Technology update
ABB and the FTTR
 Westland Helicopters' Flexible Transmission Test Rig for which ABB supplied five induction motors and other equipment. |
Westland Helicopters' Flexible Transmissions Test Rig (FTTR) has been designed to test different types of gearboxes under "practical conditions" for current and future aircraft. Historically, gearboxes have needed individual test rigs, but the FTTR, with its broad capability, is now testing WAH-64 Apache and EH101 gearboxes and will be used to develop new designs.
A major element of the FTTR's technology is the use of ac variable-speed drives and large induction motors to drive the engine inputs and exert load onto the main rotor and tail rotor outputs of a test gearbox. Working with main contractor RENK of Germany, ABB supplied the motors. The FTTR uses four identical 2000-kW AMB 560 induction motors in a symmetrical arrangement, each able to traverse up to 4 m along the side of the test rig and elevate to 300 mm, said ABB. The vertical motion is achieved via a slide-away integrated into a custom-designed motor housing. To accommodate the demands of each aircraft type, the rig is equipped with a different pallet for each gearbox. The motors are coupled through drive gearboxes mounted on the pallet, which allow motor speed and efficiency to be optimized. The pallets are pushed into position on air casters, and all input and output power connections are standardized. Cooling water and oil are connected to the pallet by a docking plate.
ABB explains that the four motors are used to transmit power to—or absorb power from—the gearbox. On a three-engine gearbox such as the EH101, three of the motors would be used to simulate engine power inputs and the fourth to simulate tail rotor drive output load. The main rotor load is simulated by an ABB uQ 800 motor rated at 5250 kW and powered by its associated ABB Variable Speed Drive. The motor is fitted above the test gearbox with shaft-down mounting. A tilt mechanism is employed for small adjustments in rotor shaft angle to suit the test gearbox.
 Development of gearboxes for aircraft such as the WAH-64 Apache is a major application of Westland Helicopters' Flexible Transmission Test Rig. |
Test rigs are commonly subjected to high loads with associated vibration and oscillation problems, demanding particular care in the design of their components. ABB said the engineering for the FTTR facility was "very specialized" to allow for a degree of movement by the motors, and it completed full load combined tests at its Birr, Switzerland, plant.
The Westland rig operates on a closed-loop system, with energy recirculated to significantly reduce demand and cost, said ABB. The energy is recirculated electrically by the variable-speed drives using a common dc link. Each motor may be used to provide energy or as a generator to absorb energy. During testing, mechanical torque is carefully applied to the gearbox input and output shafts in opposition, to 'wind up' the gearbox to simulate the loads and speeds imposed in flight conditions. Mechanical energy returning from the tested gearbox is re-converted into electrical energy and returned to the dc link of the drives. This returned energy is topped up by a Drives Supply Rectifier (DSR) to make up for any losses. ABB said that up to 6 MW of power may be necessary to test a gearbox, but that recycling the power reduces the demand to 1 MW, which can be supported by the local grid without restrictions on operation.
Only a new pallet is needed for each new gearbox type. Setting up the facility for a test run takes less than one hour.
- Stuart Birch
Automatic crimping
French company Atlantic Technologies has developed a new automatic, multicontact, universal crimping tool for the manufacture and repair of electrical harnesses. Designated P.S.U. 16-22, it is said to be able to crimp almost all the contacts in an aircraft without having to change the die or adjust the selector for jaw height. Crimping can be monitored in real time, and the system retains a complete record in memory. Atlantic Technologies said that a complete database holds essential information, including time, date, tool, and die references; contact batch and wire numbers; connector number; harness number; manufacturing file number; and aircraft number.
- Stuart Birch
Aerospace coating technology from Hardide
A gas phase coating process called Hardide is a low-temperature, super-hard (up to 3500 HV) material able to coat 'out of sight' surfaces and complex shapes uniformly. The composition of Hardide, which was originally developed in Russia, is based on tungsten carbide. Hardide Ltd. has just opened an application development center in the UK, with another one already established in Moscow.
Hardide produces a family of more than 20 coatings offering a variety of parameters to meet specific application requirements. According to the company, all of the coatings can be produced at one plant, while the composition and structure of each is controlled by process conditions. Hardide's nonporous coating can also facilitate the release of any molded product in that it has nonstick characteristics. It is also inert and so does not interact with other materials.
Accelerated wear tests have shown that five pairs of piston-sleeve hydraulic parts coated with 30 microns of Hardide outperformed case-hardened piston sleeves by a factor of seven when subjected to oil with diamond abrasive grit. According to Hardide, when exposed to more common abrasives such as sand, the difference becomes even more significant.
The company believes the coating material has many potential applications within the aerospace industry, ranging from actuators to undercarriage systems. It adds that the process, which reduces friction, could facilitate production of smaller and lighter pumps requiring less power to drive hydraulic systems. Also, fuel valves could potentially be made more efficient because of Hardide's ability to coat internal surfaces.
- Stuart Birch
UAVs used to aid firefighters
 Altus II was used to provide images of wildfires to firefighters in near real-time via the internet. |
The NASA Ames Research Center has recently conducted unmanned aerial vehicle (UAV) demonstrations to show how the aircraft could be useful to firefighters. During the demonstrations, which took place in September, the UAV called Altus II was used to provide images of wildfires to firefighters in near real-time via the Internet. Equipped with 200 lb of camera and communications gear, Altus II was flown to altitudes of 10,000-15,000 ft over a small, controlled fire near an airfield in Southern California. The airplane carried a TV camera as well as a digital multispectral scanner that can spot flames through smoke.
"The focus of the UAV disaster monitoring program is getting the right information to the right people at the right time," said Steve Wegener, a scientist at NASA Ames. "In the case of fires, we are providing wide-view aerial fire images that disaster managers have never had before and that they can overlay on maps that show exact locations of assets such as fire engines. The firemen can react more quickly to emergencies and send assets to trouble spots."
During the flight demonstration, Altus II was launched from a small dry lakebed south of the NASA Dryden Flight Research Center in Edwards, CA. The remotely piloted aircraft sent images and other data to the InMarsat satellite. This digital information was then transferred to NASA Ames for real-time image processing. Ames scientists then overlaid the fire information on maps and posted them on the Internet. The entire process takes about 10 to 15 minutes.
"We hope the combination of sensors, UAV technology, and Internet delivery will mature so that it can help firefighters view and combat large fires that exceed local capabilities," Wegener said. "We are developing this technology to enable people to better manage many kinds of disasters, including fires, floods, and earthquakes. During the next three years, we expect to conduct three UAV disaster demonstrations."
NASA is reviewing another proposed demonstration involving a larger UAV, called the Altair. The Altair has a 64-ft wingspan and can fly as high as 52,000 ft. The aircraft can also fly more fire-monitoring instruments further and for a longer time than the smaller Altus. The Altair has a 4200-mi range and can stay aloft as long as 32 h. Altair can also carry a thermal imager as well as a small synthetic-aperture radar (SAR) that is capable of seeing through water vapor, clouds, and smoke. SAR can provide very detailed images of flooding, damaged buildings, and other infrastructures difficult to detect, especially in bad weather.
- Frank Bokulich
