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Thales Watchkeeper WK450

Reconnaissance Unmanned Aerial Vehicle (UAV)

The Thales Watchkeeper WK450 Unmanned Aerial Vehicle is the British-modified equivalent of the Israeli Elbit Hermes 450 UAV series.
Authored By: Staff Writer | Edited: 6/29/2018
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Year: 2014
Status: Active, In-Service
Manufacturer(s): Thales - UK / Elbit - Israel
Production: 54
Capabilities: Reconnaissance (RECCE); Unmanned;
Crew: 0
Length: 19.69 ft (6 m)
Width: 34.45 ft (10.5 m)
Weight (MTOW): 992 lb (450 kg)
Power: 1 x Wankel rotary 52 horsepower engine driving a three-bladed propeller arranged in "pusher" configuration.
Speed: 109 mph (175 kph; 94 kts)
Ceiling: 18,045 feet (5,500 m; 3.42 miles)
Range: 124 miles (200 km; 108 nm)
Rate-of-Climb: 900 ft/min (274 m/min)
Operators: United Kingdom
The Thales "Watchkeeper" WK450 is the British Army derivative of the Israeli Elbit "Hermes" 450 Unmanned Aerial Vehicle (UAV) - or simply "drone" as it is referred to in mainstream media. The British military is currently working with Thales through the development of the Watchkeeper that is intended to serve in the intelligence gathering, surveillance and target acquisition role for near-future battlefield service. The program began in 2005 and has since seen a service entry delay of three years along with growing project expenses to the point that Watchkeeper has been under threat for cancelation or restructuring altogether. As it stands in October of 2013, the Watchkeeper is undergoing active training with British personnel in Wales and is awaiting full certification for use in manned airspace in southern England where it will be used in conjunction with artillery training (Boscombe Down). During its commitment in Afghanistan, the British Army has relied on the American General Atomics MQ-9 "Reaper" and Israeli "Hermes" UAVs though these have always been viewed as interim solutions not entirely tailored to British Army needs.

The Thales Watchkeeper makes use of a single Wankel rotary engine driving a propeller assembly at the rear of the fuselage. The fuselage is of a cigar shape with an aerodynamically-refined nose cone. Wings are straight appendages mounted at the shoulder while the tail unit sports a pair of outward-canted vertical fins negating the use of horizontal tail planes. The undercarriage consists of a three-legged arrangement with each leg managing a single wheel. The undercarriage is static and does not retract. An optics assembly is seated just aft of the nose leg with full 360-degree traversal. An air inlet is fitted at the extreme end of the fuselage underside to aspirate the Wankel engine installation. As the Watchkeeper is not (yet) cleared to carry external munitions of any kind, its payload of up to 150 kilograms is made up mainly of optics and special mission equipment for its intended battlefield roles. The onboard engine and fuel stores configuration supply the aircraft with a mission endurance window of some 17 hours before returning to base. Overall, the Watchkeeper system is intended for low-/medium-level flight and long acceptable loitering times to fulfill its mission scope.

Despite the project's 2005 origination, progress on the Watchkeeper product has been relatively slow to date. A procurement order for 54 systems was unveiled in 2007 though a first flight of a test vehicle was not recorded until April 2010, pushing back the formal expected delivery date of operational-level Watchkeepers considerably (the UAV was expected to officially enter service in September of 2010). As it now stands, the system will not be made operational until sometime in late 2013 or, more likely, 2014.

The Watchkeeper test vehicle has since accrued 1,000 flight hours on over 600 test flights.


None. Payload of optics and mission-minded sensors/tracking systems.

Variants / Models

• Watchkeeper WK450 - Base Series Designation
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