JPS6212080B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides an RSS equipped with a canard (canard).
Regarding aircraft in Relaxed Static Stability Mode.

The pitching moment characteristics of an aircraft to which a large RSS mode is applied are as shown in Figure 1.

The unstable slope of the pitching moment near the angle of attack of 0 in Figure 1 is a characteristic of the RSS mode itself, and the stable slope when the angle of attack is increased is due to the stalling of the blade surface. The center of pressure on the surface is set back from about 1/4 of the average aerodynamic chord length, and about 1/2
This is due to a shift to near the average aerodynamic chord length.

In aircraft to which RSS mode is applied, static instability is stabilized by automatically controlling pitch control using Fly-By-Wire, etc. in response to changes in angle of attack, etc. , when αcrit in Figure 1 is exceeded, the head-up moment cannot be suppressed by pitch control, and the angle of attack increases, resulting in departure, and at the point where the pitching moment becomes zero again, an equilibrium state, that is, a deep stall state is reached. This would make it impossible to restore normal flight conditions and lead to an accident.

In principle, the occurrence of departure can be avoided by increasing the rudder effect at maximum head-down, but
If the amount of instability is increased to increase the effectiveness of RSS mode, the canard that attempts to avoid deep stall by normal means becomes very large, or a horizontal stabilizer is installed at the rear of the fuselage to compensate for vertical control. etc., resulting in deterioration of aircraft performance due to increased weight and resistance of the canards, and RSS
This will reduce the mode's effectiveness.

In view of the above-mentioned points, it is an object of the present invention to solve the deep stall problem of a canard-equipped aircraft that is highly unstable in order to fully utilize the functions of the RSS mode.

Therefore, the canard-equipped aircraft of the present invention does not include a horizontal stabilizer in the fuselage part behind the main wings, but can steer the canards in an RSS mode aircraft in which the canards are provided in the fuselage part forward of the main wings. a canard steering mechanism, an angle of attack measuring means for measuring an angle of attack of the canard, a first switching to release the canard from the canard steering mechanism to bring it into a free-floating state, and a return to the steering state by the canard steering mechanism. a canard switching mechanism capable of performing the second switching, and inputs a measurement signal from the angle of attack measuring means to the canard switching mechanism, and when the absolute value of the angle of attack exceeds a predetermined value, the first The present invention is characterized in that a control means is provided for automatically performing the second switching when the absolute value of the angle of attack is smaller than a predetermined value.

In the above-mentioned aircraft with canards of the present invention, the canards have a free float function, and below the medium angle of attack, the canards can be used as fly-by-wire (Fly-By-Wire).
-Wire), and by setting the canard in a free-float state at large angles of attack, the problems of aircraft departure and deep stall, which were highly unstable in RSS mode, are solved, and the horizontal stabilizer is unnecessary. By eliminating the weight and drag of the horizontal stabilizer, the aircraft's performance can be greatly improved.

Below, a canard-equipped aircraft as an embodiment of the present invention will be explained with reference to the drawings. Fig. 2 is a plan view thereof, Fig. 3 is a side view thereof, Fig. 4 is a characteristic diagram thereof, and Fig. 5 is a diagram of the canard. It is a characteristic diagram.

As shown in Figures 2 and 3, canards 1 are mounted symmetrically via a rotating shaft 4 in the front part of the fuselage 3, ahead of the main wings 2, and the canards 1 are controlled by canard steering. This is done by mechanism 5.

A canard switching mechanism 6 such as an electromagnetic clutch is provided, which can release the canard from the canard steering mechanism 5 and switch it to a free-floating state when the angle of attack of the canard 1 exceeds a predetermined angle (medium angle of attack). .

In addition, the code 7 in Figures 2 and 3 indicates the vertical stabilizer (rudder), P ₁ is the aerodynamic center of the canard 1, the main wing 2 and the fuselage 3, P ₂ is the aerodynamic center of the main wing 2 and the fuselage 3, and CG is the center of gravity position, Lc is the canard lift force, L
_WB indicates the lift force of the main wing 2 and the fuselage 3, and L indicates the lift force of the canard 1, the main wing 2 and the fuselage 3.

This aircraft is equipped with canard 1 as described above, and the RSS mode (see Figure 4) is applied, the CG is placed behind P ₁ and forward of P ₂ , and canard 1 The rotation axis 4 of
It is placed in front of the Lc's point of impact.

Next, referring to FIGS. 3 and 4, the effects of the above-mentioned aircraft of the present invention will be explained. In this aircraft, when the absolute value of the angle of attack is smaller than αcrit, the canard 1 is steered and the aircraft is control.

When the absolute value of the angle of attack exceeds αcrit, the canard switching mechanism 6 switches the canard 1 to the free float state to generate a head-down moment, decrease the absolute value of the angle of attack, and bring it into the controllable region. You can return it and control the aircraft with the canards again.

Note that no matter what kind of movement you perform, the angle of attack is α
It is extremely difficult to take measures to limit the angle of attack so that it does not exceed crit, so if the angle of attack increases for some reason,
The ability to recover safely is important.

The symbol δcmax in FIG. 5 indicates the maximum value of the canard steering angle that can be controlled.

Since the canard 1 is controlled in the normal operating angle of attack range, and recovery from departure and deep stall areas is performed by the canard's free float, the range of the canard's steering angle that should be controllable can be reduced.

If departure is to be avoided without free float, the controllable range of canard 1 must be within the range of ±70° to ±90°, which is extremely difficult to achieve.

Note that as the absolute value of the aircraft angle of attack decreases, the canard rudder angle becomes smaller due to the moment of aerodynamic force acting on the canard 1, so the controllable rudder angle range can be made smaller.

In other words, the control surface is used for steering up to medium rudder angles, and at large rudder angles, the control surface is determined by the aerodynamic force of the horizontal canard.

When the angle of attack is α, when |α|>αcrit, switch canard 1 to the free float state,
Switching from the free float state to _the steering state must be performed when |α| Control means are provided for inputting into the mechanism 6 and automatically performing the above switching. Note that a means for performing the above switching by pilot operation may be provided.

The canard steering mechanism 5 for steering the canard 1 may be a hydraulic actuator or an electric actuator, or any other appropriate actuator may be used, and the canard switching mechanism 6 may be used to switch the canard 1 to a free-floating state. Regarding,
An oil line diverter valve, electromagnetic clutch, or other suitable means may be used.

As detailed above, according to the canard-equipped aircraft of the present invention, there is provided a canard steering mechanism capable of steering the canard, an angle of attack measuring means for measuring the angle of attack of the canard, and a release of the canard from the canard steering mechanism. a canard switching mechanism capable of performing a first switching to a free-floating state and a second switching to return the canard steering mechanism to a steering state; When the absolute value of the angle of attack exceeds a predetermined value inputted to the canard switching mechanism, the first switching is automatically performed, and the second switching is performed when the absolute value of the angle of attack is smaller than the predetermined value. Since a control means is provided to automatically perform RSS
The problems of departure and deep stall in the mode aircraft are appropriately solved, and by omitting the horizontal stabilizer, its weight and resistance can be eliminated, contributing to a significant improvement in performance.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram of an aircraft to which the RSS mode is applied, Figs. 2 to 5 show an aircraft with a canard as an embodiment of the present invention, Fig. 2 is a plan view thereof, and Fig. 3 is a Its side view, FIG. 4 is its characteristic diagram, and FIG. 5 is its canard characteristic diagram. 1... Canard, 2... Main wing, 3... Fuselage, 4
...Rotation axis, 5...Canard steering mechanism, 6...Canard switching mechanism, 7...Vertical stabilizer.

Claims (1)

[Claims] 1. In an RSS mode aircraft that does not have a horizontal stabilizer in the fuselage part behind the main wings but has canards in the fuselage part forward of the main wings, there is a canard steering mechanism that can steer the canards, and a canard steering mechanism that can steer the canards. an angle of attack measuring means for measuring an angle; and a canard capable of performing a first switching to release the canard from the canard steering mechanism to put it in a free-floating state, and a second switching to return the canard to a steered state by the canard steering mechanism. A switching mechanism is provided, and a measurement signal from the angle of attack measuring means is input to the canard switching mechanism to automatically perform the first switching when the absolute value of the angle of attack exceeds a predetermined value. An aircraft with a canard, characterized in that a control means is provided for automatically performing the second switching when the absolute value of the angle is smaller than a predetermined value.