The V-1 guidance system used a simple autopilot to regulate height and speed, developed by Askania in Berlin.[4] A weighted pendulum system provided fore-and-aft attitude measurement to control pitch, (damped by a gyrocompass, which it also stabilized). Operating power for the gyroscope platform and also the flight control actuators was provided by two large spherical compressed air tanks which also pressurized the fuel tank. These air tanks were charged to 150 atm (15,000 kPa) before launch.
There was a more sophisticated interaction between yaw, roll, and other sensors: a gyrocompass (set by swinging in a hangar before launch) gave feedback to control each of pitch and roll, but it was angled away from the horizontal so that controlling these degrees of freedominteracted: the gyroscope remained true on the basis of feedback received from a magnetic compass[citation needed], and from the fore and aft pendulum. This interaction meant that rudder control was sufficient for steering and no banking mechanism was needed. In a V-1 which landed in March 1945 without detonating between Tilburg and Goirle, The Netherlands, about 6 rolled issues of the German wartime propaganda magazine 'Signal' were found inserted into the left wing's tubular steel spar, used for weight to preset the missile's static equilibrium before launching. It is also known that several of the first buzz bombs to be launched were provided with a small radio transmitter (using a triode valvemarked 'S3' but being equivalent to a then-current power valve, type RL 2,4T1), to check the general direction of flight related to the launching place's and the target's grid coordinates by radio bearing.
An odometer driven by a vane anemometer on the nose determined when target area had been reached, accurately enough for area bombing. Before launch, the counter was set to a value that would reach zero upon arrival at the target in the prevailing wind conditions. As the missile flew, the airflow turned the propeller, and every 30 rotations of the propeller counted down one number on the counter. This counter triggered the arming of the warhead after about 60 km (37 mi).[8] When the count reached zero, two detonating bolts were fired. Two spoilers on theelevator were released, the linkage between the elevator and servo was jammed and a guillotine device cut off the control hoses to the rudder servo, setting the rudder in neutral. These actions put the V-1 into a steep dive.[9][10] While this was originally intended to be a power dive, in practice the dive caused the fuel flow to cease, which stopped the engine. The sudden silence after the buzzing alerted listeners of the impending impact. The fuel problem was quickly fixed, and when the last V-1s fell, the majority hit under power.
With the counter determining how far the missile would fly, it was only necessary to launch the V-1 with the ramp pointing in the approximate direction, and the autopilot controlled the flight.
