Tuesday, March 23, 2021

Why were so very few de Havilland Mosquitoes built/deployed in WWII

 7800 birds is hardly a few and represented a huge commitment.  Way more important is that no one could actually replicate the craft because of the use of impossible to make plywoods without a specialist plywood industry.

This became the ultimate shoot and scoot attack craft and inflicted huge losses on enemy assets.

This was never a carpet bombing freight train and delivered one 500 pound bomb, but coukd shoot everything up.  Think Warthog and Stuka for a real comparible.


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Why were so very few de Havilland Mosquitoes built/deployed in WWII if it was so successful in so many roles, had such a low loss rate, and used wood (and not relatively rare aluminum/magnesium) for manufacture?

Jan Meyer has a pretty good answer, which is elaborated on by a British materials scientist turned popular author, J. E. Gordon, in his Why Things Don’t Fall Downa book that I’ll recommend even though it is now enjoying a second life as “one of the fourteen books that inspired Elon Musk.” (I liked it before it was cool!) The Mosquito was much harder to make than it sounds when you hear it described as a “wooden aeroplane that did not use strategically vital materials.”

I hope that the coffee stain in the corner voids the eternal Flightglobal copyright!

By the way: That bit about not using strategically vital materials? Not true.

Just to step back for a moment, the idea that the Allies didn’t use enough Mosquitos in WWII is, like many apparently historical arguments, actually about the present day. You see, President Trump Obama Hilary Clinton hurricane Wall taking the knee. . .

Just kidding! Actually, it’s a debate from the 1950s, about the relative importance of various kinds of jet bombers, comparing expensive “strategic” bombers against cheaper tactical ones, the burden of the argument being that the RAF could blow up the Commies just fine, or even better, with a modern version of the Mosquito as with a modern version of the Lancaster.


By Sisaphus - Flickr - Photo Sharing!, CC BY-SA 2.0 uk, File:TSR 2 (3rd prototype).jpg

So pretty . . And the avionics! Who wouldn’t want to build some of these? Except the taxpayers, and they don’t count.

So if we confine ourselves to the actual history of the time, then, first of all, 7800 Mosquitos is many, many Mosquitos, especially considering that they were supposed to be deployed exclusively in northern Europe, where the weather is kinder on organic materials. It’s also huge training burden, in that multiengine pilots are far and away the most expensive flight specialist to train, and you need one pilot per 4000lbs bombs hauled, compared with one pilot per 12000lbs with the Lancaster. (Both numbers being a bit optimistic, operationally.)

Second, the whole “strategic materials” thing is a bit dubious. The deep background here is that aircraft makers love wood. It’s easy to work! You don’t need expensive equipment or machinists, and you can try out new aerodynamics with hand tools, instead of a huge tool room full of presses and hammers and lathes and furnaces and refrigerators and whatnot. Aircraft makers were most displeased with the RAF when it decided that future aircraft would be made of metal (to the extent possible; it took a while for practice to catch up with preference), way back in 1921. (1923? Immediately after WWI, anyway.)

One of the companies that chose to push the Air Ministry to its limits was de Havilland, which kept on making wood aircraft for commercial use and to submit to service specifications through the interwar period. However, by 1939, it was clear that that was not on, and it turned to all-metal aircraft and won a huge contract to equip an in-Europe transport wing just as the balloon went up.

(Also pretty, although to fully appreciate it, you need an Australian yelling in your ear about “De Havilland junk!” Some bitterness there.)

The war Changed Everything, as they do, and the Air Ministry ran out and placed an order for a bomber that economised on strategic materials —not the Mosquito, but a now forgotten mediocrity called the Albemarle. (So, like its namesake, there.) De Havilland cleare its throat , and you got your Mosquito.

Drawing on two decades of experience of working with wood, and a fine aerodynamics department, de Havilland turned in a design using multiple grades of precision-manufactured plywood using an amazing assortment of woods —IIRC, and for God’s sake don’t take my word for it until you’ve checked it out in the magnificent design study published by Aviation Week back in 1944, for which you’re going to need a good library or a subscription— cherry wood is specified as one of the laminate layers in one of the plywoods used. Balsa wood was used to stiffen the plywood layers, this being what I meant when I said that the Mosquito actually used strategic materials, shipping being scarce in wartime.

The exacting specifications of plywood used in the Mosquito led to the failure of attempts to replicate its success in Germany and the United States, and the very qualified success of even De Havilland Canada in Toronto. It’s hard to just jump into the manufacture of aeronautical grade, high strength plywood!

I would add, here, that we have, again, that awful story of “tech levels,” in which one country is just “more advanced” than another, and so can do all sorts of things that no other country can do. On the contrary, Russia and the United Kingdom were the only countries to have real success with plywood military aircraft in WWII, not because they were the “most advanced,” but because they had established high quality plywood industries. (More for making boats than pianos, at least in Britain.) In fact, Russia and the Scandinavian countries pioneered modern plywood manufacture, because, etc., etc.

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