Helicopter target

A remote-controlled autogyro visually and functionally simulates a helicopter with stub wings (e.g. the Hind D), so that an expendable helicopter-simulating target is produced. The target has a fixed angle rotor shaft, the rotor being solely aerodynamically controlled. The rotor blades have a negative pitch angle, and a positive conning angle. The engine is mounted at the front of the fuselage and has a downthrust angle, and the horizontal stabilizer also slopes downwardly aft. The rotor is at about the center of lift (horizontally) of the wings, and the wing span is about 50-60 percent the length of the fuselage. The ailerons and tail rudder are electrically interconnected. Remote control is provided for the elevators ailerons, and engine speed.

BACKGROUND AND SUMMARY OF THE INVENTION 
It is very important for ground troops, and other military personnel, to be 
able to distinguish between various types of aerial targets, as well as to 
have realistic practice in bringing down the targets by small arms fire or 
the like. RS Systems of Beltsville, Md., has developed a wide variety of 
aerial targets that fit this need for planes, however heretofore a 
realistic helicopter target has not been provided. 
In order for a device to be practically utilized as a target, it must be 
expendable; that is it must be able to be produced commercially at a 
relatively low cost (e.g. less than one thousand U.S. 1987 dollars). Yet, 
at the same time it must accurately simulate a helicopter, including 
having a rotating main blade assembly, so that it will be effective as a 
target, and will give those taking target practice the ability to 
distinguish it from other types of helicopters. That is, the helicopter 
simulation must be accurate enough so that the military personnel can 
learn to distinguish between relatively similar friendly and foe 
helicopters. 
According to the present invention, a target helicopter is provided that 
meets all the necessary criteria for a helicopter target. It is 
expendable, being able to be produced at a relatively low cost (e.g. less 
than one thousand U.S. 1987 dollars). It presents a very realistic 
three-dimensional visual representation of a real helicopter, and is also 
capable of performing flight patterns that will be encountered in combat 
(that is simulating the flight of a helicopter). 
While the target according to the invention is capable of simulating any 
helicopter having stub wings, it is particularly desirable for use in the 
simulation of the Hind D, one of the most effective Soviet combat 
helicopters. Of course simulation of the U.S. Apache helicopter also may 
be provided so that military personnel can learn to easily distinguish 
between foe and friendly helicopters. 
The target according to the invention comprises a wheel less, hand 
launchable remote controlled autogyro. By providing a particularly 
constructed autogyro, helicopter simulation (both visual and flight 
pattern) may be provided while allowing inexpensive production since the 
production of an actual target helicopter would be extraordinarily 
expensive, and such a target would be very difficult to effectively 
control by conventional remote control mechanisms. While the target 
according to the invention simulates the combat flight of a helicopter, it 
is essentially as easy to control as a conventional remote controlled 
target plane, such as those manufactured by RS Systems. 
The autogyro of the invention has a fuselage section which simulates the 
fuselage of a helicopter with stub wings. Preferably, the autogyro has a 
single, only aerodynamically controlled, fixed angle shaft rotor assembly. 
If there is a necessity for pre-rotation of the rotor to assist in 
launching, the shaft may be made rotatable and gearing means provided with 
it to allow for pre-rotation utilizing a hand drill or other common power 
source, to effect the initial rotation while allowing easy disengagement 
of the power source from the shaft, and hand launching. 
The remote controlled flying target according to the invention includes a 
fuselage section simulating a helicopter and having fore and aft portions, 
a rotor, a remote controlled engine for powering the target through the 
air, a horizontal stabilizer (preferably with elevators), and a pair of 
wings operatively connected to the fuselage section and extending 
outwardly therefrom, each wing having an air foil. The rotor includes a 
rotor shaft upstanding from the fuselage and attached to a rotor head. The 
rotor shaft is tilted aft a fixed angle of about 5.degree.-10.degree.. The 
rotor head includes air foil blades having a negative pitch angle between 
about 3.degree.-7.degree., and preferably having a conning angle also 
between about 3.degree.-9.degree.. Remote control elevator and roll and 
yaw structures are provided, and all of the elements comprising the target 
are constructed so that the target is capable of flight simulating the 
combat flight of a helicopter, while the device is useful as an expendable 
target. 
In order to ensure that the target craft is stable and pulled forward 
through the air, in addition to the rotor being tilted about 5.degree. 
aft, the engine--which is at the fore of the fuselage--is disposed at a 
downthrust angle of between about 5.degree.-12.degree. (e.g. 10.degree.) 
with respect to a line of horizontal movement of the helicopter. Further, 
the incidence of the horizontal stabilizer, at the rear of the target, is 
about 3.degree.-10.degree. (e.g. 7.degree.) to the horizontal line of 
flight. 
The rotor is preferably disposed at about the center of lift of the wings, 
and the wings preferably have a span of between about 50-60 percent the 
length of the fuselage, so that the wings provide sufficient lift but do 
not significantly detract from the overall helicopter simulation the 
target provides. 
The wings preferably have ailerons, and the tail is provided having a 
rudder. The ailerons and rudder are operatively linked together to 
cooperate to provide effective right or left roll and yaw control. A very 
simple remote control device may be utilized, including a throttle control 
for the engine and a joy stick for controlling the elevators, the roll, 
and yaw. 
As previously mentioned, not only is the target according to the invention 
capable of flight simulating combat flight of a helicopter, but it is hand 
launchable. Also it may be recovered after use if not shot down (or was 
used in a tracking or indoctrination session), and reused. 
It is the primary object of the present invention to provide an effective 
helicopter simulating, expendable target. This and other objects of the 
invention will become clear from an inspection of the detailed description 
of the invention, and from the appended claims.

DETAILED DESCRIPTION OF THE DRAWINGS 
The target according to the present invention is shown generally by 
reference numeral 10 in FIG. 1 and includes as the major portions thereof 
a fuselage section 11, wings 12, a rotor assembly shown generally by 
reference numeral 13, a remote controlled engine shown generally by 
reference numeral 14, a horizontal stabilizer 15, and a tail 16. The 
engine 14 is disposed at the fore portion of the fuselage 11, while the 
tail 16 is at the aft portion. 
Note that the fuselage section 11 in the embodiment shown in the drawing 
simulates a Hind D helicopter. Note that the target 10 provides a very 
accurate three-dimensional simulation of a Hind D helicopter. However 
since the target is an autogyro rather than a helicopter there are certain 
distinctions between it and the real helicopter it simulates, including the 
particular disposition of the rotor (both with respect to the wings and 
fuselage), the span of the wings, the position of the horizontal 
stabilizer with respect to the fuselage, the angular relationship and 
dispositions of the elements, and of course the provision of a power 
source (14) at the fore portion of the fuselage. 
The engine 14 is a conventional liquid fuel-powered remote controlled 
engine such as used on conventional remote controlled target planes of RS 
Systems. The fuselage section 11 is primarily styrofoam, as for 
conventional RS Systems' target planes, with interior components of other 
materials as will be hereafter described. The wings 12 also preferably are 
of styrofoam, while the shaft 20 of the rotor 13 is of metal. The rotor 
head 21, which includes blades 22, may also be made of metal, with the 
blades 22 themselves of beech wood or the like. Preferably the rotor is a 
three-bladed rotor. 
As seen in FIG. 6, relatively rigid interior components may be provided for 
mounting the engine 14, etc., to provide sufficient rigidity for the 
working components of the target 10 so that it is operational. For example 
an aluminum generally L-shaped bar (known as a "motor bearer") 25 may be 
provided to which the motor 14 is attached at end 26 thereof, in a manner 
conventional for RS Systems' target airplanes, and a piece of relatively 
rigid sheet material (such as plywood) 27 is provided to which the wings 
12 are glued after the wings are moved into abutting engagement with the 
plywood 27. Openings (not shown) in the styrofoam fuselage will be 
provided to allow insertion of portions of the wings 12 to abut the 
plywood 27. 
In the embodiment illustrated in FIG. 6, the plywood 27 also comprises a 
means for mounting the rotor shaft 20, which shaft is fixed, the head 
portion 21 including bearings to allow rotation of the blades 22 about an 
axis defined by the shaft 20. The shaft 20 preferably comprises an 
elongated bolt having a head 30 with a flattened portion thereof 31 at one 
end, and a screw-threaded portion 32 or the like for receiving a nut (not 
shown) for holding the head portion 21 in place on the shaft 20. A pair 
J-bolts 33 or the like may be provided for holding the shaft 20 onto the 
plywood 27 so that the shaft 20 upstands from the plywood 27 and motor 
bear 25. 
The various angular dispositions and orientations of the components of the 
target 10 that allow it to effectively simulate helicopter flight are seen 
most clearly in FIGS. 4 and 5. 
Note that in FIGS. 4 and 5, the angular relationships are greatly 
exaggerated for clarity of illustration. For example, the angle B is shown 
at about 30.degree., when in fact it would only be between about 
5.degree.-10.degree.. 
The shaft 20 is tilted aft a fixed angle A, which is between about 
5.degree.-10.degree., and the rotor blades 22 preferably have a conning 
angle B which is between about 3.degree.-9.degree.. The engine 14 includes 
a propeller 35 and a propeller shaft 36. The engine 14 (actually the 
propeller shaft 36) has a downthrust angle C with respect to the line 38, 
the angle C being between about 5.degree.-12.degree.. The line 38 is a 
datum line extending generally along a horizontal line of travel of the 
target 10. 
The horizontal stabilizer 15 is disposed at an angle E with respect to the 
datum line 38, or any line parallel thereto. Preferably the angle E is 
between about 3.degree.-10.degree., with the horizontal stabilizer 15 
sloping downwardly aft. The air foil plates 22 of the rotor 13 (see FIG. 
5) provide stability for the target 10, being disposed at a negative pitch 
angle D which is between about 3.degree.-7.degree., the edge 40 providing 
the leading edge of the air foil blade 22 while the edge 41 is the 
trailing edge. 
The shaft 20 (rotor 13) is disposed horizontally along the fuselage 11 at 
approximately the center of lift of the wings 12, such a disposition of 
the rotor 13 being illustrated in the drawings. Also, the wings 12 angle 
slightly downwardly as they move away from the fuselage, and have a 
significant span, although the area thereof is not too important. The span 
of the wings 12 typically would be between about 50-60 percent of the 
length of the fuselage 11. The wing span should be such that the wings 12 
provide sufficient lift but do not significantly detract from the overall 
helicopter simulation the target presents. 
In a specific exemplary embodiment of the target 10 according to the 
invention, the following specific dimensions are provided: fuselage length 
85 inches; fuselage height 18 inches; fuselage width 9 inches; wing span 48 
inches; rotor diameter 60 inches; angle A 6.degree.; angle B 7.degree.; 
angle C 10.degree.; angle D 5.degree.; angle E 4.degree.. 
In order to provide for effective flight control of the helicopter 10, the 
wings 12 preferably are provided with ailerons 45, the tail (vertical 
stabilizer) 16 is provided with a rudder 46, and the horizontal stabilizer 
15 has elevators 47. The ailerons 45 and rudder 46 are electrically 
connected together so that they provide effective roll and yaw control 
(i.e. right roll and left roll), and the elevators 47 are also remote 
controlled. 
FIG. 7 illustrates the aft portion of the fuselage 11 adjacent the vertical 
stabilizer 16 and shows a cut-out 50 formed in the styrofoam fuselage 
section for mounting the horizontal stabilizer at the top of the fuselage 
section, extending angularly downwardly as described earlier. 
In one form of target according to the invention, the rotor shaft is fixed, 
as illustrated in FIG. 6. The rotor 13 is only aerodynamically controlled. 
This is distinct from most autogyros which provide some mechanism for 
adjusting the position of the rotor shaft and/or other components with 
respect to the fuselage. 
A power assist can be provided to help in launching of the target 10. One 
way that this could be done is illustrated schematically in FIG. 8 in 
which the shaft 55 is the rotor shaft (connected at the opposite end from 
that illustrated in FIG. 8 to the rotor head) and is rotatable with 
respect to the fuselage 11, one or more bearings (schematically 
illustrated at 56 in FIG. 8) being provided. Adjacent the bottom of the 
rotor shaft 55 is a first gear 58. A second gear 59 is mounted on a small 
shaft 60 and is movable against the bias of the coil spring 61 from a 
first position (illustrated in FIG. 8) in which it is spaced from the gear 
58, to a second position wherein the gears 58, 59 engage (mesh). The free 
end 62 of the shaft 60 typically would be dimensioned and/or shaped so 
that it could be readily engaged by a power source to effect rotation of 
the shaft 60, and thereby rotation of the gears 59, 58 and the shaft 55. 
In the use of the launch assist illustrated in FIG. 8, the person doing the 
launching, or a helper, would hold the fuselage 11 in place and access the 
end 62 of the shaft 60 through the opening 64 provided at the bottom of 
the fuselage 11 for access-gaining purposes. The shaft end 62 would then 
be engaged by a power source, such as by an adaptor connected to a hand 
drill, an upward force would be applied causing the gear 59 to move to its 
second position against the bias of the spring 61, and rotation of the 
shaft 60 would be effected, which of course would in turn effect rotation 
of the rotor shaft 55. Once the desired speed of rotation of the shaft 55 
had been achieved, the power source would be removed from operative 
association with the shaft 60, the gear 59 would move away from the gear 
58 under the bias of spring 61, and the target would be hand launched. 
FIG. 9 illustrates schematically an exemplary simple remote control unit 
which may be utilized for use with the target 10. The remote control unit 
65, which of course would be held by the person "flying" the target 10, is 
as simple as that for conventional target planes, such as those of RS 
Systems. A throttle control lever 66 is movable from an off to a full 
throttle position, while a joy stick 67 is provided for elevator control, 
and pitch and yawl control. Movement of the joy stick in the dimensions 
indicated by line 68 moves the elevators, while movement of the joy stick 
in the dimension indicated by line 69 effects movement of the rudder and 
ailerons (which are electrically tied together, as mentioned earlier). 
No tail rotor is necessary for proper operation of the target since it is 
an autogyro, not a helicopter (although it simulates a helicopter). 
However if desirable, a tail rotor may be attached to the vertical 
stabilizer 16 for cosmetic purposes. 
According to the invention, an autogyro is thus constructed which very 
accurately simulates a helicopter for target purposes, both visually and 
by flight pattern. The target 10, with or without the launch assist of 
FIG. 8, is hand launchable, requiring no wheels or a "take-off" area, 
which is extremely advantageous considering that the target will often be 
optimally utilized in rough terrain. Further, the target is constructed 
having sufficiently good flight characteristics that it can normally land 
without crashing even though it does not have landing gear, so that it may 
be reused. With a 1.08 cubic inch engine 14, and the other dimens:ons set 
forth in the exemplary embodiment above, the craft is capable of a speed 
range of between about 10-40 knots, a flight duration of 12 minutes at 
full throttle or 15 to 18 minutes at a normal cruising speed, and can 
accurately simulate combat maneuvers of a Hind D. For example, the target 
10 according to the invention is capable of performing high speed 
approaches down to near-hover conditions. For example if wind conditions 
are right, considering its low stall speed (approximately 10-13 miles per 
hour), the target can appear to be hovering. Also, the target 10 is 
capable of tight turns (at less than full throttle), and low speed and 
gentle landings. 
It will thus be seen that according to the present invention an effective 
target simulating a helicopter has been provided. While the invention has 
been herein shown and described in what is presently conceived to be the 
most practical and preferred embodiment thereof, it will be apparent to 
those of ordinary skill in the art that many modifications may be done 
thereof within the scope of the invention, which scope is to be accorded 
broadest interpretation of the appended claims so as to encompass all 
equivalent structures and devices.