[科技前沿]電動車之後，電動飛機問世

First electric cars, now electric planes

GM (MTLQQ) has earned high praise this summer – and deservedly so – for its announcement that the forthcoming Chevy Volt electric car will get as much as much as 230 miles per gallon for in-town driving.

But while Detroit was stealing headlines on the ground, a little-known Chinese company was doing something even More incredible in the skies.

At the OshKosh AirVenture show a few weeks ago, Beijing startup Yuneec International took the wraps off the world’s first commercially produced electric aircraft, the E430.

Powered by lithium polymer batteries, weighing close to a thousand pounds, and sipping about $2.50 worth of electricity per hour of flight, the E430 has completed more than 20 hours in test runs during the last couple months, including one in Camarillo, CA, that can be seen here.

Little more has been revealed about the E430, other than some technical specifications and that it can operate for up to three hours without a charge.

Today: adding electricity-powered systems

And while the E430 may be the aircraft equivalent of an auto show concept-car, there’s a good deal of progress being made in the advancement of electrical aeronautics on the whole. “What’s going on with modern aircraft is a revolution, whether you’re thinking about commercial or military aircraft,” says Bob Smith, VP of advanced technology at Honeywell Aerospace, a unit of Honeywell (HON).

Smith doesn't mean fully electric-powered aircraft – at least not yet. In aeronautic jargon, he’s talking about developing More Electric Architecture (MEA). Enabled by much larger and more sophisticated next-gen aircraft and more efficient generators, Honeywell is replacing the pneumatic and hydraulic power transference systems of with new electric versions.

“If you look at how much power a Boeing 777 generates, it’s on the order of 200-300 kilowatts. If you look at the 787, a next-gen aircraft, it’s 1.5 megawats,” he says. “That’s a massive change, because the generator technology has improved so much.”

Moving power around aircraft has always been cumbersome. In last-gen aircraft, high-pressure gas is taken from the engine and transported through bleed valves to the auxiliary power system, which controls air-conditioning, for example. This is a massively inefficient process due to the energy required to heat and cool the gases and because of the weight of the systems. “If you can put a more efficient generator in there, you have a power station as opposed to a boiling room,” says Smith.

Electrical systems are now being used to power reverse-thrusters – air brakes, essentially - in aircraft like the A380 – and for de-icing wings.

The upside: gains in fuel efficiencies

But two of the greatest benefits electrical systems provide are simplicity and merely lightening the load. Eliminating hydraulic systems reduces the complexity of repairing leaks and eliminating hundreds of pounds of tubing.

This can lead to as much as 30% gains in fuel consumption. For military aircraft, such a system is revolutionary. In the F35 Joint Strike Fighter, Honeywell’s system carved 1,000 pounds off the weight and 11 inches off the length of the plane.

Does Honeywell have its own E430 read for prime time? Not quite, but Smith suggests the real near-term potential for fully electric aircaft comes in the form of unmanned drones. Think about light-weight drones that travel constantly, their electric systems being continually replenished by advanced technologies like super capacitors, fuel cell systems and solar power.

“Once you have large power-generating systems, you have the capability of moving the power around a lot of different ways,” says Smith. “Then things get pretty interesting, allowing you to get into very long surveillance periods.”

通用汽車(GM)今夏獲得盛讚，這一點是實至名歸的，因爲公司宣佈即將推出雪佛蘭Volt電動車，該車在城市路況下可實現相當於230英里每加侖的燃油經濟性。當通用汽車在地面上的新舉動搶佔媒體頭條之時，一家不太知名的中國公司正在天空中進行更加不可思議的創造。

在幾周前舉辦的奧什科什航空展中，北京新創企業Yuneec國際公司展示了世界上第一架商用電動飛機--E430。

E430以鋰聚合物電池爲動力，機身重近1000磅，飛行中每小時消耗價值2.5美元的電。在過去幾個月裏，E430完成了總計超過20小時的多次試飛，包括在美國加州卡馬裏羅市的一次試飛。

關於E430的信息，只披露了一些技術規格，以及它每次充電後連續操作時間長達3小時。

今日：增添電力動力系統

E430飛機的出現就像車展中的概念車。與此同時，電子航空領域整體上也取得了很大的進展。霍尼韋爾（Honeywell）旗下霍尼韋爾航空公司的新技術副總裁鮑勃•史密斯(Bob Smith)表示：“無論是商用機還是軍用機，當代飛機正在經歷一場革命。”

史密斯所指的並不是完全以電力爲動力的飛機，這一點至少在目前還無法實現。在航空領域的行話裏，史密斯指的是開發更加電氣化的框架。受到更大更復雜的下一代飛機和更高性能的發動機的推動，霍尼韋爾正在以新的電子系統替換氣液動力傳輸系統。

史密斯表示：“波音777所產生的動力在200到300千瓦之間。而下一代飛機波音787，就增加到了1.5兆瓦。這是一個重大改變，因爲發動機技術已得到很大發展。”

飛機的動力傳輸設備向來比較笨重。舉個例子，在上一代飛機中，引擎中的高壓氣通過排除閥到達輔助動力系統，該系統控制着空調設備。這是一個效率極低的流程，因爲加熱或冷卻氣體需要能量，並且這種系統也很重。史密斯表示：“如果能夠裝備更加高效的發動機，你將會擁有一個發電站而不是一個沸騰室。”

電子系統現在應用於A380這樣的飛機中的逆功率推進器，主要是氣閘，以及爲機翼除冰。

有利的一面：節約能耗

但是電子系統提供的兩個最重要的好處是簡化系統和減輕重量。停用液壓系統避免了修復泄漏的複雜局面，並且省下了重達數百磅的管材。

這種做法節省了30%的燃料消耗。對於軍用機來說，這一系統是革命性的。在F35聯合攻擊戰鬥機上，霍尼韋爾的這一系統幫助機身減輕1000磅，縮短11英寸。

霍尼韋爾是否擁有自己的E430，可以在黃金時段大加宣傳呢？現在還沒有。但是史密斯表示，短期內有可能真正實現無人駕駛飛機的完全電動化。想想長時間飛行的輕型飛機，它們的電子系統持續得到先進技術的補充，比如超級電容器、燃料電池系統以及太陽能供電。

史密斯表示：“一旦有了大型發電系統，你就有能力用多種不同的方法進行動力傳輸。這將使事情變得非常有趣，讓你可以進行長時間的監測。”