Jet Rocket

Jet Rocket

The advantage of the rocket over the jet motor is obvious since it eill run in a vacuum, it would fly us to the moon, if we could fly to the moon. But the rocket pays a heavy price for this advantage, in a literal sense. The major part of the weight of a rocket is its initial fuel load, and of the fuel load the oxygen is the largest part, in ratio of not less than three to one, in some cases as high as eight to one. Thus the "pay load" the additional weight that a rocket can carry for each pound of its fuel is relatively small. In fact, it has been computed that to lift one pound of pay load into outer space, away from the earth's gravitation, would require hundreds of thousands of tons of ordinary combustion fuel.

The jet motor, by drawing on the atmosphere for its oxygen, saves greatly in weight and so has a much higher pay load. That is why, during World War 2, rocket propulsion was applied only to relatively small projectiles, while jet propulsion was invoked to carry the huge loads in "buzz" bombs and V-bombs.