经济学人下载:怎样建造时速1000英里的汽车

A rocket works by burning fuel with an oxidiser, which provides a source of oxygen for combustion. The hot exhaust gases are then blasted through a nozzle to produce thrust. Rockets using liquid propellants can be shut down reasonably easily by turning off the pumps delivering the fuel and oxidiser, but they tend to be complex and their propellants, such as liquid hydrogen and liquid oxygen, difficult and hazardous to handle.

火箭发动机工作通过燃烧带有氧化剂的燃料，氧化剂提供燃烧需要的氧气，排放的热气于是通过一个喷嘴喷出以产生推力。使用液态推进剂的火箭发动机可以通过关闭输送燃料和氧化剂的泵而被相当容易地关掉，但是它们往往很复杂，而且它们的推进剂操作困难且有危险性，比如液态氢和液态氧。

Solid-fuel rockets, in which the fuel and oxidiser are pre-mixed into a stable, solid propellant and then packed inside the case of the rocket, are simpler, lighter and relatively safer. But once a solid-fuel rocket is ignited, it is off like a firework and keeps going until all the fuel is burned up. About the only way to stop it is to blow it apart. In a car, that would not do.

固体燃料火箭发动机的构造更简单、分量更轻，而且相对更安全。在固体燃料火箭发动机里，燃料和氧化剂被预先混合成稳定的液态推进剂，然后被塞满火箭发动机的燃料箱里。但是一旦固体燃料火箭发动机被点燃，它将象二踢脚一样发射出去并一直跑，直到全部燃料烧完为止。是它停止的几乎唯一的方法，就是将它甩掉。而在汽车上，这做不到。

Rubber power
橡胶动力

The hybrid design which Mr Jubb has come up with uses a solid fuel called hydroxyl-terminated polybutadiene, a form of synthetic rubber used to make things like aircraft tyres. It is contained within the case of the rocket, into which is pumped a liquid oxidiser called high-test peroxide (HTP), a concentrated form of hydrogen peroxide which is relatively safe to handle. When the HTP comes into contact with a catalyst contained within the rocket, it turns into steam and oxygen. And it does so at a high enough temperature to ignite the solid fuel. This provides the added advantage of not having to build an ignition system into the rocket.

兆伯提出的混合设计使用一种叫做端羟基聚丁二烯的固体燃料。端羟基聚丁二烯是一种合成橡胶，用于制造象飞机轮胎等这样的东西，它被置于火箭发动机的燃料箱里，一种叫做高挥发性过氧化氢(HTP)的液体燃料被吸入燃料箱。高挥发性过氧化氢是过氧化氢的浓缩形态，它操作起来相对安全。当HTP接触到火箭发动机内的催化剂时，就转变成气体和氧气。在足以点燃固体燃料的高温中，HTP就是这样反应的。这一过程有一个另外的好处，就是不必为火箭发动机建造一个点火系统。

If the hybrid rocket needs to be shut down in a hurry all you need do is turn off the pump delivering the oxidiser. That is where the Cosworth engine comes in. Apart from generating auxiliary power for Bloodhound SSC’s electrical and hydraulic systems, it also drives a high-speed pump capable of delivering all 800 litres of HTP in the tank to the rocket in 20 seconds.

如果混合火箭发动机需要立即关掉，那么你需要做的全部事情就是关掉传送氧化剂的泵。那个泵位于接入考斯沃斯发动机处。除了给“侦探犬”号超音速车的电子及液压系统产生辅助动力之外，它还驱动一个能在20秒内将燃料箱里的全部800升的HTP输送给火箭发动机的高速泵。

The rocket gives the car plenty of power, but it is either on or off. To provide some form of throttle to allow acceleration and deceleration, the vehicle’s designers added the EJ200 jet engine. This will be used by Andy Green, a Royal Air Force pilot who will drive the car, to get the vehicle moving. At about 200mph he will start the pump to deliver the HTP into the rocket.

火箭发动机给汽车提供大量的动力，但是操作它只是开或关。为提供某种节流阀以加速或减速，该车的设计者们增加了“EJ200”喷气式发动机。这个发动机将被皇家空军飞行员安迪．格林用以驾驶这辆车。在大约时速200英里时他将启动为火箭发动机传送HTP的泵。