Bore (aviation)

See also: Gimlet

The gimlet is the complex trajectory of a plane which even goes down while turning on him.

When this trajectory is desired, it is a figure of Aerobatics.
In popular speech one says that the plane descends " in sheet morte".

Aerodynamics

Technically, the gimlet is a maintained dissymmetrical Décrochage.
the plane goes down almost to the vertical,
it even turns on him (in autorotation), a turn taking from 2 to 5 seconds (for a light plane),
the Assiette is variable, of punt with pricked (from -10 to -70 degrees),
it also undergoes a side skid and oscillations in Roulis.

The gimlet subjects the pilot of rotations and important accelerations (confusion, tiredness).

Setting in gimlet

When the plane goes down under the speed which brings a minimal lift to him, it “  décroche  ”  : it pricks (rotation in Tangage) and is inserted (vertical adjustment) in a more or less controllable way.

So at this time there there is dissymmetry (attacks oblique), obtained by steering of the ordering of direction or involuntarily, the plane can leave in vrille : it turns in a way more or less ordered around its axis of Lacet (the vertical axis which passes by the center of gravity of the plane).

Influencing factors the gimlet

The characteristics supporting the release of the gimlet are numerous:
  • Effects of the masses:
back Centering,
Moment of inertia in lace (masses in ends of wing) which maintains rotation,
  • aerodynamic Effets:
back Forms of the fuselage influencing the air supply of the Empennage S with the great angles of plate and skid,
Dimension of the empennage,
Standard of empennage, in particular position of the Drift compared to the taken down wake of the horizontal stabilizer,
slipstream

Spin recovery

The exit of a gimlet is generally caused by the steering of the rudder in the direction opposed to rotation. It can be decorated according to the planes of an action to prick and an action on the throttle control. Each gimlet on the same plane is different and each plane has its particular characteristics, it is thus difficult to generalize. But the action on the swing bar is a constant.

Bore in stunt-flying

In stunt-flying, the gimlets are traditional figures. They can be at the beginning in flight belly or flight back. A gimlet batten comprises a number of revolutions which is a multiple of 90 degrees (example 1 turn 1/4). The departure of the gimlet must be a frank unhooking followed by a setting in gimlet by steering of the rudder. The spin recovery must be in vertical trajectory (what is not natural according to rotations).

Sources

In-flight tests, Pierre Bonneau and Christian Briand

Aerodynamic

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