Archive for the ‘aircraft’ tag
Honeycomb materials offer noise reduction
A prototype microchanneled material composed of many metallic nanotubes was developed at the Georgia Tech Research Institute (GTRI) to validate acoustic absorption experiments designed to reduce noise in aircraft.
By taking a new approach to the physics of noise, engineers at the Georgia Tech Research Institute (GTRI) have found a way of reducing the noise created by commercial and military jet aircraft, using honeycomb-like structures composed of many tiny tubes or channels.
Jason Nadler, a GTRI research engineer, explained: “This approach dissipates acoustic waves by essentially wearing them out. It’s a phenomenological shift, fundamentally different from traditional techniques that absorb sound using a more frequency dependent resonance.”
Most sound deadening material – such as foams or other cellular materials comprising many small cavities – exploit the fact that acoustic waves resonate through the air on various frequencies. The drawback with these traditional noise-reduction approaches is that they only work with some frequencies – those that can find cavities or other structures in which to resonate.
The research involves broadband acoustic absorption, a method of reducing sound that doesn’t depend on frequencies or resonance. In this approach, tiny parallel tubes in porous media such as metal or ceramics create a honeycomb-like structure that traps sound regardless of frequency. Instead of resonating, sound waves plunge into the channels and dissipate through a process called viscous shear. This involves the interaction of a solid with a gas or other fluid. In this case, a gas – sound waves composed of compressed air – contacts a solid, the porous medium, and is weakened by the resulting friction.
Read more on: Aerospace, aircraft, Design, georgia tech, MilitaryHelicopters teach themselves to fly - Video
Stanford computer scientists have developed an artificial intelligence system that enables robotic helicopters to teach themselves to fly difficult stunts by watching other helicopters perform the same maneuvers.
The result is an autonomous helicopter than can perform a complete airshow of complex tricks on its own.
The stunts are “by far the most difficult aerobatic maneuvers flown by any computer controlled helicopter,” said Andrew Ng, the professor directing the research of graduate students Pieter Abbeel, Adam Coates, Timothy Hunter and Morgan Quigley.
Read more on: Aerospace, aircraft, helicopters, RoboticsMAV flies into dangerous areas
Based on the ‘dragonfly’, the DelFly Micro Air Vehicle (MAV) from TU Delft, is an ultra-small remote-controlled, camera equipped aircraft, with the potential for use in observation flights in difficult to reach or dangerous areas.
The MAV barely weighs 3g – 1g of which is the weight of the battery. It can fly for approximately three minutes, and has a maximum speed of 5m/s.
The DelFly has a tiny on-board camera that transmits signals to a ground station. Using software developed by TU Delft, objects can be independently recognised.
In the next step of the project, TU Delft plans to develop the DelFly NaNo, which will measure 5cm and weigh 1g.
Read more on: aircraft, camera, Design, robot, Robotics, softwareRotorcraft takes to remote regions
The Boeing Company and SkyHook International are to work together to develop a new commercial heavy-lift rotorcraft designed to address the limitations and expense of transporting equipment and materials in remote regions.
The SkyHook JHL-40 aircraft will be capable of lifting a 40 ton sling load and transporting it up to 200 miles without refuelling in harsh environments such as those found in Canada and Alaska. Currently, conventional land and water transportation methods in these underdeveloped regions are inadequate, unreliable and costly. With its lifting capacity and range, the JHL-40 aircraft could change this for a variety of industries.
The neutrally buoyant aircraft allows SkyHook to safely carry payloads unmatched by any rotorcraft currently in existence. The helium-filled envelope is sized to support the weight of the vehicle and fuel without payload. With the empty weight of the aircraft supported by the envelope, the lift generated by four rotors is dedicated solely to lifting the payload, leaving the aircraft naturally buoyant.
Read more on: Aerospace, aircraft, Design, lifting, rotorcraftWEAV for surveillance
An associate professor from the University of Florida has developed a ‘wingless electromagnetic air vehicle’ (WEAV), a small, circular spinning aircraft reminiscent of the spaceships seen in films.
The prototype proposed by Subrata Roy, is less than six inches in diameter, and efficient enough to be powered by on-board batteries along with magnetohydrodynamics, or the force created when a current or a magnetic field is passed through a conducting fluid. In the case of the WEAV aircraft, the conducting fluid will be created by electrodes that cover each of the vehicle’s surfaces and ionise the surrounding air into plasma.
The force created by passing an electrical current through this plasma pushes around the surrounding air, and that swirling air creates lift and momentum and provides stability against wind gusts. In order to maximise the area of contact between air and vehicle, the WEAV design is partially hollow and continuously curved.
The WEAV has no moving parts, such as propellers or jet engines, and so is expected to be more reliable. This design also allows the WEAV to hover and take off vertically.
Read more on: Aerospace, aircraft, Design, electrodes, Electronics