher of Dauphin, Manitoba in 1970. ToCanadian Museum of Flight and Transportation at Surrey, BC in 1982. Partially restored, displayed marked as RCAF 9120. To Quebec Air & Space Museum at St. Hubert, Quebec in 1995, for further restoration. Still under restoration in 2010. The museum is now called the Canadian Aviation Heritage Museum.[38]
10201 – Mk. IVT airworthy with the Aircraft Restoration Company inDuxford, Cambridgeshire. It was restored as a Blenheim Mk.1F, using a Blenheim Mk I nose which had previously been converted to a car. It is registered as G-BPIV.[49]
Guns: 1× fixed forward firing.303 inBrowning machine gun and one .303 in Browning machine gun in power operated dorsal turret, alternately in the IVT, two Browning machine guns in a Bristol Type B1 Mk IV turret[55]
^"BRISTOL BOLINGBROKE IVT".Canada Aviation and Space Museum. Canada Science and Technology Museums Corporation. Archived fromthe original on 28 May 2017. Retrieved3 May 2017.
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