Note: Descriptions are shown in the official language in which they were submitted.
7 32,~
This invention relates generally to forward glide types of para-
chute 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 distribu-
tion 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 mlmber 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 hereto-
fore utilized in that the outer airfoil surface portions are formed from
elongated flexible panels sewn to each other along seams extending chord-
wise 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
~ ~ 722~,~
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 as compared to inflated airfoil shaped canopies. Further, none
of such hemispherical sail wing canopies have airfoil forming 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 sail wing
canopies.
Figure 1 is a perspective view of a parachute canopy constructed
i 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 ifi 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 irlcludes 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 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 thereto along chord-
wise extending seams 24.
Heretofore, the outer surface portions of the canopy were madefrom a minimum of five to seven flexible panels of fabric elongated in the
chordwise direction and sewn to each other along chordwise e~tending seams
in contrast to the arrangement shown herein, wherein flexible elongated
panels are sewn to each other along spanwise extending seams 26 in trans-
verse 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
i 3 L
A 28, 30 and ~ 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 of the transverse intersecting
relationship between seams 24 and 26.
