EP0543170B1 - High speed aerial tow target, made of textile material, with reduced towing drag - Google Patents
High speed aerial tow target, made of textile material, with reduced towing drag Download PDFInfo
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- EP0543170B1 EP0543170B1 EP92118104A EP92118104A EP0543170B1 EP 0543170 B1 EP0543170 B1 EP 0543170B1 EP 92118104 A EP92118104 A EP 92118104A EP 92118104 A EP92118104 A EP 92118104A EP 0543170 B1 EP0543170 B1 EP 0543170B1
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- Prior art keywords
- air
- high speed
- bag
- tow target
- drag
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F41—WEAPONS
- F41J—TARGETS; TARGET RANGES; BULLET CATCHERS
- F41J9/00—Moving targets, i.e. moving when fired at
- F41J9/08—Airborne targets, e.g. drones, kites, balloons
- F41J9/10—Airborne targets, e.g. drones, kites, balloons towed
Definitions
- the invention relates to a high-speed air drag bag made of textile material with reduced aerodynamic drag, according to the preamble of claim 1.
- Such air drag sacks which usually consist of natural or art textile material, serve as air drag targets dragged by an aircraft, which are used for practice shooting at flying targets, whereby a hit position sensor system built into the drag target detects the passage location of projectiles flying past and displays them as a hit display on the ground brings.
- so-called soft tow targets made of textile materials so-called hard tow targets are also used. The latter are designed as rigid towers.
- the known soft towing targets are predominantly drag sacks of the generic type, which are inflated and held in a stable manner by the dynamic pressure of the incoming air and which offer cost advantages compared to rigid towing bodies, as well as greater security against damage when impacted or torn off towing targets which could cause them on the ground.
- air drag bags compared to the towed bodies are that they do not offer the possibility of carrying smoke cartridges that mark the tow target after remote ignition.
- the clear visibility of a target is an indispensable security requirement to avoid confusing the towing target with the tow plane under all circumstances.
- air drag bags have to be manufactured in much larger dimensions than towed bodies in order to achieve sufficient visibility and thus differentiation.
- these relatively large dimensions have the disadvantage of increased air resistance, which is generally ten to twenty times greater than that of towed bodies at a given towing speed.
- the drag resistance is decisive for the maximum deployment speed of a towing target, since the tensile strength of the towing ropes and the engine thrust reserves of the tow plane have performance limits.
- the high drag resistance of previously used drag sacks is not only due to their large dimensions, but also due to the aerodynamically unfavorable shape and flow.
- This shape is characterized in that the approximately circular cylindrical drag bags are open at the front and flat at the rear end in the manner of a cylinder bottom.
- the inflow penetrates into the front opening, which is perpendicular to the through numerous equally long cords, the so-called spider
- the inflow is kept open and inflates the drag sack due to the dynamic pressure.
- the pull cords are bundled towards the tow rope and connected to it by a rope coupling.
- a high speed air drag bag of the type mentioned in the opening paragraph is known from Figure 1 of GB-A-2 034 267.
- This air drag bag is cylindrical; its rear end is closed by a bottom wall.
- Outlet openings are provided in the area of the cylindrical bag wall.
- the air outlet openings are directed completely radially outwards.
- an air drag bag is known from US-A-2 238 876, which has a central opening at its rear end. The air can only escape from this drag sack through the central opening. This results in stronger turbulence at the end of the air drag sack, which increases drag resistance.
- the invention has for its object to provide a high-speed air drag bag of the type mentioned above, in which the drag resistance is lower and at the same time the position stabilization about the longitudinal axis is improved.
- a prerequisite for the dimensional stability of the drag bag is that the total area of the rear air outlet openings is smaller than the front air inlet opening of the air drag bag. If this condition is not met, fluttering of the towing bag walls disturbing operation occurs, which increases the towing resistance and the acoustic noise suddenly and can lead to the mechanical destruction of the towing bag by local mechanical strain on the textile material.
- a convergent, ie tapering shape of the rear part of the air drag sack avoids a drag-increasing flow stall.
- the flow through the axially oriented air outlet openings is used in order to keep the shape of the drag sack tail stable in shape due to the dynamic pressure occurring.
- the low-turbulence straight-line design of the flow through the sack enables the outgoing air to be combined with the flow around the sack in the rear area with little tears and swirls.
- the contour tapering towards the end of the drag bag can be realized according to the invention by means of an elliptical rotation configuration.
- the risk of fluttering of the textile material at the rear end increases as a result of the decreasing difference between local internal and external pressure.
- the air outlet opening cross section can be dimensionally stabilized by a rigid ring which is firmly connected to the textile towing bag tail, for example sewn in, and can be braced on the towing bag wall by means of tensioning straps to avoid lateral vibrations.
- the air drag bag is preferably manufactured in a precisely cylindrical shape. In this way, it is possible to maintain a constant main direction of the main weave of the textile material over the entire circumference of the air drag bag and to minimize seam distortion due to the oblique fiber course along the drag bag seams.
- Such a drag bag offers the advantage of the pendulum stabilization of the flight position, ie the off-axis arrangement of the hit sensor electronics in the drag bag wall and a nevertheless reduced drag resistance due to largely deflection-free and low-turbulence air guidance. If an exact cylindrical design is selected, the additional advantage of simpler manufacture can be achieved.
- the cylindrical drag bag 1 shown by way of example in FIG. 1 is provided with a conical rear part 2, at the end of which there is an air outlet opening 9 which is mechanically reinforced by a rigid ring 12, the arrangement of which can be seen in FIG. 2.
- the drag bag cylinder 1 is pulled with the aid of pull cords 3 which act on its front end provided with the air inlet opening 7 and form the so-called spider.
- These pull cords 3 converge on a rope coupling 4, which establishes the connection to the tow rope 5 pulled by a tow plane.
- the drag sack is inflated by the dynamic pressure of the air flow 6 and forms the front air inlet opening 7.
- the hit sensor electronics are located in an off-axis arrangement 11 to stabilize the pendulum in a constant flight position about the longitudinal axis.
- Fig. 2 shows the vibration-preventing bracing of a rigid ring 12 in the air outlet opening by means of pull cords or straps 13, which are fastened to the cylindrical drag bag wall 1 by fastening elements 14, for example eyelets.
- the position and shape of the conical rear part 2 are stabilized by this bracing.
- FIGS. 1 and 2 which has a conically tapering rear part 2, is not an exemplary embodiment of the invention.
- the embodiment of the air drag bag according to the invention shown in FIG. 3 has a conical configuration 17, consisting of a practically air-impermeable textile material.
- the rear part 15 has an elliptically tapered contour 16.
- the air flowing into the sack through the air inlet opening 19 at the front accumulates inside the sack and exits through several axially symmetrically arranged air outlet openings in the form of holes 18 in the sack wall in the rear third of the tapering contour 16 .
- the airbag has a semi-airtight bottom 20.
- the air drag bag can consist of a textile material, the main fiber direction of which extends in the axial direction.
- the condition is also fulfilled that the total area of the air outlet openings 18 is smaller than the cross-sectional area of the front air inlet openings 19.
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- Aviation & Aerospace Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Air Bags (AREA)
- Professional, Industrial, Or Sporting Protective Garments (AREA)
Description
Die Erfindung betrifft einen Hochgeschwindigkeits-Luftschleppsack aus textilem Material mit reduziertem aerodynamischen Schleppwiderstand, nach dem Oberbegriff des Anspruchs 1.The invention relates to a high-speed air drag bag made of textile material with reduced aerodynamic drag, according to the preamble of
Derartige Luftschleppsäcke, die gewöhnlich aus natur- oder kunsttextilem Material bestehen, dienen als von einem Flugzeug nachgeschleppte Luftschleppziele, die für das Übungsschießen auf fliegende Ziele benutzt werden, wobei eine in das Schleppziel eingebaute Trefferlagesensorik den Passaceort vorbeifliegender Geschosse erfaßt und als Trefferanzeige am Erdboden zur Anzeige bringt. Neben sogenannten weichen Schleppzielen aus textilen Materialien sind auch sogenannte harte Schleppziele gebräuchlich. Letztere sind als starre Schleppkörper ausgebildet.Such air drag sacks, which usually consist of natural or art textile material, serve as air drag targets dragged by an aircraft, which are used for practice shooting at flying targets, whereby a hit position sensor system built into the drag target detects the passage location of projectiles flying past and displays them as a hit display on the ground brings. In addition to so-called soft tow targets made of textile materials, so-called hard tow targets are also used. The latter are designed as rigid towers.
Die bekannten weichen Schleppziele sind vorwiegend Schleppsäcke der gattungsgemäßen Art, die durch den Staudruck der anströmenden Luft aufgeblasen und formstabil gehalten werden und gegenüber starren Schleppkörpern Kostenvorteile bieten sowie eine größere Sicherheit gegen Schäden beim Aufschlag abgeschossener oder abgerissener Schleppziele, die diese am Boden verursachen könnten.The known soft towing targets are predominantly drag sacks of the generic type, which are inflated and held in a stable manner by the dynamic pressure of the incoming air and which offer cost advantages compared to rigid towing bodies, as well as greater security against damage when impacted or torn off towing targets which could cause them on the ground.
Der Nachteil der Luftschleppsäcke gegenüber den Schleppkörpern besteht darin, daß sie keine Möglichkeit bieten, Rauchpatronen mitzuführen, die nach Fernzündung das Schleppziel markieren. Die eindeutige Sichtbarkeit eines Zielkörpers ist jedoch eine unverzichtbare Sicherheitsforderung, um eine Verwechslung des Schleppzieles mit dem Schleppflugzeug unter allen Umständen auszuschließen. Daher müssen Luftschleppsäcke zur Erzielung einer ausreichenden Sichtbarkeit und damit Unterscheidungsfähigkeit in wesentlich größeren Abmessungen hergestellt werden als Schleppkörper. Diese relativ großen Abmessungen haben jedoch den Nachteil des erhöhten Luftwiderstandes, der bei gegebener Schleppgeschwindigkeit in der Regel zehn- bis zwanzigmal größer ist als derjenige von Schleppkörpern. Der Schleppwiderstand ist aber maßgeblich für die maximale Einsatzgeschwindigkeit eines Schleppzieles, da die Zugfestigkeit der Schleppseile und die Triebwerksschubkraftreserven des Schleppflugzeuges Leistungsgrenzen besitzen.The disadvantage of air drag bags compared to the towed bodies is that they do not offer the possibility of carrying smoke cartridges that mark the tow target after remote ignition. However, the clear visibility of a target is an indispensable security requirement to avoid confusing the towing target with the tow plane under all circumstances. For this reason, air drag bags have to be manufactured in much larger dimensions than towed bodies in order to achieve sufficient visibility and thus differentiation. However, these relatively large dimensions have the disadvantage of increased air resistance, which is generally ten to twenty times greater than that of towed bodies at a given towing speed. However, the drag resistance is decisive for the maximum deployment speed of a towing target, since the tensile strength of the towing ropes and the engine thrust reserves of the tow plane have performance limits.
Der hohe Schleppwiderstand bisher gebräuchlicher Schleppsäcke kommt aber nicht nur durch deren große Dimensionen zustande, sondern auch durch die aerodynamisch ungünstige Formgebung und Strömungsführung. Diese Formgebung ist dadurch gekennzeichnet, daß die in etwa kreiszylindrischen Schleppsäcke vorne offen und am hinteren Ende nach Art eines Zylinderbodens flach abgeschlossen sind. Die Anströmung dringt in die Frontöffnung, die durch zahlreiche gleich-lange Schnüre, die sogenannte Spinne, senkrecht zur Anströmung offengehalten wird, ein und bläst den Schleppsack durch den Staudruck auf. Die Zugschnüre sind zum Schleppseil hin gebündelt und mit diesem durch eine Seilkupplung verbunden.However, the high drag resistance of previously used drag sacks is not only due to their large dimensions, but also due to the aerodynamically unfavorable shape and flow. This shape is characterized in that the approximately circular cylindrical drag bags are open at the front and flat at the rear end in the manner of a cylinder bottom. The inflow penetrates into the front opening, which is perpendicular to the through numerous equally long cords, the so-called spider The inflow is kept open and inflates the drag sack due to the dynamic pressure. The pull cords are bundled towards the tow rope and connected to it by a rope coupling.
Bei dieser praxisüblichen Bauart der Schleppsäcke entstehen im Frontbereich sowie am Heck erhebliche Luftturbulenzen, die die wesentliche Ursache des hohen Schleppwiderstandes sind. Insbesondere kommt es an der nahezu senkrecht zur Sacklängsachse stehenden heckseitigen Bodenwand zu Strömungsabriß und Verwirbelungen über die gesamte Fläche.With this practical design of the drag sacks, considerable air turbulence occurs in the front area and at the rear, which are the main cause of the high drag resistance. In particular, the rear wall of the rear wall, which is almost perpendicular to the longitudinal axis of the sack, stalls and swirls over the entire surface.
Bei der gebräuchlichen Verwendung einer akustischen Treffersensorik im vorderen Schleppsackbereich ist es erforderlich, die frontseitigen Luftturbulenzen und damit die akustischen Störgeräusche zu vermindern. Dies wird mit Hilfe eines Kranzes relativ kleiner, radialer Löcher in der hinteren Sackwand erreicht, durch die ein Teil der Anströmung hindurchtritt, so daß die frontseitigen Turbulenzen vermindert werden. Das seitliche Ausblasen der Luft aus diesen Löchern vergrößert zwar den Schleppwiderstand, wirkt sich jedoch vorteilhaft auf die Fluglage-Stabilität aus, da solche Schleppsäcke als Folge unsymmetrischer Herstellungstoleranzen gewöhnlich um ihre Längsachse rotieren. Diese Rotation ist wegen der laufend wechselnden Orientierung und betriebswidrigen seitlichen Anströmung der akustischen Treffersensoren jedoch unerwünscht.When using an acoustic hit sensor system in the front drag bag area, it is necessary to reduce the air turbulence on the front and thus the acoustic noise. This is achieved with the help of a ring of relatively small, radial holes in the rear wall of the sack, through which part of the inflow passes, so that the turbulence at the front is reduced. The lateral blowing out of the air from these holes increases the drag resistance, but has an advantageous effect on the attitude stability, since such drag bags usually rotate about their longitudinal axis as a result of asymmetrical manufacturing tolerances. However, this rotation is undesirable because of the constantly changing orientation and improper flow against the side of the acoustic hit sensors.
Man hat nun festgestellt, daß Schleppsäcke mit dem genannten seitlichen, heckseitigen Lochkranz langsamer rotieren als ohne einen solchen Kranz, weil die seitlich austretenden Luftstrahlen eine rotationsdämpfende Wirkung haben. Das Problem des zu großen Luftwiderstandes wird jedoch auch mit solchen Schleppsäcken nicht gelöst, da die Schleppsackabmessungen etwa so groß bleiben müssen wie bei Säcken ohne Hecklochkranz.It has now been found that drag sacks with the lateral, rear-side perforated rim rotate more slowly than without such a rim, because the air jets emerging from the side have a rotation-damping effect. However, the problem of excessive drag is also not solved with such drag bags, since the drag bag dimensions have to stay about as big as sacks without a rear perforated rim.
Zwar ist es gelungen, eine rotationsdämpfende Wirkung dadurch zu erhalten, daß die Schleppsackform von vorne nach hinten leicht konisch aufgeweitet ist. Dadurch vergrößert sich jedoch der Luftwiderstand. Die Herstellung derartig konisch ausgebildeter Luftsäcke wirft jedoch im Hinblick auf die Anforderungen bezüglich Genauigkeit und Symmetrie Probleme auf, da solche Schleppsäcke aus trapezförmigen Textilstoffzuschnitten zusammengenäht werden, wobei sich regelmäßig nicht-parallele Webfaserverläufe entlang den Nähten ergeben.It has indeed been possible to obtain a rotation-damping effect by slightly tapering the shape of the drag bag from front to back. However, this increases the air resistance. The production of such conical air bags, however, poses problems with regard to the requirements with regard to accuracy and symmetry, since such drag bags are sewn together from trapezoidal textile fabric blanks, with non-parallel weave fibers routing along the seams regularly occurring.
Ein Hochgeschwindigkeits-Luftschleppsack der eingangs erwähnten Art ist aus Figur 1 der GB-A-2 034 267 bekannt. Dieser Luftschleppsack ist zylindrisch ausgebildet; sein hinteres Ende ist mittels einer Bodenwand verschlossen. Im Bereich der zylindrischen Sackwandung sind Austrittsöffnungen vorgesehen. Die Luftaustrittsöffnungen sind vollständig radial nach außen gerichtet. Bei dieser Anordnung ist eine doppelte Umlenkung der den Luftschleppsack verlassenden Luft erforderlich, und zwar einmal eine Umlenkung der im Innenraum des Luftschleppsackes befindlichen Luft aus der parallel zur Längsachse gerichteten Strömung in eine radial nach außen gerichtete Strömung und schließlich von der radial nach außen gerichteten Strömung in eine außerhalb des Luftschleppsackes angeordnete Strömung mit axialer Hauptkomponente, die wieder etwa parallel zur Längsachse des Luftschleppsackes ausgerichtet ist. Ferner ist aus der US-A- 2 238 876 ein Luftschleppsack bekannt, welcher an seinem hinteren Ende eine zentrale Öffnung aufweist. Die Luft kann also aus diesem Schleppsack lediglich durch die zentrale Öffnung nach außen hin entweichen. Dadurch ergeben sich am Ende des Luftschleppsackes stärkere Turbulenzen, die den Schleppwiderstand erhöhen.A high speed air drag bag of the type mentioned in the opening paragraph is known from Figure 1 of GB-A-2 034 267. This air drag bag is cylindrical; its rear end is closed by a bottom wall. Outlet openings are provided in the area of the cylindrical bag wall. The air outlet openings are directed completely radially outwards. With this arrangement, a double deflection of the air leaving the air drag sack is required, namely a redirection of the air inside the air drag sack from the flow directed parallel to the longitudinal axis into a radially outward flow and finally from the radially outward flow into a flow arranged outside the air drag bag with the main axial component, which is again aligned approximately parallel to the longitudinal axis of the air drag bag. Furthermore, an air drag bag is known from US-A-2 238 876, which has a central opening at its rear end. The air can only escape from this drag sack through the central opening. This results in stronger turbulence at the end of the air drag sack, which increases drag resistance.
Der Erfindung liegt die Aufgabe zugrunde, einen Hochgeschwindigkeits-Luftschleppsack der oben erwähnten Art zu schaffen, bei dem der Schleppwiderstand geringer und gleichzeitig die Lagestabilisierung um die Längsachse verbessert ist.The invention has for its object to provide a high-speed air drag bag of the type mentioned above, in which the drag resistance is lower and at the same time the position stabilization about the longitudinal axis is improved.
Diese Aufgabe wird erfindungsgemäß durch einen Hochgeschwindigkeits-Luftschleppsack mit den Merkmalen des Anspruchs 1 gelöst. Vorteilhafte Weiterbildungen sind Gegenstand der Unteransprüche.This object is achieved according to the invention by a high-speed air drag bag with the features of
Die Lösung der vorgenannten Aufgabe geht von der Beobachtung aus, daß es bei sehr hoher Fertigungsgenauigkeit des Luftschleppsackes möglich ist, diesen durch ein Massependel, beispielsweise die Anordnung der Treffersensor-Elektronik in der Schleppsackwand und damit in exzentrischer Lage, weitgehend lagestabil zu halten und auf den üblichen radialen Hecklochkranz vollständig zu verzichten und statt dessen mehrere axial orientierte Luftaustrittsöffnungen im Schleppsackheck anzuordnen, wodurch die Widerstandserhöhung durch radiale, seitliche Luftausblasung erheblich verringert oder im Grenzfall vollständig vermieden wird.The solution to the above problem is based on the observation that it is possible with a very high manufacturing accuracy of the air drag bag to keep it largely stable in position by a pendulum, for example the arrangement of the hit sensor electronics in the drag bag wall and thus in an eccentric position to completely dispense with the usual radial rear perforated rim and instead to arrange several axially oriented air outlet openings in the rear of the drag bag, thereby increasing the resistance is significantly reduced by radial, lateral air discharge or completely avoided in the limit case.
Voraussetzung für die Formstabilität des Schleppsackes ist, daß die Gesamtfläche der heckseitigen Luftaustrittsöffnungen kleiner ist als die frontseitige Lufteintrittsöffnung des Luftschleppsackes. Ist diese Bedingung nicht erfüllt, so treten betriebsstörende Flatterbewegungen der Schleppsackwände auf, die den Schleppwiderstand und die akustischen Störgeräusche sprunghaft erhöhen und durch örtliche mechanische Uberbeanspruchung des textilen Materials zur Zerstörung des Schleppsackes führen können.A prerequisite for the dimensional stability of the drag bag is that the total area of the rear air outlet openings is smaller than the front air inlet opening of the air drag bag. If this condition is not met, fluttering of the towing bag walls disturbing operation occurs, which increases the towing resistance and the acoustic noise suddenly and can lead to the mechanical destruction of the towing bag by local mechanical strain on the textile material.
Durch eine konvergente, d.h. sich verjüngende Formgebung des Heckteils des Luftschleppsackes wird ein widerstandsvergrößernder Strömungsabriß vermieden. Dabei wird die Durchströmung der axial orientierten Luftaustrittsöffnungen benutzt, um durch den auftretenden Staudruck die Form des Schleppsackhecks formstabil zu halten. Die turbulenzarme Geradeausführung der Durchströmung des Sackes ermöglicht in diesem Zusammenhang eine abriß- und wirbelarme Zusammenführung der austretenden Luft mit der Umströmung des Sackes im Heckbereich.A convergent, ie tapering shape of the rear part of the air drag sack avoids a drag-increasing flow stall. The flow through the axially oriented air outlet openings is used in order to keep the shape of the drag sack tail stable in shape due to the dynamic pressure occurring. In this context, the low-turbulence straight-line design of the flow through the sack enables the outgoing air to be combined with the flow around the sack in the rear area with little tears and swirls.
Die sich zum Schleppsackende hin verjüngende Kontur läßt sich erfindungsgemäß durch eine rotationselliptoidische Konfiguration verwirklichen. Mit zunehmend schlankerer Verjüngung des Schleppsackhecks vergrößert sich jedoch die Gefahr von Flatterbewegungen des textilen Materials am Heckende als Folge der abfallenden Differenz zwischen lokalem Innen- und Außendruck. Als Folge solcher Flatterbewegungen ergeben sich periodische Veränderungen des Durchströmquerschnitts, die die Flugstabilität, den Schleppwiderstand und den akustischen Störgeräuschpegel nachteilig beeinflussen. Zur Vermeidung solcher Flatterbewegungen läßt sich der Luftaustrittsöffnungsquerschnitt durch einen starren Ring formstabilisieren, der mit dem textilen Schleppsackheck fest verbunden, beispielsweise eingenäht ist, und zur Vermeidung seitlicher Schwingungen mittels Spannbändern an der Schleppsackwandung abgespannt werden kann.The contour tapering towards the end of the drag bag can be realized according to the invention by means of an elliptical rotation configuration. However, with an increasingly slimmer tapering of the rear of the sack, the risk of fluttering of the textile material at the rear end increases as a result of the decreasing difference between local internal and external pressure. As a result of such flutter movements, there are periodic changes in the flow cross-section, which adversely affect flight stability, drag resistance and acoustic noise level. To avoid such flutter movements, the air outlet opening cross section can be dimensionally stabilized by a rigid ring which is firmly connected to the textile towing bag tail, for example sewn in, and can be braced on the towing bag wall by means of tensioning straps to avoid lateral vibrations.
Zur Erzielung einer hohen Fertigungsgenauigkeit und -symmetrie wird der Luftschleppsack vorzugsweise in genau zylindrischer Form gefertigt. Auf diese Weise ist es möglich, über den ganzen Umfang des Luftschleppsackes eine parallele Hauptwebfaserrichtung des textilen Stoffes konstant beizubehalten und Nahtverziehungen infolge schrägen Faserverlaufs entlang von Schleppsacknähten auf ein Minimum zu beschränken.To achieve high manufacturing accuracy and symmetry, the air drag bag is preferably manufactured in a precisely cylindrical shape. In this way, it is possible to maintain a constant main direction of the main weave of the textile material over the entire circumference of the air drag bag and to minimize seam distortion due to the oblique fiber course along the drag bag seams.
Ein solcher Schleppsack bietet den Vorteil der Pendelstabilisierbarkeit der Fluglage, d.h. der außeraxialen Anordnung der Treffersensor-Elektronik in der Schleppsackwandung und eines dennoch verminderten Schleppwiderstandes infolge weitgehend umlenkungs- und turbulenzarmer Luftführung. Falls eine genaue zylindrische Bauform gewählt wird, läßt sich der zusätzliche Vorteil einer einfacheren Fertigung erzielen.Such a drag bag offers the advantage of the pendulum stabilization of the flight position, ie the off-axis arrangement of the hit sensor electronics in the drag bag wall and a nevertheless reduced drag resistance due to largely deflection-free and low-turbulence air guidance. If an exact cylindrical design is selected, the additional advantage of simpler manufacture can be achieved.
Ein Ausführungsbeispiel des Erfindungsgegenstandes wird nachfolgend anhand der Zeichung näher erläutert. Es zeigen:
- Fig. 1
- eine schematische Seitenansicht eines zylindrischen Luftschleppsackes;
- Fig. 2
- eine schematische Darstellung einer schwingungsverhindernden Abspannung eines starren Rings am Heckteil des in Fig. 1 gezeigten Luftschleppsackes, und
- Fig. 3
- eine schematische Seitenansicht eines erfindungsgemäßen konisch geformten Luftschleppsackes mit einer rotationselliptoidischen Kontur des Heckteils und mehreren auf einem Kranz axialsymmetrisch angeordneten Luftaustrittsöffnungen am Heckteil.
- Fig. 1
- a schematic side view of a cylindrical air drag bag;
- Fig. 2
- a schematic representation of a vibration-preventing bracing of a rigid ring on the rear part of the air drag bag shown in Fig. 1, and
- Fig. 3
- is a schematic side view of a conically shaped air drag bag according to the invention with a rotationally elliptical contour of the rear part and several air outlet openings arranged axially symmetrically on a ring on the rear part.
Der beispielhaft in Fig. 1 dargestellte zylindrische Schleppsack 1 ist mit einem konischen Heckteil 2 versehen, an dessen Ende sich eine Luftaustrittsöffnung 9 befindet, die mechanisch durch einen starren Ring 12, dessen Anordnung aus Fig. 2 ersichtlich ist, verstärkt ist. Der Schleppsackzylinder 1 wird mit Hilfe von Zugschnüren 3, die an seinem frontseitigen, mit der Lufteintrittsöffnung 7 versehenen Ende angreifen und die sogenannte Spinne bilden, gezogen. Diese Zugschnüre 3 laufen an einer Seilkupplung 4 zusammen, die die Verbindung zu dem von einem Schleppflugzeug gezogenen Schleppseil 5 herstellt. Durch den Staudruck der Luftanströmung 6 wird der Schleppsack aufgeblasen und bildet die frontseitige Lufteintrittsöffnung 7.The
Am Heckteil des Luftschleppsackes strömt der größte Teil der Luftanströmung als Umströmung 8 um die Außenwand des Schleppsackes herum und verbindet sich wirbelarm mit der richtungsparallelen Durchströmung 10, die aus der Luftaustrittsöffnung 9 entweicht. Zur Pendelstabilisierung einer konstanten Fluglage um die Längsachse befindet sich die Treffersensor-Elektronik in außeraxialer Anordnung 11.At the rear part of the air drag sack, the largest part of the air flow flows as a
Fig. 2 zeigt die schwingungsverhindernde Abspannung eines starren Ringes 12 in der Luftaustrittsöffnung mittels Zugschnüren oder -bändern 13, die durch Befestigungselemente 14, beispielsweise Ösen, an der zylindrischen Schleppsackwand 1 befestigt sind. Lage und Form des konischen Heckteils 2 werden durch diese Abspannung stabilisiert.Fig. 2 shows the vibration-preventing bracing of a
Bei dem in den Fig. 1 und 2 dargestellten Luftschleppsack, der ein, konisch sich verjüngendes Heckteil 2 aufweist, handelt es sich nicht um ein Ausführungsbeispiel der Erfindung.The air drag bag shown in FIGS. 1 and 2, which has a conically tapering
Die in Fig. 3 gezeigte erfindungsgemäße Ausführungsform des Luftschleppsackes weist eine konische Konfiguration 17 auf, bestehend aus einem praktisch luftundurchlässigen textilen Material. Das Heckteil 15 besitzt eine sich rotationselliptoidisch verjüngende Kontur 16. Die durch die frontseitige Lufteintrittsöffnung 19 in den Sack einströmende Luft staut sich im Sackinneren und tritt durch mehrere axialsymmetrisch angeordnete Luftaustrittsöffnungen in Form der Löcher 18 in der Sackwandung im hinteren Drittel der sich verjüngenden Kontur 16 aus. In diesem Bereich weist der Luftsack einen halb luftundurchlässigen Boden 20 auf.The embodiment of the air drag bag according to the invention shown in FIG. 3 has a conical configuration 17, consisting of a practically air-impermeable textile material. The
Im Falle der Ausführungsform nach Fig. 3 kann der Luftschleppsack aus einem textilen Material, dessen Hauptwebfaserrichtung in axialer Richtung verläuft, bestehen.In the case of the embodiment according to FIG. 3, the air drag bag can consist of a textile material, the main fiber direction of which extends in the axial direction.
Bei der Ausführungsform nach Fig. 3 ist darüber hinaus die Bedingung erfüllt, daß die Gesamtfläche der Luftaustrittsöffnungen 18 kleiner ist als die Querschnittsfläche der frontseitigen Lufteintrittsöffnungen 19.In the embodiment according to FIG. 3, the condition is also fulfilled that the total area of the
Durch die konvergente, sich verjüngende Kontur 15 des Heckteils des Luftschleppsackes wird die Turbulenz der Luftströmung im Heckbereich und damit der Luftwiderstand deutlich reduziert und damit die Einsatzfähigkeit des Schleppzieles erheblich verbessert. Diese Einsatzfähigkeit wird durch die Zugfestigkeit der Schleppseile und die Triebwerksschubreserven bzw. den Kerosinverbrauch des Schleppflugzeuges, Größen also, die vom Schleppwiderstand abhängig sind, wesentlich mitbestimmt.Due to the convergent, tapering
Claims (8)
- High speed aerial tow target (17), made of textile material, with reduced towing drag, provided with a front side having an air entrance orifice (19) and provided with several axial symmetrical air outlet orifices (18) as well as a tail (15) comprising a bottom (20), wherein the whole surface ofthe air outlet orifices (18) is smaller than a cross section of the air entrance orifice (19), characterized in that the tail (15) of the tow target (17) has a contour (16) in form a rotational-ellipsoid tapering to the rear end of the bag target, and that the air outlet orifices (18) in the rear third of the contour (16) in the wall of the bag target are formed in such a manner that the air jets leaving the air outlet orifices (18) are nearly axially directed.
- High speed aerial tow target according to claim 1, characterized in that the wall (20) forming the bottom of the aerial tow target (17) is manufactured between the end of the bag and the air outlet orifices (18) of a semi-airtight material.
- High speed aerial tow target according to claim 1 or 2, characterized in that the air outlet orifices (18) are formed by a netlike web.
- High speed aerial tow target according to claim 1 or 2, characterized in that the air outlet orifices (18) are formed by a netlike lattice.
- High speed aerial tow target according to one of the forgoing claims, characterized in that the cross section of the air outlet orifice is stabilized in configurational aspects by a solid ring (12) which is kept under tension by tensioning strings fixed at the wall of the tow bag and is preferably sewed into the tail of the tow bag.
- High speed aerial tow target according to one of the foregoing claims, characterized in that the aerial tow target has the configuration of a cylinder between the air entrance orifice (19) and its tail (15).
- High speed aerial tow target according to one of claims 1 to 5, characterized in that the aerial tow target has the configuration of a truncated cone (17) between its air entrance orifice (19) and its tail (15) which truncated cone expands in the direction of the tail (15).
- High speed aerial tow target according to one of the foregoing claims, characterized in that the main direction of the weaving thread of the textile material of which the aerial tow target (17) consists, extends in axial direction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4138726 | 1991-11-19 | ||
| DE4138726 | 1991-11-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0543170A1 EP0543170A1 (en) | 1993-05-26 |
| EP0543170B1 true EP0543170B1 (en) | 1996-05-22 |
Family
ID=6445536
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP92118104A Expired - Lifetime EP0543170B1 (en) | 1991-11-19 | 1992-10-22 | High speed aerial tow target, made of textile material, with reduced towing drag |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5338199A (en) |
| EP (1) | EP0543170B1 (en) |
| DE (2) | DE4140863A1 (en) |
| IL (1) | IL103762A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10252949B4 (en) * | 2002-11-14 | 2005-03-24 | Bundesrepublik Deutschland, vertreten durch das Bundesministerium der Verteidigung, dieses vertreten durch das Bundesamt für Wehrtechnik und Beschaffung | Rope visual aid |
| US11440680B2 (en) * | 2019-07-09 | 2022-09-13 | United States Of America As Represented By The Secretary Of The Navy | Tether management system for a tethered UAV |
| CN113340561B (en) * | 2021-08-02 | 2021-10-29 | 中国空气动力研究与发展中心空天技术研究所 | Eccentric cylindrical single-hole pneumatic probe for measuring precision in high altitude |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR496230A (en) * | 1918-02-13 | 1919-10-30 | Haeberlin Emilie | Objective sleeve for aerial shots |
| US1860982A (en) * | 1931-03-27 | 1932-05-31 | John A Binnie | Aerial device |
| US2269469A (en) * | 1935-06-05 | 1942-01-13 | Manson Frank George | Aerial trailer |
| US2238876A (en) * | 1939-08-14 | 1941-04-15 | Frank G Manson | Aerial trailer |
| US3000634A (en) * | 1946-03-26 | 1961-09-19 | Frank C South | Target sleeve |
| US2807287A (en) * | 1955-12-23 | 1957-09-24 | Massillon Cleveland Akron Sign Co | Tow target construction |
| FR1435960A (en) * | 1965-03-09 | 1966-04-22 | Aerazur Constr Aeronaut | Fabric windsock, fixed or towed, with device increasing its stability in the wind |
| DE2604929A1 (en) * | 1976-02-09 | 1977-08-11 | Gfh Ges Fuer Flugtechnik Mbh | Aerial firing practice target - has metal coating for radar beam reflection on trailing sack fabric |
| DE2850171A1 (en) * | 1978-11-18 | 1980-05-22 | Dornier Gmbh | TOWING DEVICE ON AIRCRAFT |
| DE3312820A1 (en) * | 1983-04-09 | 1984-10-18 | Autoflug Gmbh, 2084 Rellingen | BATTLE TARGET AIR TOWING BAG |
-
1991
- 1991-12-11 DE DE4140863A patent/DE4140863A1/en not_active Withdrawn
-
1992
- 1992-10-22 EP EP92118104A patent/EP0543170B1/en not_active Expired - Lifetime
- 1992-10-22 DE DE59206358T patent/DE59206358D1/en not_active Expired - Fee Related
- 1992-11-16 IL IL10376292A patent/IL103762A/en not_active IP Right Cessation
- 1992-11-16 US US07/976,962 patent/US5338199A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE59206358D1 (en) | 1996-06-27 |
| EP0543170A1 (en) | 1993-05-26 |
| IL103762A (en) | 1995-06-29 |
| DE4140863A1 (en) | 1993-05-27 |
| US5338199A (en) | 1994-08-16 |
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