The Secret Mosquito Stash

When Airbus tried to demolish a building, it uncovered treasure.

A Mosquito in flight; of the more than 7,000 built, only three known airworthy examples survive.
A Mosquito in flight; of the more than 7,000 built, only three known airworthy examples survive.

When Airbus Industries prepared to bulldoze a small World War II-era building at its Broughton, England facility last August, the crew found something astonishing: thousands of forgotten 80-year-old technical drawings for the de Havilland Mosquito, at one time the fastest aircraft in the world. Demolition was halted while Airbus contacted The People’s Mosquito, a U.K. charity hoping to restore and fly a version of the Royal Air Force’s versatile twin-engine bomber, and asked if they’d be interested in the documents.

John Lilley, chairman of The People’s Mosquito, immediately drove to the site. “When he got there,” says Ross Sharp, the charity’s director of engineering and airframe compliance, “he found himself staring at a filing cabinet full of more than 22,000 aperture cards.” (An aperture card is a microfilm image mounted on stiff card stock.) “It was an emergency situation,” Sharp continues, “so they put the cards—all 148 pounds of them—into refuse bags and loaded them into his car.”

The Secret Mosquito Stash
“The Mosquito FB.XVIII—sometimes known as the Tsetse—was highly unusual,” says Ross Sharp. “An FB.VI was modified to carry a 57mm field gun; obviously such a huge weapon was difficult to fit into the Mosquito, and the nose had to be strengthened. (The first time it was fired—on the ground—the nose cap was buckled by the blast.)” A total of just 18 of these attack aircraft were produced. (Click on the image to see a larger version.)

The cards, some in need of restoration themselves, were immediately scanned, at a cost of about $6,000. Sharp’s job is to assess their relevance; he is almost halfway through the collection. “Some of these drawings have an ethereal beauty,” he says, “although they contain much more than drawings, in that some include scribbled notes and rough sketches. Some of the cards contain annotations, things like ‘first two prototypes only.’ You are actually looking at a complete history of an aircraft, its evolution and its variants, including unbuilt versions.”

The Secret Mosquito Stash
“The Mosquito was always intended to be used in defence of Britain’s far-flung Empire,” says Sharp. “Consequently, a drawing assigned to ‘Mosquito Mk I, Tropics’ shows a full-set of desert equipment. As well as a large water tank and individual water bottles and emergency rations, the rear fuselage contains communications aids (hand mirror, signal strips), aircraft picking gear and a tool kit. Also provided was a hand starting handle for the Merlin engines!” (Click on the image to see more detail.)

It makes sense that the documents were found at the Airbus facility; it was a de Havilland factory during the war, but much more recently serviced British Aerospace’s DH.98 Mosquito—the last airworthy Mosquito in all of Europe—until its crash at the Barton airshow in 1996. The documents are a mix of British Aerospace, Hawker Siddeley (the predecessor to British Aerospace) and de Havilland drawings, making classification a challenge. “I opened up one the other day,” says Sharp, “and I thought Wait a minute! That’s not a Mosquito—unless we suddenly started building a biplane version. It was actually specifications on how to completely re-cover, with Irish linen, a de Havilland Tiger Moth. The drawing just snuck in there.”  

The Secret Mosquito Stash
“Initially specified to carry just 4 x 250-lb bombs,” says Sharp, “the bomber version of the Mosquito had its warload doubled by some thoughtful engineering on the part of the de Havilland team. The company developed a specially-shortened tail fin for the standard RAF 500lb MC (Medium Case) bomb, thereby allowing four of these to be fitted into the Mosquito’s bomb bay. Observe the slight nose-down angle of the rear pair of bombs when secured on their bomb beam. Other ordnance, including 250-lb SAP (Semi-Armour Piercing), 500-lb GP (General Purpose) or SBC (Small Bomb Containers) could be carried. Later in the war, bomber versions of the Mosquito were built which could carry the monstrous 4,000 HC (High Capacity) blast bomb. This infamous ‘cookie’ was a much feared weapon, even by RAF crews, as it could not be dropped ‘safe.’ ” (Click on the image to see more detail.)

The drawings will help the organization in its restoration of a Mosquito NF.36 that crashed near RAF Coltishall airfield in February 1949. Instead of having to reverse-engineer parts of the bomber—a time-consuming and costly process—they can simply get the specs for the parts from the drawings.

“Things like the main hydraulic reservoir, that stands out,” says Sharp. “And we now have drawings for the internal baffles for the main fuel tanks. And there are minor things, like how to construct the navigator’s folding seat, its precise layout and the actual cotton and wadding that you use. It’s rather elegant.” The cost of the restoration is estimated at $9 million; if the entire funding were in place, says Sharp, the aircraft could be completed in about three and a half years.

The Secret Mosquito Stash
“In the Mosquito,” says Sharp, “the navigator (who also doubled as the bomb aimer or radar operator) was seated slightly behind and to the right of the pilot on a folding seat. Before material shortages really took hold, this was constructed of pieces of sorbo rubber on a plywood frame covered with green upholstery leather. You can see the result of wartime austerity on the right side of the drawing. Quilted pads of cotton waste and open-weave cotton fabric are dividing layers of kapok, which has replaced the sorbo rubber. The leather is also gone, with ‘green, fire-proofed upholstery cloth’ used as a substitute. The back of the seat is now covered in ‘strong canvas.’ ” (Click on the image to see more detail.)

Restoration has already begun; Aerowood Ltd., an aviation wood specialist in New Zealand, has started production on the aircraft’s wing ribs, using Canadian spruce cut from the same area—Queen Charlotte Islands—that generated lumber for wartime Mosquitoes produced by de Havilland Canada. During the war, 900 men—“former wrestlers, boxers, and local tough guys,” reported the Hartford Courant in 1943—worked 10-hour days cutting spruce trees for airplane production. “There are six main woods used in the Mosquito,” says Sharp, “all engineered, brilliantly, for what they do. Only one in 10 spruce trees were actually capable of meeting the exacting specifications for the aircraft.”  

The airplane, known as the “Wooden Wonder” was originally built to be an unarmed fast bomber, but proved so versatile it was used as a night fighter, for photo-reconnaissance, as a light bomber, and as a maritime strike aircraft. Of the more than 7,000 Mosquitoes built, only a handful remain, and only three known airworthy examples survive, two in the United States, and one in Canada. The discovery of these priceless drawings has galvanized the members of The People’s Mosquito, who hope to see the aircraft once again flying over Britain. “We must fly and we must educate and we must remember,” says Sharp, “and honor all of those who have served in the Mosquito, including those that built her. And that’s just what we’re doing.”   

The Secret Mosquito Stash
“The Mosquito was constantly being developed throughout its service life,” says Sharp. “The B. Mk V was a direct modification of the early bomber version, the B.Mk IV. but with a new, standard wing. This was capable, as seen here, of carrying either 50-gallon drop tanks or, initially, 250-lb bombs. Only one B. Mk V was built, but a small series of B. Mk VII bombers were built by de Havilland Canada. This aircraft was intended for long missions, as it could carry overload fuel tanks in the bomb bay, and was equipped with a long range oil tank, to handle the increased oil consumption of the twin Merlins.” (Click on the image to see a larger version.)

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This story is a selection from the December/January issue of Air & Space magazine

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