GB2084090A

GB2084090A - Gliding airfoil parachute canopy construction

Info

Publication number: GB2084090A
Application number: GB8127552A
Authority: GB
Original assignee: Para Flite Inc
Current assignee: Para Flite Inc
Priority date: 1980-09-23
Filing date: 1981-09-11
Publication date: 1982-04-07
Also published as: DE3137304C2; IL63867A; AU7521881A; FR2490587A1; IT8124072A0; FR2490587B1; CA1172228A; IT1139465B; GB2084090B; KR890000531B1; ZA816329B; AU528256B2; KR830007361A; DE3137304A1

Abstract

The outer airfoil surface portions (14 and 16) of a forward gliding type parachute canopy are made from flexible panels (28, 30, 32) secured to each other along spanwise extending seams (26) in transverse intersecting relation to chordwise extending seams (24) connecting spaced ribs (22) to the outer surface portions to form internal airflow channels. Each panel is substantially equal in length to the spanwise dimension of the canopy. <IMAGE>

Description

SPECIFICATION Gliding airfoil parachute canopy construction This invention relates generally to forward glide types of parachute canopies that are ram air inflated to an airfoil shape, and more particularly to construction of such parachute canopies.

Parachute canopies of the foregoing type are made from a minimum of five to seven elongated flexible panels sewn to each other along chordwise seams extending between leading and trailing edges of the canopy. The panels must not only be dimensioned in length substantially equal to the chordwise dimensions of the canopy but must be cut to an appropriate width so that the seams between panels will coincide with chordwise seams at which ribs are connected to the airfoil surface portions. Such a constructional arrangement was heretofore deemed necessary to form a canopy with optimum stress distribution under forces experienced by ram air inflated, gliding airfoil canopies.

It is therefore an important object of the present invention to provide a more efficient constructional arrangement for canopies of the aforementioned type whereby the amount of wasted material, the number of seams and material cutting operations may be reduced.

The foregoing objectives have been achieved unexpectedly through use of a constructional arrangement for canopies of the ram air inflated airfoil-shaped type that is different from the basic arrangement heretoFore utilized in that the outer airfoil surface portions are formed from elongated flexible panels sewn to each other along seams extending chordwise in transverse intersecting relation to the seams connecting the spaced internal ribs to the outer airfoil surface portions. The uninterrupted lengths of the panels are therefore substantially equal to the spanwise dimensions of the canopy and the side edges of the panels sewn to each other need not be cut or located in any particular relationship to the rib seams as in the case of prior art constructional arrangements.A reduction in the number of panels necessary to form an airfoil surface portion may thereby be realized as well as a reduction in the number of seams.

The concept of merely arranging continuous flexible panels lengthwise in a spanwise direction for hemispherical canopies is already known, as shown in U.S. Patent No. 2,959,385 and for sail wing canopies as shown in U.S. Patent No. 3,830,512.

However, significantly different stress distributions are associated with hemispherical and sail wing canopies. Further, none of such hemispherical sail wing canopies have airfoil forming ribs associated therewith tha heretofore dictated an arrangement of panels with chordwise extending seams therebetween. Accordingly, the advantages resulting from the spanwise arrangement of panels in accordance with the present invention, were not applicable to hemispherical and sail wing canopies.

Figure 1 is a perspective view of a parachute canopy constructed in accordance with the present invention.

Figure 2 is a top plan view of the canopy shown in Figure 1.

Figure 3 is a section view taken substantially through a plane indicated by section line 3--3 in Figure 2.

Referring now to the drawings in detail, a gliding type of airfoil shaped parachute canopy is shown generally referred to by reference numeral 10. The canopy is connected during deployment to a payload (not shown) by means of suspension lines 12. In this type of parachute, the canopy is inflated to and maintained in an airfoil shape by means of a ram air effect during foward glide descent.

In the illustrated embodiment, the canopy 10 includes an outer airfoil surface formed by an upper flexible skin generally denoted as 14 and a bottom sheet 16 from which the suspension lines extend.

Such outer surface portions 14 and 16 are usually made of a flexible material or fabric extending lengthwise from a leading edge portion 18to a trailing edge portion 20. When inflated, the outer surface portions of the canopy are held spaced apart by spanwise spaced ribs 22 secured thereto along chordwise extending seams 24.

Heretofore, the outer surface portions of the canopy were made from a minimum of five to seven flexible panels of fabric elongated in the chordwise direction and sewn to each other along chordwise extending seams in contrast to the arrangement shown herein, wherein flexible elongated panels are sewn to each other along spanwise extending seams 26 in transverse intersecting relation to the chordwise extending rib seams 24. Three panels consisting of end panels 28 and 30 and intermediate panel 32 are utilized to form the outer surface portions 14 and 16. Each of the panels 28,30 and 38 therefore has an uninterrupted length that is substantially equal to the spanwise dimension of the canopy, with the sides of adjacent panels secured to each other along the spanwise extending seams 26.The unattached sides of the end panels 28 and 30 form the leading and trailing edge portions of the canopy. The unattached sides of the end panels 28 respectively associated with the upper skin 14 and bottom sheet 16 also respectively associated with the upper skin 14 and bottom sheet 16 also define the inlet opening at the leading edge portion through which inflow of air is conducted into the airflow channels between the ribs 22 causing inflation of the canopy to the airfoil shape shown. The ribs 22 may be located in spaced relation to each other wherever desired without regard to the location of the connecting seams 26 between the panels because ofthetrans- verse intersecting relationship between seams 24 and 26.

1. For use in a forward gliding parachute having a ram air canopy, including an uninterrupted top flexible surface portion extending chordwise between a leading edge portion and a trailing edge portion and a plurality of spanwise spaced ribs depending from the top surface portion to form airflow channels therebetween through which airf

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Gliding airfoil parachute canopy construction This invention relates generally to forward glide types of parachute canopies that are ram air inflated to an airfoil shape, and more particularly to construction of such parachute canopies. Parachute canopies of the foregoing type are made from a minimum of five to seven elongated flexible panels sewn to each other along chordwise seams extending between leading and trailing edges of the canopy. The panels must not only be dimensioned in length substantially equal to the chordwise dimensions of the canopy but must be cut to an appropriate width so that the seams between panels will coincide with chordwise seams at which ribs are connected to the airfoil surface portions. Such a constructional arrangement was heretofore deemed necessary to form a canopy with optimum stress distribution under forces experienced by ram air inflated, gliding airfoil canopies. It is therefore an important object of the present invention to provide a more efficient constructional arrangement for canopies of the aforementioned type whereby the amount of wasted material, the number of seams and material cutting operations may be reduced. The foregoing objectives have been achieved unexpectedly through use of a constructional arrangement for canopies of the ram air inflated airfoil-shaped type that is different from the basic arrangement heretoFore utilized in that the outer airfoil surface portions are formed from elongated flexible panels sewn to each other along seams extending chordwise in transverse intersecting relation to the seams connecting the spaced internal ribs to the outer airfoil surface portions. The uninterrupted lengths of the panels are therefore substantially equal to the spanwise dimensions of the canopy and the side edges of the panels sewn to each other need not be cut or located in any particular relationship to the rib seams as in the case of prior art constructional arrangements.A reduction in the number of panels necessary to form an airfoil surface portion may thereby be realized as well as a reduction in the number of seams. The concept of merely arranging continuous flexible panels lengthwise in a spanwise direction for hemispherical canopies is already known, as shown in U.S. Patent No. 2,959,385 and for sail wing canopies as shown in U.S. Patent No. 3,830,512. However, significantly different stress distributions are associated with hemispherical and sail wing canopies. Further, none of such hemispherical sail wing canopies have airfoil forming ribs associated therewith tha heretofore dictated an arrangement of panels with chordwise extending seams therebetween. Accordingly, the advantages resulting from the spanwise arrangement of panels in accordance with the present invention, were not applicable to hemispherical and sail wing canopies. Figure 1 is a perspective view of a parachute canopy constructed in accordance with the present invention. Figure 2 is a top plan view of the canopy shown in Figure 1. Figure 3 is a section view taken substantially through a plane indicated by section line 3--3 in Figure 2. Referring now to the drawings in detail, a gliding type of airfoil shaped parachute canopy is shown generally referred to by reference numeral 10. The canopy is connected during deployment to a payload (not shown) by means of suspension lines 12. In this type of parachute, the canopy is inflated to and maintained in an airfoil shape by means of a ram air effect during foward glide descent. In the illustrated embodiment, the canopy 10 includes an outer airfoil surface formed by an upper flexible skin generally denoted as 14 and a bottom sheet 16 from which the suspension lines extend. Such outer surface portions 14 and 16 are usually made of a flexible material or fabric extending lengthwise from a leading edge portion 18to a trailing edge portion 20. When inflated, the outer surface portions of the canopy are held spaced apart by spanwise spaced ribs 22 secured thereto along chordwise extending seams 24. Heretofore, the outer surface portions of the canopy were made from a minimum of five to seven flexible panels of fabric elongated in the chordwise direction and sewn to each other along chordwise extending seams in contrast to the arrangement shown herein, wherein flexible elongated panels are sewn to each other along spanwise extending seams 26 in transverse intersecting relation to the chordwise extending rib seams 24. Three panels consisting of end panels 28 and 30 and intermediate panel 32 are utilized to form the outer surface portions 14 and 16. Each of the panels 28,30 and 38 therefore has an uninterrupted length that is substantially equal to the spanwise dimension of the canopy, with the sides of adjacent panels secured to each other along the spanwise extending seams 26.The unattached sides of the end panels 28 and 30 form the leading and trailing edge portions of the canopy. The unattached sides of the end panels 28 respectively associated with the upper skin 14 and bottom sheet 16 also respectively associated with the upper skin 14 and bottom sheet 16 also define the inlet opening at the leading edge portion through which inflow of air is conducted into the airflow channels between the ribs 22 causing inflation of the canopy to the airfoil shape shown. The ribs 22 may be located in spaced relation to each other wherever desired without regard to the location of the connecting seams 26 between the panels because ofthetrans- verse intersecting relationship between seams 24 and 26. CLAIMS

1. For use in a forward gliding parachute having a ram air canopy, including an uninterrupted top flexible surface portion extending chordwise between a leading edge portion and a trailing edge portion and a plurality of spanwise spaced ribs depending from the top surface portion to form airflow channels therebetween through which airf low is conducted from the leading edge portion toward the trailing edge portion to inflate the canopy into an airfoil shape; the improvement residing in construction of said canopy from a plurality of elongated panels of uninterrupted fabric to form said top surface portion and securing means interconnecting said panels at connecting seams extending spanwise in transverse relation to the ribs.

2. The combination of claim 1 wherein said ribs are secured to the panels in intersecting relation to said connecting seams between the panels.

3. The combination of claim 2 wherein said canopy includes a bottom surface portion spaced from the top surface portion by said ribs, said bottom surface portion being formed from a plurality of elongated panels of ininterrupted fabric secured to each other along connecting seams extending transverse to the ribs, one of the panels associated with each of the top and bottom surface portions having elongated sides at the leading edge portion forming an inlet opening to the airflow channels.

4. The improvement as defined in claim 1 wherein each of said panels is made of an uninterrupted, unitary piece of flexible material having spaced sides substantially equal in spanwise dimension to the canopy, at which the connecting seams are located.

5. The combination of claim 4 wherein said outer airfoil surface portion of the canopy includes an upper skin from which the ribs depend.

6. The combination of claim 5 wherein said outer airfoil surface portion further includes a bottom sheet to which the ribs are secured, one of the panels associated with each of the upper skin and bottom sheet having unattached sides spaced from each other at the leading edge portion of the canopy to form an inlet opening into airflow inflating channels formed between the ribs.

7. A combination substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.