Title of Invention

A DROGUE ASSEMBLY FOR INFLIGHT REFUELING

Abstract "A drogue assembly for in-flight refueling" ort arms. Each A drogue assembly comprises a circumferential array of triangular swinging movement support arm is pivoted and mounted on a pivot pin at its apex for in a radial direction. Each juxtaposed pair of support arms is joined together by a net hich is joined to each of those support arms at spaced intervals therealong. The w J su ort arms carry a drogue parachute which extends circumferentially around their pp shortest sides.
Full Text

This invention relates to a drogue assembly for inflight refuelling.
Drogues are used to stabilise refuelling hose trailing
from a tanker aircraft in a generally horizontal attitude.
They provide drag for a refuelling coupling at the
trailing end of the refuelling hose which is to be coupled
> for in-flight refuelling with a probe from a following
aircraft which is to be refuelled. This drag resists the
forward movement of the probe*
A known form of drogue assembly for in-flight
refuelling comprises a circumferential array of support
arms, each pivotaliy mounted on a respective pivot pin, the
pivot pins being arranged in a ring from which the support
arms extend in one direction which is generally parallel to
an axis with which the array is concentric, each support
arm being mounted so as to be pivotable in a direction
which is radial with respect to said axis, each support arm

support arm nearer to the axis being longer and the side remote from the ring being shorter than the third side, and a drogue parachute which is fitted to the shorter sides of the support arms, the arrangement being such that the support arms with the drogue parachute thereon can be collapsed within a cylindrical envelope having a diameter
which is approximately that of the rin§ of pivot $£fit/
whereas the drogue assembly is towed by an aircraft in

flight, being extended in the manner of a parachute with the support arms flared outwardly from the axis, trailing the ring of pivot pins.
If tie wires, each having a retaining ball at either end, are provided for limiting the circumferential spacing between adjacent support arms of the circumferential array, there is a risk of engine damage should such tie wires break, as the broken tie wire pieces may be dislodged from the drogue assembly and drawn into an engine air intake. This problem can be reduced, but not eliminated, by providing each tie wire with a third retaining ball between its ends so only part of the wire with a single ball may be dislodged in the event of a break.
One object of this invention is to provide a drogue
assembly of the kind referred to above with means for
limiting the circumferential spacing of the support arms
which is unlikely to break into pieces which may be dislodged from the assembly*
According to this invention there is provided a drogue assembly of the kind referred to above, wherein each adjacent pair of support arms are joined together by a net.
Preferably each net is joined to a respective support arm at spaced intervals along the latter. Each joint may comprise a loop of the net material which is retained within a respective aperture in the support arm. The apertures may be in a row, adjacent apertures being interconnected by respective elongate passages which are in line and the loops being retained within their respective

apertures by a common pin which is inserted into the aligned passages so that it bridges each of the apertures wherein it is threaded through the respective loop so that the net is joined to the support arm by the pin which is threaded through the row of loops and which is retained within the aligned passages. Preferably each loop of net material is wound circumferentially around a reel through which the pin extends, the reel being entrapped within the net by the loop that is wound around it. Conveniently the reel is flanged at either end so that it forms an annular channel within which the cord material wound therearound is received. There may be an arcuate link formed integrally with the remainder of the reel and joined at either end ,to a respective one of the flanges so as to cooperate with the flanges to form an aperture through which the net material wound around the reel is passed.
In a preferred embodiment of this invention, each support arm is provided with a hook element at either end of its shortest side, each hook element facing the other and receiving the respective edge portion of the drogue parachute which is retained therein by retaining means fitted therein, whereby the drogue parachute is fitted to the circumferential array of support arms.
Preferably the retaining means comprise a strap element which is enlarged at its free end and which is joined to the outer surface of the respective hook element, the enlarged end being a sliding fit within the hook cavity.

One form of drogue assembly in which this invention is embodied is described now by way of example with reference to the accompanying drawings, of which:-
Figure 1 is a general view in perspective of a drogue assembly, with its clamping rings shown separately, displaced therefrom;
Figure 2 is a section on the line II-II of Figure 1, showing a support arm in elevation with part of the drogue parachute to which it is to be fitted;
Figure 3 is a view on arrow III in Figure 2 of a fragment of the drogue assembly; and
Figure 4 is a fragmentary view in the direction of arrow IV in Figure 2«
The drawings show a drogue assembly 10. The drogue assembly 10 comprises a circumferential array of support arms 11. Each support arm 11 comprises a generally triangular metal frame 12 having a short side 13 and two longer sides 14 and 15. One, 14, of those longer sides , which is a little longer than the other longer side 15, is disposed radially inwardly with respect to that other side 15 and is fitted into the channel of a metal channel section member 16♦ There is a clearance between the edge of the frame 12 within the channel and the base of that channel. The frame 12 is rivetted to the channel section member 16. The short aide 13 of each support arm 11 has a hook element 17,18 of plastics material secured to it at

either end by bolts so that the hook cavities of the two hook elements 17 and 18 face each other.
Each support arm 11 is pivotally mounted in the region of its apex 19 which is formed by the two longer sides 14 and 15, for swinging movement in a radial direction* Each support arm 11 is pivotally mounted on a pivot pin 21 which passes through a hole 22 in the frame 12 in the region of the apex 19. The pivot pins 21, which aire arranged end to end in a ring, as can be seen in Figures 1 and 2, are trapped between inner and outer clamp rings 23 and 24. The inner clarap ring 23 is castellated around its outer surface at one end so that it forms a circumferential array of abutments 25 against which the pivot pins 21 are held by the outer clamp ring 24 which is fitted over the remainder of the inner clamp ring 2 3 which projects through the ring of pivot pins 21. The outer clamp ring 24, which tapers away from the support arms 11, has an annular array of
slots 26 formed in its larger diameter end, eaeh slot 26 being aligned with a respective one of the support arms 11.
The slots 26 are also aligned with the spaces between the
abutments 25 and each slot 26 and the space with which it
is aligned allows for the swinging movement of the aligned
support arm 11. The clamp rings 23 and 24 ate bolted
«
together with pivot pins 21 trapped between them. The
pivot pins 21 are trapped between the clamp rings 23 and 24 in a mannar which allows each support arm 11 to pivot
independently of the others.



respective support arm 11. A pin 36 extends through the aligned passages 35 from and to end of the frame 12 so that it bridges the line of apertures 34 and is passed through
i
the central aperture of each reel 33 in each aperture 34 ; whereby each reel 33 is retained within the respective i
i
aperture 34 and the nets 27 on either side of each support arm 11 are connected to that support arm 11. The pin 36 has a hooked end 37 (see Figure 3) which is fitted into an alcov4 in the hook element 18 at the adjacent end of the short side 13 so that it is entrapped therein, the alcove having a slot-shaped mouth through which the pin 36 projects.
Figure 1 shows that the support arms 11 carry a drogue parachute 38 which extends circumferentially around their short sides 13* The drogue parachute 38 comprises a circumferentially continuous strip of fabric which is reinforced along each of its axially-spaced peripheral edges by a respective fabric cord hoop 39,41. Figures 3 and 4 shows that the fabric of the drogue parachute 38 is cut away in the region of each hook element 17,18 to expose the respective hoop 39,41 which is received in the hook cavity of that hook element 17,18. There is sufficient clearance at the mouth of the hook cavity for the hoop 39,41 to be passed through it during assembly. Each hoop 39,41 is retained in the respective hook cavity by an enlarged end 42 of a strap element 4 3 which is fitted into the hook cavity between the hoop 39,41 and th« mouth of the hook cavity and which is too large to be passed through the

mouth of the hook cavity. The enlarged end 42 was inserted
into the hook cavity from one side thereof and is a sliding
fit therein. The remainder of the strap element 43 extends
frbm the enlarged end 42 through the mouth of the hook i > cavity and around the outer surface of the respective hook
element 17,18 to which it is joined.The strap element 43/
including its enlarged end 42, is integral with the
respective hook element 17,18, the whole being a moulding
of plastics material.



1. A drogue assembly for in-flight refuelling
comprising a circumferential array of givotally-mounted
support arms, each extending in one direction which is
generally parallel to an axis with,which the array is
? concentric, each support arm being pivotable in a direction
which is radial with respect to said axis,|&nd a drogue parachute which is fitted to the support arms, the arrangement being such that the support arms with the drogue parachute thereon can be collapsed within a cylindrical envelope having a diameter substantially that of the pivot mounting of the array, whereas when the drogue assembly is towed by an aircraft in flight, it is extended in the manner of a parachute with the support arms flared outwardly from the axis, trailing the pivot mounting, wherein each adjacent pair of support arms are joined together by a net.
2. A drogue assembly according to claim 1, wherein each net is joined to a respective support arm at spaced intervals along the latter.
3. A drogue assembly according to claim 2, wherein each joint comprises a loop of the net material which is retained within a respective aperture in the support arm*
a
4. A drogue assembly according to claim 3, wherein
the apertures are in a row, adjacent apertures being
interconnected by respective elongate passages which are in
♦ * *
line and the loops being retained withini their respective apertures by a common pin which is inserted into the

aligned passages so that it bridges each of the apertures wherein it is threaded through the respective loop so that the net is joined to the support arm by the pin which is threaded through the row of loops and which is retained within the aligned passages.
5- A drogue assembly according to claim 6. A drogue assembly according to claim 5, wherein the reel is flanged at either end so that it forms an annular channel within which the net material wound therearound is received.
7. A drogue assembly according to claim 6,
including an arcuate link formed integrally with the
remainder of the reel and joined at either end to a
respective one of the flanges so as to cooperateiwith the
flanges to form an aperture through which the net material
wound around the reel is passed.
ft, A 4royu# a*fi*fftt)ly according to any ©no of oiaims
1 to 7, wherein each support arnuis provided with a pair of
hook elements at its end remote from its pivot mounting,
the hook elements being spaced apart in the direction of
pivotable movement of the support arms and each hook
element facing the other and receiving a respective edge
portion of the drogue which is retained therein by

retaining means fitted therein, whereby the drogue is fitted to the circumferential array of support arms.
9. A drogue assembly according to claim 8, wherein
the retaining means comprise a strap element which is
enlarged at its free end and which is joined to the outer
surface of the respective hook element, the enlarged end
being a sliding fit within the hook cavity.
10. A drogue assembly substantially as described
hereinbefore with reference to and as illustrated in the
accompanying drawings.


Documents:

441-mas-1998-abstract.pdf

441-mas-1998-claims duplicate.pdf

441-mas-1998-claims original.pdf

441-mas-1998-correspondence others.pdf

441-mas-1998-correspondence po.pdf

441-mas-1998-description complete duplicate.pdf

441-mas-1998-description complete original.pdf

441-mas-1998-drawings.pdf

441-mas-1998-form 1.pdf

441-mas-1998-form 26.pdf

441-mas-1998-form 3.pdf

441-mas-1998-form 4.pdf


Patent Number 208536
Indian Patent Application Number 441/MAS/1998
PG Journal Number 27/2007
Publication Date 06-Jul-2007
Grant Date 02-Aug-2007
Date of Filing 04-Mar-1998
Name of Patentee FLIGHT REFUELLING LIMITED
Applicant Address WIMBORNE ,DORSET,BH21 2BJ.
Inventors:
# Inventor's Name Inventor's Address
1 ROY G S YOUNG WIMBORNE ,DORSET,BH21 2BJ.
PCT International Classification Number B64D39/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 9704472.1 1997-03-04 U.K.