The US Air Force has come up with a novel way to its cool Global Hawk unmanned air vehicles in the extreme temperatures of Southwest Asia - hosing them down.
The overheating problem occurs on the ground, when troubleshooting the aircraft in the midday sun sends temperatures in its avionics compartments soaring.
Without airflow over the wing to dissipate heat accumulated by the fuel, which is used as a sink for heat generated by avionics and sensors, internal temperatures can exceed operating limits on the electronics.
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Because of the extreme temperatures, aircraft are kept in an air-conditioned hangar and almost all launches and recoveries are performed at night, "when it is 'slightly' cooler", says the US Air Force.
Recently, when a Global Hawk was forced to return to base because of an inflight discrepancy, the USAF says, overheating of the main computer on the spare aircraft prevented it being launched.
When a similar event occurred the next day, and a spare aircraft again had to be launched in the midday heat, concerns about a repeat of the overtemperature problems led to the inpromptu solution of getting a fire truck to hose down the wing to help cool the fuel that in turn cools the electronics.
"Operators indicated that the internal component temperatures were cooler then some of the launches we do at night. The aircraft launched and completd a successful mission," the USAF says.
Source: FlightGlobal.com
