Workhorse of the Desert Air Force – The Blenheim Mk. IV

Workhorse of the Desert Air Force – The Blenheim Mk. IV


Many Royal Air Force enthusiasts have a soft sport for the Bristol Blenheim, and regard her quite highly. There is a good bit of nostalgia though, and it is arguable that even by the start of the war in 1939, the Blenheim was not really a competitive plane anymore. By the time of Operation CRUSADER, the only thing it had going for it was that it was available as a light strike plane without having to rely on US allocations of superior light/medium bombers such as the Douglas Boston or Martin Baltimore.

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The Fighter Collection Blenheim I at Leicester War & Peace Show, 2015. Collection.


In the popular imagination. Airfix Box Art for the Blenheim IV kit, showing a raid by No. 342 (Free French) ‘Lorraine’ Squadron on Bardia, 1941.

Design History

The Blenheim (Bristol Type 142) was originally designed in 1935, and was a well advanced airplane for its time. It was faster than the fighters that would defend airspace against it, had a modern fuselage, a reasonable defensive equipment and bomb load. By 1939 however, other light/medium bombers such as the Fiat BR.20, the Martin 167 Maryland and the German Dornier 17Z had similar or better performance, carrying more bombs at similar speeds and distances. Modern fighters such as the Bf 109 had entered service that outperformed the Blenheim by a considerable margin.

An attempt was made to address shortcomings of the Blenheim I by modifying it substantially, adding range and dealing with the flawed nose design. The new Type 149 became the Blenheim IV or Bolingbroke, reaching frontline units in 1939. This did however not address the fundamental flaw, which was that a weakly defended, slow light bomber needed three crew members and the servicing personnel for a squadron of 12 twin-engined planes to be able to carry 48 250lb bombs to enemy territory. Nevertheless, with nothing else available, the type soldiered on.

The final variant was the Blenheim V, also called Bisley, Type 160. Almost 1,000 of the type were produced from 1941 onwards, but it was no longer competitive at all. When they entered combat during Operation TORCH in 1943, they were slaughtered by the German fighters.


The Blenheim IV, the only type to serve in the frontline during CRUSADER, could carry a lot of 4x 250lb bombs sufficiently far to attack Derna or Benghazi from the most advanced landing grounds in Egypt. Malta-based Blenheims could reach Tripoli, the coastal road, Benghazi, and most of the shipping lanes from Italy to North Africa. A typical squadron mission of 10 planes, allowing for two to be unserviceable, could therefore carry 10,000lb of bombs on target. 

105 Blenheim

Bristol Blenheim Mark IV, V6014 ‘GB-J’, of No. 105 Squadron RAF Detachment in a dispersal at Luqa, Malta. Canvas covers protect the cockpit and glazed nose section from the sun. From July to September 1941, 105 Squadron was detached from the United Kingdom to Malta, to operate against targets in the Mediterranean and North Africa, losing 14 aircraft during the period. Note the modified gun mounting under the nose. IWM CM1357

The Blenheim in CRUSADER

Blenheim IVs came in two types during operation CRUSADER. Most squadrons were equipped with the bomber version, while No. 113 Squadron had received the fighter version known as Blenheim IVF. Squadrons had a frontline establishment of 12 planes, and the Blenheim Squadrons operating in the desert were Squadron Nos. 8, 11, 14, 45, 55, 84, 113 (Fighter), 203 (Naval Co-Operation) and the Free French Lorraine Squadron, while in Malta Squadron Nos. 18, 107 and a detachment of No. 40 Squadron operated the type for ground attack and anti-shipping missions. Of these, seven bomber squadrons as well as the fighter squadron No. 113 were considered operational, with a total of 112 Blenheims reported ready on 16 November 1941[1].


In the run-up to CRUSADER, Egypt-based Blenheims conducted bombing raids on Axis installations such as ports and landing grounds all over Marmarica and Cyrenaica. The Blenheims of No. 201 (Naval Cooperation) Group conducted maritime surveillance.

Malta-based Blenheims were also busy, being tasked with convoy interdiction. While the Fleet Air Arm with its Swordfish torpedo bombers striking convoys at night captured the popular imagination, many ships fell victim to daylight attacks by Blenheims. But these shipping strikes came at a very high cost, as e.g. events on 12 September or 11 October 1941 showed clearly. The high cost of these strikes was not enough to deter them however, since the prize was also high, and an instruction came from London that these high losses had to be accepted.

In the end, the shipping attacks continued successfully, but at a high cost, with No. 107 Squadron at one point commanded by a Flight Sergeant, since all its officers were gone.

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Telegram Chief of Air Staff to R.A.F. H.Q. Middle East, 19 October 1941. AIR20/2109

Once the attack started, Blenheims were busy during CRUSADER, with many squadrons carrying out 1-2 sorties per day, weather permitting, and became ridiculously busy during the final stage of the siege of Bardia and Halfaya, when the garrisons were bombed constantly. This generated an inquiry from London, whether this scale of attack was justified when the garrisons could just be hammered by artillery instead.

The fighter Blenheims of No. 113 Squadron operated from a clandestine landing ground inside Libya, as long-range strike planes, disrupting Axis traffic on the coastal road from Tripoli to Benghazi, and also attacked Axis landing grounds in western Cyrenaica.

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Exchange of Telegrams between Tedder and London on the question of excessive raids by Blenheims on Bardia. Air20/2109

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Telegram, Tedder to Air Ministry, 1 December 1941, leaving little to be clarified regarding his opinion of Bristol’s light bomber designs. AIR20/2109

The End

CRUSADER was in many ways the swan song of the Blenheim in the fight against the Axis forces. More and more of the better US planes became available, and once squadrons converted to these, there was no way back, as set out in the telegram from Tedder to the Air Ministry in London above. It clearly sets out the concern about losing Douglas Bostons from the allocated volume from the US production to the Soviet front, and the potential impact on morale to have crews switch back from more modern US models to the Blenheim, be it Mk. IV or V (Bisley). At the same time, a continued role of light bomber strikes was acknowledged, but the expectation was that these would be carried out by more capable types. For the Western Desert, this meant US types, since Mosquitos, with the exception of some photo-reconnaissance planes on Malta, were not making it out to the Middle East. Nevertheless, squadrons such as No. 107, which was withdrawn from Malta to the UK in January 1942, converted to the type there.

By January 1942, confirming Tedder’s judgement, the remaining Blenheim squadrons in the Middle East were sent to the Far East, where they would serve in all theaters for another period, but suffering equally against Japanese high-performance fighters. A policy of handing down obsolete planes to the Far East, driven by an underestimation of the performance of the latest Japanese fighters, was going to have disastrous consequences for the crews. Unlike obsolete tanks, such as the Matilda II, or the US-built M3 Stuart and Grant tanks, there was no second life for obsolete planes in the Far East.

In the desert then, through early 1942, the obvious replacements arrived in the form of US-made Douglas Bostons and Martin Baltimores. At the same time, a surprising transformation also took place. Technological change made itself felt, and the air/ground war of 1942 would look very different to that in 1941. 

The Rise of the Fighter Bomber

A very important point in the evolution of light bomber strikes is the switch from twin-engined to single-engined planes, enabled by the introduction of better-performing engines from the late 1930s. This is a point I am indebted to Justin Bronk for. 

The Luftwaffe had very successfully experimented with fighter bombers in 1940, by equipping its Bf109E fighters with a single bomb carried under the fuselage during the battle of Britain. It never looked back, but it took it years to be able to produce the numbers of single-engine fighters to be able to spare some for this task. The introduction over England had been a whirlwind of successes and failures, but overall with the good initial successes by 3./Erprobungsgruppe 210, validating the concept of the single-engine fighter bomber.

By 1941, the R.A.F. was  experimenting with the same approach by introducing the Hurribomber, a variant of the Hurricane with hard-joints under the wings that enabled it to carry 8x40lb bomblets. The first full squadron equipped with these Hurribombers in the desert was No. 80 Squadron, and it took up operations in November with the start of CRUSADER. The squadron showed the potential of the fighter bomber, but the Hurricane was not the right plane, lacking power and consequently performance when encumbered with external ordnance loads.

By the end of 1941, a new type of fighter was arriving in the Mediterrean theatre, the Curtiss P-40 Kittyhawk, another derivative of the Curtiss P-40 airframe with some modifications. While never a first-class air superiority fighter due to its failure to perform well at height, the Kittyhawk had the sturdiness to serve in a different role, as a highly capable fighter bomber. One of the first squadrons to receive the Kittyhawk Mk. Ia, No. 3 Squadron R.A.A.F. was ordered to train as a fighter-bomber squadron on 7 April 1942.

Almost from the start the Kittyhawk provided a new capability to the light strike force, being able to carry a 500lb bomb, a load which neither the Blenheim nor the Maryland could carry. Alternatively, it carried 2x250lb bombs alongside under the main fuselage. Hardpoints were also provided under the wings for 40lb bombs, such as those used on the Hurribomber, but these were apparently not used. In the desert, with vehicles and men practicing dispersion, lighter bomb weights restricted the damage potential from a raid considerably.

By August 1942 therefore, newly introduced US-made 500lb bombs were routinely carried to target, and a year later, the Kittyhawk’s latest upgrade, the Mk. III, also named the Warhawk, had substantially increased its capability, and could carry up to 6x250lb bombs, i.e. 50% more of these type than the Blenheim Mk. IV could carry, by utilizing hardpoints under the wings.

This meant that a squadron of 16 fighters, employing less than half of the flying personnel, and requiring 1/3 less of engine maintenance, compared to a squadron of 12 Blenheims, could now deliver 24,000lb of ordnance in a single strike, twice that compared to the 12,000lbs that a Blenheim squadron could deliver. It could also do so faster and more accurately by using dive bombing techniques and it came with a better ability to defend itself and/or to undertake follow-on strafing attacks after a bombing run.

The power of being able to quickly assemble large numbers of these fast fighter bombers was impressively shown when 50 of them attacked an Italian convoy at the end of April 1943, rapidly sinking the destroyer Lampo. She was attacked by P-40 Warhawk fighter bombers of the USAAF’s 79th Fighter Group, with 86th, 87th and 316th Fighter Squadrons and sunk in Tunisian waters when her escort of Regia Aeronautica fighter planes was simply overwhelmed by the number of attackers.

This was not an ‘either/or’ proposition however, and both the R.A.F. and the U.S.A.A.F. continued to operate large numbers of light/medium bombers such as the B-25 Mitchell and the B-26 Marauder of US production as well as the British De Havilland Mosquito, with good results. 

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Western Desert, Libya. 1 June 1942. The American Curtiss P-40 Kittyhawk bomber aircraft which is proving highly successful in the present desert operations. Diving at terrific speed on the enemy’s colunns this aircraft releases its bombs at low level, climbing rapidly up again to resume its original role as a fighter. Kittyhawk bombers have already knocked out or heavily damaged some hundreds of enemy vehicles. This aircraft, code name GA-F, of No. 112 Squadron RAF, sits on the airfield showing teeth painted on the fuselage to resemble the jaws and teeth of a shark. AWM MED0445 

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Front view of a P40 Kittyhawk aircraft of 450 Squadron RAAF. The aircraft is carrying six 250 lb bombs. AWM P03372.011


[1]These statistics do not seem completely reliable.

Further Reading

Air Support for 8 Army

4 Battle Sorties

A costly strike

Air/Sea Battle in the Med

Notes from the Receiving End

No. 3 Squadron R.A.A.F.

No. 211 Squadron Website

No. 113 Squadron Website

Australians at War – No. 113 Squadron

Bae Heritage – Blenheim IV/Bolingbroke

Scott, S.R. Battle Axe Blenheims – History of No. 105 Squadron

Bronk, J. The Rise of the Fighter Bomber in the Western Desert, RUSI Journal

Goss, C. Cornwell, P. & Rauchbach, B. Luftwaffe Fighter-Bombers Over Britain: The Tip and Run Campaign 1942-43, Stackpole 2010

Rickard, J (26 June 2007), Bristol Bisley

Panton, Alastair Six Weeks of Blenheim Summer, Penguin

Primary Sources

AIR23/6200 – History of Operations RAF Middle East, November 1941 – May 1942

AIR22/1 – RAF Middle East Aircraft Strength Returns

AIR20/2109 – Telegrams Tedder/London