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Technology update
Cool image for Eurofighter
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Eurofighter Typhoon can be subjected to temperatures from -70 ° to +70 ° C at DERA's environmental facility.
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The Spanish CASA DA6 Eurofighter Typhoon (one of seven development aircraft) is undergoing a wide-ranging environmental
test program at the
Defence Evaluation and Research Agency's (DERA), Boscombe Down facility in the UK. DERA describes its environmental hangar and blower tunnel as a "unique" facility in Europe. The environmental program is an element of the Eurofighter organization's multinational approach of using the best appropriate facilities available in the four European partner countries (UK, Germany, Spain, and Italy). During the environmental hangar phase of the program, the aircraft is being subjected to extreme hot and cold temperatures and humidity levels to simulate the conditions it could be expected to experience in operational conditions anywhere in the world. The environmental hangar is understood to be the only facility of its kind in Europe sufficiently large to accommodate a full-size combat aircraft.
The Eurofighter Typhoon is exposed to 30 ° C temperature drop at DERA's blower facility.
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According to DERA, the scenarios created are as realistic as possible and include the running of engines, APUs (auxiliary power units), and all main mechanical and electrical systems. The facility has solar array equipment to simulate the effects of direct sunlight on the upper surfaces of the aircraft.
DERA's "blower tunnel" is being used for a trial,
exposing the aircraft to simulated icing conditions. A real-world icing test program begins later this year. The tunnel introduces water and liquid nitrogen into the airflow to produce realistic icing conditions. Test pilots from the partner nations who are involved in the work at Boscombe Down wear fully instrumented flying clothing to enable medical staff to monitor and evaluate the effects of wide-ranging environmental conditions on the human system.
According to DERA, the icing trials at Boscombe Down will provide evidence/clearance for airborne flight-in-icing-conditions trials using a Dornier aircraft as an ice generator. That element of the program will lead to initial operational clearance. The Boscombe Down work sees the aircraft hot- and cold- soaked to check system functionality and anti-icing systems efficacy on flying surfaces and engine intakes while simulating operation in a moving airflow. The blower tunnel comprises a
3-m tube. Fans embedded in the tunnel are driven by four Rolls-Royce Merlin piston engines (the type used to power the World War II Spitfire and Hurricane fighters and similar to the Packard-Merlin used in the North American P-51 Mustang). Each engine is capable of producing 1184 kW. Airspeed is varied by using combinations of number and speed of the engines, and by varying the diameter of the exit nozzle. The tunnel can provide relative airspeeds up to 350 kts and a temperature reduction of up to 30° C.
DERA explained that to simulate Arctic conditions, an insulated test chamber was constructed. Stabilized temperatures of -50° C can be maintained and exposure to -70° C can be readily simulated. Layers of ice can also be applied to equipment within the chamber to check performance. For high-temperature and high- humidity environments, air is circulated via fan-assisted heaters capable of raising the temperature to +70° C. Water content of the air can be increased by injecting steam. Relative humidity of 95% at +40° C can be achieved and controlled. The heating effects of solar radiation on the whole aircraft are being studied. An ancillary plant can supply conditioned air to simulate air-conditioning systems.
Stuart Birch
Aerospace Engineering May 2000
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