de Havilland Mosquito

The Mosquito began as a private de Havilland proposal for an unarmed, high-speed bomber — a concept the Air Ministry initially rejected as absurd. De Havilland’s insight was that if an aircraft were fast enough it would need no defensive guns at all: it would outrun the fighters sent to stop it, saving the weight and drag of turrets and gunners and turning speed itself into protection.

It first flew on 25 November 1940, and the prototype proved faster than the Spitfire then in service. The idea that had been dismissed as foolish went on to be built in ~7,781 examples and to fly as a bomber, a pathfinder, a night fighter, an anti-shipping striker, a photo-reconnaissance aircraft and a civil courier.

Its defining feature was the very thing that had made the Air Ministry baulk: it was built almost entirely of wood. The fuselage was a smooth monocoque of plywood–balsa–plywood sandwich, the wing was a one-piece wooden structure, and assembly went not to metal aircraft plants but to cabinet-makers, furniture firms and piano manufacturers whose craftsmen already knew how to shape and glue wood.

The logic was sound on two counts. Wood was a non-strategic material, so the aircraft did not compete for aluminium, and the workforce did not compete for skilled metalworkers — while the light, smooth structure cut both drag and weight. The drawback was real and would surface later, in the tropics, where the glues failed.

Two Rolls-Royce Merlin engines of roughly 1,480–1,710 hp gave the faster marks about 668 km/h — for a period one of the quickest operational aircraft anywhere, and enough to leave contemporary interceptors behind. The crew was two, sitting side by side in a compact cockpit.

The airframe also proved unusually adaptable. The same basic design stretched to carry a 4,000 lb (1,814 kg) “Cookie” blast bomb, airborne-interception radar, four 20 mm cannon, rockets, cameras — and, in the “Tsetse”, a 57 mm Molins anti-shipping gun in the nose. Wingspan was 16.52 m, length 12.43 m, maximum take-off weight around 10,000 kg.

As a bomber it carried a load out of proportion to its size. The B.IV took four 500 lb bombs to Berlin; from 1944 the B.XVI, with a bulged bomb bay and two-stage Merlins, lifted a single 4,000 lb “Cookie” above 9,000 m — the same weight of bomb a Flying Fortress carried, delivered by a two-man wooden aircraft German night fighters struggled to reach. Crews of the Light Night Striking Force sometimes flew two Berlin sorties in one night.

Oboe-equipped Mosquitoes of No. 8 (Pathfinder) Group dropped the markers on which the whole Main Force effort depended. The type’s loss rate — around one aircraft per 2,000 sorties in 1944–45 — was the lowest in Bomber Command. On 30 January 1943 Mosquitoes made the first daylight raid on Berlin, timed to interrupt the broadcasts marking the tenth anniversary of the Nazi regime.

Radar-equipped night fighters — the NF.II of 1942, then the centimetric-radar NF.XIII, XIX and NF.30 — defended Britain and, with No. 100 Group, hunted German night fighters in their own landing circuits. In the summer of 1944 the Mosquito was one of the few aircraft fast enough to catch the V-1 flying bomb, and destroyed around 600 of them.

The fighter-bomber FB.VI was the most-built mark: four 20 mm Hispano cannon, four 0.303 in machine guns, bombs and eight RP-3 rockets. It flew day and night intruder work over occupied Europe, and with the Banff Strike Wing attacked shipping and U-boats along the Norwegian coast into 1945.

On the night of 5/6 June 1944 forty-nine Mosquitoes were among the 1,012 aircraft that bombed the Normandy coastal batteries, while No. 100 Group flew 25 intruder patrols in support and lost two. Once the Germans stopped moving reinforcements in daylight, FB.VIs were given patrol sectors over Normandy and worked them at night against trains, road transport, gun positions and Luftwaffe airfields.

On 18 February 1944 Mosquitoes of 21 Squadron RAF, 464 Squadron RAAF and 487 Squadron RNZAF, escorted by Typhoons, flew to Amiens to break open the prison where the Gestapo held members of the French Resistance. Twelve had already been executed there, and more were reported to be facing a firing squad the following day. The bombs were fused with an 11-second delay, timed to breach the outer wall and then the inner buildings.

The walls came down. Of roughly 700 prisoners, 102 were killed by the bombing and 74 wounded; between 255 and 258 got out, and 182 of those were recaptured. Group Captain Percy Pickard, who led the raid, was shot down and killed with his navigator, Flight Lieutenant Alan Broadley.

The same technique was turned on Gestapo offices in occupied Scandinavia: Oslo on 25 September 1942, the university buildings at Aarhus on 31 October 1944, and the Shellhus in central Copenhagen on 21 March 1945 — Operation Carthage, flown at the repeated request of the Danish resistance, which wanted the Gestapo’s files destroyed and its prisoners freed. The RAF had refused twice, on the grounds that the target stood in a crowded city centre.

The Shellhus was destroyed and 18 prisoners got out. But one Mosquito of the first wave struck a lamppost and crashed into the Jeanne d’Arc School, about 1.5 km short of the target; aircraft of the second and third waves bombed the burning school, taking it for the objective. 86 schoolchildren and 18 adults were killed there.

Photo-reconnaissance Mosquitoes flew unarmed and unescorted over Berlin, Prague and the Norwegian fjords throughout the war, relying on the same thing the first bombers had: being too fast to catch. The PR.34 of 1945 could reach targets 5,600 km away.

There was also a civil operation. Mosquitoes in BOAC markings flew a courier route across German-held airspace to neutral Sweden, carrying diplomatic mail and ball-bearings Britain could not otherwise obtain — and occasionally a passenger, lying in the bomb bay with a flask and an oxygen mask.

The wooden structure met its limit in the Far East. Four squadrons flew Mosquitoes from Indian bases — No. 45, No. 47, No. 82 and No. 110 — against Japanese airfields, railways and bridges in Burma. Through 1944 aircraft began coming apart in the air. The failures were attributed to the casein glue, which did not hold in the heat and humidity of India; the underlying cause was the swelling and shrinking of the wood itself, which delaminated the wing skins and failed the spars.

In November 1944 Mosquito operations over Burma were suspended entirely while the aircraft were inspected, and modified airframes built for the tropics did not begin arriving until 28 January 1945. The squadrons went back to work, and on 20 August 1945 No. 110 Squadron dropped what are recorded as the last bombs of the Second World War, on Japanese positions in Burma.

• C. Martin Sharp & Michael J. F. Bowyer, Mosquito (Crécy) — the classic history.
• Stuart Howe, De Havilland Mosquito: An Illustrated History (Crécy).
• Philip Birtles, Mosquito: A Pictorial History of the DH98 (Jane’s).
• Martin W. Bowman, De Havilland Mosquito (The Crowood Press).