The plane truth: Scientist reveals how wings really work

 

The classic explanation of how a wing generates enough lift to keep a plane or a bird in the air is wrong, according to a Cambridge University physicist.

Many textbooks and aircraft manuals say that a wing produces lift because air travelling over the curved topside of a wing has to travel further than wind flowing around the flat underside and so has to travel faster to keep up, generating lift. But this standard explanation has been shown to be wrong by a simple experiment where a wing is placed in an air tunnel with jets of smoke flowing over the upper and lower surfaces, said Professor Holger Babinsky.

"A wing lifts when the air pressure above it is lowered. It's often said this happens because the airflow moving over the top, curved surface has a longer distance to travel and needs to go faster to have the same transit time as the air travelling along the lower, flat surface," he said.

"But this is wrong," said Professor Babinsky. "In the worst case, [this explanation] can lead to a fundamental misunderstanding of aerodynamics.".

A video of the experiment carried out at Cambridge shows that air does indeed move faster over the upper, curved surface of a wing, but this is because of the curvature of the upper surface. The air does not move faster in order to "catch up" with the air moving over the relatively shorter distance of the lower wing surface, Professor Babinsky said.

The slow-motion video of the smoke jets shows that the air moving over the upper surface of the wing travels further in the same amount of time than wind flowing past the lower surface. In other words there is no "equal transit time" between the upper and lower surfaces, as demanded by the classic explanation.

"What actually causes lift is introducing a shape into the airflow, which curves the streamlines and introduces pressure changes – lower pressure on the upper surface and higher pressure on the lower surface," Professor Babinsky said.

Suggested Topics
PROMOTED VIDEO
News
ebooksNow available in paperback
Arts and Entertainment
American singer, acclaimed actor of stage and screen, political activist and civil rights campaigner Paul Robeson (1898 - 1976), rehearses in relaxed mood at the piano.
filmSinger, actor, activist, athlete: Paul Robeson was a cultural giant. But prejudice and intolerance drove him to a miserable death. Now his story is to be told in film...
News
Neglect, prejudice and invisibility in the classrooms and playground is a way of life for LGBT children
education
Arts and Entertainment
Kieron Richardson plays gay character Ste Hay in Channel 4 soap Hollyoaks
tv

Regular cast member Ste Hay, played by Kieron Richardson, is about to test TV boundaries

Life and Style
tech
Life and Style
techPerils of 'text neck' revealed
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Argyll Scott International: FP&A Manager Supply Chain

Benefits: Argyll Scott International: Argyll Scott is recruiting for a Permane...

Austen Lloyd: Commercial Property NQ+

£30000 - £50000 per annum + EXCELLENT: Austen Lloyd: COMMERCIAL PROPERTY SOLI...

Argyll Scott International: Retail Commercial Finance Analyst

Benefits: Argyll Scott International: Due to further expansion, a leading inte...

Langley James : Senior Technician; Promotion & Training Opp; Borough; upto £32k

£27000 - £32000 per annum + training: Langley James : Senior Technician; Promo...

Day In a Page

Travelling to work by scooter is faster than walking and less sweaty than cycling, so why aren’t we all doing it?

Scoot commute

Travelling to work by scooter is faster than walking and less sweaty than cycling, so why aren’t we all doing it?
Paul Robeson: The story of how an American icon was driven to death to be told in film

The Paul Robeson story

How an American icon was driven to death to be told in film
Synagogue attack: Fear unites both sides of Jerusalem as minister warns restoring quiet could take 'months'

Terror unites Jerusalem after synagogue attack

Rising violence and increased police patrols have left residents of all faiths looking over their shoulders
Medecins sans Frontieres: The Ebola crisis has them in the headlines, but their work goes far beyond West Africa

'How do you carry on? You have to...'

The Ebola crisis has Medecins sans Frontieres in the headlines, but their work goes far beyond West Africa
Isis extends its deadly reach with suicide bombing in Kurdish capital

Isis extends its deadly reach with suicide bombing in Kurdish capital

Residents in what was Iraq’s safest city fear an increase in jihadist attacks, reports Patrick Cockburn
Underwater photography competition winners 2014 - in pictures

'Mysterious and inviting' shot of diver wins photography competition

Stunning image of cenote in Mexico takes top prize
Sir John Major: Negative West End portrayals of politicians put people off voting

Sir John Major hits out at theatres

Negative West End portrayals of politicians put people off voting
Kicking Barbie's butt: How the growth of 3D printing enabled me to make an army of custom-made figurines

Kicking Barbie's butt

How the growth of 3D printing enabled toy-designer to make an army of custom-made figurines
Will Smith's children have made waves with a gloriously over-the-top interview, but will their music match their musings?

What are Jaden and Willow on about?

Will Smith's children have made waves with a gloriously over-the-top interview, but will their music match their musings?
Fridge gate: How George Osborne keeping his fridge padlocked shows a frosty side to shared spaces

Cold war

How George Osborne keeping his fridge padlocked shows a frosty side to shared spaces
Stocking fillers: 10 best loo books

Stocking fillers: 10 best loo books

From dogs in cars to online etiquette, while away a few minutes in peace with one of these humorous, original and occasionally educational tomes
Malky Mackay appointed Wigan manager: Three texts keep Scot’s rehabilitation on a knife-edge

Three texts keep Mackay’s rehabilitation on a knife-edge

New Wigan manager said all the right things - but until the FA’s verdict is delivered he is still on probation, says Ian Herbert
Louis van Gaal: the liberal, the enemy and... err, the poet

Louis van Gaal: the liberal, the enemy and... err, the poet

‘O, Louis’ is the plaintive title of a biography about the Dutchman. Ian Herbert looks at what it tells us about the Manchester United manager
Isis in Iraq: Baghdad hails the retaking of the Baiji oil refinery as the start of the long fightback against the Islamist militants

Isis takes a big step back

Baghdad hails the retaking of the Baiji oil refinery as the start of the long fightback against the Islamist militants
Bill Cosby: America’s beloved TV ‘dad’ or serial rapist?

Bill Cosby: America’s beloved TV ‘dad’ or serial rapist?