Download A Small Semi-Autonomous Rotary-Wing

5
had several innovative flight controls. The altitude was measured by an aneroid
barometer until the aircraft reached its desired altitude, at which point the altitude
was maintained with a gyroscope linked to the elevator. Another gyroscope was
used to maintain heading and an anemometer was used to determine distance. A
subtracting counter was used to determine the distance at which the Bug should
dive at its preset target, either by releasing its detachable wings or short-circuiting
the ignition [2, 4].
Lawrence Sperry was working on an Army contract to use Messenger biplanes
as aerial torpedoes when it was recognized that the unmanned aircraft were navigating as accurately as possible given the current technology. The difficulty in
compensating for unpredictable changes in wind conditions was limiting the accuracy of the aircraft navigation. This realization helped result in the first use of a
radio to control an aircraft in May of 1922. Heading corrections were sent by radio
to the Messenger from an escorting aircraft that flew within sight of the Messenger
during tests on targets 30, 60, and 90 miles away. Remote control was also used
by the Royal Aircraft Establishment in the United Kingdom to provide inputs to
aircraft using a pilot in the loop. Using this radio control, flight speeds of 100 mph
and a range of 65 miles were achieved in 1924 [2, 4].
1.1.3
Target Drones and World War II UAVs
The British extended their success in remote control to fly Fairey Queen Bee
biplanes, one of which is shown in figure 1.4, as radio-controlled target drones for
naval warships [2, 4, 6]. During one of the first demonstrations, the British Fleet
fired at a drone for two hours without damaging the Fairey Queen. A contract