DE2162349A1 - RULES TO AVOID THE BUILDING UP OF AIRCRAFT - Google Patents

Description

Regulation to avoid the raising of missiles.

The invention relates to a control system for avoiding rearing up of aerodynamic missiles, in particular of aircraft, in which a device is provided, which at a predetermined Combination of the angle of attack and the aerodynamic pitch angle speed the rearing process stops in such a way that corresponding counter-forces act on the control mechanism of the missile or the Plane to be raised. Certain types of aircraft tend to be ddzj, getting caught in a dogfight or attacking in Raising up close to the ground, i.e. assuming impermissibly high angles of attack, waj often has catastrophic consequences. This is especially true when üochleiütungsflugzeugen the case, their tailplane relative is still arranged.

Line relevant establishment of a regulator to avoid the rearrangement of aircraft is described and illustrated, for example, in US Pat. No. 3,015,450 '. This known scheme works as a function of both the Mach number and the permissible elevator angle. The latter means an indirect dependence on the steady-state permissible angle of attack.

Line more pertinent establishment is through the US patent 2 953 327 [, became known. This regulator prevents one Quasi-stationary stalling of the aircraft by limiting the Lao multiple. It becomes the permissible C. value or the permissible -value corresponding load factor by means of an analogue

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circuit calculated and with the respective value from an acceleration sensor compared. This arrangement is based on an indirect determination of the permissible angle of attack by measurement the dynamic pressure and calculation of the weight.

In addition to the state of the art shown, please refer to U.S. Patents 2,584,298, 2,923,499, 3,172,079, 3,292 and 3 518 621 ^, in which essentially only the required Negative pressure on the suction side of the wing profile or the permissible airspeed or the permissible angle of attack is used as a criterion for preventing and / or indicating the rearing up. These prior publications contain similar like the aforementioned - not that for high-performance aircraft required lead signal for the aerodynamic pitch angle speed.

Other known, relevant controllers stop the rearing up process when the control is too rapid, primarily as a function of the aerodynamic pitch angular velocity. However, this procedure has - like the practice of relevant high-performance aircraft has proven - the disadvantage that the maximum permissible value of the angle of attack is or can only rarely be exhausted.

In terms of flight technology, it can generally be stated that the critical angle of attack limit at which the tendency to rear up occurs, must not be exceeded. To ensure that the aircraft in question is intercepted before this state is reached, not least because of the given dynamic conditions, e.g. the inertia of the aircraft, a lead signal determine whether and, if so, how quickly the aircraft is approaching the dangerous state. It was therefore in given cases obvious and so far partly also common, the angle of attack and its change over time as response signals in the relevant Enter controller. In practice this is e.g. the signal of the moment via a so-called wind vane Angle of attack and the means of electrical networks on the Change in the angle of attack over time, transformed time function the pitch angle speed in the controller's computer as an output

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release signal entered. The latter means that the pitching speed signal picked up at the pitching gyro uses suitable filters is changed so that after the filtering there is a function of time that is approximately comparable to the change in the angle of attack over time. As is known, a signal proportional to the angle of attack is added to this and the sum obtained is compared with a reference value.

Auen these rearing controllers, which have been built so far, are in a certain sense Respect in a significant contradiction to their function, which they are actually supposed to exercise. You have the disadvantage that their primary dependence on the nod signal causes them to rearrange also often stop too early and therefore in many cases cause a floor overrun that should have been avoided can be.

The invention is thus based on the knowledge that rearing controller missiles or aircraft do not work optimally can if they are based exclusively on the angle of attack or exclusively on the hacking angle speed. Even when limits are set for both controlled variables, but these are not sensibly coordinated with one another, an optimal one can be used Regulation to prevent the rearing of missiles did not take place.

According to the invention is therefore to avoid the disadvantages shown suggested that the opposing forces for stopping or avoiding the Aufbäumvorgangs primarily at an optimally permissible Orientate the limit of the angle of attack, and that for the aerodynamic pitch angle speed and for the nieksignal as well an optimally permissible limit is provided, which corresponds to the optimally permissible limit for the angle of attack in such a way that that only those control processes are stopped prematurely, which would exceed the permissible angle of attack. The invention thus offers the main advantage that - especially in air combat - an optimal use of the flight performance of the relevant Aircraft is possible; by the fact that at

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.Medium and low rudder speeds of the controls still ■ does not come into action compared to comparable devices of the known state of the art. However, if the stick is moved too quickly by the pilot saved the aircraft from rearranging by making the response limits according to the invention more sensible »Veise through optimal, mutual coordination correct impermissible control process. Since an aircraft therefore does not rear up within the framework of the regulation according to the invention can, the pilot has the opportunity to safely fully exploit the maximum performance inherent in the aircraft.

The invention further SIENT before that the Ruderlaufgeschwindig- W automatically or manually ness of the respective missile towards optimal allowable 'values is adjustable. This measure increases the safety of an aircraft in ground combat in particular, since the rudder running speed can be optimally limited to the value that still results in flight reactions within the permissible limits for the pitch angle speed and the angle of attack, which ensures that all control processes are carried out that the controller does not have to take action. Every action of the controller and the associated correction of the control process means a loss of flight altitude. This, in turn, can have catastrophic consequences for man and machine, especially in the Jjrdkampf through contact with the ground. By the measure according to the invention. However, the aircraft in question can be intercepted optimally in relation to its flight performance.

Finally, it is provided within the scope of the invention that the response limits of the controller for both the angle of attack and the aerodynamic pitch angle speed individually can be varied in order to set the optimal, mutually corresponding conditions required for the respective mission to be able to.

The invention is illustrated graphically in the figures. Ls show:

Fig. 1 is a diagram with conventional, known limits for the

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Angle of attack and the aerodynamic pitch angular velocity;

FIG. 2 shows a diagram according to FIG. 1 with the limits according to the invention for the stated values;

Fig. 3 is a diagram corresponding to FIGS. 1 and 2 with particular. Limit setting.

In all diagrams, the angle of attack CX and is on the abscissa on the ordinate the aerodynamic pitch angular velocity AJy applied.

As can be seen from FIG. 1, the previous response limit for the controller represents a straight line 1 which is defined in the specified coordinate system by a specific value Wy ₀ and a specific value Oi - in this case 0 { perm . The response limit just allows, as shown, to set the angle of attack A to the value H dynamically (7? - ^) in the lower angle change range. As in FIG. 1, Iciiir, iyt the next step of changing the angle of attack from B to C can no longer be carried out, since the pitch angle speed limit is exceeded at U, although the limit (X perm. Of the optimally permissible angle of attack by far This means that in this known regulating device the regulator takes action too early.

In order to avoid this disadvantage, according to the invention, according to FIG. 2, it is proposed that the permissible pitch angle speed limit 2 be coordinated with the limit for (X perm.) In such a way that the automatic rearing control only starts when there is a risk that both limits will be exceeded in the event of an excessive change in the angle of attack will.

The boundary line according to the invention, which when exceeded the controller goes into action to avoid the rearrangement process, is thus made up of straight line 2 and a further straight line 3, which intersect at point Iu , as shown in FIG. The straight line 2 is the limit line of the pitch angle speed, the straight line 3 the limit

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line of the optimal angle of attack CK. . These two boundary lines do not necessarily have to be straight. From the changes in the angles of attack from A to B, B to C and in particular from C to C ₁ , it can be clearly seen that the change curve 4 at most conforms to the two boundary lines 2 and 3. This means that the aircraft in question can optimally settle to the new angle of attack C.

The dashed line 5 in Fig. 2 indicates that the response limit 2 of the aerodynamic pitch angle speed within the scope of the invention, depending on the mission of the aircraft in question is adjustable in the controller.

The Fig. 3 finally shows a practical application of the protection sought far ACCORDING £ · Claim 2, according to which the Ruderlaufge-

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speed T) is limited to the optimum permissible values for uoj / and © C is. In this case, in the case of special tax transactions, Avoid any action by the controller, especially in combat.

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Claims (3)

MESSERSCHHITf-BÖLKOW-BLOHM - 7 - Ottobrunn, December 14, 1971 Society Frc / Schö with limited liability
Munich Claims A regulator to avoid the rearing up of aerodynamic missiles, in particular aircraft _} in which a device is provided which stops the rearing process at a predetermined combination of the angle of attack and the aerodynamic pitch angle speed, in such a way that corresponding counterforces on the control mechanism of the missile or of the aircraft are triggered, thereby g β characterizes that the opposing forces are primarily based on an optimally permissible limit of the angle of attack ((X), and that an optimally permissible limit is also provided for the aerodynamic pitch angular velocity (ä) y), which is with corresponds to the optimally permissible limit (^ perm.) for the angle of attack (Oi) in such a way that all control processes are stopped prematurely which would exceed ^ perm. 2. Regulator according to claim 1 to avoid the Aubäumens of aerodynamic missiles, characterized by net that the rudder speed (^) is automatic or can be set manually to optimally permissible values. 3. Regulator according to claims 1 and / or 2, thereby g e - nc indicates that the response limits (C /. << J J ) ·. for the controller can be varied to match those for the respective Mission necessary optimal, mutually corresponding relationships to be able to set or choose. 3G9826 / 0Q4S Blank page