211 Badge
Bristol Blenheim I

 Bristol Blenheim I (Type 142M)
 

Bristol Blenheim I  211 Squadron 1939 LJ-R L1490
Bristol Type 142M Blenheim I
211 Squadron El Dabaa 1939, LJ-R (L1490) leading (CFR Clark)

The 1930s background
Progress in military aviation was very rapid in the mid to late 1930s. This short period saw the introduction of stressed-skin monoplane designs with flaps, retractable undercarriages, powered turrets and variable pitch propellers to match increased engine power. A revolution in design in a time of rapid expansion, while some aspects of operational doctrine languished. A glance at the types available in Britain, France, Germany, Italy and the USA between the Munich crisis and the outbreak of war reveals the heights of success and the depths of failure which these challenges brought forth.

In Britain, the metropolitan airforce grew rapidly with the successive expansion plans of the period, the Blenheim for example being one element of Expansion Scheme 'C'. In the flurry of rapid growth, the Air Ministry and Air Staff struggled to juggle resources and to rethink requirements as better designs came into being through the specification system and through private venture. Here, too, lay the roots of somewhat confused progress among the sound, the not so sound and the ill-judged, with fatally slow development for some projects (like the Boulton Paul Defiant), effectively none for others pressed into production (like the Fairey Battle), and comparatively speedy development for others (like the Armstrong-Whitworth Whitley and the Blenheim).

Bristol beginnings
Many a woolly story continues to circulate about the Bristol Aeroplane Company’s Blenheim and its origins. Lord Rothermere, a newspaper owner (The Daily Mail) whose brother (Northcliffe) was proprietor of The Times, had earlier been the first Secretary of State for the Royal Air Force in the turbulent World War I period under Lloyd George. Still actively interested in aviation, Bristol's Type 135 design for a 6 passenger twin (2xBristol Aquila) came to Rothermere’s attention in early 1934, his interest in a fast personal transport having been piqued by that of Beaverbrook (also a media magnate) in the Douglas DC1. In the end, after some cautious discussion with both the Air Ministry and with the press baron, Bristols offered and Rothermere ordered the up-rated Type 142 private venture (2xBristol Mercury), which as built became his personal aircraft “Britain First”.

This, the sole Type 142, was donated by its owner to the Air Ministry shortly after delivery. The original Bristol Type 135 design was never built, proceeding instead to a further development, the Type 143 with 2xAquilas and slightly enlarged to 8 passengers plus 2 crew. A single Type 143 was built in parallel with the Type 142. A militarised transport version of the Type 143 was also proposed (the Type 143F with 2 Mercury IX). With an interchangeable nose/armament option and provision for a "free-mounted Lewis" in a dorsal position, the Type 143F design attracted the attention of the Finnish government who opened negotiations to buy 9 of the type. However, the Finnish proposal was overtaken by the RAF's initial order for 150 of the Type 142M Blenheim (which the Finns subsequently both bought and license built). Likewise, Bristols were unable to take up Rothermere's offer to order a replacement for his donated Type 142.

Blenheim development
As delivered, the Type 142 “Britain First” was a 6 seat, low-wing transport with a crew of 2. To transform this rich man's toy into the Type 142M Blenheim bomber was not the simple task that some sloppy research pretends. The task was a major redesign: of the wing centre-section and fuselage (raising the wing to mid-fuselage to provide for a bomb-bay stressed for 1000lbs); of the nose (to provide navigating and bomb-aiming positions beside the pilot); of the rear fuselage (to add the dorsal turret and radio operator's position); and for provision of all the associated military equipment (turret hydraulics, flares, bombing and gunnery hardware, radio, hatches, dinghy, external hard points); and re-stressing of the airframe for military use. Result: a 2,400 lb or 24% increase in all-up weight to 12,200lb (though weight reports vary) and the raising of the tailplane by 8". A major redesign, by any standard.

Development was quick in the sense that production orders were placed straight off-plan: that is, off the Type 142M plans. Following the "Britain First” first flight at Bristol Filton in April 1935, Bristol's July 1935 Type 142M proposal was met with Air Ministry Spec B.28/35 (bomber) in August, incorporating the modifications described above and followed immediately by the first production order for 150 aircraft. The first flight of the Type 142M/Blenheim I prototype K7033 took place on 25 Jun 1936, 14 months after the "Britain First" flight. Service trials followed, and the design was given final production approval in December 1936. The first service delivery (K7036) on 10 March 1937 was just short of 2 years development since the "Britain First" flight, and not far short of 4 years from Barnwell's initial twin design. Successful conversion: no doubt. Quick? Perhaps. A tribute to Barnwell's expertise? Certainly. But let's not pretend it was simple.

The fabled top speed of 307 mph (and more realistically, of 285 mph with maximum load) were in fact those achieved by "Britain First", and in its as-delivered condition. Mischievously, Jane's 1939 edition quoted the latter as the Type 142M/Blenheim I top speed, often re-quoted since, alongside the equally unattainable 295mph for the Mark IV.

Development summary

Type 135

2xAquila. Design only July 1933. None built.

Type 142

2xMercury. One ordered March 1934, and built."Britain First", civil registration allotted G- ADCZ but unused. Flown 12 April 1935. To the RAF and allotted R-12 experimental Jun 1935, until taken on charge and allotted K7557 July 1935.

Type 143

2xAquila: test bed. One only built. Allotted G-ADEK March 1935, flown January 1936 and to the RAF as R-14 but retained at Bristol Filton.

Type 142M

2xMercury VIII. Proposed July 1935. Design August 1935 Air Ministry Spec 28/35. Air Ministry production order 150 aircraft September 1935. First Type 142M Blenheim prototype: K7033 June 1936. First service delivery K7036 March 1937.

Into service
The Bristol Blenheim I (Bristol Type 142M) thus entered RAF service in 1937 described (CAS to Air Ministry 1935) as a twin-engined high-performance medium bomber – a day bomber, in short. To the RAF, even post Munich Crisis, a "big" twin like the Blenheim was a “medium”, and was so described throughout the war (Air Ministry - Pilot's Notes, all marks). Hinds were still in operational use for some time to come: that was a light bomber.

Bristol Blenheim Mark I cutaway
Blenheim Mark I cutaway (Aeroplane)

For the period between its service entry in March 1937 and the arrival of Hawker Hurricanes in 111 Squadron at Christmas that year, the Blenheim was as fast as any fighter in the RAF. Bristol figures show, for production Blenheim Mark Is, a maximum full-load speed of 279 mph at 15,000 ft and of 265 mph at 10,000 ft. For the Mark IV, Bristol data show a maximum speed of 266 mph at 11,800 ft. By 1941, ageing operational aircraft could not have achieved these speeds in level flight. In action, fully laden aircraft on a long sortie might cruise at 180 mph or 200mph for an endurance of around 5 hours. At high rates of power, the consumption of the Mercuries made daunting inroads into the 280 gallon fuel capacity of the Mark I. While cruising with the mixture set fully lean, you might eke out 55 gallons an hour: pull on the boost in rich mixture to dodge an unwelcome visitor and you might be looking at 150 gallons an hour or more.

By the time Mark IV Blenheims entered service at home in early 1939, Mark Is had found their way to the Middle East and the Far East. By 1940 in Europe, and by 1941 overseas, the Blenheim's place as a "fast" medium day bomber had been eclipsed by later developments. Under-bombed, under-gunned and under-powered, Mark Is and Mark IVs alike were obsolescent if not obsolete. Even so, the Blenheim had been built in large numbers and was very active in the early part of the RAF’s war.

Operating in every conceivable role and in literally every Home and Overseas Command, the Blenheim recorded many “firsts”, apart from the early technical achievements already noted. Its service as the first radar night fighter may stand as exemplar for them all. With the Battle of Britain and the beginning of Luftwaffe night bombing attacks, 6 RAF Squadrons were equipped with Blenheim IFs converted to the night fighter role, fitted successively with Aerial Interception (AI) Mark II, III and IV radar sets. At the time, a nimble multi-seat twin was highly desirable as a night fighter, the early AI radar sets weighing around 600 lb. The first successful radar night interception was achieved by a Fighter Interception Unit Blenheim IF with AI Mark IV on 22/23 July 1940, guided to AI range by Ground Controlled Interception (the standard technique). The Blenheims continued radar night fighter operations with modest success until April 1941, even as Beaufighters were being introduced. As radar development continued, Blenheim Mark IFs with obsolete AI sets accompanied Mark IV bombers on offensive night intruder operations over occupied Europe.

The Blenheim paid the price for being conceived in that period of rapid development which saw it arrive as the premier medium day bomber of the time (with the similarly tasked Battle its contemporary), just as equally radical development in fighter design was bearing fruit. The Air Ministry and the Air Staff had contemplated and successfully encouraged development of high speed monoplane bomber and interceptor designs virtually simultaneously in 1934 and 1935. The urgent need to expand with modern equipment apart, the rationale for pressing ahead with lightly armed day bombers in quantity while developing the Hurricane and Spitfire remains to be explained. The entry to service of high speed, single-seat multi-gun monoplane fighters rendered the fast medium day bomber role untenable for the time being. Speed, power, armament and endurance all advanced very greatly in those few short years before war finally came again to Europe. All were to advance again in the press of war.

Blenheim Is in Middle East and Far East Commands
In the late 1930s, with Egypt a British Protectorate and the Italians bombing the herdsmen of Abyssinia in a drive for Empire and Mare Nostrum, RAF Middle East Command had long-since matured from putting the fear of God into desert tribesmen. The Command’s remit included Iraq (the oil), Egypt (the canal), Aden (the Red Sea port), the Sudan and East Africa.

When Italy entered the war in June 1940, the Middle East Command order of battle included nine Blenheim squadrons:

  • five in Egypt (Nos. 30 (MkIF), 45 (Mk Is), 55 (Mk Is), 113 (Mk IVs), and 211 (Mk Is));
  • No 84 in Iraq with Mk Is; and
  • three in Aden (Nos. 8 , 11 and 39 (all with Mk Is)).
    8 Squadron still rejoiced in the possession of one flight of Vickers Vincents at that time.

In Far East Command at the same date, 27 Squadron was equipped with the Blenheim IF (the fighter version, created by the addition of a four Browning gun belly pack under the bomb bay), while 34, 60 and 62 Squadrons operated Blenheim Is.

By May 1941, Middle East Command had at its disposal the following 11 Blenheim Squadrons:

  • No 39 at Shandur,
  • Nos 45 and 55 at Maaten Bagush.
  • Remnants of 11, 30 and 113 Squadrons in Crete or en route to Egypt and Palestine.
  • 84 Squadron and 211 Squadron already re-established in Palestine, having withdrawn from Greece.
  • 203 Squadron (Mk IVs) with detachments all over the Command.
  • At Port Sudan, 14 Squadron having disposed first of its Wellesleys then its Gladiators between September 1940 and March 1941, had re-equipped with Blenheim IVs.
  • In Aden, 8 Squadron was still operating a mixed bag that included Blenheim Is and IVs and still soldiering on, a flight of Vincents.

In Jan 1942, 84 Squadron and 211 Squadron (211 having been rested from June 1941 while operating as 72 OTU) had re-equipped with Mk IVs and were in transit to the Far East. 113 Squadron had departed the Middle East in early January, to fight in Burma at Toungoo and Mingaladon alongside 45 Squadron, until forced to withdraw to India. By March 1942, 11 Squadron had transferred to Colombo, disaster having befallen the other Blenheim Squadrons (Nos 27, 34, 60 (Mk Is and Buffalos), 62 (Mk Is and Hudsons), 84, and 211) in the struggle for Singapore, Sumatra and Java.

By April 42, Middle East Cmd was still operating Blenheim units in the Western Desert, for example 203 Squadron, 55 Squadron, (Mk IVs), 14 Squadron, (Mk IVs) at various posts.

The best in-print sources recognise that the official records of these Units, their movements and their place in Orders of Battle is incomplete and occasionally in conflict, as are later interpretations of the state of play. It was a difficult period of WWII.

L6670
This aircraft was flown by Squadron Leader JR Gordon-Finlayson (GF or The Bish) on a number of occasions in early December operations from Menidi. Shown here with the Squadron's wartime UQ code but without an individual letter, L6670 also operated as UQ-R for some period before arrival in Greece. In the RAF phonetics alphabet (up until 1942, at least) R was voiced as "R Robert" — a name The Bish was wont to use of himself. At some period in 1939, L1490, too had operated as R-Robert: but wearing the codes LJ-R.
See CFR Clark Part V.

Bristol Blenheim I L6670 Menidi
L6670 coming in to land (Crown Copyright)
One of the best known pictures of a 211 Squadron aircraft, shown here in desert paint (Middle Stone and Dark Earth). This photograph has been been published on a number of occasions captioned as “at a forward landing ground” or “at Paramythia”, but see the next photograph.

Bristol Blenheim I L6670 Menidi
L6670 coming in to land: Menidi (Tatoi) late 1940 (Crown Copyright)
Compared with the highly cropped state so often used, here the original full-frame photograph shows L6670 caught mid-flare and within feet of the ground, quite unmistakably at Menidi (Tatoi) with the mass of Parnes in the background. For other pictures of Menidi (Tatoi) topography see
Clark Part V, Checketts, Cooper, Fryatt, Tatoi today.

It seems that the enlarged, cropped version is the source of the confusion in reference works and illustrations about the correct Squadron code at this period: UQ, applied in red, has often been misinterpreted.

Photo source: Royal Air Force in the World War, Volume 3 1940-1945, N Macmillan (Harrap 1949). Macmillan gave no attribution, though the cropped version is sometimes credited to the Imperial War Museum. In 1998 I inquired of the IWM Photograph Archive about photographs of 211 Squadron personnel or aircraft. Their response was that there were none.

211 Squadron Blenheim Is
Blenheim Is in 211 Squadron service included:

    May 1939 to June 1940
    L1482, L1483, L1484, L1486, L1488, L1490 (LJ-R), L1492, L1493, L1496, L1535, L4909, L6634, L8389

    June 1940 to June 1941
    47 aircraft recorded as used operationally. 14 recorded as lost on operations, not counting those “Damaged” or “Forced landing”.
    L1097, L1382, L1393, L1420, L1428, L1434*, L1481, L1482, L1486, L1487*, L1490, L1496, L1528, L1535*, L1539*, L1540 (UQ-P)*, L1542, L4819*, L4910, L4926*, L5481, L6634, L6647, L6654, L6657, L6658, L6670 (UQ, UQ-R), L6866, L8382, L8383, L8390, L8411†, L8431, L8443, L8449*, L8471, L8477, L8478*, L8501, L8513, L8523, L8531**, L8533, L8536*, L8541, L8542*, L8664 (UQ-S)*
    *Lost on operations
    **Destroyed on the ground, Paramythia
    †Single engine wheels-up forced landing, Corfu

    June 41 onwards operating as 72 OTU
    L1482, L1492, L1520, L1533, L6655, L6663, L8517, L8539.

Note: These lists of aircraft flown by 211 Squadron personnel were sourced from the Operations Record Book and from Logbook facsimiles or transcripts of the crews. In the nature of things, aircraft recorded as flown by 211 Squadron crews may not have been recorded as on 211 Squadron charge. ORB and Logbook entries or transcripts are good sources but may nevertheless contain errors. There are some discrepancies with Warner’s account.

Specifications

General

Medium day bomber. Twin-engined, mid-wing cantilever stressed-skin monoplane.
Fabric-covered control surfaces.

Crew

Pilot; Observer (ie Navigator/Bomb-aimer); Wireless Operator/Rear Gunner. The well in the wing centre-section carry-through could take one passenger or freight. In emergency, it was possible to carry at least 6 passengers.

Engines

2xBristol Mercury VIII 9-cylinder radial. Single stage supercharging to maximum 840hp at +5lb boost (maximum 5 minutes). 87 Octane fuel.

Armament

One fixed, wing-mounted forward-firing .303” Browning machine gun. One turret-operated .303” Vickers K gun. About 200 converted to Mark IF with 4x.303” Browning machine gun belly pack.

Bomb load:

1000lbs variously disposed, as 4x250lb, 2x500lb, or mixed with the standard Small Bomb Container (SBC) for incendiaries, 20lb or 40 lb anti-personnel bombs, or with the external Light Series Carrier (LSC) commonly fitted in Middle East Command.

Range:

1,125 miles (at 220mph with full load), an endurance of 5 hours.

Stalling speed
Safety speed
Final approach
Maximum speed

Flaps & undercarriage up: 70mph. Flaps and undercarriage down: 60mph
120mph (also initial climb speed and maximum speed for flaps)
85mph
Variously quoted. 265mph at 10,000 ft.
Vne quoted as 285mph or 287mph

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Updated 27 Jul 2003

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