America has turned to propeller fighter planes to help battle ISIS in Afghanistan because they're more rugged and adaptable - and they don't have to worry about enemy jets
- The US is selling the Embraer A-29B Super Tucano to the Afghanistan army
- The plane is able to fly low and slow to support ground troops better than jets
- It can also land on dirt and can fly for up to three hours without refueling
- But it can still pack high-tech equipment including infra-red sensors
- The Marines have been trying to get the planes for their use for years
- A reliance on high-tech jets is making that kind of purchase hard, however
- Despite that, experts say prop planes are more practical for AfghanistanThe US might have access to the most cutting-edge war technology on the market, but sometimes the oldies really are the best.
- Huge craft capable of carrying 500 tonnes of cargo in a single trip
- Uses an effect known as ground effect to trap a air underneath its giant wing. This crafts can be made of composite materials like the plane above that is lighter and stronger ship structure,and can absorve punishment from projectiles like warships made of steel,Stavatti unveiled designs for a new attack plane called the 'Machete' that consists of a new metal foam developed in conjunction with the US Department of Energy. The metal foam is lightweight and strong - and can stop bullets in much less space than traditional armor canHe stressed the design has evolved and is more advanced than its early 2009 beginnings.'It's basically doubled in weight' to 30,000 pounds, Beskar explained, which is close to the same weight as an A-10.Adding the new metal foam into the design allows the plane to stop projectiles in a lesser amount of space than the traditional armor.'We could stop the bullet at a total thickness of less than an inch, while the indentation on the back was less than eight millimeters,' said Afsaneh Rabiei, an engineering professor at North Carolina State University, who tested the metal foam.'To put that in context, the [National Institute of Justice] standard allows up to 44 millimeters indentation in the back of an armor.'
The composite material is built like a sandwich: Between two pieces of aluminum, each just two millimeters thick, is a 25-millimeter-thick layer of the “foam,” actually a low-density, sponge-like composite of magnesium, silicon, and copper, and aluminum. And like a good sandwich, there’s no glue. The layers are held together by metallic bonding, the electrostatic attraction of negatively charged electrons and positively charged ions.The result is a material that’s 20 percent lighter than traditional fiberglass, which is commonly used on high-speed train cabs. That’s a big advantage when the goal is to move faster and more efficiently. Even better, it doesn’t come at the cost of a weaker train. “The outer shell is so stiff that you need no ribs inside,” says Dr. Thomas Hipke, head of lightweight construction at the Fraunhofer Institute for Machine Tools and Forming Technology, which helped to design the prototype train cab. Peel tests of aluminum foam—in which force is applied to pull apart the layers of the material—destroy the foam interior instead of breaking the bonds between the layers, demonstrating the strength of the bonding.That strength matters a lot when you’re traveling at 150 to 200 mph, fast enough to keep up with a jet at takeoff. While crashes are rare, high-speed trains are regularly hit by small objects, which can cause trouble. “Aluminum foam has a very high and comfortable impact resistance, especially for small impacts like stones, bottles or just birds,” says Ralf Uhlig of Voith Engineering Services, which was involved in the construction of the prototype cab. Collisions with our feathered friends are relatively frequent and can pose real dangers to passengers. In 2013, a high-speed train en route to Beijing was forced to stop after a bird strike cracked the train’s exterior.The comparably cushy substance makes the inside of the train safer in a collision, too. Crash tests with human dummies have confirmed the material efficiently absorbs energy and protects passengers from “secondary impacts”—i.e., slamming into the wall or a seat back when the train lurches unexpectedly. Tests run by the Transportation Research Board in Washington, D.C. showed packing seat backs with aluminum foam reduced head injury values by 80 percent in an 8g impact.Aluminum foam was invented back in 1968, but the longstanding drawback for industrial applications has been the difficulty of shaping the material without relying on expensive tooling. Now, engineers at the Fraunhofer Institute and Voith Engineering Services have demonstrated aluminum foam surfaces can be formed economically using embossing tools: The contours of the material are set during the foaming process, rather than conventionally stretching the material around a blank of the desired shape. “We save approximately 60 percent on tool costs,” says Dr. Hipke. Train cabs assembled from aluminum foam are expected to be built within the next year.