Note: Descriptions are shown in the official language in which they were submitted.
- 17gO054
V 1 4
COMPOSITE LEADING EDGE FOR AIRCRAFT
BACKGROUND
The invention relates to leading edges of
aircraft sections and particularly to such leading
edges which include rubber coverings such as deicer or
erosion shoes or boots.
Certain sections of today's aircraft employ
rubber sheet-like components along portions of their
leading edges, such as deicer or erosion "shoes". These
rubber components, also sometimes referred to as
"boots" or "blankets", are often attached along leading
edges o aircraft sections through use of a suitable
adhesive or cement disposed between the outer,surface
o~ the section leading edge portion and the inner
surface of the rubber component. Actual application of
the rubber component to the leading edge portion is
sometimes performed in the field or may be done in the
factory of the rubber component manufacturer who is
furnished all or a portion of an appropriate aircraft
section structure in order to apply the component.
Because selected sections of aircraft such as
airfoils or nose sections, are critically contoured
metal structures, great care must be exercised to
assure that the aontour of the leading edges of such
sections remain aerodynamically suitable during applica~
tion of the rubber component and that the adhesion
between the leading edge surface and the rubber is of
such uniformity and strength that the rubber component
will remain secure during service conditions. Alsol
care must be exercised to assure that the outer surface
.
of the applied rubber component remains as smooth as
possible for aerodynamic reasons.
Despite extreme care taken in applying these
rubber components to leading edges, it is common to
find that aircraft sections have irregular or non-
smooth rubber component surfaces at their Ieading
edges. Also, it is possible that the rubber component
can be destroyed or lost during service due to in-
sufficient adhesion. Furthermore, it has bee~ found
that when replacement of rubber components is necessary,
this operation is d7fficult and inefficient.
SUMM~RY
This invention provides a removable leading
edge portion for a selected section of an aircraft
which leading edge portion is a molded non-metallic
composi~e member consisting of an inner rigid component
and an outer sheet like flexible elastomeric compon~nt.
The composite is shaped and formed in a mold with the
rigid component orming to substantially the leading
edge contour and the elastomeric component mold
bonding to the outer surface of the inner component and
conforming to the proper aerodynamic contour. The
outer surface of the outer rubber component forms
substantially free of surface irregularities or wrinkles
due to the fact that substantially all irregulaxities
of the elastomeric component occur along the interface
of its inner surface and the rigid component outer
surface. These molded composites are readily installed
to function as the Leading edge of a selected aircraft
section, are easily replaceable, provide a substantially
wrinkle-free outer elastomeric surace for the leading
edge, and provide an elastomeric shoe or ~oot which is
uniformly and strongly bonded because of its being
ormed simultaneously with the inner component in an
appropriate mold. The molded composite~as applied to
an aircraft~section, provides a desired aerodynamic
surface and an aerodynamic force load carrying me~ber
or aerodynamic force transmitting member according to
the composite design and manner of attachment.
THE DRAWINGS
In the drawings of this speciication, the
invention is illustrated with respect to several pre-
sently preferred embodiments wherein
. ~
:
Fig. 1 is a perspective view of a portion of
an aircra~t wing structure;
Fig. 2 is a cross-section o the wing structure
of Fig. 1 taken along lines 2 - 2 of Fig. l;
Fig. 3 is a cross-sectional view similar to
Fig. 2 of a wing structure illustrating a modification;
Fig. 4 is a perspective view of a portion of
an aircraft; and
Fig. 5 is a cross-sectional view of the nose
structure o~ the aircraft shown in Fig. 4, taken along
lines 5 - 5 of Fig. 4~
DESCRIPTION
In Fig. 1 of the drawings, an aircraft wing
is generally referenced 10, which wing comprises a
principal or main body portion 12 and a leading edge
portion 14. The leading edge portion 14 is illustrated
as removably secured to the wing main portion 12 by a
series of spaced fasteners 16. Although not shown, the
removable leading edge portion 14 is understood to
extend con~inuously to the wing tip ~also not shown).
The construction of this leading edge portion is in
accordance with a presently preferred embodiment of
the present invention shown in more detail in Fig~ 2,
ox, alternatively, in Fig. 3.
In Fig. 2, removable leading edge portion 14
is shown as a ~tructural composike comprising an outer
~lexible sheetlike component 20 and an inner rigid
component 24. Outer component 20 is preferably composed
of flexible reinforced or unreinorced rubber, or
xubbexlike material. Innex component 24 is pre~exably
composed of rigid nonmetallic material such as plastic.
The outer and inner components are mold bonded to each
other (i.e. are united in a mold used to form the
composite to the leading edge contour).
The rubber outex component 20 as shown in
Fig. 2 and in accordance with a preferred embodiment is
a deicer shoe or blanket. As such, component 20
includes a plurality of chambers 22 adapted to receive
fluid, such as air, from a 1uid source (not shown~.
Upon receipt of air into chambers 22, portions of the
outer surface 26 of flexible component 20 expand or
bulge such as to break up ice which may form along the
leading edge portion of the wing. Deicers such as just
described are generally known a~ pneumatic deicers. It
is understood that deicer component 20 could also be an
electrical type deicer wherein a rubber blanket or shoe
is provided with embedded resistance coils which, when
energized, generate heat to melt ice which may form
along the leading edge of the wing. Control of deicer
operation, whether pneumatic or electrical, is usually
by the aircraft operator .
As stated, inner component 24 is preferably
of rigid plastic material and more preferably, is
constructed of such plastic reinforced by glass fibers.
This more preferred material, which is easily formed to
selected contours by molding, manifests strength and
durability in performance comparable to that of a metal
leading edge. Inner component 24 is carefully formed
to a preselected contour dictated by the required aero-
dynamic shape of the structure of which it is to form
part.
As seen urther in Fig. 2, deicer outer
component 20 is of such area so as to cover ~ubstan-
tially all of the outer surface 27 of inner component
24. This enables a good bond to be formed along the
inner surface 25 of deicer 20 and outer surface 27 of
component 24 during mold forming of the composite 14-
Also, as seen in Fig. 2, the marginal areas 23 o~
component 24 are not covered by deicer 20 and are
formed slightly thicker than remaining areas so as to
receive fasteners 16 securing the composite 14 to the
main body 12 of the wing. It is also understood that
composite 14 may be secured to the wing body 12 by
means other than fasteners, such as, for example, by
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suitable adhesives.
In Fig. 3, an alternate design is shown
wherein composite 14' secured to wing body 12' ~y
fasteners 16' comprises a flexible rubber outer compon~
ent 20' and an inner rigid plastic component 24'. The
difference between composite 14' and composite 14 as
shown in Fig. 2 is that outer component 20' of compos-
ite 14' is a simple rubber sheet member which does not
function as a deicer. Thus, in this case rubber com-
ponent 20' functions solely as a protective coveringfor the leading ~dge area of the aircraft. These
protective coverings or "erosion shoes" are often used
rather than deicer blankets where ice ormation is not
an expected occurrence.
In both Figs.2 and 3, it is noted that the
~ composites are applied to a wing structure which is
- foreshortened at what is typically its leading edg~
section such that the inner components 24 (Fiy. 2) or
24' (Fig. 3) become th force load carrying or aero-
dynamic force transmitting members. It is understood,
however, that composites according to the present
invention may be applied in glove-like fashion over
wing sections which have not been foreshortened where a
leading edge portion of the wing remains integral with
the wing body. This alternate ~orm has the advantage
that the force carrying and transmitting function of
the rigid component of the composite is complemented by
the wing proper through presence of the integral
leading edge of the wing.
Figsr4 and 5 illustrate another preferred
environment where the present invention is applicable.
Fig. 4 shows an aircraft 30 wherein the nose area 32
thereof is constructed in accordance with the present
invention. Sensitive equipment such as radar equipment
is often mounted within these nose portions and such
nose portions commonly feature eroslon shoes or blankets.
As seen in Fig. 5, nose portion 32 of plane
30 is a removable composite comprising an inner rigid
component 44 and an outer flexible component 40 shown
in the form of an erosion shoe.
Erosion shoe 40 of composite 32 forming the
; nose portion of aircraft 30 is also composed of 1exible
reinforced or unreinforced rubber or rubberlike material.
Inner rigid component 44 is preferably rigid plastic,
and also, more preerably, fiber reinforced plastic as
10 is the inner components 24 and 24' of leading edge
composites 14 or 14'. As in the embodiments previously
described~ inner component is carefully formed to a
preselected contour in a mold along with the erosion
shoe sheet to achieve strong and uniform bonding
15 between the inner surface 45 of the erosion shoe
component 40 and the outer surface 47 of inner compon-
ent 44.
From the foregoing, it is evident that this
invention has application to other aircraft sections
20 where rubber covered leading edges are used. Thus, for
example, these removable leading edge composites could
be used as the leading edges of tail wings, tails,
propellers or rotor blades in rotary winy type aircraft.
As previously indicated, leading edge com-
posites constructed in accordance with the present
invention are readily molded composites. Typica]ly
these composites can be mold formed by placing within a
mold cavity of required pre elected aerodynamic contour
the two component materials in uncured, partially cured
30 or cured states. Specifically, a suitable sized layer
or layers of rubber can be placed against the female
portion of the mold, against which rubber layer is
placed the fiber reinforced plastic layer in a par-
tially cured state. A male mold member, or preferably
35 conventional bagging techniques, can then form
the composite by pressure against the female mold
member, while heat introduced into the mold cures the
composite within the aerodynamically contoured cavity
between the mold members. Mold forming these composites
in this manner has been found to provide a leading edge
with well-bonded components wherein the outer rubber
component is substantially smooth and wrinkle~free.
This latter characteristic is believed due to phenomena
occurring during the molding operation, where surface
irregularities appear adsorbed along the interface
between ~he inne~ surface of the outer flexible component
and the outer surface o~ the inner rigid component.
From the foregoing specification which describes
the invention in several preferred embodiments, it is
evident that departures from and modifications to these
embodiments can be made within the scope of the invention,
which scope is to be measured by the following claims.
