ENGINE: NOT ENOUGH THRUST
No existing engine has the power to lift the 13 tonne rocket, so the Nazis must develop one themselves.
The enemy’s cities are hundreds of km away, and existing rocket engines have neither the lifting power nor the reach to carry 1,000 kg of explosives that far.
Luckily for the Nazis, physicist Robert H. Goddard in 1926 invented a rocket, powered by liquid fuel instead of solid fuel, providing high stable performance. On the downside, it requires a more complex engine – a problem for a large, heavy rocket such as the V-2. Many problems arise. Either the high temperture mix of fuel and liquid oxygen burns through the walls of the combustion chamber, or the engine thrust is too low to produce sufficient lifting force.
The Nazis experiment for a long time before developing a powerful, barrel-shaped combustion chamber with alcohol- cooled, double-skinned walls. Moreover, they boost the engine with two turbo pumps, which inject fuel and oxygen into the combustion chamber at an unprecedented rate of 125 litres per second.
All in all, the V-2 produces a thrust of 25 t – 17 times more than any other rocket of the time.