JPS6226960B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for restoring vertical maneuverability in an aircraft.

Figure 1 shows the pitching moment characteristics of an aircraft that has become highly unstable by applying the RSS (Relaxed Static Stability) mode.

Such aircraft have the advantages of reduced trimdrag, a smaller and lighter tail for static stability, and improved maneuvering response; There is a stable slope.

When the angle of attack is increased, the stable slope is such that as the wing stalls, the center of pressure on the wing recedes from about 1/4 of the average aerodynamic chord length, and becomes around 1/2 of the average aerodynamic chord length. This is due to movement.

In an RSS aircraft, static instability is stabilized by maneuvering using angle of attack feedback, etc., but as it approaches αcrit in Figure 1, it enters the daypart range where the head-up moment cannot be suppressed by steering. In other words, the state of Cm = 0 in Figure 1 is an essential condition for level flight, but as shown in Figure 1, when α > αcrit, even if pitch control is performed with the maximum head down, Cm
>0, and control becomes impossible. In addition, when the angle of attack increases and the pitching moment becomes zero again, the aircraft enters an equilibrium state, that is, a deep stall state, and it becomes impossible to recover to normal flight conditions, leading to an accident.

In principle, it is possible to avoid the occurrence of departure by increasing the rudder effect at maximum head down, but if the amount of instability is increased to increase the effect of RSS, this can be done by increasing the pitch control ability. If an attempt is made to cover this, the control surface and rudder angle will become extremely large, which will increase the weight of the control surface and steering actuator and increase the resistance of the control surface, leading to deterioration of aircraft performance and diminishing the effectiveness of RSS.

The present invention attempts to solve the above-mentioned problems, and is aimed at solving the above-mentioned problems.
An object of the present invention is to provide a device for restoring longitudinal control capability of an aircraft, which enables recovery from a deep stall by simple automatic control means.

For this reason, the device of the present invention is equipped with a detection mechanism that detects the angle of attack at which the angle of attack becomes too large and makes vertical control impossible, and converts the above angle of attack into a sideslip angle to improve the ability to perform vertical control. In order to recover this, the vehicle is characterized by a lateral steering control system that automatically performs lateral steering to maintain the bank angle at around 90 degrees based on the detection signal from the detection mechanism.

Hereinafter, an aircraft vertical maneuverability recovery device as an embodiment of the present invention will be explained with reference to the drawings.
FIG. 2 is a perspective view schematically showing an aircraft equipped with the device of the present invention, and FIG. 3 is a block diagram showing the device of the present invention and its operating system.

The aircraft shown in Figure 2 has the above-mentioned RSS characteristics (first
(see figure), and is equipped with a detection mechanism K (see figure 3) that detects the angle of attack _α0 , which causes the angle of attack to become too large and make vertical control impossible (deep chur, deep stall). ing.

This detection mechanism K is configured to compare the signal from the angle of attack meter with the reference signal corresponding to the angle of attack α ₀ , and output when the measured angle of attack becomes larger than the angle of attack α ₀ . has been done.

The lateral steering control system is automatically activated via an electromagnetic switch S that is closed when a signal is output from the detection mechanism K.

When the lateral control surface 1 is automatically steered by this lateral steering control system, a computer (or logic circuit) determines whether the output of the bank angle cm 2 exceeds the value corresponding to a bank angle of 90 degrees. As determined in step 3, if the bank angle becomes 90 degrees or more, the direction of side steering is reversed to maintain the bank angle near 90 degrees, thereby converting the aircraft's angle of attack into a sideslip angle.

As a result, the angle of attack becomes less than αcrit in Figure 1, and vertical maneuverability is restored.

Note that the sideslip angle generated by the above conversion from the angle of attack can be reduced by directional stabilization and/or directional control of the aircraft.

Generally, in an aircraft, the inertia factor around the longitudinal axis is smaller than the inertia factor around the left-right axis and the vertical axis, so even when the angle of attack is large,
Sideways maneuvers tend to rotate around the fore-and-aft axis rather than around the direction of flight.

In this way, when the aircraft rotates around the longitudinal axis, the angle of attack is converted to the sideslip angle at a bank angle of 90 degrees.

The above tendency is remarkable in supersonic aircraft, where the angle of attack is almost converted into a sideslip angle by sideways maneuvering.

For aircraft with significant RSS characteristics, αcrit in Figure 1 is not so large, so the effectiveness of side control near αcrit does not decrease significantly.

As described in detail above, according to the device for restoring longitudinal control capability of an aircraft according to the present invention, the detection mechanism detects the angle of attack at which the angle of attack becomes too large and a state in which longitudinal control becomes impossible (deep chare, deep stall) occurs. In order to convert the angle of attack into a sideslip angle and recover the vertical maneuverability, a lateral maneuver control system is provided that automatically performs lateral maneuver keeping the bank angle around 90 degrees based on the detection signal from the detection mechanism. With the simple configuration provided, the recovery of vertical maneuverability, which is an important issue in aircraft to which the RSS mode is applied, is carried out extremely efficiently and reliably, which can contribute to improving aircraft safety. It is.

[Brief explanation of the drawing]

Fig. 1 is a graph showing pitching moment characteristics of an aircraft to which RSS is applied, Fig. 2 is a perspective view schematically showing an aircraft equipped with the device of the present invention, and Fig. 3 is a graph showing the device of the present invention and its operation. FIG. 3 is a block diagram showing the system. 1... Lateral control surface, 2... Bank angle sensor, 3
...Computer (or logic circuit), K...
...detection mechanism, S...electromagnetic switch.

Claims (1)

[Claims] 1. An aircraft is equipped with a detection mechanism that detects the angle of attack at which the angle of attack becomes too large and becomes impossible to perform longitudinal control. A device for restoring vertical maneuverability of an aircraft, characterized in that it is equipped with a horizontal maneuvering control system that automatically performs horizontal maneuvering to maintain a bank angle near 90 degrees based on a detection signal from the mechanism.