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 simply outrun the fighters sent to stop it, saving the weight and drag of turrets and gunners and turning speed itself into armour.

First flown on 25 November 1940, the prototype stunned the sceptics by proving faster than the Spitfire. What had been dismissed as a foolish idea was suddenly one of the most promising aircraft in Britain — and within two years it would be doing jobs no one had ever imagined for it.

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

The logic was inspired. Wooden construction used non-strategic materials and a workforce that did not compete with the rest of the aircraft industry for aluminium or skilled metalworkers, while the light, smooth structure cut drag and weight. It had real drawbacks — in hot, humid tropical climates the glues could degrade and the airframe delaminate — but in the temperate skies of Europe the “Wooden Wonder” was a triumph of unconventional engineering, and some 7,781 were built.

Two Rolls-Royce Merlin engines of roughly 1,480–1,710 hp gave the Mosquito a top speed around 668 km/h (415 mph) in its faster marks — for a time one of the fastest operational aircraft in the world, and enough to leave contemporary interceptors behind. A crew of two sat side by side in a compact cockpit.

Above all the design proved astonishingly adaptable. The same basic airframe stretched to carry a 4,000 lb (1,814 kg) “Cookie” blast bomb, airborne-interception radar, four 20 mm cannon, rockets, cameras — even a 57 mm anti-shipping gun in the “Tsetse” version. Few aircraft of the war were asked to do so many different jobs, and fewer still did them all well.

As a bomber the Mosquito carried a load out of all 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” to over 9,000 m — a load-to-target that German night fighters could barely intercept. Crews of the Light Night Striking Force sometimes flew two Berlin sorties in a single night.

Oboe-equipped Mosquitoes of No. 8 (Pathfinder) Group dropped the target markers on which the whole Main Force bombing 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 disrupt the radio broadcasts marking the Nazi regime’s tenth anniversary.

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

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

The Mosquito became famous for pinpoint raids flown at treetop height. On 18 February 1944 (Operation Jericho) Mosquitoes breached the walls of Amiens prison to free members of the French Resistance awaiting execution. Gestapo headquarters were hit in Oslo (25 September 1942), Aarhus (31 October 1944) and Copenhagen (the Shellhus raid, 21 March 1945) — attacks demanding navigation and bombing accuracy measured in metres.

Photo-reconnaissance Mosquitoes ranged unarmed as far as Berlin, Prague and the Norwegian fjords throughout the war; the PR.34 of 1945 could photograph targets 5,600 km away. Mosquitoes of BOAC even flew a civilian courier route to neutral Sweden, carrying ball-bearings — and occasional VIP passengers strapped into the bomb bay.

About 7,781 Mosquitoes were built. Fast, elegant and endlessly versatile, it validated de Havilland’s heretical idea that speed could replace armour and guns, and it did so while conserving the metals and manpower Britain most needed.

The Mosquito’s significance is technical rather than sentimental. An unarmed, wooden, twin-engine design built outside the light-alloy supply chain outperformed orthodox metal rivals across a wider range of duties than any other aircraft of the war — bomber, night fighter, pathfinder, strike and reconnaissance — and roughly 7,781 were built.

• 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).