A variometer (from Latin vario - change + other Greek. Μέτρον - measure) in aviation - an aerobatic device that shows the rate of change in flight altitude of an aircraft [1] .
Principle of Operation
The variometer measures the difference in air pressure in the atmosphere and inside the device’s body, which communicates with the atmosphere by a capillary . This pressure difference occurs when the altitude changes and disappears when the aircraft flies at a constant height. Designed to measure and display the vertical airspeed of the aircraft when reducing or climbing. The principle of operation is based on measuring the rate of change of static pressure with a change in flight altitude. The structure of the design includes a block gauge box, arrow, capillary, pipeline, scale.
A gauge box is used as a sensitive element. The internal cavity of the sealed instrument housing communicates directly with the static pressure line through the capillary. Capillary - a glass tube with a small section opening. If the plane flies horizontally, then the static atmospheric pressure inside the pressure gauge box and the pressure inside the body will be the same and the arrow of the device shows zero vertical speed. When the altitude changes, the static pressure changes. Inside the gauge box, this pressure is set almost instantly, and in the case of the device, due to capillary resistance, the pressure changes more slowly than inside the gauge box. The greater the vertical flight speed, the greater the pressure difference. Under pressure differential pressure gauge box is deformed. Deformation of the box through the transmission mechanism is transmitted to the arrow, which deviates from the middle position upward when climbing, downward when lowering.
See also
- Air pressure receiver
Notes
- ↑ Variometer (in aviation) // Great Soviet Encyclopedia : [in 30 vol.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.