Though the wing-flapping contraptions of early human flight haven’t quite caught on, researchers think birds may still have something to teach us about navigating the air: how to land. MIT researchers have made a system that can bring a modified glider to an elegant bird-like stop, causing it to set down on its tail.
Russ Tedrake of MIT’s Computer Science and Artificial Intelligence Laboratory and his student Rick Cory developed the computer model to bring a basic foam glider to a unique landing. The principle behind the plane’s stop is the same one used by stunt planes–stall. When its wings tilt back, the plane loses lift and falls from the sky. Traditional planes don’t use this method to land because the airflow is chaotic (see smoke visualization above) making it hard to predict how the plane will behave.
Birds come to a stop by tilting their wings back at sharp angles. This creates turbulence and large, unpredictable whirlwinds behind the wings. If an airplane pointed its wings up in this way, it would lose lift and fall out of the sky. But MIT researchers wanted to take advantage of stall–specifically, post-stall drag–to help a plane come to a controlled landing. [Popular Science]
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Success for Solar Impulse: This morning the solar-powered plane touched down in Switzerland after more than 26 hours in the sky—including flying overnight on battery power.
As we noted yesterday, this was by far the most ambitious test of adventurer Bertrand Piccard’s experimental aircraft, which is covered by 12,000 solar cells. Swiss pilot André Borschberg had to decide last night whether those cells had absorbed enough battery power during the day to coast through the night, and he managed to do it.
“I’ve been a pilot for 40 years now, but this flight has been the most incredible one of my flying career,” Mr. Borschberg said as he landed, according to a statement from the organizers of the project. “Just sitting there and watching the battery charge level rise and rise thanks to the sun. I have just flown more than 26 hours without using a drop of fuel and without causing any pollution” [The New York Times].
As I write this, a plane powered by the sun is flying somewhere over Europe, undertaking its most ambitious test flight yet.
When we last left the Solar Impulse back in April, the experimental aircraft had flown a two-hour test to prove it was flight-worthy. Today, the pilot in the plane, which weighs about as much as a car and is covered in 12,000 solar cells, will try to stay aloft for 24 hours, even cruising along during the nighttime hours.
“The goal of the project is to have a solar-powered plane flying day and night without fuel,” said team co-founder Bertrand Piccard, adding that this test flight – the third major step after its first ‘flea hop’ and an extended flight earlier this year – will demonstrate whether the ultimate plan is feasible: to fly the plane around the world. “This flight is crucial for the credibility of the project” [AP].
It was a big week for experimental military aircraft, with the Air Force’s secretive X-37B space plane and the Navy’s biofuel-powered “Green Hornet” both achieving successful test flights. But the most ambitious—the HTV-2 hypersonic glider under development by the Defense Advanced Research Projects Agency (DARPA)—lost contact with its operators during its run.
Launched from Vandenberg AFB, Calif. on April 22, the unmanned HTV-2 was planned to cross the Pacific and impact the ocean north of Kwajalein Atoll in the first of two flights to demonstrate technology for a prompt global strike weapon [Aviation Week]. It successfully achieved separation from its booster rocket high in the atmosphere; however, nine minutes into the test the glider lost communication. Now the military is studying the test flight telemetry to figure out where the HTV-2 would have crashed down.
The F/A-18 Super Hornet burns through more fuel than any other aircraft in the United States Navy, whose pilots have flown more than 400 of the jets. But with the week of Earth Day upon us, the Navy is trying to use the jet to show it can mend its fuel-guzzling ways. Tomorrow the “Green Hornet,” an F/A-18 running on a half-petroleum, half-biofuel blend, will make a test flight from Maryland.
Secretary of the Navy Ray Mabus has set a target that half of naval energy consumption will come from alternative sources by 2020. A “Great Green Fleet,” to sail by 2016, will include nuclear ships, as well as surface combatants with hybrid electric power systems using biofuel and biofuel-powered aircraft [National Geographic]. Before we can talk about ambitious deployment targets, however, the Navy has to prove that its “green” fighter has got what it takes, and so the experimental F/A-18 will try to break the sound barrier.
For the better part of a decade, the Global Hawk unmanned aerial vehicle has coasted through the stratosphere, surveilling vast panoramas of land below for the U.S. Air Force and Navy. Now the plane’s broad reach will serve science. NASA announced this week that it had completed the first test flight of a Global Hawk retrofitted with monitoring equipment to help scientists study the the oceans, the atmosphere, and more.
“We can go to regions we couldn’t reach or go to previously explored regions and study them for extended periods that are impossible with conventional planes,” said David Fahey, co-mission scientist and research physicist [CNN]. From the comfort of their offices in Dryden Flight Research Center in the Mojave Desert, pilots flew the plane 14 hours up to the Arctic Ocean on this test run. Though this flight lasted about 14 hours, the Global Hawk can stay aloft for 30, and reach altitudes of 60,000, or twice as high as your last commercial airline flight attained.
When you see a flock of birds flying in formation, it might seem like their group dynamics are fairly simple: The one out front leads the way. But does the same birds always take the lead in a group? And do the birds in the back follow the overall leader, or rather the middle managers in front of them?
To find out, Tamás Vicsek and colleagues strapped backpacks equipped with GPS sensors to pigeons for a study out this week in Nature. The lightweight trackers recorded the birds on both solo flights and group flight and measured their positions five times per second. Indeed, Vicsek found, birds fly according to the group pecking order, with the leader out front. When it changed direction, its direct followers would do the same in less than a second, and then the more junior members of the group would respond to the direction of those middle managers.
But there were surprises, too. Sometimes the lead bird wouldn’t fly out front; it may have been tired from leading the pack and needed some time off. So perhaps birds are like cycling teams, occasionally trading off who carries the taxing burden of leading the group.
For more details about the study—including why it’s not as obvious as you might think that the leading bird flies in the front of the group, and why left and right matter so much to pigeons—check out DISCOVER blogger Ed Yong’s post at Not Exactly Rocket Science.
Not Exactly Rocket Science: GPS Backpacks Identify Leaders Among Flocking Pigeons
Not Exactly Rocket Science: Light-detecting backpacks record the complete migration routes of songbirds
80beats: “State of the Birds” Report, and is Climate Change Shrinking Avians?
80beats: To Read the Brain of a Pigeon, Scientists Outfit It with a “Neurologger”
80beats: Tiny Bird Backpacks Reveal the Secrets of Songbird Migration
Image: Zsuzsa Ákos
This time, Solar Impulse has really taken to the skies.
When we last left Swiss adventurer and around-the-world ballooning enthusiast Bertrand Piccard, he and his team were celebrating their first test flight of their solar-powered plane in December. However, those tests were really just “flea hop” tests to get the plane a couple feet off the ground. This time, though, Solar Impulse has completed a two-hour true test flight, a big step toward Piccard’s goal of flying the solar plane around the world.
At a military airport in the Swiss countryside, the “Solar Impulse” plane lifted off after only a short acceleration on the runway, reaching a speed no faster than 45 kph (28 mph). It slowly gained altitude above the green and beige fields, and disappeared eventually into the horizon as villagers watched from the nearest hills [AP]. Piccard says the test proved his plane—which weighs about as much as a car and runs on 12,000 solar cells with lithium batteries and electric engines as emergency backup—can not only fly, but fly straight. Since the plane will be flying without a drop of liquid fuel, he says, it must stay on its planned trajectory and conserve energy.
We gave the BBC a hard time this morning for going a little overboard in declaring the Large Hadron Collider a broken-down mess. But here’s something cool: In a new documentary, a team simulated the blast that “Underwear Bomber” Umar Farouk Abdulmutallab tried to create on Christmas Day last year. Their finding: Even if he had blown up the bomb successfully, it wouldn’t have been enough to take down flight 253 from Amsterdam to Detroit.
Dr John Wyatt, an international terrorism and explosives adviser to the UN, replicated the conditions on board the Detroit flight on a decommissioned Boeing 747 at an aircraft graveyard in Gloucestershire, England [BBC News]. Wyatt used the same amount of the explosive pentaerythritol that the bomber carried, about 80 grams, which packs about the punch of a hand grenade. They put it on the same seat and lit off a controlled explosion, which sent a shock wave through the aluminum exterior.
Thanks to a little technological ingenuity, we may soon get a look at what exactly is happening in the flying brain. In the journal Nature Neuroscience, Caltech researchers document how they managed to monitor the brain activity of fruit fly in flight.
“The challenge was to be able to gain access to the brain in a way that didn’t compromise the animal’s ability to fly, or to perform behavior,” said study researcher Michael Dickinson of Caltech. “We couldn’t just rip the brain out of the body and put it into a dish” [LiveScience]. Researchers have previously studied activity in the tiny brain of a living fruit fly, but only when it was restrained. Dickinson’s team created a way to look inside while the bug was flying around.