DE1111515B - Safety device in aircraft for monitoring the take-off start - Google Patents

Description

Safety device in aircraft The invention relates to a Safety device for monitoring take-off in aircraft for monitoring of the start-up, which indicates after the start of acceleration whether the Aircraft sufficient lift within the distance available for take-off and can stand out from the ground.

For runways of unlimited length, you needed a take-off run-up The aircraft does not have to monitor the runway lengths of the existing airfields but just enough for many of the newer, fast types of aircraft, so that safety precautions must be taken in order to get the start-up on the to monitor the specified route.

The operational characteristics of every aircraft are well known in order to be able to assess before the start of the start-up whether one would be a successful one Sufficient runway length is available at the start. Circumstances arise, however which eliminates one or more of the factors on which the estimate is based on deviate from the assumed values, so that there is a risk of accident.

Sometimes in such a case the pilot may be unable to take off recognize the aircraft in good time before reaching the critical point stop within the remaining length of the runway; on the other hand an accident would be inevitable.

The aim of the invention is to avoid these inconveniences. To this The purpose is a safety device for monitoring the take-off of aircraft proposed, which according to the invention is characterized in that a computing device is provided, which monitors the take-off and checks whether the aircraft has met predetermined start conditions since the start of the start-up, the computing device continuously displays the start-up process on a display device.

For the sake of simplicity, the term »start-up« is used in the following. used regardless of whether the aircraft eventually comes off the ground or not.

The monitoring is based on those physical quantities that can be obtained by time integration of the measured aircraft acceleration. as The starting condition is based on the predetermined average acceleration placed, wherein the computing device makes out whether the aircraft the predetermined Normal average acceleration over the one rolled over since the device was switched on Has maintained distance. The device expediently takes the first time integral the aircraft acceleration to determine the instantaneous speed of the aircraft and the second time integral of the acceleration to determine the time taken by the aircraft distance traveled calculated. These instantaneous sizes should go along with corresponding fixed values, the take-off speed and the specified take-off distance represent; indicate whether the relationship between these quantities is a success or a failure of the start can be expected.

The device is therefore designed so that the computing device continuously determines whether the value of the expression di falls below a predetermined value, vi being the instantaneous speed of the aircraft after traveling a distance di from the runway. The predetermined value is represented by the form dr , where v is the safe take-off speed of the aircraft and dr is a predetermined runway distance. The computing device has adjustable organs, whereby the signals corresponding to the vr and d, values are set.

To get a measure of the airspeed over the ground, introduced a correction signal that takes the wind speed into account.

In the drawing are some exemplary embodiments of the safety device shown; 1 to 3 show graphical representations for explanatory purposes the relationship between take-off speed and distance, Fig. 4 shows a schematic representation of a safety device for monitoring the start-up of an aircraft, FIGS. 5 to 7 in a schematic representation modified embodiments the safety device according to FIG. 4.

Assuming constant acceleration during take-off, the square of the aircraft speed increases linearly with the runway length traversed from zero. A graphical representation of the relationship between speed and distance, as it is necessary for such an aircraft to reach its take-off speed v, at a predetermined distance d, - is formed (Fig. 1) by the hypotenuse of a right triangle whose base (abscissa ) and height (ordinate) are proportional to d and 1r2, respectively. This triangle serves as a reference figure when comparing the similarity with other triangles, which are correspondingly given by the instantaneous values of the actual speed square vi2 and the actually covered distance di. A triangle given in this way is placed on the reference triangle (Fig. 1) and in this case is similar to it, so that the following relationship exists: Relationship (1) means that the aircraft will reach its take-off speed just after the predetermined distance available to the aircraft for take-off.

In FIG. 2, the triangle defined by the instantaneous values is dissimilar to the reference triangle and results in the following relationship It can therefore be predicted from relation (2) that the aircraft will reach its take-off speed before it has passed the predetermined take-off length. Therefore, if one of the relationships (1) or (2) exists during take-off, the pilot is insured for a successful take-off.

However, if the triangles are dissimilar (Fig. 3), that is, it can be concluded from this that the aircraft will only reach the take-off speed after the predetermined distance provided for take-off has been exceeded.

The various embodiments of the safety devices relate to devices that indicate which of the relationships (1), (2), (3) exists during the take-off start of an aircraft. In the embodiment shown in FIG. 4, this is achieved, for example, by combining the product vi 'dr with the product v,? di compares and shows the result of the comparison on a suitable display device. If v :? d, _> v ,? di holds, then there is obviously one of the favorable relations (1); (2). On the other hand, if vi2 d, < v, 2 di, then the unfavorable relationship (3) exists.

Referring to Fig. 4, there is shown a signal generating linear accelerometer 6 which is mounted in an aircraft so that it is responsive to the forward acceleration of the aircraft and provides an electrical output signal proportional to the acceleration. The acceleration signal is given over the line 7 to the amplifier 8, which forms part of an electromechanical integrator 9, which in turn rotates a shaft proportional to the aircraft speed. This rotation is brought about by the movement of the output shaft 10 of a motor 11, which is excited by the amplifier 8 and drives a tachometer-like generator 12. The output signal of the generator 12 is fed with negative feedback to the amplifier 8, so that the shaft 10 is driven at a speed which is proportional to the acceleration signal of the accelerometer 6. The aircraft speed vi is therefore represented proportionally by the angular rotation of the shaft 10 from its position assumed at the beginning of the acceleration at every instant during the take-off acceleration.

The shaft 10 is in drive connection via an electromagnetically controlled coupling 13 with the grinding arm of a potentiometer-like signal generator 14, in which the mechanical signal of the shaft, which is proportional to vi, is converted into a likewise proportional electrical signal. The winding of the generator 14 is fed from the terminals 15 of an alternating current source; the output signal vi of the generator 14 occurs between lines 24, 25 which are connected to the wiper arm of the generator or to one side of its winding.

The sliding arm of the generator 14 is mechanically connected to a spring 18 which, when the clutch 13 is disengaged, moves the arm into a setting position of the generator 14 with an output signal of zero. A control winding 19 for the clutch is connected to the terminals 23 of an alternating current source via the lines 20, 21 and a switch 22. The switch 22 is placed in its closed or take-off position by the pilot before the start of take-off, whereby the control winding 19 is excited and the clutch 13 is engaged. To disengage the clutch for setting the generator 14, the switch 22 is placed in its open or set position.

The lines 24; 25 are connected to the input of an amplifier 26 which forms part of an electromechanical integrator 27. The integrator 27 rotates a shaft proportionally to the time integral of vi, ie proportionally to the distance di which was covered by the aircraft to reach the speed and which is represented at each instant by the vi signal from the generator 14 . The integrator 27 can be constructed in the same way as the integrator 9 and has a motor 28 which is excited by the amplifier 26 and has an output shaft 29 which drives a tachometer-like generator 30 for feedback purposes.

The shaft 29 is in drive connection via an electromagnetically controlled coupling 31 with the wiper arm of a potentiometer signal generator 32, which converts the di proportional mechanical signal of the shaft into a proportional electrical signal. The generator 32 similar to the generator 14 is also fed from an alternating current source; its grinding arm is pulled to a zero exit position by a biasing spring. The clutch 31 corresponds to the clutch 13, and the control winding 33 is therefore in parallel with the control winding 19; such that both generators 14, 32 are simultaneously brought into their zero position when the switch 22 is in the set position, and that both are driven by their respective drive shafts when the switch 22 is in the start position.

The DI output signal of the generator 32 is via lines 34, 35 on the square winding of a potentiometer-like analog multiplier 36 by it with the square of the known take-off speed vr of the aircraft in question is multiplied. A button 37 for setting a speed in one calibrated scale is connected to the grinding arm of the multiplier 36 such that the pilot chooses to move the grinding arm from its position for zero output by one vr can adjust the corresponding amount. This arrangement gives between the output lines 38, 39 of the multiplier 36 a proportional to the product v, 1 di Signal.

The lines 38; 39 are connected to a pair of input terminals of a display device 40 connected, which has a further pair of input terminals to which the output lines 41, 42 of a potentiometer-like analog multiplier 43 with a linear winding lie. The winding of the multiplier 43 is based on the current aircraft speed vil energized by means of lines 16, 17, which are the output lines of a potentiometer-like Function generator 4 form. The grinding arm of the generator 4 is mechanically with connected to the wiper arm of the generator 14 and similarly by a spring biased. The winding of the generator 4 is fed from the terminals 15 and is wound according to such a function that on the output lines 16, 17 a the square of the grinding position, d. H. the square of the current aircraft speed vil proportional signal arises.

A button 44 for reading on a distance-calibrated scale is connected to the grinding arm of the multiplier 43 so that the pilot can adjust the arm from the position with zero exit by an amount corresponding to the predetermined available safe take-off length dr. A signal proportional to the product vi2 d is thus obtained at the output lines 41, 42 of the multiplier 43.

The display device 40 is preferably a voltmeter with a zero display, the pointer of which points to a zero mark arranged in the center of the scale, as long as the mentioned input signals given to the instrument are of the same size. The input signals are dimensioned in such a way that they actually match in size if the products they represent are of the same size. The display device 40 thus allows the product vif d, v with the product, di compare 1 and display the result of the comparison by the pointer position. That half of the scale next to the zero mark which the needle shows when vr2 di > v12 dr, for example, can be colored red to indicate that the aircraft will not take off within the distance d i.

Since vi is a base speed, button 37 is preferably given a setting that corresponds to the vr as the base speed. Is z. B. the known take-off speed is 240 km / h with a headwind component 30 km / h, a basic speed of 210 km / h is required to take off the aircraft, to which the button 37 is preferably set. If one neglects the headwind component, this only introduces an additional safety factor; i.e., the device will require a higher instantaneous velocity vi for the distance di than is actually required for a safe start.

In the embodiment shown in FIG. 5, the pilot sets the button 37 to the known air speed and at the same time another button 60, depending on the prevailing conditions, corresponding to the headwind or tailwind speed. One input of a mechanical differential 61 is not reversibly connected to button 37, and its other input is not reversibly connected to button 60. The output side of the differential 61 is connected to the wiper arm of the analog multiplier 36. The knob 60 is set on a scale calibrated in wind speeds, with a setting of the knob 60 in the center of the scale corresponding to zero wind speed. When there is a headwind, one half of the scale is set to subtract the wind speed from the air speed. Correspondingly, when there is a tailwind, the other side of the scale is set; whereby the tailwind speed is added to the air speed. With this arrangement, the grinding arm of the multiplier 36 is set according to the starting speed calculated as the base speed, the conversion from the starting speed specified as the air speed being carried out mechanically by the differential 61 .

The display device 40 delivers immediately after the start of the runway run an indication of the likelihood of whether the startup will succeed or fail will. Used at the beginning of the runway run, for example when a quarter of the predetermined Distance d, passed through, a false start as likely predicted so the pilot may still wish to continue taking off in the hope that promised a successful start before reaching the critical point will. To ensure that the pilot does not spend too long on a favorable display waiting, an alarm device is provided which comes into action when briefly a failure of the start is predicted before reaching the critical point.

The electrically operated alarm system 45 (Fig. 4) is in series with a battery 46 and a pair of switches 47, 48, the alarm switch 47 short-circuits itself in time to catch the pilot before reaching the turning point give the opportunity to bring the aircraft to a stop before the end of the runway. For this purpose, the switch 47 has a motion meter with a pointer 49; the which forms one contact of this switch and according to the instantaneous value of the traveled Distance di is adjusted; for this purpose, the motion meter is controlled by a potentiometer Signal generator 50 energized, the grinding arm of which with the grinding arm of the di-signal generator 32 connect and how this is biased by a spring. The other contact 51 of the Sehalters 47 is along the path of the pointer 49 by a drive 52 from Knob 44 adjustable. The drive 52 brings the contact 51 into such a position, that the pointer 49 touches the contact 51 shortly before reaching the reversal point.

The alarm switch 48 is designed so that it is only during the Time for which the display device closes 40 a failure of the start. The switch 48 has for this purpose a fixed contact segment 53, which cooperates with a movable grinding arm 54. A connection 55 between the pointer of the display device 40 and the grinding arm 54 causes this only then touches segment 53 and thus closes switch 48 if a failure occurs the start is predicted. Therefore, the switch 48 closes after the aircraft has covered a sufficient distance so that switch 47 also closes, so the alarm circuit is closed, and the pilot receives a final additional Warning to bring his plane to a halt.

The embodiment shown in FIG. 6 indicates which of the relationships (1), (2) exists during the start-up when the quotient compared with the quotient and the result of the comparison on a Display device similar to device 40 (Fig. 4) is displayed. if then there is obviously one of the favorable relationships (1), (2). If on the other hand so there is the unfavorable relationship (3).

The output of the accelerometer 6 is obtained by the integrator 9 again integrated according to the time and a mechanical signal in the form of a shaft rotation generated, which is proportional to the instantaneous speed vi. The mechanical signal is in turn by a potentiometer-like generator 14 in a vi proportional converted into an electrical signal that occurs on lines 24, 25. The vi2 signal is here, however, by a potentiometer-like multiplier 60 with a grinding arm and a linear winding generated according to the current aircraft speed v1 are driven or excited. For this purpose, the winding of the multiplier 60 is with connected to the output of the generator 14 via lines 61, 62. The grinding arm of the Multiplier 60 is connected to the mechanical output of integrator 9. A potentiometer type analog divider 56 with a through the vr button 37 driven grinding arm receives the vi2 output signal of the multiplier 60. The winding of the dividing device 56 is wound according to such a function, so that the output of this device is proportional.

The vi proportional electric The signal on the lines 24, 25 is integrated by the further integrator 27, which forms a mechanical signal in the form of a shaft rotation which is proportional to the instantaneous value of the distance di. This mechanical signal is converted by the potentiometer-like signal generator 32 into a di-proportional electrical signal between the lines 34, 35. The lines 34, 35 here, however, pass the di signal as a dividend into a potentiometer-like analog dividing device 57, while the button 44 inputs the d, signal as a divisor into the dividing device 57, so that the output signal of the dividing device 57 becomes proportional. The output variables of the dividing devices 56 and 57 then reach the display device 40 for comparison. It is readily apparent that, instead of the special products or quotients described in connection with FIGS other sizes can be compared. For example, the dividing device 57 (FIG. 6) can be used to divide the V12 output signal of the multiplier 60 by the di output signal of the integrator 27, while in another dividing device a v, 1, signal (which is generated by a function generator after Type of generator 4 of Fig. 4 can be formed) is divided by the output of the button 44, so that the quotient can be compared with the quotient. Finally you can the desired indications regarding the success or failure of the start-up can also be obtained by comparing in the comparison device one variable only with a second, which is multiplied by a third and divided by a fourth, for example vi2 with In the description of the various embodiments so far, it has been assumed that the acceleration of the aircraft remains essentially constant during take-off. This assumption holds true for many aircraft, particularly jet aircraft that require long take-offs. In the case of other aircraft, in particular those with piston engines, however, the acceleration-distance characteristic at take-off can be non-linear. FIG. 7 shows the device shown in FIG. 4 with modifications for monitoring the take-off start for aircraft with a non-linear acceleration-distance characteristic.

The winding of the analog multiplier 43 (Fig. 7) is controlled by the output signal energized a non-linear potentiometer signal generator 58, which in place of the Generator 4 (Fig. 4) occurs. The non-linear generator 48, whose grinding arm by the integrator 9 is driven is suitable for the aircraft in question designed so that its output signal increases linearly with distance or, in other words, that the square root of its output is linear with the Time increases although the integrator wave is due to the variable acceleration signal from the accelerometer 6 is not rotating at a constant speed. Of the remaining part of the arrangement shown in Fig. 7, in which the size v, 2 di formed and given to the display device 40 agrees with the corresponding parts the arrangement shown in FIG.

In Figures 5 and 7 are the alarm device and potentiometer feedback arrangement 4 has been omitted for the sake of clarity; Of course can use these devices in the arrangements shown in FIGS. 6 and 7 without further in the manner shown in Fig. 4 can be provided.

Claims (13)

PATENT CLAIMS 1. Safety device for monitoring the start-up of aircraft, characterized in that a computing device (4, 6, 9, 14, 43, 44, 27, 32) is provided, which monitors and controls the start-up, whether the plane predetermined start conditions since the start of the start-up met, wherein the computing device continuously the start process on a display device represents. 2. Apparatus according to claim 1, characterized in that the start condition is a predetermined average acceleration and that the computing means determines whether the aircraft is at the predetermined normal average acceleration Maintained over the distance rolled over since the device 1 was switched on Has. 3. Apparatus according to claims 1 and 2, characterized in that the computing device continuously determines whether the value of the expression falls below a predetermined value, vi being the instantaneous speed of the aircraft after traveling a distance di from the runway. 4. Device according to claim 3, characterized in that the predetermined value is determined by the speed of the aircraft and d, a pre- is shown, where v, the safety start-determined runway distance, and that the computing device has adjustable members (37 and 44) , whereby the signals corresponding to the v, - and d, -values are set. 5. Device after Claim 4, characterized by a signal as a measure for the airspeed, ; which is corrected by a signal corresponding to the wind speed to to get a measure of the airspeed over the ground. 6. Device according to claim 4 or 5, characterized in that the computing device is an accelerometer (6), which is the instantaneous forward acceleration of the aircraft corresponding signal generated that this signal is a first integrator (9) as Input is supplied, which is used as an output of the instantaneous speed vi des The corresponding output signal produced by the aircraft is the output signal of the integrator a second integrator (27) is supplied, the output signal of which is a measure for represents the distance di over which the aircraft rolled on the runway, that a device is provided that the signal corresponding to the vi value in converts a signal corresponding to the value vi2, and that a device is provided which converts the signal corresponding to the v, value into a signal corresponding to the value v, 2 Signal transformed. 7. Apparatus according to claim 4, characterized in that a device (43, 4) is provided which converts the signals corresponding to the values of vi and d, into a signal corresponding to the product vi2 d, that a device (36) is provided which converts the signals corresponding to the values of v, and di into a signal corresponding to the value of the product v, 2 di, and that a comparison indicator (40) is provided to which the signals corresponding to the values of vi2 dr and vr2 di as Input and which indicates which of the two signals is greater. B. Apparatus according to Claim 4, characterized in that a device (60 and 56) is provided which converts the values of vi and v. corresponding signals are converted into a signal which corresponds to the value that a device (57) is provided which converts the signals corresponding to the values of di and dr into a signal corresponding to the value corresponds, and that a comparison indicator (40) is provided to which the signals corresponding to the two values as an input and which shows which of the two values is greater. 9. Device according to claims 4 to 7, in particular for an aircraft with non-linear acceleration, characterized in that the signal corresponding to the value vi2 is from a non-linear Signal generator (58) is supplied, which is driven by the output of the first integrator and generates an output signal that is related to the input signal, which corresponds to the non-linear acceleration characteristic of the aircraft. 10. Device according to Claims 1 to 9, characterized by an alarm device (45 to 54) for false starts shortly before reaching a predetermined distance from the runway. comes into action when is less than. 11. Device according to claim 10, characterized in that the alarm device for false starts has two switches (53, 54 or 49, 51) in series, of which the first (53, 54) is open at the beginning of the start-up and closes as soon as the distance covered di is just slightly smaller than the predetermined distance, while the switch (49, 51) only closes when is smaller than 12. Apparatus according to claim 11, characterized in that the switch (51, 49) has a setting scale with an adjustable fixed contact (51) and a pointer (49) which forms the movable contact and adjusts itself according to the value of di. 13th Device according to Claim 12, characterized in that the movable contact (49) is set by the output shaft of the electromechanical integrator (27).