Why are airplanes slower than they used to be? - Alex Gendler

Prevodilac: Saša V Lektor: Ivana Korom

In 1996, a British Airways plane flew from New York to London

1996. godine, avion Britiš Ervejz je preleteo od Njujorka do Londona

in a record-breaking two hours and 53 minutes.

u rekordnih dva sata i pedeset tri minuta.

Today, however, passengers flying the same route

Ipak, danas putnici koji lete istom rutom

can expect to spend no less than six hours in the air— twice as long.

mogu da očekuju da će provesti ne manje od

šest sati u vazduhu - duplo više.

So why, in a world where everything seems to be getting faster,

Zašto, u svetu gde se čini da sve postaje brže,

have commercial flights lagged behind?

komercijalni letovi zaostaju?

The British-and-French-made Concorde began shuttling passengers

Britansko-francuski Konkord je počeo da prevozi putnike nebom u ’70-im.

across the sky in the 1970s.

Jetting between destinations like New York, Paris, Bahrain, and Singapore,

Letom između destinacija kao što su Njujork, Pariz, Bahrein, i Singapur,

it clocked in at over 2,000 kilometers per hour,

dostiglo je brzine od 2 000 kilometara po satu,

more than twice the speed of a normal airliner.

duplo veća brzina od normalnog putničkog aviona.

However this was also about 800 kilometers per hour faster than the speed of sound.

Ipak, ovo je bilo i za oko 800 kilometara po satu brže nego brzina zvuka.

And that created a surprising problem for people on the ground.

I to je stvorilo iznenađujuć problem za ljude na zemlji.

When an object moves at supersonic speed,

Kada se objekat kreće supersoničnom brzinom,

it generates a continuous moving shockwave known as a sonic boom.

stvara kontinuirani pokretni udarni talas poznat kao zvučni prasak.

This produces a loud, startling noise,

Ovo stvara glasni, zapanjujuć zvuk,

as well as rattling windows and dislodging structural elements of buildings.

kao i zveckanje prozora i pomeranje strukturnih elemenata zgrada.

Since a plane flying at an altitude of 15 kilometers

Pošto avion koji leti na visini od 15 kilometara

can affect an area with an 80 kilometer diameter on the ground below,

može da utiče na oblast prečnika 80 kilometara na zemlji,

complaints and concerns from residents in the Concorde’s flight path

žalbe i brige od stanovnika na letnom putu Konkorda

restricted it to mostly ocean routes.

ga je ograničilo na većinski okeanske rute.

Because of these restrictions and other fuel and engineering requirements,

Zbog ovih ograničenja i drugih zahteva oko goriva i inženjerstva,

supersonic flights turned out to be very expensive

supersonični letovi su ispali vrlo skupi

for both airlines and passengers.

i za avionske kompanije i za putnike.

A single transatlantic round-trip could cost the equivalent

Jedan povratni let preko Atlantika bi mogao da košta više od 10 000$ danas.

of more than $10,000 today.

With additional strain on the airline industry

Sa dodatnim naporom na avionsku industriju

due to decreased demand for flights after September 11th, 2001,

zbog smanjene potražnje za letove posle 11. septembra 2001. godine,

this became unsustainable, and the Concorde was retired in 2003.

ovo je postalo neodrživo i Konkord je penzionisan u 2003.

So even when superfast flights existed, they weren't standard commercial flights.

Čak i kada su vrlo brzi letovi postojali, nisu bili standardni komercijalni letovi.

And while we might think that advances in flight technology

Iako možda mislimo da bi napreci u tehnologiji letenja

would make fast flights less expensive, this hasn’t necessarily been the case.

načinili brze letove jeftinijim, ovo nije nužno bio slučaj.

One of the biggest concerns is fuel economy.

Jedna od najvećih briga je ekonomija goriva.

Over the decades, jet engines have become a lot more efficient,

Tokom decenija, mlazni motori su postali efikasniji,

taking in more air and achieving more thrust—

uzimajući više vazduga i postižući više pogonske snage —

traveling further for every liter of fuel.

putujući dalje za svaki litar goriva.

But this efficiency is only achieved at speeds

Ali ova efikasnost je postignuta samo na brzinama

of up to around 900 kilometers per hour— less than half the speed of the Concorde.

do 900 kilometara po času — manje od polovine brzine Konkorda.

Going any faster would increase air intake and burn more fuel per kilometer flown.

Kretanjem bržim od ovoga bi se povećalo uzimanje vazduha

i sagorevanje goriva po preletenom kilometru.

A standard transatlantic flight still uses as much as 150,000 liters of fuel,

Standardni let preko Atlantika i dalje koristi čak 150 000 litara goriva,

amounting to over 20% of an airline’s total expenses.

iznoseći preko 20 posto ukupnog troška avio kompanije.

So any reduction in fuel economy and increase in speed

Tako da bilo kakvo smanjenje u ekonomiji goriva i porast u brzini

would significantly increase both flight costs and environmental impact.

bi znatno povećalo i cenu letova i uticaj na okolinu.

What about ways to make a plane faster without burning lots of fuel?

Šta sa načinima da avion bude brži bez sagorevanja mnogo goriva?

Adjusting the wing sweep, or the angle at which wings protrude from the fuselage,

Nameštanjem strele krila, ili ugla pod kojim krila izlaze iz trupa,

to bring the wings closer in can make an aircraft faster

da bi se krila približila može da učini

avion bržim smanjivanjem aerodinamičnog otpora.

by reducing aerodynamic drag.

But this means the wings must be longer to achieve the same wingspan,

Ali ovo znači da krila moraju biti duža da bi se ostvario isti raspon krila,

and that means more materials and more weight,

i to znači više materijala i težine,

which in turn means burning more fuel.

što znači sagorevanje više goriva.

So while airplanes could be designed to be more aerodynamic,

Dakle, iako se avioni mogu dizajnirati da budu aerodinamičniji,

this would make them more expensive.

ovo bi ih načinilo skupljim.

And generally, airlines have found that customer demand for faster flights

I generalno, avio kompanije su otkrile da potražnja kupaca za bržim letovima

is not sufficient to cover these costs.

nije dovoljna da se pokriju ovi troškovi.

So while military aircraft conduct high speed flights

Tako da, iako vojni avioni sprovode letove velikih brzina

over water and at high altitudes,

preko vode i na visokim nadmorskim visinama,

supersonic commercial flights seemed like a brief and failed experiment.

supersonični komercijalni letovi se čine kao kratki i neuspešni eksperiment.

But recent advances may make them feasible again.

Ali skorašnji napreci će ih možda ponovo učiniti izvodljivim.

Research by NASA and DARPA has shown that modifying an aircraft’s shape

Istraživanje NASA-e i DARPA-e je pokazalo da modifikovanje oblika aviona

can reduce the impact of its sonic boom by 1/3.

može da smanji uticaj soničnog praska za trećinu.

Extending the nose with a long spike can break the shockwave into smaller ones,

Izduživanje nosa sa dugačkim šiljkom može da razdvoji udarni talas u manje,

while another proposed design features two sets of wings

dok još jedan predložen dizajn ima dva seta krila

producing waves that cancel each other out.

koja stvaraju talase koji poništavaju jedni druge.

And new technologies may solve the energy efficiency problem

I nove tehnologije možda reše problem sa efikasnosti energije

with alternative and synthetic fuels, or even hybrid-electric planes.

sa alternativnim i sintetičkim gorivima, ili čak hibridnim električnim avionima.

It may yet turn out that the last few decades of steady flying

Možda će ispasti da su poslednjih par decenija postojanog letenja

were just a brief rest stop.

bile samo kratko odmorište.