GB1561976A - Aircraft arrest or launch tapes - Google Patents

Description

(54) fPROVEMENiS IN OR RELATING TO AIRCRAFT ARREST OR LAUNCH TAPES ( We, BBA GROUP LIMITED, of Whiteehapel Road, P.O. Box No. 20, Cleckheaton, Yorkshire, BDl9 6HP, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment:- This invention relates to an aircraft arrest or launch tape of the kind used in arrested landing or catapult assisted launching of aircraft whereby the tape is intended to wind out from a roll on, or wind on as a roll on a drum during respective arresting or catapulting of the aircraft; such a tape is well known in the art and is hereinafter referred to as being of the kind specified.

In conventional aircraft arrester gear a synthetic woven tape of the kind specified is wound as a roll around a rotatable drum while the free end of the tape is attached to a wire hawser which stretches across the aircraft landing surface. As an aircraft lands a hook which it carries engages with the hawser causing the tape to unwind from its roll on the drum. As the tape is drawn from the rotating drum the latter is progressively braked in order to bring the aircraft to rest.

In some instances tapes of the kind specifled are coated to alleviate abrasion and loss of strength due to actinic degradation.

When used in wet conditions such a tape may not unwind from its roll on the drum in a progressive manner so that tension in the tape during aircraft arresting ceases to be uniform. This undesirable characteristic of wet arrester tapes is known in the art as "stick slip" and can adversely affect the stability of an aircraft which is being arrested. Similar adverse characteristics may be encountered in aircraft catapult launching systems when a wet tape of the kind specified is rapidly wound on to a rotating drum to assist in accelerating an aircraft for take-off and it will be apparent that if the winding up of the tape does not progress uniformly the take-off of the aircraft may be unstable.It is an object of the present invention to provide an aircraft arrest or launch tape of the kind specified and having a structure which will alleviate the aforementioned adverse "stick slip" characteristics when the tape is used in wet conditions.

According to the present invention there is provided an aircraft arrest or launch tape of the kind specified comprising a woven carcass having one of its broader faces substantially plain and wherein the other, opposed, broader face has a spaced array of ridges which provide high spots on said other broader face and form an array of substantially parallel channels which extend longitudinally of the carcass and are spaced over the width of the carcass so that when the tape is formed as a roll with the broader faces in overlying relationship, the ridges between the overlying layers in the roll abut the said one broader face and water flow from between overlying layers of the tape in the roll is facilitated through the channels.

By the present invention as the aircraft arrest or launch tape is wound as a roll on to the drum the ridges on the one broader face will abut the plain other broader face of the tape on the immediately adjacent layer in the roll. In this way it is believed that water which may be carried on the faces of the tape can be located as a layer below the level of the ridges forming the high spots so that the material of the ridges can directly contact the material of the overlying plain broader face in adjacent layers of the roll. Direct contact between the ridges and the plain broader face should maintain a high coefficient of friction between adjacent layers of the rolled tape (even when the latter carries surface water) and thereby alleviate the possibility of "stick slip" conditions resulting as the tape is wound on to, or off, the drum.By arranging the ridges to form the channels it is believed that such channels will accommodate surface water without adversely affecting the function of the ridges and it is likely that the surface water will be dispersed along the channels as a result of a squeezing effect to which the tape is subjected whilst it is being wound on to, and unwound from, the drum. It will be appreciated that excess surface water on the tape may be squeezed away from the high spots of the ridges during coiling of the tape on, and uncoiling of the tape from, the drum either or both in a longitudinal or a transverse direction. On this latter point it is preferred that the ridges are discontinuous over their longitudinal extent to provide secondary channels which extend transversely of the carcass on its one broader face.

Preferably the ridges comprise predetermined warp and or weft yarns which are prominent in the one broader face of the carcass. Usually the ridges will be formed by selected warp yarns which are evenly spaced across the width of the tape and are of a coarser and/or thicker nature than the remaining warp yarns and the weft yarns in the one broader face of the carcass so that the ridges extending in the warp direction form lines of undulating high spots spaced across the width of the tape. The structure of -the woven carcass can take many forms and in accordance with conventional practice may include stuffer warp yarns and warp or weft binder yarns. However, it is believed that a simple plain weave can be used for forming both broader faces of the carcass with the one broader woven face having thicker predetermined spaced warp yarns to form the ridges of high spots.The plain woven broader faces may sandwich stuffer threads and be held together by appropriate binder yarns.

It will be realised that the high spots formed by the ridges of warp or weft yarns can be accentuated by increasing the thickness of these yarns, for example by cabling several yarns together as one or by decreasing the tension on the ends of the yarns forming the ridges.

Generally the tape carcass will comprise synthetic yarns such as continuous filament polyamides. Any elastomeric coating on the carcass as a whole must follow the profile of the opposed broader faces of the carcass and so present the high spots of the ridges.

One embodiment of an aircraft arrest or launch tape of the kind specified and constructed in accordance with the present invention will now be described by way of example only with reference to the accompanying illustrative drawings in which: Figure 1 is a perspective view of part length of the tape carcass and illustrates the high spots thereon formed as ridges which extend in the warp direction, and Figure 2 diagrammatically shows the construction of, and the weave used in, the tape carcass of Figure 1.

The tape carcass illustrated may be formed wholly of nylon yarns having continuous filaments and has a width in the order of 20.5 centimetres and a thickness of approximately 0.9 centimetres. This carcass has parallel and opposed broader faces 1 and 2 of which the broader face 1 has integrally formed therewith a parallel array of ridges 3 which extend discontinuously in the direction of the warp and are spaced at approximately 1.3 centimetre intervals evenly across the whole width of the tape.

Each ridge 3 being discontinuous presents a longitudinal array of high spots 4.

Each of the broader faces 1 and 2 of the carcass is formed as a plain weave comprising weft yarns 5 and warp yarns 6 ,(see Figure 2). The opposed plainly woven broader faces sandwich non-interlaced stuffer warp yarns 7 which are held together with the weave of the broader faces by warp binder yarns 8.

The nylon yarns in the weave of the face 2, conveniently the stuffer warp yarns 7, the weft yarns in the face 1 and the majority of the warp yarns in the weave of the face 1 are all of similar diameter and structure.

However, to form the aforementioned ridges of high spots pre-selected warp yarns 6 in the weave of the broader face 1 are considerably thicker than the remaining yarns in that face 1. These thicker yarns 6 are illustrated in Figure 2 and conveniently comprise cabled yarns which are formed by twisting together several other doubled yarns as one. By constructing the carcass in this way the high spots 4 form arrays of undulating peaks in their respective ridges which latter together form an array of channels 9 which extend in the warpwise direction of the carcass and a further array of smaller secondary channels 10 which extend in the weftwise direction of the carcass or transversely of the tape.

The carcass will be coated with an elastomeric polymer which closely follows the profiles presented on the broader faces of the carcass.

In use of the aircraft arrest or launch tape in wet conditions water may collect as a layer on both of its broader faces. As the wet tape is wound as a roll with the faces 1 and 2 in overlying relationship on to, and unwound from, a drum the peaks of the high spots 4 will directly abut the substantially plain broader face 2 of the adjacent layer of tape in the roll while the water gathers in the channels 9 and 10 and may be dispersed along the channels by a squeezing effect as the tape is wound on to, and un wound from, the drum.Engagement between the high spots 4 of the ridges and the plain surface 2 in adjacent layers of the rolled tape will, it is believed, maintain sufficient friction to alleviate the "stick slip" problem so that during arrest or launch of an aircraft the tape may be drawn from or wound on the drum uniformly and at progressively increasing tension to effect stable arresting or launching respectively of the aircraft.

In the above described embodiment each ridge 3 is discontinuous to form a longitudinally extending array of discrete high spots on the broader face 1. If required however, each ridge 3 (or one or more of the ridges) can be formed, by an appropriate weave, as a continuous longitudinally extending rib on the broader face 1; by this latter construction the rib or each such continuous rib will itself constitute a longitudinally extending high spot on the side face 1.

WHAT WE CLAIM IS: 1. An aircraft arrest or launch tape of the kind specified comprising a woven carcass having one of its broader faces substantially plain and wherein the other, opposed, broader face has a spaced array of ridges which provide high spots on said other broader face and form an array of substantially parallel channels which extend longitudinally of the carcass and are spaced over the width of the carcass so that when the tape is formed as a roll with the broader faces in overlying relationship, the ridges between the overlying layers in the roll abut the said one broader face and water flow from between the overlying layers of the tape in the roll is facilitated through the channels.

2. A tape as claimed in claim 1 in which the ridges are formed by predetermined yarns in the weave which are more prominent in the said one broader face of the carcass than the other yarns in the said one broader face.

3. A tape as claimed in claim 2 in which the predetermined yarns which form the ridges are of a thicker and/or coarser nature than the other yarns in the one broader face.

4. A tape as claimed in either claim 2 or claim 3 in which the predetermined yarns which form the ridges are woven in the carcass under a tension less than that of the other yarns in the one broader face.

5. A tape as claimed in any one of claims 2 to 4 in which the ridges are formed by predetermined warp yarns which are prominent in the said one broader face of the carcass.

6. A tape as claimed in any one of the preceding claims in which the ridges are discontinuous over their longitudinal extent to provide secondary channels which extend transversely of the carcass on said one broader face.

7. A tape as claimed in any one of the preceding claims in which the carcass is provided with an elastomeric coating which follows the profile of the broader faces of the carcass and of the ridges on the said one broader face.

8. An aircraft arrest or launch tape of the kind specified and substantially as herein with reference to the accompanying illustrative drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. wound from, the drum. Engagement between the high spots 4 of the ridges and the plain surface 2 in adjacent layers of the rolled tape will, it is believed, maintain sufficient friction to alleviate the "stick slip" problem so that during arrest or launch of an aircraft the tape may be drawn from or wound on the drum uniformly and at progressively increasing tension to effect stable arresting or launching respectively of the aircraft. In the above described embodiment each ridge 3 is discontinuous to form a longitudinally extending array of discrete high spots on the broader face 1. If required however, each ridge 3 (or one or more of the ridges) can be formed, by an appropriate weave, as a continuous longitudinally extending rib on the broader face 1; by this latter construction the rib or each such continuous rib will itself constitute a longitudinally extending high spot on the side face 1. WHAT WE CLAIM IS:

1. An aircraft arrest or launch tape of the kind specified comprising a woven carcass having one of its broader faces substantially plain and wherein the other, opposed, broader face has a spaced array of ridges which provide high spots on said other broader face and form an array of substantially parallel channels which extend longitudinally of the carcass and are spaced over the width of the carcass so that when the tape is formed as a roll with the broader faces in overlying relationship, the ridges between the overlying layers in the roll abut the said one broader face and water flow from between the overlying layers of the tape in the roll is facilitated through the channels.

2. A tape as claimed in claim 1 in which the ridges are formed by predetermined yarns in the weave which are more prominent in the said one broader face of the carcass than the other yarns in the said one broader face.

3. A tape as claimed in claim 2 in which the predetermined yarns which form the ridges are of a thicker and/or coarser nature than the other yarns in the one broader face.

4. A tape as claimed in either claim 2 or claim 3 in which the predetermined yarns which form the ridges are woven in the carcass under a tension less than that of the other yarns in the one broader face.

5. A tape as claimed in any one of claims 2 to 4 in which the ridges are formed by predetermined warp yarns which are prominent in the said one broader face of the carcass.

6. A tape as claimed in any one of the preceding claims in which the ridges are discontinuous over their longitudinal extent to provide secondary channels which extend transversely of the carcass on said one broader face.

7. A tape as claimed in any one of the preceding claims in which the carcass is provided with an elastomeric coating which follows the profile of the broader faces of the carcass and of the ridges on the said one broader face.

8. An aircraft arrest or launch tape of the kind specified and substantially as herein with reference to the accompanying illustrative drawings.