Loiter (aeronautics)

In aeronautics and aviation, loiter is a phase of flight. The phase consists of cruising for a certain amount of time over a small region. The loiter phase occurs, for general aviation, generally at the end of the flight plan, normally when the plane is waiting for clearance to land.

In military flights, such as aerial reconnaissance or ground-attack aircraft, the loiter phase is time the aircraft has over a target. Cruise is the time period the aircraft travels to the target and returns after the loiter.

In astronautics, the loiter phase of spacecraft used for human spaceflight may be as long as six months, as is the case for Soyuz spacecraft which remain docked while expedition crewmembers reside aboard the International Space Station.

Endurance

The endurance of the aircraft during the loiter phase is calculated using the following (Breguet formula):

where:

is the endurance (dimensions of Time)

is the Specific Fuel Consumption (dimensions of 1/Time)

is the total lift force on the aircraft

Flight

Flight is the process by which an object moves, through an atmosphere (the air in the case of earth) or beyond it (as in the case of spaceflight) without direct support from any surface. This can be achieved by generating aerodynamic lift, propulsive thrust, aerostatically using buoyancy, or by ballistic movement.

Many things fly, from natural aviators such as birds, bats and insects to human inventions such as missiles, aircraft such as airplanes, helicopters and balloons, to rockets such as spacecraft.

The engineering aspects of flight are studied in aerospace engineering which is subdivided into aeronautics, the study of vehicles that travel through the air, and astronautics, the study of vehicles that travel through space, and in ballistics, the study of the flight of projectiles.

Types of flight

Buoyant flight

Humans have managed to construct lighter than air vehicles that raise off the ground and fly, due to their buoyancy in air.

An aerostat is a system that remains aloft primarily through the use of buoyancy to give an aircraft the same overall density as air. Aerostats include free balloons, airships, and moored balloons. An aerostat's main structural component is its envelope, a lightweight skin containing a lifting gas to provide buoyancy, to which other components are attached.