In the late 1930s, the dark cloud of war was lurking on the horizon in Europe. Even as the United Kingdom and France employed diplomats to appease Hitler with compromises, each country also began reinforcing its military in anticipation of hostilities. Among other preparations, Britain's air force ramped up production of its state-of-the-art bombers. These large aircraft were well-armored and capable of delivering a brutal amount of destruction; but the four-engine steel/aluminum planes were slow and ungainly, leaving them highly vulnerable to fighter planes and anti-aircraft weaponry.
Despite shortages in the metal supply, the Royal Air Force (RAF) made plans to broaden their air fleet to include a new variety of bomber which was somewhat smaller and faster. In 1936 the RAF commissioned several companies to submit designs for such a plane, and a civilian outfit called De Havilland responded with a highly unorthodox concept: a bomber constructed almost entirely out of plywood. Initially the British Air Ministry scoffed at the idea, and suggested that the airplane company instead use its resources to construct wings for existing bomber designs. But the people at De Havilland were convinced that their unconventional idea had some merit.
The aircraft designers originally conceived of a wooden airframe armed with several gun turrets and a six-man crew, all propelled by a pair of Rolls-Royce Merlin engines. A series of calculations soon indicated that such a plane wouldn't be particularly fast given its heavy weight, so the engineers discussed adding two additional engines to bring it up to the speed of existing bombers. After some consideration, the original thinkers at De Havilland concluded that the best way to defend an aircraft wasn't with bristling machine guns, but by making it so fast that nothing in the sky could catch it.
The approach seemed reasonable, so the design team continued to tinker with their wooden aircraft concept-- though it still hadn't received the blessing of the RAF. They discarded the gun turrets and four of the crew positions, a reduction which significantly decreased the estimated weight. They also paid close attention to the aerodynamics of the craft, aiming for a skin as slippery as that of a fighter plane. With its pair of supercharged Merlin engines, the lightweight plywood design was estimated to have a top speed of 400 miles per hour with a full bomb load, easily outpacing Germany's fastest fighters.
The RAF continued to be apprehensive in spite of the impressive specs; a lightly-armed wooden bomber was profoundly contrary to the thinking of the time. Fortunately De Havilland had an ally in the British Air Ministry, a man named Sir Wilfrid Freeman. Freeman had been friends with the De Havilland family since World War I, and he saw the potential in the new design. At his coaxing, the Air Ministry finally authorized construction of the prototype, largely due to Freeman's observation that the wooden airplane would not sap the country's already bedraggled metal supplies.
After some setbacks due to equipment shortages and German bombings of the De Havilland buildings, the Mosquito prototype was transported to the town of Hatfield for a test flight on 25 November 1940. Its final construction was heat-formed plywood over a wooden frame, with sections glued and screwed for extra strength. It employed Ecuadorean balsawood sandwiched with Canadian birch, a particularly strong and lightweight grade of plywood. Metal was used in only a few parts, including the engine housings and some control surfaces. The wooden sections were covered in fabric and the prototype was painted bright yellow to discourage British anti-aircraft crews from firing upon the top-secret airplane. A series of test flights over the following months confirmed that the Mosquito was an extremely agile and swift machine, executing impressive acrobatics and reaching speeds up to 392 miles per hour. Further testing also discovered that the aircraft could easily heft four times the load it had been designed for.
Official attitudes towards the Mosquito quickly changed after observing the prototype in action. The RAF ordered a number of the aircraft in several configurations, including bombers, heavy fighters, and photo reconnaissance. De Havilland enlisted the assistance of carpenters, piano makers, cabinet builders, and other woodworkers who had been previously unable to make an appreciable contribution to the war effort. Sub-assemblies were constructed in places such as furniture factories, then sent to the De Havilland plant for final assembly in large concrete moulds. To speed production, engineers developed a technique where the glue was rapidly dried with the assistance of microwaves.
The unlikely wooden aircraft quickly established itself as one of the most useful planes in the Royal Air Force. The bomber varieties could deliver a payload comparable to that of the flying fortresses, while consuming less fuel, putting fewer lives in danger, and cruising at about twice the speed of the larger bombers. The Mosquito was also useful for low-altitude runs, where squadrons of Mosquitos flying at rooftop heights dropped their ordnance with precision, departing at full speed with German interceptors in hopeless pursuit.
The heavy-fighter version proved to be fast and deadly, flying bomber escorts and shooting down almost 500 of Germany's V-1 rockets. Some fighters were given a 57mm cannon and rockets for sinking U-boats at sea. A night-fighter variant was equipped with Britain's new top-secret radar set, allowing the Mosquito to find its prey in the darkness.
When British intelligence learned that the commander of the German Luftwaffe Hermann Göring was due to address a Nazi parade in Berlin on 31 January 1943, they devised a plan to demoralize the enemy. Göring had long boasted that Germany's capital was safe from Allied bombers, but on that morning the lie was given to his claims when a mess of bombs was delivered to the rally by a gaggle of Mosquitos. Another squadron of Mosquitos went on to disrupt a second rally in Berlin on the same afternoon. On a separate occasion, British Mosquito pilots conducted very-low altitude bombing of Gestapo headquarters, destroying important records and freeing numerous prisoners. Due to daring raids such as these, the Mosquito came to be affectionately known by the nicknames "Wooden Wonder" and "Timber Terror." Even Hermann Göring himself held the Mosquito in high regard:
"In 1940 I could at least fly as far as Glasgow in most of my aircraft, but not now! It makes me furious when I see the Mosquito. I turn green and yellow with envy. The British, who can afford aluminium better than we can, knock together a beautiful wooden aircraft that every piano factory over there is building, and they give it a speed which they have now increased yet again. What do you make of that?"
Perhaps the most daring Mosquito raid was that of Operation Jericho, a bold and somewhat desperate undertaking meant to free condemned prisoners of war. On 18 February 1944, a flight group consisting of nineteen Mosquito bombers along with fighter escorts dashed at top speed over Nazi-occupied France towards Amiens Prison. Allied forces had learned that one hundred and twenty captured members of the French Resistance were scheduled to be executed there the following day, and an audacious plan was hatched in the hopes that some of the prison's 717 prisoners might escape.
Just after noon the first wave of Mosquitos roared into view over the prison, and pilot Maxie Sparks started a dive through a storm of anti-aircraft fire. Their crate weathered a number of rounds from the defenders before it let loose its first bomb, which struck the prison wall as planned. The Mosquito came around for a second pass, and navigator Cecil Dunlop executed another expert drop which blew a second, even bigger hole in the outer wall. Amidst the smoke and chaos, many prisoners fled from the prison as the second wave of Mosquitos arrived and targeted the Nazi guard quarters. Although 102 prisoners were killed, 258 managed to escape, including seventy-nine of those who had been scheduled for execution. Some historians have speculated that the D-Day landings which followed a few months later might not have been successful without the help of the French Resistance prisoners which were freed from Amiens.
For several years the inexpensive Mosquito bombers dominated the skies in terms of speed and versatility. Eventually a handful of German fighter planes were developed which were slightly faster than the Mosquitos, but most of the time the wooden bombers were already on their way home by the time the interceptors arrived, and the small speed advantage was insufficient to close the gap in a reasonable time. Towards the end of the war Germany finally developed a jet-powered plane with enough speed to catch the Timber Terror, but their introduction came too late to make a significant impact. The Mosquito also played a small role in the Pacific theater, but its use was limited because its wood-and-glue construction proved to be problematic in the humid climate. Some planes quite literally came unglued due to the heat and moisture, a problem which may have led to a few crashes.
By the time the war was over, not only had the Mosquito proven itself to be capable, but in many ways extraordinary. These aircraft-- primarily built by carpenters using commonplace materials-- flew over 28,000 missions for Bomber Command, and only 193 of them were lost in the duration of the war. A Mosquito named F for Freddie held the record for the most bombing runs by a single aircraft in World War 2, having executed 213 sorties. The last Mosquito was built in 1950, and the Wooden Wonder remained the fastest aircraft in Bomber Command until 1951.
Unfortunately the wood construction has not weathered the years as well as it weathered the war; only about thirty preserved specimens remain, and none are airworthy. The original prototype survived, however, and is currently undergoing complete restoration in the De Havilland Aircraft Heritage Centre in Hertfordshire, United Kingdom.