The Amazing de Havilland Mosquito

Quote of the Day

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? There is nothing the British do not have. They have the geniuses and we have the nincompoops. After the war is over I'm going to buy a British radio set – then at least I'll own something that has always worked!

— Herman Göering, Germany’s wartime aviation minister (Source)

Introduction

Figure 1: de  Havilland Mosquito fighter‑bomber. (Wikipedia)

During the routine demolition of an old de Havilland Aircraft building in 2017, a treasure trove of 20K aperture cards (a microfilmed archive) was uncovered that contained plans for the Mosquito fighter-bomber (Figure 1). These plans have been lost since Mosquito production ended in  1950.

This discovery was a gold mine for WW2 aviation buffs. While nearly 8000 Mosquitos were produced, few have survived. Its wooden construction requires meticulous care to preserve and only four airworthy Mosquitos remain (link). Flying these old birds can be very dangerous, with two Mosquito pilots killed back in 1996 (link). The recovered plans are now being used to build a new Mosquito known as the "The People's Mosquito." With a bit of luck, a new Mosquito should be flying in a few years.

In this post, I will be looking at Mosquito production using Excel. For those who like to follow along, you can download my Excel workbook here. This workbook processes serial number data from a De Havilland historical web page.

Discussion

Mosquito Role

Figure 2: Mosquito Production By Role.

The Mosquito was produced in the following variants:

• tactical bomber
• high-altitude night bomber
• pathfinder
• day fighter or night fighter
• fighter-bomber
• intruder
• maritime strike
• photo-reconnaissance
• target tug

In many ways, the Mosquito was the ultimate multi-role aircraft. Even though propeller-driven, it proved useful enough to the UK to remain in production until the end of 1950 (link).

Table 1 shows the production numbers by role. Night fighter and fighter-bomber were roles filled by 2/3 of the production.

As is often the case with WW2 data, different sources have different totals. The source used in this post (link) shows 7778 units while other sources list 7781, a discrepancy of 3 units, which I view as minor.

Critical Woodworking Technologies

The Mosquito is a superb example of an aircraft design tailored to use the resources available, particularly those resources associated with wood construction. The Germans tried to build wooden aircraft because they were short of critical raw materials like aluminum. However, Germany's wooden aircraft attempts were unsuccessful in part because they lacked two key technologies that the UK had:

• Resorcinol Adhesive
  The Mosquito's wooden members were glued together using resorcinol adhesive, which was an adhesive technology the German's did not have. The German's also tried to make wooden aircraft (He 162, Bachem Natter) but failed with one major reason being the lack of an adequate adhesive.
• Plywood Laminated UsingResorcinol Adhesive
  The UK worked with US plywood manufacturers to develop plywood that was laminated using resorcinol glue. Prior to WW2, the US was manufacturing large quantities of marine plywood for use in the manufacture of civilian boats and wartime-production of PT boats and landing craft. De Havilland sought out US manufacturing that could build structural-grade plywood to their exacting specifications. They settled on a manufacturer in Wisconsin (link), who then went out and bought an estate loaded with virgin timber.

Manufacturers

A key motivation for building the Mosquito out of wood was that it would allow the UK to use its well-trained woodworking population to work on a strategic need. The Mosquito's design was robust enough that it could be built at nine sites in three different countries. Table 2 shows a summary of where the Mosquitos were assembled and in what quantities.

Figure 3 shows Mosquito production by year during WW2. Wartime production was 5938 (source). Note that some sources list higher production figures during WW2 (example: 6710). I have defined WW2 production as terminating on VJ Day, so 1945 was a shortened production year.

Figure 3: Wartime Mosquito Production By Year.

Many of the structural components were assembled by furniture manufacturers at High Wycombe from imported plywood (link).

Figure 4 shows a good video on how the Mosquito was manufactured, with much of the aircraft being made from wood.