经济学人下载:空中旅行 起飞准备

Science and technology
科学技术

Air travel
空中旅行

Preparing for take-off
起飞准备

A cheaper, cleaner way for the long taxi to the runway
一种更便宜更清洁的飞机跑道滑行方式

ENGINES on airliners are highly efficient when they are in flight, but not when operating on the ground.
飞机上的发动机在飞行过程中效率是很高的，但是在地面上的时候却不是这样。

When a plane is taxiing under its own power, the engines burn vast amounts of fuel.
飞机依靠自身动力滑行时，发动机燃烧掉大量的燃料。

A Boeing 747 can consume a tonne of fuel and emit several tonnes of carbon dioxide during an average 17-minute taxi to take-off.
一架波音747起飞一般需要滑行17分钟，要消耗1吨燃料并且释放出几吨二氧化碳。

And when the aircraft lands there is likely to be another long drive to the passenger gate.
飞机着陆时，也要滑行很长一段才能到达乘客出口。

Which is why there are various methods being developed for aircraft to use other means of propulsion while moving around an airport.
这就是为什么要研究不同的方法让飞机在机场运行时使用其他的动力方式。

Towing aircraft with a tug, similar to how they are pushed back from the gate, is one way.
用飞机拖拉车牵引就是一种办法，类似于发动机的推力。

But constantly pulling on the front landing gear can lead to mechanical problems.
但是经常拉拽前起落架可能会导致机械故障。

Many pilots would also prefer to be in control of the driving once their aircraft is on the taxiway.
许多驾驶员在飞机滑行的时候也喜欢自己来控制操作。

One method that addresses both concerns is a semi-robotic tug called TaxiBot, developed by Israel Aerospace Industries.
能同时解决这两方面问题的一种方法是一种半机器人化的牵引车:牵引机器人。

Instead of using a tow bar attached to the aircraft's nose wheel, TaxiBot employs a mechanism which automatically scoops the wheel up into a rotating turret.
它是由以色列航空工业公司研发的。牵引机器人运用一种机械装置可以自动托起飞机前起落架与旋转塔台连接。

The TaxiBot also avoids having any complicated links to connect to the cockpit, yet still gives the pilots driving control.
牵引机器人连接驾驶舱也不需任何复杂的元件，驾驶员却可以控制操作。

It does this by accelerating to the speed set for the taxiway, using its inbuilt GPS map system.
牵引机器人利用内置的GPS地图系统给跑道速度控制装置加速即可。

The pilots then use their usual controls to steer with the nose wheel and to brake with the main landing gear.
驾驶员用通常的控制器完成头部机轮的控制和主起落架的制动。

A safety driver remains in the TaxiBot, and he also drives the vehicle to and from the aircraft.
牵引机器人里也有一位司机，负责将其开到地方和驶离。

With the high price of aviation fuel—a tonne can cost more than $1,000—the savings at a busy airport could be large.
航空燃料的价格很高，一吨价值1000多美元，一个业务繁忙的机场因此可以节省大批资金。

At some airports the passenger gates can be several miles from the runway.
一些机场登机门和跑道之间相距好几英里。

All told, the world's airlines spend $7 billion-8 billion a year taxiing between passenger gates and the runway, says Yehoshua Eldar, who is in charge of business development at IAI.
以色列航空工业公司业务发展部负责人约书亚.埃尔达说：全世界的机场每年在跑道和登机门之间滑行上的花费合计达70-80亿美元。

The TaxiBot, though, uses just 20-30 litres of fuel for a typical trip.
可是牵引机器人一次标准的旅行却仅用20-30升燃料。

It also reduces the risk of debris being ingested by the engines and causing damage.
而且牵引机器人还可以降低飞机发动机吸入碎片造成破坏的风险。

Germany's Lufthansa will trial the system at Frankfurt Airport from May 2013.
德国汉莎航空公司将从2013年5月开始试行这个系统。

In the future some airliners may be driven to and from the runway with electric power.
将来飞机可能会利用电力在跑道上滑行。

The German Aerospace Centre has tested this idea in an aircraft using a fuel cell to power two electric motors built into the hub of an aircraft nose wheel.
德国宇航中心已经就此进行了实验：在一架飞机上用燃料电池给装在飞机头部机轮轮毂里的两台电动机提供动力。

The centre reckons that up to 19% of current airport emissions could be saved using such a system.
该中心测算出应用这一系统最多可以减少19%的飞机排放物。

And it would also please the neighbours: there would be hardly any noise during taxiing.
而且机场周围的邻居也会高兴：飞机滑行过程中几乎没有任何噪音。