Plywoods

More Mosquito footage, some good quality stuff.

The de Havilland Mosquito was a British combat aircraft that excelled in a number of roles during the Second World War. It served with the RAF and many other air forces both in the Second World War and postwar. The Mosquito was powered by a pair of Rolls-Royce Merlins with the pilot and navigator sitting side by side. In the conceptual design stage, de Havilland designers found that adding any defensive armament would significantly reduce the aircraft’s maximum speed. Realising that the loss in performance was not worth the benefit, the initial bomber version was designed without any guns. The various roles of the Mosquito included: tactical bomber, pathfinder, day or night fighter, fighter-bomber, intruder, maritime strike and photo reconnaissance aircraft.

The de Havilland company conceived the idea of a wooden aircraft to take advantage of the underused resources and skills of the furniture industry at a time of great pressure on the conventional aircraft industry combined with wartime shortages of steel and aluminium. The Air Ministry was initially not interested in the innovative approach; de Havilland, under chief designer Ronald Bishop, developed the Mosquito on a speculative basis. The ministry became interested when they saw the Mosquito prototype’s performance. Throughout the 1930s, de Havilland had established a reputation in developing innovative high-speed aircraft such as the DH.88 Comet mailplane and DH.91 Albatross airliner that had already successfully employed the composite wood construction that the Mosquito would use.

Construction: The bulk of the Mosquito was made of plywood. Stronger and lighter than most grades of plywood, this special plywood was produced by a combination of 3/8″ sheets of Ecuadorean balsawood sandwiched between sheets of Canadian birch plywood. Like a deck of cards, sheets of wood alternated with sheets of a special casein-based (later formaldehyde) wood glue. The fuselage was formed in concrete moulds. Left and right sides of the fuselage were fitted with bulkheads and structural members separately while the glue cured. Reinforcing was achieved with hundreds of small brass wood screws. This arrangement greatly simplified the installation of hydraulic lines and other fittings, as the two halves of the fuselage were open for easy access by workers. The halves were then glued and bolted together, and covered with doped Madapolam fabric.
The wings were also made of wood. To increase strength, the wings were made as one single assembly, onto which the fuselage, once both halves had been mated, was lowered and attached. Metal was used sparingly in the construction of structural elements. It was mostly used in engine mounts and fairings, control surfaces, and, of course, brass screws. The glue used was initially casein-based. It was changed to a formaldehyde-based preparation when the Mosquito was introduced to fighting in semi-tropical and tropical climates, after some unexplained crashes led to the suspicion that the glue was unable to withstand the climate. De Havilland also developed a technique to accelerate the glue drying by heating it using microwaves.

In England fuselage shells were mainly made by E. Gomme, Parker Knoll and Styles & Mealing. Wing spars were made by J.B. Heath and Dancer & Hearne. Many of the other parts, including flaps, flap shrouds, fins, leading edge assemblies and bomb doors were also produced in High Wycombe, Buckinghamshire, which was well suited to these tasks due to a well established furniture making industry. Dancer and Hearne processed much of the wood from start to finish, receiving timber and transforming it into finished wing spars at their High Wycombe factory. Around 5,000 of the total 7,781 Mosquitos ever made contained parts made in High Wycombe.

The specialized wood veneer used in the construction of the Mosquito was made by Roddis Manufacturing in Marshfield, Wisconsin, United States. Hamilton Roddis had teams of dexterous young women ironing the (unusually thin) strong wood veneer product before shipping to the UK.

General characteristics (DH.98 Mosquito B Mk XVI)

Crew: 2: pilot, bombardier/navigator
Length: 44 ft 6 in (13.57 m)
Wingspan: 54 ft 2 in (16.52 m)
Height: 17 ft 5 in (5.3 m)
Wing area: 454 ft² (42.18 m²)
Empty weight: 14,300 lb (6,490 kg)
Loaded weight: 18,100 lb (8,210 kg)
Max takeoff weight: 25,000 lb (11,000 kg)
Powerplant: 2× Rolls-Royce Merlin 76/77 (left/right) liquid-cooled V12 engine, 1,710 hp (1,280 kW) each
Performance
Maximum speed: 361 knots (415 mph, 668 km/h) at 28,000 ft (8,500 m)
Range: 1,300 nm (1,500 mi, 2,400 km) with full weapons load
Service ceiling: 37,000 ft (11,000 m)
Rate of climb: 2,850 ft/min (14.5 m/s)
Wing loading: 39.9 lb/ft² (195 kg/m²)
Power/mass: 0.189 hp/lb (311 W/kg)
Armament: Bombs: 4,000 lb (1 800 kg)
Avionics: GEE radio-navigation

Duration : 0:8:45

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music “music” by killing joke – so be prepared to lower volume …
conceived as an unarmed fast bomber, uses of the Mosquito included: low to medium altitude daytime tactical bomber, high altitude night bomber, pathfinder, day or night fighter, fighter-bomber, intruder, maritime strike and photo reconnaissance aircraft.
The bulk of the Mosquito was made of custom plywood. The fuselage was a frameless monocoque shell made of ⅜ in (9.5 mm) sheets of Ecuadorean balsawood sandwiched between sheets of Canadian birch, but in areas needing extra strength—such as along cut-outs—stronger woods replaced the balsa filler. The plys were formed to shape by band clamps over large concrete moulds, each holding one half of the fuselage, split vertically. While the casein-based glue in the plywood dried, carpenters cut a sawtooth joint into their edges while other workers installed the controls and cabling on the inside wall. When the glue was completely dried, the two halves were glued and screwed together. A covering of doped Madapolam (woven cotton) fabric completed the unit.

The wings were similar but used different materials and techniques. The main wing was built as a single unit. To form the basic shape, two birch plywood box spars were connected by plywood ribs, and stringers spanned the ribs. The skinning was also birch plywood, one layer thick on the bottom and doubled up on the top; between the two top layers was another layer of fir stringers. Building up the structure used an enormous number of brass screws, 30,000 per wing. The wing was completed with wooden flaps and aluminium ailerons.
When both parts were complete the fuselage was lowered onto the wing, and once again glued and screwed together. The remainder consisted of wooden horizontal and vertical tail surfaces, with aluminium control surfaces. Engine mounts of welded steel tube were added, along with simple landing gear oleos filled with rubber blocks. Wood was used to carry only in-plane loads, with metal fittings used for all triaxially loaded components such as landing gear, engine mounts, control surface mounting brackets, and the wing-to-fuselage junction. The total weight of metal castings and forgings used in the aircraft was only 280 lb (130 kg)

Duration : 0:6:28

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