Aircraft engine protective cover

This invention relates to a shroud or flexible wall cover which is adapted to be placed onto the nacelle of an aircraft engine. The shroud is positioned to cover the nacelle discharge port through which hot, high velocity exhaust gases normally are discharged. The formation of a provisional closure across the exhaust gas discharge port precludes the entry of fumes and/or mist from inadvertently spilled fuel entering the discharge port and igniting when coming into contact with hot engine parts. The shroud is provisionally placed into operating position immediately prior to a transfer of fuel from a fueling vehicle into the wind tanks of the aircraft.

BACKGROUND OF THE INVENTION 
In many types of aircraft, particularly those utilizing multiple jet 
engines, the latter are mounted in an underslung position on the 
aircraft's wings. The engines or power units are normally surrounded by a 
streamlined, cylinder-like closure or nacelle. The latter is shaped to 
intake air at one end, which is guided to the jet engine, and then 
discharged through an exhaust port as hot gas. 
It is also customary in aircraft design to position fuel tanks inside the 
aircraft wings. As a practical matter, locating fuel tanks near to the 
wing supported engines, facilitates metering of the fuel to control the 
engines. 
Normally, when an aircraft has landed after a flight, and is to continue to 
another destination, common practice in the industry is to position a 
mobile refueling vehicle underneath, or adjacent to the aircraft wings. 
Thus, fuel can be pumped upwardly through a fuel hose at the underside of 
the wing, and into the wing tanks. 
On occasion, due to a defect in fuel pumping equipment, or to human error 
or accident at the loading site, fuel under pressure will be discharged 
into the atmosphere and onto the ground. The released fumes, being lighter 
than air, will tend to rise. Raw fuel under pressure will be released into 
the surrounding area. 
If the aircraft's engines have been operating within sufficiently hot 
temperatures to exceed the auto ignition temperature of the fuel vapor and 
mist contact of the vapors with such hot parts could trigger ignition. The 
ensuing flames and/or explosion could prompt injury or even death to 
personnel in the vicinity. The aircraft will also suffer damage or 
complete destruction in the conflagration. 
Toward precluding this undesired eventuality, there is presently provided a 
flexible wall shroud member adapted to operate in conjunction with an 
aircraft refueling operation. The shroud is shaped such that it can be 
folded and stored conveniently when not in use. However, it can be readily 
opened and registered onto an engine nacelle. 
The shroud is conformed that it will cover only the discharge end of an 
engine nacelle where hot gases are discharged into the atmosphere and 
where the engine parts retain the greatest heat. It thus furnishes a 
protective shield or provisional enclosure across the nacelle discharge 
port. 
It is therefore an object of the invention to provide means for safely 
permitting the transfer of vaporous fuel into an aircraft fuel tank, while 
minimizing the possibility of fuel vapor and/or mist ignition. 
A further object is to provide a flexible wall closure which provisionally 
engages a portion of an aircraft engine nacelle, thereby defining a 
closure across the latter's discharge port which would otherwise allow 
access of vapor and fuel mist to hot engine parts.

Referring to the drawings, an aircraft 10 of the type to which the present 
invention applies can assume any of a number of configurations without 
departing from the novel concept of the invention. Illustrative of such an 
aircraft is the type wherein wing 11 is sufficiently large that an engine 
12 or a plurality of engines can be mounted in an underslung position 
beneath the wing. 
Engine 12 as shown, is connected in supporting relation to the underside of 
wing 11 by a support brace 14. The latter is normally provided with a 
shaped housing to assure streamlining of the structure to minimize 
resistance as the craft travels through the air. 
Engine 12 as shown in FIG. 2, includes an internal jet power plant 16 which 
is provided with an external, nacelle 17. The latter is generally, as a 
matter of convenience, fashioned in discrete, individual segments. 
Preferably, nacelle 17 is cylindrical in configuration, having an enlarged 
air intake opening 18 at the forward end and an annular exhaust gas 
discharge port 19 at the rear end. This structure will allow nacelle 
segments to be removed individually and permit access to various parts of 
power plant 16. The nacelle is normally fabricated of aluminum or 
titanium, the segments being held in position by a suitable fastening 
means such as screws, rivets, etc. 
The forward end of nacelle 17 is shaped with a rounded edge at enlarged 
opening 18 to allow entry of air into jet power plant 16 as the aircraft 
moves rapidly through the atmosphere. The nacelle's discharge or rear end 
port 19 is defined by a peripheral rim 21. 
A conically shaped gas flow guide 20 positioned coaxial of nacelle 17, 
extends rearwardly from the discharge port to define port 19 into an 
annular opening. Said member functions to guide engine exhaust gases into 
the atmosphere. 
The plane's fuel holding tanks are normally positioned in the wings, 
preferably adjacent to the aircraft body. To facilitate a fuel loading 
operation, an access opening to the respective fuel tanks is formed into 
the wing undersurface. This positioning permits ground personnel to 
simplify a refueling operation by locating a mobile fueling vehicle 26 
adjacent to the wing. Thereafter communication is achieved through a flow 
control nozzle 27 which sealably engages fuel loading port 29 by way of a 
hose 28. 
Prior to commencing pressurized flow from the mobile fueling vehicle 26 
into the aircraft tanks, a shroud 31 is disposed over at least a part of 
the engine nacelle 17 surface. Shroud 31 is formed of a flexible or 
non-rigid material which facilitates its being folded into a compact unit 
for storage on the fueling vehicle or in ancillary carrying means. The 
resiliency of shroud 31 will cause the shroud fabric to conform to the 
contour of nacelle surface when supported thereon. 
Referring to FIG. 3, Shroud 31 is shaped to be manually slid onto the rear 
portion or discharge end of nacelle 17. The shroud includes an elongated 
conical body 34 having an adjustable collar 32. Collar 32 is comprised of 
a periplheral lip 41 which engages the enlarged end of body 34 by way of 
an intermediate segment 42. Since the shroud is formed of a reinforced 
fabric or the like, the pieces and segments which comprise the whole unit 
are preferably joined through several seams. 
The shroud, when properly placed, forms a generally conical configuration 
extending rearwardly from fastening collar 32, being supported by the 
nacelle's surface as well as by the protruding conical exhaust gas guide 
20. In effect, shroud 31 in its reclining position on the engine nacelle, 
defines a closure across the entire rear of the nacelle as well as the 
annular discharge port 19 between rim 21 and conical gas guide member 20. 
To fix, or provisionally fasten shroud 31 in place, means is provided at 
collar 32 such that the latter can be contracted or drawn tightly around 
the periplheral nacelle rim 21 to a sufficient degree to avoid the shroud 
falling from the nacelle. Without proper fastening, the shroud could be 
dislodged accidentally, particularly in an open area, due to the wind 
blowing it from its position. Collar 32 can therefore be provided with an 
external belt 33 or an internal drawstring type arrangement. Either 
alternative would allow the collar to be pulled tight into a constricted 
peripheral seal when it is in place on rim 21. 
Alternatively, the shroud might be adjusted into the tight, sealed position 
by a Velcro connection wherein cooperating elements of the Velcro member 
are positioned on corresponding segments of collar 32. Firm positioning of 
the collar about rim 21, whether it be a belt, a Velcro connection, or 
other, will permit the shroud to accommodate, or be adapted to a number of 
different nacelle configurations. This is a desired feature since all 
aircraft engines do not conform to a common dimension. 
Shroud 31 is constructed preferably to be of a quasi-rigid nature, with a 
conical rear portion which, as noted, engages rearwardly extending conical 
gas guide 20. Thus, during a refueling operation, should the pressure hose 
28 which connects the fueling vehicle fuel pump, with flow control nozzle 
27, be inadvertently broken or subjected to sufficient strain as to 
rupture, a tragic and expensive accident will be avoided. The pressurized 
fuel flow can be discharged into the atmosphere in the vicinity of the 
fueling vehicle and/or aircraft with minimal concern of the vapors 
igniting. Since the exhaust gas discharge port 19 is provided with a 
closure by means of the shroud, ignitable fuel mist and vapors emanating 
from spilled or discharged fuel, will be blocked from entering the nacelle 
discharge port to contact the hot engine parts. 
At the completion of a refueling sequence, loading hose 28 and its flow 
control nozzle 27 are disconnected from the wing fuel inlet port 29. 
Shroud 31 is detached by loosening fastening collar 32 from its sealed 
condition about the nacelle discharge ring 21. Shroud 31 will thereby be 
loose enough to be slid rearwardly across conical element 20. It can 
thereafter be folded into a more compact form until its use is again 
required. 
Structurally, shroud 31 is formed of a composite material such as 
fiberglass impregnated canvas to furnish the member sufficient strength, 
as well as a degree of resiliency. To endure normal handling under severe 
operating conditions, the shroud material must further be heat resistant 
to a minimum temperature of about l000.degree. F. Preferably, and as 
mentioned, a material suitable to this application would be a composite of 
one or more fabrics which are layered or impregnated with a strengthening 
agent. 
Referring to FIG. 4, in one embodiment shroud 36 when unfolded, takes the 
preferred configuration of a generally conical body segment having a 
closed cap at one end, and a periplherally adjustable collar 37 at the 
other. To facilitate shroud 36 being manually placed onto an engine 
nacelle, collar 37 can be provided with extended rods 38 and 39 at 
opposite sides of collar 37 at rod end sockets 44 and 46. Thus, the shroud 
can be lifted manually to a height wherein the opened shroud can be pulled 
along the rear end of an engine nacelle to engage the discharge opening 
rim or the outer surface of the nacelle whereby to be firmly fastened in 
place. 
To further facilitate a proper fit between the shroud and an engine 
nacelle, collar 37, as shown in FIG. 4, can include an adjusting section 
at which the collar ring is split. Each side of the split, i.e. 51 and 52, 
can be provided with a mating component of a Velcro connection. This 
take-up feature will supplement the main collar tightening feature as the 
latter is fastened. 
Referring to FIG. 4, to accommodate nacelles which may have unusual 
structural features, the shroud can be altered by the addition of cutaway 
sections in the collar or the conical body. Alternately, such cutaways can 
be provided with fastening means such as Velcro connectors, or the like. 
It is understood that although modifications and variations of the 
invention can be made without departing from the spirit and scope thereof, 
only such limitations should be imposed as are indicated in the appended 
claims.