The plane truth: Scientist reveals how wings really work
Steve Connor is the Science Editor of The Independent. He has won many awards for his journalism, including five-times winner of the prestigious British science writers’ award; the David Perlman Award of the American Geophysical Union; twice commended as specialist journalist of the year in the UK Press Awards; UK health journalist of the year and a special merit award of the European School of Oncology for his investigative journalism. He has a degree in zoology from the University of Oxford and has a special interest in genetics and medical science, human evolution and origins, climate change and the environment.
Wednesday 25 January 2012
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.
Regular cast member Ste Hay, played by Kieron Richardson, is about to test TV boundaries
- 1 Lee Evans announces retirement from comedy on The Jonathan Ross Show
- 2 Pirelli calendar 2015: The problem with 'plus-size' models like Candice Huffine
- 3 These grandmas smoking weed for the first time are wonderful
- 4 Woman opens professional cuddling shop – gets 10,000 customers in first week
- 5 Angelina Jolie confuses everyone with 'ay up me duck' East Midland's greeting to Derby actor Jack O'Connell at awards show
Jeff Fletcher dead: Britpop guitarist is decapitated by lorry in horrific traffic accident
These grandmas smoking weed for the first time are wonderful
Jimmy Ruffin dead: Motown legend, who wrote 'What Becomes of the Brokenhearted', dies aged 78
New York snowstorm: Five dead and state of emergency declared as 'wall of snow' buries Buffalo
Woman opens professional cuddling shop – gets 10,000 customers in first week
G20 summit: Enter Putin. Accompanied by four warships. To the sound of mockery
'Muslims pre-date Columbus in discovering America,' says Turkish president Erdogan
David Cameron 'compares Vladimir Putin’s Russia to Nazi Germany' ahead of tense meeting
Former Tory PM Sir John Major says 'we would not have an NHS without migrants'
France 'blocks' Russian sailors from boarding a warship
G20 summit: David Cameron warns Vladimir Putin that Russia's relationship with the West is at a 'fork in the road' over Ukraine
Benefits: Argyll Scott International: Argyll Scott is recruiting for a Permane...
£30000 - £50000 per annum + EXCELLENT: Austen Lloyd: COMMERCIAL PROPERTY SOLI...
Benefits: Argyll Scott International: Due to further expansion, a leading inte...
£27000 - £32000 per annum + training: Langley James : Senior Technician; Promo...