U.S. patent number 3,750,981 [Application Number 05/188,289] was granted by the patent office on 1973-08-07 for man-powered glider aircraft.
Invention is credited to Alfred G. B. Prather.
United States Patent |
3,750,981 |
Prather |
August 7, 1973 |
MAN-POWERED GLIDER AIRCRAFT
Abstract
The aircraft wings have means for varying their camber and
include a fan-like tail section hinged to the rear of a rigid frame
surrounding the pilot's space between the inner ends of the side
wing sections, in substantially the same plane therewith, a
unicycle being fixed to said rigid frame to provide a seat for the
pilot. A collapsible propeller is mounted on a shaft extending
forwardly from a bearing on the front of said rigid frame, and is
driven by a chain or belt drive from a sprocket or pulley on the
wheel of the unicycle, the blades of the propeller being keyed to
the propeller shaft through limited annular slot and key
connections between adjacent blade bearings, to spread the blades
to their proper angular spacing whenever the shaft is driven, and
to return them to a common vertical hanging position so as to
reduce their drag during gliding operations whenever no power is
applied. The pilot sits on the unicycle seat, drops a yoke harness
over his shoulders which is operatively connected to control the
inclination and twist of the hinged tail section, whereby the
shifting of his body forward, lifts the tail section to cause an
increase in the angle of attack of the side wing sections, and by
shifting his body rearward the tail section is lowered to decrease
the angle of attack, and if he moves his body from side to side he
can twist the tail section accordingly. After placing this yoke
over his shoulders, the pilot inserts his arms through openings in
the inner ends of said wing sections and grasps the handles of the
corresponding hand control plates which are operatively connected
to control the cambers of the side wing sections, the warping of
the outer ends of these sections and the spread of the fan-like
tail section.
Inventors: |
Prather; Alfred G. B. (Lanham,
MD) |
Family
ID: |
22692541 |
Appl.
No.: |
05/188,289 |
Filed: |
October 12, 1971 |
Current U.S.
Class: |
244/16;
244/64 |
Current CPC
Class: |
B64C
11/28 (20130101); B64C 31/04 (20130101) |
Current International
Class: |
B64C
11/28 (20060101); B64C 11/00 (20060101); B64C
31/04 (20060101); B64C 31/00 (20060101); B64c
031/04 () |
Field of
Search: |
;244/16,64,49 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Buchler; Milton
Assistant Examiner: Sotelo; Jesus D.
Claims
What is claimed is:
1. A glider aircraft comprising
a pair of side wing sections having their inner ends spaced to
provide room for the pilot's bust to extend therethrough,
a continuous rigid beam forming the leading edges of both of said
wing sections and providing the front frame member of said pilot's
space,
the rear portions of said inner ends of said wing sections being
faired into a tail hinge section forming the rear forming frame
member of said pilot's space,
a unicycle fixed to said frame members and providing a seat for the
pilot,
a fan-like tail section hinged at its forward edge to the rear edge
of said tail hinge section, and having means for varying its spread
operatively connected to hand control plates inside of said wing
sections, accessible from said pilot's space through armholes in
the inner ends of said wing sections,
means for twistingly warping the outer ends of said side wing
sections operatively connected to said hand control plates, and
means for varying the inclination of said tail section to the plane
of said wing sections operatively connected to a portion of the
pilot's body for control by the movements thereof.
2. A glider aircraft as defined in claim 1,
said side wing sections having axially flexible sheet material
extending from the lower edge of said rigid beam and forming a
lower normally substantially flat wing surface, and a curved
axially flexible sheet material extending from the upper edge of
said rigid beam and forming a substantially curved upper wing
surface, the upper and lower wing surfaces defining the cambers
thereof, and
means for varying said upper wing surface camber operatively
connected to said hand control plates for simultaneous and
independent spreading of said tail section and increasing of the
camber of said upper surface of said wings.
3. A glider aircraft as defined in claim 1, and
a propeller having a shaft mounted on said front frame member, with
drive means operatively connected to the wheel of said
unicycle.
4. A glider aircraft as defined in claim 3,
said propeller having a plurality of blades with bearings keyed to
its shaft through stepped annularly extending lost motion slot and
pin drive connections between adjacent bearings to cause the blades
to be spread to their proper angular spacing when the shaft is
driven forward, and to bring them together in vertically hanging
collapsed position when no drive torque is applied to the shaft,
whereby propeller drag is reduced during gliding operations.
Description
Various man powered glider aircraft have been developed in the
past, but none have been found which have a collapsible propeller
to reduce its drag when it is not being used during gliding
operations, and no prior art has been found in which such aircraft
uses a spreadable tail section and wings with a variable camber
with simple cooperative controls for warping the tips of the wings,
for varying of the spread and the inclination of the tail section
and the camber of the wings and for bending the rear edges of the
wings like wing flaps.
Accordingly, the main object of the present invention is to produce
a man powered glider aircraft which will enable its self 5
launching from a downwardly inclined strip of ground by means of a
cycle undercarriage and the assistance of a man powered propeller,
and more natural wing and tail section controls approaching those
of birds in soaring flight.
A further object is to provide a collapsible propeller to reduce
its drag in flight when power is not applied to it.
A further object is to provide a variable camber wing section by
varying the curvature of the upper surface member thereof, or by
bending the rear edge of the lower surface member, or both, the
forward edges of said members being joined to a rigid nose member
defining the leading edge of the wing.
A further object is to provide a spreadable as well as twistable
fan-like transversely hinged tail section for aircraft,
approximating the natural functions of a bird's tail in flight: for
increasing lift, for assisting in steering and rolling maneuvers as
well as pitching and looping, for braking the speed of flight as in
landing, etc.
Further and more specific objects will become apparent in the
following detailed description of the invention, as illustrated in
the accompanying drawings, wherein:
FIG. 1 is a front view of the propeller in its collapsed
position,
FIG. 2 is a side view of this collapsed propeller showing a
sectional view of its mounting,
FIG. 3 is a front view of the propeller when power is applied to
it.
FIG. 4 is a front view of the glider aircraft on take-off,
FIG. 5 is a substantially diagrammatic cross sectional view of a
wing section, showing one form of cam means for varying its
camber,
FIG. 6 is a similar view of another form of cam means, and pull
string means for bending the rear edge downwardly,
FIG. 7 is a substantially diagrammatic axial cross sectional view
of the aircraft,
FIG. 8 is a plan view of the aircraft with most of the upper
surface of the right wing section broken away,
FIG. 9 is a perspective view of the aircraft, and
FIG. 10 is a detail plan view of the tail section.
The specific form of this invention, as illustrated in the
drawings, has a pair of side wing sections 10 having a common
leading edge beam forming the rigid nose portion of the wings and
extending across the space between the inner ends of said wing
sections to form the front frame portion of the opening through
which the pilot's bust 42 normally extends.
The aircraft illustrated has the rear portions of the inner ends of
the side wing sections faired into a tail hinge section which has a
hinge rod 84 mounted in side bearings 70 at its rear edge, on which
the forward edge 68 of the tail section 12 is rotatably mounted for
angular adjustment relative to the plane of the tail hinge section.
The tail section 12 has central brackets 50 extending above and
below the forward edge thereof. The springs 52 and 54 which are
connected to pins at the upper and lower ends of said brackets are
adjusted to normally resiliently hold the tail section in
substantial alignment with the plane of said side wing sections for
level flight.
A rigid strap 46 is fixed at its forward end by means of shoulder
straps 44 to the back of the pilot 42, and its rear end has a
sleeve mounted rotatably on the rod 48 which is pivoted to pins
133, 134 and 135 at the tops of the brackets 49, 50 and 51
respectively, so that by moving his body from side to side, the
pilot can control the twist in the tail section accordingly. For
example, if the pilot moves his body to the left, rod 48 is pivoted
about pin 134 to its dotted line position shown in FIG. 9 and moves
the brackets 49 and 51 in opposite directions about hinge pin 84,
thus lowering the left side and raising the right side of the tail
section to provide a corresponding twist therein. By moving his
body forwardly or to the rear, the tail section may be angularly
raised or lowered.
While thus controlling the pitch angle and twist of the tail
section, the pilot has a hand controlled pull string 66 connected
through lines 74 which are directed over pulleys to one side edge
of each hand plate 116 which is pivoted to a rod 118 slidably keyed
in an axially rotatable sleeve 120 which is a part of the frame
member 122 in the flexible wing tip portion 124 extending
rearwardly from the rigid nose beam 30 of the wing sections 10. The
chord portions 126 and 128 of the frame member 122 are formed to
provide the contour of the wing tip portions over which a flexible
cover is stretched. The stiffly resilient rear edge member 124
provides a resiliently flexible rear edge for said wing tip
portions.
Turning the hand plate 116 axially of sleeve 120 causes the frame
member 122 to turn, thus warping the wing tip portion
correspondingly. The controls in the other side wing section,
although not shown in FIG. 8, are exactly the same as in the right
side wing section, except that they are in reverse relation with
respect to the aircraft axis.
The other side edge of the pivoted hand plate 116 is connected by
lines 88 and their extensions 96 to the rear edge 86 and the camber
increasing pulleys 94 respectively, to simultaneously bend the rear
edges 86 downwardly and increase the camber of the upper surfaces
of the wing sections when that side edge of the hand plate 116 is
drawn toward the pilot by pulling the hand plate 116 straight, or
also twisting and turning it in accordance with the desired effect
on the other controls. The camber cams 92 are fixed to the sides of
their respective pulleys 94, and are normally resiliently held down
in the reduced camber positions for high speed streamlining, by the
assistance of tension springs 82 stretched between the rear edge 86
of the lower wing surface sheet 76 and the rear edge 80 of the
upper surface sheet 78. Guideways 98 are provided for slidably
guiding the rear edges 80 over the top surface of the sheets
76.
Pulley brackets 90 are provided under the sheets 76 for the pull
lines 88 to draw the rear edges 86 downwardly.
Any other camber camming means may be used besides the oval cams
92. As shown in FIG. 5, two pairs of folding legs 100 may be
pivoted to the lower sheet 76 at a common pivot and extend in
opposite fore and aft directions. The outer ends of each pair are
biased to the left in FIG. 5, by tension springs 102 and 104. When
line 106 is pulled and line 108 released, a high camber position of
their upper hinges is assumed as shown, and when line 108 is pulled
and line 106 released the legs are stretched to a low camber
position of their upper hinges.
The lines 74 being connected to the corresponding side edges of
their hand plate 116, control the spread of the tail section, the
line 66 being connected at 72 to the middle of the stiffly
resilient member 58 which is normally bowed back by springs 60 and
62, the rear end of spring 60 being fixed to the rear edge of the
tail section at 64. The ends of the bowed member 58 are fixed
pivotally to the opposite sides of the tail section at 56, and a
tension spring 62 is fastened at its ends to the same pivots at 56,
to normally hold the tail section folded at its minimum spread as
limited by spacers 110 on spring 62.
When line 74 is pulled against the tension of spring 60, the bowed
member 58 is made straighter, causing its ends to spread the tail
section to the dotted line positions of the sides 112, as shown in
FIG. 10, the spring 62 and the bowed member 58 being passed through
slots in the fan folds of the tail section so as to keep them in
the plane of the tail section in any of its twisted positions. Thus
the tail section can be spread independently of the other controls
by pivoting the hand plate 116 about the point at its opposite side
edge to which the line 88 is connected, as the slidable rod 118
allows the pivot of the hand plate to be correspondingly pulled
out. If desired, the wing tip flexure can at the same time be
controlled by turning the keyed sleeve 120, and the camber of the
wings can also be simultaneously controlled by pivoting the hand
plate about the side edge to which the line 74 is connected.
Whenever it is necessary to increase the relative wind speed, this
glider aircraft is provided with a man-powered propeller 14, driven
by a chain or belt 38 between the sprocket or pulley 36 on the
wheel 20 of a unicycle 18 which is fixed to the frame 16 under the
pilot's space frame, and the drive sprocket or pulley 28 of the
propeller drive shaft 26 which is mounted in bearing supports on
the nose beam 30 between the inner ends of the side wing sections
10. At the same time, the unicycle seat 22 provides a seat for the
pilot, and lower and upper back rests 17 and 19 may be provided on
the frame 16, while the pilot's arms are passed through armholes in
the inner ends of the side wing sections so that he may grasp the
hand control plates 116 inside the wing structure for manipulating
the various controls either independently or in various combined
control movements in a way to more closely simulate the natural
bird's wing and tail controls in soaring flight and in turning
rolling, pitching, landing, and other maneuvers.
The collapsible propeller shown, has three blades 24 on the
propeller shaft 26, one blade bearing being keyed to the shaft, the
other blade bearings being connected to their adjacent bearing by
120 degree annular slot and pin lost motion drives, so as to
provide their proper spacing whenever power is supplied to the
propeller shaft. Whenever the shaft is left free, it will tend to
stop with the keyed propeller blade hanging downwardly, while the
other blades will tend to continue turning with the aid of the slip
stream until their 120 degree lost motion drive connections are
taken up to bring them adjacent the keyed blade in its hanging
position, where the blades will overlap to some extent and will be
in a less exposed position, to reduce their air resistance to a
minimum.
Many obvious modifications in the details and arrangement of the
parts illustrated may be made without departing from the spirit and
scope of the present invention.
* * * * *