Further Background on Germany’s V-2 Rocket

A V-2 rocket on its mobile moving wagon.

In a previous post, I griped and moaned about the use of immense brainpower being applied to create weapons of war.

But I will concede, my readings into the workings of the V-2 rocket brought about a sense of wonderment at how incredibly advanced of a machine it was. The Wikipedia page lays out all of the technical details of the rocket in molecular detail, and this post by BBC was also informative. According to History.com, the first successful test of the rocket was October 3, 1942 – nearly 73 years ago. The V-2 missiles were also the first man-made objects in space. This fellow gives an excellent overview of the aiming and guidance of the missile. This video gives an idea of how important trial-and-error was to solving the numerous problems with missile design. This video gives a complete overview of the assembly and launching of the missile.

A good summary of the technical capabilities is given by this paragraph:

“The V-2 was unique in several ways. First, it was virtually impossible to intercept. Upon launching, the missile rises six miles vertically; it then proceeds on an arced course, cutting off its own fuel according to the range desired. The missile then tips over and falls on its target-at a speed of almost 4,000 mph. It hits with such force that the missile burrows itself into the ground several feet before exploding. It had the potential of flying a distance of 200 miles, and the launch pads were portable, making them impossible to detect before firing.”

This paragraph made my engineering bunny ears perk up. Lay people have little conception as to how fantastically difficult this little set of miracles was to perform. I’ve made a brief list of all the technical problems I foresaw with this – and yet the Germans were somehow able to overcome them all and successfully deploy this weapon against the Allies. It didn’t win the war for them, but it certainly spread a lot of terror and fear in England and Belgium.

  • First, there is the general problem of the design of the missile and its engine. A previous post I made on fluid mechanics linked to a series of videos that discussed difficult problems such as nozzle design, and aerodynamic drag. Bear in mind again, there were no computers in 1942 (well, there were, just not as we know them today). There was no computational fluid dynamics software. There was no internet. And this technology was brand-spanking new. How do you design a fabricate a missile to go as fast as it possibly can?
  • How do you account for the drag force on the missile when it is in the upper atmosphere? In this regime, the continuum assumption is invalid, and a statistical theory of fluid mechanics would be required to calculate the correct drag coefficients and drag forces on the missile. Good luck solving those equations by hand in 1942 – or even today. Hopefully though, one can make the assumption that the missile is heavy enough to be unaffected by aerodynamic drag in the upper atmosphere.
  • Then there is the gyroscopic guidance system, which I consider to be the supreme achievement of the V-2 program (and according to the sources, is what the Allies were most interested in after the war was over). The equipment would also be subjected to enormous acceleration forces, since the missile was able to ascend to the top of its parabolic trajectory in only 1 to 2 minutes. How do you build a guidance system that can stand up to that kind of punishment, and still be accurate enough to guide the missile?
  • These same acceleration forces could also run the risk of setting off the explosive warhead in flight (I learned later from one of the sources that premature detonation was a problem with the V-2). Intense vibrations on the descent phase also could set off the warhead.
  • How do you mix the fuel and oxidizer in the correct amounts at all times? Too much and the engine will snuff out. Too little, and nothing will happen. Only in a certain band of compositions can you ensure combustion will occur and the rocket will achieve a thrust.
  • How do you build pumps that can handle liquid oxygen (-183 Celsius) without freezing over?

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