. Space Industry and Business News .




.
AEROSPACE
Helicopters set to become more manoeuvrable - using humpback whales as the prototype
by Staff Writers
Berlin, Germany (SPX) Feb 06, 2012

Photomontage of a humpback whale and the DLR helicopter Bo 105.

Modern helicopters could be significantly faster and more manoeuvrable - if aerodynamics did not impose limitations on them. Researchers at the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) in Gottingen have now discovered and flight-tested a way to increase manoeuvrability using an idea they got from observing humpback whales.

Helicopters owe their special ability to vertically take off and land to their main rotor, but this also contributes to aerodynamic disadvantages.

The airflow over a backward-moving main rotor blade separating from the aerofoil during fast forward flight or manoeuvring, referred to as a 'dynamic stall', creates turbulence, loss of lift and exerts large forces on the rotor. Drag increases and the rotor head control rods are subjected to large dynamic loads.

"This limits the top speed of helicopters at high altitude and, in particular, their manoeuvrability," explains Kai Richter from the DLR Institute of Aerodynamics and Flow Technology in Gottingen. In addition, the resulting vibration compromises passenger comfort. Modern engines would be able to deliver significantly better flight performance were it not for these limitations.

"Stalling is one of the most serious problems in helicopter aerodynamics - and one of the most complex," says Richter. Generating a computer simulation of a moving rotor is significantly more complicated than modelling a fixed-wing aircraft.

Acrobatic marine mammals
When looking for ways to delay the onset of stalling in helicopters, researchers at Gottingen struck gold with humpback whales - which is somewhat surprising at first glance.

"These marine mammals are renowned for their great speed and acrobatic skills," says Holger Mai from the DLR Institute of Aeroelasticity. This is due to their unusually large pectoral fins, which have characteristic bumps along the front edge.

"Research has shown that these bumps cause stalling to occur significantly later underwater and increase buoyancy."

DLR researchers translated the idea of using bumps for delaying the onset of stalling to helicopter rotors, and patented it as Leading-Edge Vortex Generators (LEVoGs) "Flow phenomena in water are similar to those in air; they just need to be scaled accordingly," says Mai.

The artificial bumps on helicopters are smaller than those on a humpback whale; they have a diameter of six millimetres and weigh just 0.04 grams.

Experiments conducted in the wind tunnel were promising, enabling a test flight using the DLR Bo 105 research helicopter in Braunschweig to be successfully carried out, as part of the DLR SIMCOS (Advanced Simulation and Control of Dynamic Stall) project. 186 rubber LEVoGs were glued to each of the helicopter's four rotor blades.

"The pilots have already noticed a difference in the behaviour of the rotor blades," says Richter. The main objective of the initial test flight was to demonstrate the safety of this new technique. "The next step is a flight using special measuring equipment to accurately record the effects," Richter explains.

If the concept proves successful, DLR researchers hope that existing helicopters could be retrofitted at little expense. For new helicopters, contours could be milled into the front edges of existing titanium blade designs during the manufacturing process.

Related Links
DLR
Aerospace News at SpaceMart.com




.
.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries






.

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



AEROSPACE
Snow and fog ground half of London Heathrow's flights
London (AFP) Feb 5, 2012
Thousands of passengers were stranded on Sunday after heavy snow and forecasts of freezing fog forced London Heathrow Airport to cancel 50 percent of its scheduled flights. "Airlines expect to operate about 50 percent of the 1,300 flights originally scheduled for today," the west London airport said in a statement on its website. Six centimetres (2.4 inches) of snow blanketed Heathrow ov ... read more


AEROSPACE
iPhone leaps to third place in mobile market

Apple's iPhone hot but Android handsets on fire

Samsung condemns 'anti-Iran' ad featuring its tablet

Malaysia plant threatens China grip on rare earths

AEROSPACE
Brazil to assemble Harris tactical radio

Northrop Grumman Wins Award for USAF Design and Engineering Support Program

Fourth WGS Satellite Sends First Signals from Space

Boeing to Build More Wideband Global SATCOM Satellites for USAF

AEROSPACE
SpaceX flight to ISS could be late March: NASA

Launch of Proton-M with Dutch Satellite Postponed

First Vega rocket assembled on launch pad

Ukraine, Russia to Launch 2 Dnepr Carrier Rockets in 2012

AEROSPACE
EU signs orders for eight new Galileo space satellites

SSTL-OHB System consortium to build a further eight Galileo FOC satellites

Eight more Galileo navsats agreed

ESA Director General praises UK space innovation

AEROSPACE
China bans airlines from paying EU carbon charges

Helicopters set to become more manoeuvrable - using humpback whales as the prototype

Snow and fog ground half of London Heathrow's flights

Singapore Airlines 3Q net profit down 53 percent on-year

AEROSPACE
Jumpstarting computers with 3-D chips

Researchers Devise New Means For Creating Elastic Conductors

Cooling semiconductor by laser light

A new class of electron interactions in quantum systems

AEROSPACE
NASA's GCPEX Mission: What We Don't Know about Snow

China considers Google Maps request

NASA Finds 2011 Ninth-Warmest Year on Record

Satellite observes spatiotemporal variations in mid-upper tropospheric methane over China

AEROSPACE
Environment agency becomes crunch issue in Rio talks

Scavengers face tough times as Mexico dump closes

India's air the worst, says study

Eight executives detained in China pollution case


.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement