Gliding airfoil parachute canopy construction

The outer airfoil surface portions of a forward gliding type parachute canopy are made from one-piece flexible panels secured to each other along seams extending in transverse intersecting relation to the seams connecting spaced ribs to the outer surface portions to form internal airflow channels. Each panel is substantially equal in length to the spanwise dimension of the canopy.

BACKGROUND OF THE INVENTION 
This invention relates generally to forward glide types of parachute 
canopies of the ram air type which are inflated to an airfoil shape, such 
as shown in prior U.S. Pat. No. Re. 26,427 and U.S. Pat. Nos. 3,524,613, 
3,724,789, and 4,015,801 which include an upper surface, a bottom surface 
and a series of ribs extending therebetween to divide the parachute into 
cells, and more particularly to construction of such parachute canopies. 
Parachute canopies of the foregoing type have been made for many years 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 for each the bottom and top surfaces have been 
dimensioned in length substantially equal to the chordwise dimensions of 
the canopy and have been cut to an appropriate width so that the seams 
between panels will coincide with chordwise seams at which the ribs are 
connected to the airfoil surface portions. Such a constructional 
arrangement was heretofore deemed necessary by persons skilled in the art 
so as 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. 
SUMMARY OF THE INVENTION 
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, upper and 
lower are both formed from elongated flexible panels sewn to each other 
along seams extending spanwise in transverse intersecting relation to the 
seams connecting the spaced internal ribs to the outer airfoil surfaces. 
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 constructions. 
As a result of this arrangements, a reduction in the number of panels 
necessary to form each airfoil surface may thereby be realized as well as 
a reduction in the number of cells, thus reducing the number of ribs and 
chordwise seams necessary to assemble the parachute. 
The concept of merely arranging continuous flexible panels lengthwise in a 
spanwise direction for hemispherical canopies is already known, as shown 
in U.S. Pat. No. 2,959,385 and for small sail wing canopies as shown in 
U.S. Pat. No. 3,830,512. However, significantly different stress 
distributions and manufacturing problems are associated with hemispherical 
and sail wing canopies as compared to ram air canopies. Further, none of 
such hemispherical or sail wing canopies have airflow channel dividing 
ribs associated therewith that 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 small 
sail wing canopies. 
These together with other objects and advantages which will become 
subsequently apparent reside in the details of construction and operation 
as more fully hereinafter described and claimed, reference being had to 
the accompanying drawings forming a part hereof, wherein like numerals 
refer to like parts throughout.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
Referring now to the drawings in detail, a ram air 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 forward 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 surface 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 18 to a trailing 
edge portion 20. When inflated, the outer surface portions of the canopy 
are held spaced apart by spanwise spaced ribs 22 secured to the outer 
surface portion along chordwise extending seams 24 which form pressure 
cells or airflow channels in the canopy between the upper surface 14 and 
bottom surface 16. 
Heretofore, the outer surface portions of the canopy were always made from 
a minimum of five to seven flexible panels of fabric cut from a bolt of 
cloth, laid in the chordwise direction and sewn to each other along 
chordwise extending seams. In contrast, in the arrangement of the present 
invention flexible elongated panels are sewn to each other along spanwise 
extending seams 26 in transverse intersecting relation to the chordwise 
extending ribs 22 and seams 24. Three panels consisting of end panels 28 
and 30 and intermediate panel 32 are utilized to form each of 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. Further, it will be observed 
that both outer surface portions have at least two transverse seams which 
intersect substantially perpendicularly to the chordwise seams 24 thus 
significantly increasing the strength and integrity of the overall canopy. 
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 define the inlet opening at the leading edge portion through which 
inflow of air is conducted into the pressure cells or 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 of the transverse intersecting relationship 
between seams 24 and 26. Hence, the ribs can be positioned where best 
suited for the performance of the canopy. 
The suspension lines 12 are attached to the bottom surface 16 at or near 
the point of transverse intersection between the chordwise rib seams 24 
and the spanwise connecting seams 26, where stress distributing tapes 
extend upwardly, as at 34. By such point of attachment, the load from the 
suspension lines is introduced into the canopy at reinforcing intersecting 
seams and transmitted to the top surface through the tapes, as described 
in U.S. Pat. No. 3,724,789. 
The foregoing is considered as illustrative only of the principles of the 
invention. Further, since numerous modifications and changes will readily 
occur to those skilled in the art, it is not desired to limit the 
invention to the exact construction and operation shown and described, and 
accordingly, all suitable modifications and equivalents may be resorted 
to, falling within the scope of the invention.