Why doesn't everyone have a jetpack? - Richard Browning

Translator: pamela lam Reviewer: Thomas Tam

On April 12, 1961, Soviet cosmonaut Yuri Gagarin

喺 1961 年 4 月 12 日 蘇聯太空人 Yuri Gagarin

piloted a 2,400 kilogram spacecraft in humanity’s first manned space flight.

駕駛一艘 2400 公斤嘅太空船 進行人類首次載人嘅太空飛行

One week later, Bell Aerosystems debuted another advancement in aviation:

一周後，貝爾航空系統 推出咗另一項先進航空技術：

the gas-powered rocket pack.

燃氣驅動火箭組件

Capable of flying 35 meters in just 13 seconds,

能夠喺 13 秒內 飛行 35 米嘅火箭組件

the rocket pack thrilled onlookers.

令到圍觀者極之興奮

But the device’s engineers were less enthused.

但一班設備嘅工程師 就冇噉嘅熱情

Despite years of cutting-edge work,

儘管多年從事尖端工作

they knew this short flight was all the rocket pack could muster.

知道呢次短途飛行 係火箭組件竭盡所能才做到

So why was a massive spacecraft easier to send flying than a single pilot?

噉點解大型太空船 比單一飛行員更容易飛行呢？

According to Newton's laws of motion,

根據牛頓動力定律

the physics behind flight are actually quite simple.

飛行背後嘅物理學其實非常簡單

All you need is a powerful enough upward force

你只要有足夠強大嘅向上動力

to counteract the downward force of gravity.

嚟抵消向下嘅地心吸力就可以喇

And since objects with more mass experience stronger gravitational forces,

由於質量更大嘅物體 會受到較強嘅地心吸力

lighter objects should be easier to get off the ground.

因此較輕嘅物體 應該更容易離開地面

However, modern jet engines, our primary tool for flight,

主要嘅飛行工具 即係現代噴氣式引擎

actually get more efficient the larger they are.

實際上，越大效率就越高

噴氣式引擎嘅運作原理 係吸入大量空氣

Jet engines work by sucking in huge volumes of air,

and then expelling that air as quickly as possible.

然後儘快排出呢啲空氣

While most of this actually bypasses the inner machinery,

實際上，其中大部分 繞過咗內部機械

it still contributes to a huge portion of the engine's thrust.

但佢仍然係推動引擎嘅主要原因

But the air that does enter the engine’s core gets compressed

但係進入引擎核心嘅空氣會被一系列

by a series of tightly packed blades.

緊密排列嘅葉片壓縮

That compressed air then enters the combustion chamber,

壓縮空氣跟住進入燃燒室

where it is injected with jet fuel and ignited.

喺嗰度註入噴氣燃料然後點燃

The heat causes the compressed air to rapidly expand,

熱量令到壓縮空氣迅速膨脹

bursting out of the exhaust and propelling the engine forward.

從排氣中噴出並驅動引擎前進

As air leaves the engine it also turns a turbine embedded in the exhaust nozzle.

喺空氣離開引擎嗰陣 會轉動鑲嵌喺排氣噴嘴中嘅渦輪機

This turbine powers the fan and the compressor blades,

渦輪機向風扇 同埋壓縮機葉片提供動力

creating a cycle that maintains thrust for as long as there’s fuel to burn.

形成一個循環 只要有燃料燃燒就保持著推力

The more air an engine can take in and expel the more thrust it can produce.

引擎吸入同埋排出嘅空氣越多 產生嘅推力就越大

On a modern jet, the diameter of a frontal fan is larger than a truck.

喺而家嘅噴射機 前面嘅風扇直徑比貨車仲要大

And even spinning at relatively low speeds,

即使以相對較低嘅速度旋轉

these engines produce more than enough thrust to maintain the necessary speed

呢啲引擎亦產生足夠嘅推力

for flying a passenger aircraft.

嚟維持客機飛行所需嘅速度

But smaller engines simply can’t take in this much air.

但較小嘅引擎根本無法吸入咁多空氣

For most of the 20th century, engineers couldn’t produce an engine

大部分 20 世紀工程師 都無法製造

small and light enough for an individual to wear,

細緻而輕巧 可供個人穿著嘅引擎

yet powerful enough to lift itself alongside its pilot and fuel.

而且更唔可以將飛行員同埋燃料並肩飛行

Designs could only carry enough fuel for 30 seconds of flight,

設計淨係可以攜帶燃料 足夠飛行 30 秒

and when airborne, the powerful thrust in a single direction

而喺空中飛行嗰陣 單方向嘅強大推力

made jetpacks difficult and dangerous to control.

令到噴氣背包難以控制、而且危險

But the new millennium brought advances in materials, manufacturing,

但新千年帶嚟材料、製造業

and computing technology,

同電腦技術嘅進步

including systems which could manage fuel injection with incredible precision.

包括極度準確嘅燃油噴射處理系統

Together, these dramatically improved the fuel efficiency

總體呢講，佢哋顯著提高咗燃油嘅效率

and power-to-weight ratio of jet engines.

同噴氣發動機嘅功率重量比率

喺 2016 年 一個咖啡罐大嘅微型引擎

By 2016, micro-engines the size of a coffee can

and weighing less than 2kg

重量唔夠兩公斤

could achieve 220 Newtons of force.

就達到 220 嘅牛頓力

This was when an English engineer named Richard Browning

當時，一位叫做 Richard Browning 嘅英國工程師

saw the opportunity to create a new kind of lightweight jetpack.

睇到咗創造一種 新輕型噴氣式背包嘅機會

In addition to a single engine strapped to the back,

背部綁著一個引擎之外

this so-called Jet Suit involved a pair of micro-engines on each arm

呢套所謂嘅噴氣服 仲包括一對手臂上嘅微型引擎

to split and balance the thrust.

用嚟分散同平衡推力

同背部引擎一起運作嘅時候 佢哋提供咗三個穩定點

Working with the back engine, these provided three-points of stability,

which some pilots describe as being akin to comfortably leaning on crutches

一啲飛行員形容為類似 兩手舒服噉放喺柺杖上

while a friend supports your back.

同身體挨住穩陣舒適嘅靠背

It may seem complicated to manage all these engines at once,

同時間處理所有引擎似乎好複雜

但好多飛行員喺一日內就掌握操縱

but many pilots master it in less than a day

with the help of another advanced computer system— their brain.

蹺妙係運用另一個先進嘅電腦系統 即係佢哋嘅大腦

大腦嘅唔同區域同埋多種感官系統

Various brain regions and multiple sensory systems

perfectly calibrate our sense of balance and spatial orientation,

準確噉校準咗我哋嘅 平衡感同空間定位

helping pilots smoothly direct their flights.

幫助飛行員順利指揮飛行

Slight movements of the arms allow operators to increase and decrease lift,

手臂嘅輕微移動 允許操作員增加同減少上升力量

quickly turn in mid-air, or glide forward for up to 5 minutes.

喺半空中快速轉彎 或向前滑行長達 5 分鐘

This technology is still fairly new,

呢項較新嘅技術

and without major advances in fuel efficiency and engine technology,

喺燃油效率同引擎技術方面 仲未有重大進步

don’t expect to have a jetpack of your own any time soon.

唔好指望而家好快 就擁有自己嘅噴氣背包

But if reaching for the sky already got us this far,

但係今日我哋已經可以飛上天空

who knows where we'll fly next?

接下來會飛到去邊度呢？