Fighting in the air

12 May 2020

Interview with 

Craig Murray, Imperial War Museum Duxford


A spitfire aeroplane, flying through the air


One of the most iconic images of the war is that of aerial combat. The Battle of Britain, which began in 1940, revolved around fighting in the sky, and one of the planes at the centre of it all, is the Supermarine Spitfire aircraft. But just a few short years before the planes were old time biplanes, used for taking photos. How did we we get to the Spitfire from there? Adam Murphy spoke to Craig Murray, curator in the Imperial War Museum in Duxford about aircraft history...

Craig - Most of the changes really come in the 1930s but within the 1920s period after the first world war, you have the allies are left with an awful lot via craft from that period, but there's a lot of economic restrictions post-war and also there's no actual threat. So really the main things that do change here are a movement away from wooden frames to metal frames, but still covered with fabric as they have been already. But also there's much more of an advancement in aero engines, if they're not been weaponised they're certainly performance and streamlining of aircraft has been improved upon. Aircraft have been rather restricted, land aircraft rather, taking off from airfields have been instructed by fixed props and it's not really until the early 1930s when the first viable variable pitch prop comes in that the aircraft on the ground become more efficient.

What I mean by that is when taking off, it requires quite a lot of power for the engine and if you don't have a variable pitch prop, you have to have quite a long airfield to take off in. And what the variable pitch of the prop does is that it makes the engine more efficient at certain points. If you have in on fine pitch, it cranks up the revolutions per minute for taking off. And when you're cruising you can put it on what's called coarse pitch. So the engine's working in its most efficient manner, but I suppose interestingly a lot of the developments come in the civilian field rather than the military field at this point. And it's with flying boat racing basically, you know, the aircraft that can take off. The Schneider Trophy is really this kind of thing. But, as things start to move into the thirties we start to see the move away from these sort of, you have seen with air racing a move away from biplanes into these monoplane designs, low-wing monoplanes because they're more efficient and you start to see a moving into more metal aircraft.

Certainly in that sense the Boeing company in the United States in 1931 were sort of ahead of the game militarily. They sort of saw the coming of the metal, the metal skinned monoplane fighter. So they built a bomber at the time, which was the first sort of metal monoplane and it was quicker than any biplane about at the time. And a few years later there's another, there's another one comes in which advances it further and then they obviously have their famous B17 flying fortress which they come up with in 1935, which is very heavily armed, based on the theory a bomber should be able to always be get through to the target as long as it's got enough guns to fight off the fighters that are incoming.

Adam - And what about those more famous planes? The Hurricane and of course the Spitfire? 

Craig - And sort of concurrently at this time in Britain you have the development of the Spitfire and the Hurricane. The Hurricane is slightly more traditional. It's got metal tubing frame and the rear part of the fuselage is still covered in fabric. But the Spitfire is a pure metal semi-monocoque fighter. Semi-monocoque, meaning this is a stress skin over a frame as opposed to fully monocoque, which is essentially an egg which supports the structure. The difference with the Spitfire is, again, it's all metal like the 109, but it's a pure thoroughbred of a fighter. R.J. Mitchell, a designer who is also designing the Supermarine aircraft that were winning the Schneider Trophy, he's not overly concerned with budget. He just wants to build a pure fighter. Very, very difficult engineering design that has this elliptical wing, other people have tried it. It's been difficult to do or too expensive. Expense is often a big thing, but it's a pure fighter. It's best handled by experienced pilots, whereas the Hurricane is an easier aircraft to fly and is paradoxically more sturdy, even though it's partly fabric, it can take a lot of battle damage. It can turn a lot sharper than say the BF 109, which shall be its main opponent during the battle of Britain in 1940. It's not actually a pure fighter. It's been designed by Willy Messerschmitt as essentially an ambush predator, it bounces aircraft, it comes down from high out of the Sun and ambushes.

Adam - Without these advances in air combat, the landscape of world war two would have been very different. So how does it move quite so fast?

Craig - Well, I mean, you've gone, I mean aircraft technology moves massively quick from the Wright brothers. Even in the first world war, you're going from the Wright brothers, something that was essentially flying at walking pace almost, to fighters that can fly a hundred miles an hour in the space of maybe 10 years or so. So it has jumped exponentially very, very quickly.



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