Airspeed indicator

Abstract: Problems involved in measuring speed and altitude with pressure-actuated instruments (altimeter, airspeed indicator, true-airspeed indicator, Machmeter, and vertical-speed indicator) are examined. Equations relating total pressure and static pressure to the five flight quantities are presented, and criteria for the design of total and static pressure tubes are given. Calibrations of typical static pressure installations (fuselage nose, wing tip, vertical fin, and fuselage vent) are presented, various methods for flight calibration of these installations are described, and the calibration of a particular installation by two of the methods is described in detail. Equations are given for estimating the effects of pressure lag and leaks. Test procedures for the laboratory calibration of the five instruments are described, and accuracies of mechanical and electrical instruments are presented. Operational use of the altimeter for terrain clearance and vertical separation of aircraft is discussed, along with flight technical errors and overall altitude errors of aircraft in cruise operations. Altitude-measuring techniques based on a variety of properties of the Earth and the atmosphere are included. Two appendixes present airspeed and altitude tables and sample calculations for determining the various flight parameters from measured total and static pressures.

Abstract: There is disclosed apparatus for instrument landing of aircraft presenting to the pilot, from glide path and range signals originating on the ground and from aircraft-originated signals on altitude, airspeed and aircraft attitude, a three-dimensional representation of a roadway in the sky down which the aircraft is to be navigated to a touchdown point on an airport runway, together with indications of the departure of the aircraft from proper position and altitude with reference to that roadway, and departures from desired airspeed along it.

Abstract: In a helicopter having an automatic pilot system for controlling the main rotor collective pitch, main rotor longitudinal and lateral cyclic pitch, and tail rotor collective pitch, in response to inputs provided from normal sensors, navigational instruments and controls, (which include among others as is known, doppler radar, a pilot panel, an air speed indicator, a radar altimeter, a barometric altimeter and a longitudinal accelerometer), commands to control automatic approach to a desired hover position are provided to the autopilot system in response to signals normally supplied by a TACNAV unit as well as the sensors, navigational units and controls; controls are provided for altitude and rate of descent, so as to terminate in hover at a desired altitude, as well as for turns, courses, and speed so as to approach the desired point of hover upwind and to decelerate in a controlled fashion to hover.

Abstract: A system for correcting errors in static pressure, airspeed or airspeed rate caused by maneuvering that causes variations in static air pressure measurements compares a barometrically derived vertical velocity or altitude signal with an inertially-derived vertical velocity or altitude signal to provide a correction signal that is representative of changes in static air pressure and is used to correct the static pressure, airspeed or airspeed rate signal.