Hawker Siddeley Harrier single lever added in the cockpit. For horizontal flight, the nozzles are directed rearwards by shifting the lever to the forward position; for short or vertical takeoffs and landings, the lever is pulled back to point the nozzles downwards. The Harrier has two control elements not found in conventional fixed-wing aircraft: the thrust vector and the reaction control system. The thrust vector refers to the slant of the four engine nozzles and can be set between 0° (horizontal, pointing directly backwards) and 98° (pointing down and slightly forwards). The 90° vector is normally deployed for VTOL manoeuvring. The reaction control
Hawker Hoopoe fitted during the short trial period, two variants of the Bristol Mercury were later replaced by an Armstrong Siddeley Jaguar and Panther with an increase in performance. Trials at Felixstowe in 1929 with floats fitted showed that the aircraft was severely underpowered with the Mercury powerplant, requiring the change to the Jaguar engine. Service interest in the type had waned by autumn 1930 although the single prototype continued in development flying with Armstrong Siddeley and the Royal Aircraft Establishment until 1932 when the Hoopoe was scrapped. Hawker Hoopoe The Hawker Hoopoe was a British prototype naval fighter aircraft designed and