Roy Mueller, et al.
Rotary Arch Kite [ Skybow ]
An extreme sport application of the
Magnus Effect -- with apparent potential for power-generation
200 foot Blue and Pink Skybows wereTested
in Winds ~10-12 MPH. Rotation speed is at ~5000 RPM's
Skybow Rotary Arch
Kite spins @ 5000 RPM's
Two Turbo-Jet Skybow Airfoil Ribbons Flying
in the Sky Together in light winds 10-12 MPH. Arch is ~35 feet
A Pair of New Rotary Skybow
The New Skybow-PRO Electro Kite
75M/250'. By WindMueller Aerology Lab. Boca Raton Florida.
Digital scale test with winds ~ 10 mph
(200 foot / 60 meter) Skybow tested Dec.
2009 with Digital Scale in 10-12 MPH Winds showed pulling up to
17.68 Lbs. on one end ...
Jim's Skybow FAQ
It's a new kind of kite that acts sort of like an anti-gravity
rope---when you and a friend at the other end hold it across the
wind it pulls upward making a huge arch in the sky.
Who is flying
Kite enthusiasts worldwide are experimenting with skybows,
improving flying techniques, design and materials.
How does it
It's not really a rope at all. It's a rapidly spinning ribbon.
Have you ever noticed
that a dropped card or ticket stub can start spinning and glide
away from you as it falls? A skybow's ribbon is attached to
swivels that allow it to spin the same way.
So why does
spinning make it go up?
That's a subtle question, but it's basically the same reason a
spinning ping-pong ball takes a curved flight. It's called the Magnus-Robins effect
Okay, so why
up instead of down?
With flat-ribbon skybows the
fliers may have to help the ribbon start spinning in the correct
direction---the top of the ribbon should spin downwind
. Other skybows have creased edges and
always spin the same direction, these skybows must be set up
properly in relation to the direction of the wind.
started spinning in the wrong direction a skybow is just as happy
to spin the otherway and fly into the ground!
Why does it
make that eerie sound?
The aerodynamic forces always act nearly at right angles to the
ribbon face, but the ribbon is constantly turning. This produces a
rapidly varying reaction against the air ---sound is the natural
result. Since the ribbon has two faces, the frequency of the sound is twice the spin rate.
A skybow flying well makes a howling sound reminiscent of the
sound of high wind in a pine woods, a skybow that is not entirely
steady sounds like a motorcyle race, with repeated accelerations
and sudden downshifts of pitch.
Loudness increases drastically with wind speed. At 20 mph (32
km/hr) the curious have been drawn from a quarter-mile (400m)
away. The sound is very directional, with a quiet spot near the
fliers and directly behind them.
Why are there
sometimes swivels in the middle of the arch, not just at the
A skybow needs to spin faster
where the wind is faster in order to fly high. Multiple sections
that spin idependently can accomodate differences in windspeed
along the skybow. Usually the fastest winds hit the high center
of the arch. Sometimes a single-section skybow is tapered ---
it's made wider in the center than at the ends so that the high
windspeeds at the center can be accomodated when the whole
ribbon is spinning at the same rpm.
How long can
a skybow be?
The record so far, 1000 ft (303 m) long is held by, Mr. Big, a six
section skybow 5/8" wide (1.6 cm). Tony Frame and Jim Mallos flew
Mr. Big over the Washington Monument Grounds, Washington, DC on
November 10, 1997.
The maximum length of a skybow is
proportional to the strength-to-weight ratio of the ribbon
material. There are fibers made with ten times the
strength-to-weight ratio of Mr. Big's ribbon, so skybows two
miles long (3 km) may be possible.
How wide can
a skybow be?
Tony Frame and I have flown skybows in widths ranging from 10mm to 25mm.
(Tell me about
How do you
Skybows are launched by pulling
them taut across the wind.
They can be launched all at
once, or in stages letting one section go up at a time.
Skybow Builder's Notes
Mr. Big was made from a sandwich of two outer layers of
premium-grade box sealing tape (3M #3750), with a narrow middle
layer of heavy-duty surveyor's flagging tape from
blackburnflag.com . This design was prone to snap where the edges
of Mr. Big's 5/8" wide ribbon:
Polypropylene gift-wrapping ribbon is very strong and colorful,
but it is difficult to attach centerweighting in a really
The best design so far is an unsymmetrical sandwich of 3M's #863
tape (a transparent monofilament-reinforced polypropylene
strapping tape), which is very strong for its weight and lets the
color of the bottom layer show through, with a narrow middle layer
of polyethylene adhesive tape as the centerweighting, and a bottom
layer of 50-micron (2-mil) thick colored polyethylene bag plastic
There are apparently no retail sources for the 3M #863 tape---you
have to order a carton of 36 from a tape wholesaler.
To fly, a skybow needs a strip of stretchy material
(centerweighting) running along the center of the ribbon. The
centerweighting, needs to be stretchier than the rest of the
ribbon so that it shares little of the ribbon's tension. Inelastic
materials will not have a stabilizing effect.
Roughly speaking, the centerweighting should increase the weight
of the ribbon by 50% and be narrower than 75% the ribbon width.
An adhesive vinyl tape, such as electrician's tape, can be simply
stuck on one or both sides of a ribbon, or a non-adhesive vinyl
tape, such as surveyor's flagging tape, can be used in a sandwich
construction. Polyethylene adhesive tape, such as "Frost King
Weatherseal Tape," which is used to install plastic-film storm
windows, is better than vinyl because it is less prone to
It seems that the function of the centerweighting is to make
tranverse waves move along the skybow more slowly than the
torsional (twist) waves. There two other ways to accomplish this
1) carry all the tension at the very edges of the ribbon by
placing low-stretch fibers there, or
2) give the a ribbon a tube-like cross section so it can act a
like a flexible shaft.
These should be fruitful areas for research.
Skybows rely on damping from aerodynamic forces to spin smoothly,
so the skybow must be rather light. A rule of thumb is that the
skybow should not weigh more than 15 times the weight of the air
in the cylinder that circumscribes it. For example a 17mm wide
skybow can spin smoothly if its weight is 4 g/m---and even lighter
A skybow does need a certain stiffness across its width so that
when twisted under tension it will not buckle and twist up like
The ends of a skybow segment must be held by very low friction
swivels. Only high quality (e.g. SAMPO) ball-bearing fishing
swivels will work. Use the largest size you can find, as the small
ones will wear out in a few minutes even though the tension is
moderate. For some reason the black swivels last longer than the
nickel plated ones. Lubricate each swivel with a drop of sewing
machine oil. Do everything you can to keep the swivels out of the
For long-life swivels you have to take the trouble to make your
own, using quality ball bearings with rubber seals. I am using
MR115-2RS bearings from bocabearings.com.
A skybow needs to be long enough to power the spinning of its
bearings. This minimum length depends on the width of the ribbon.
We've had success with 30m lengths at 19mm width, and 50m lengths
at 15mm width. When multiple segments are used in a bow (as in Mr.
Big), the segments can be shorter since in general one segment
only needs to power one swivel instead of two. Most recently I
have been making 17mm-wide skybows with multiple segments just 24m
long. In the eastern U.S. the flying fields are never big enough,
so short segments are more convenient.
The longest single section we've flown was about 114m, but really
long single sections are in danger of twisting up like twine if
the windspeed varies greatly along the length of the bow
Finally!! After 16 Years of Research, 7 Miles of Ribbon,
100's of Variations of Materials and Swivel Systems, we have
sorted out All The Best... To bring to you the Ultimate in Skybow
Design and Performance.
Introducing The Original WindMueller Turbo-Jet Skybow!!!
The complete system was developed and is manufactured at the
WindMueller Aerology Laboratory
(Based in Boca Raton Florida since 1991). The NEW Basic
Skybow Unit is NOW comprised of 1 Continuous 200' Section of
Rip-Stop Airfoil Ribbon, which translates into a Top Arch Height
of ~24Meters/77 Feet. Available soon from our site, we will
have add-on, connectable sections that come in 30M/100' &
60M/200' lengths, to build an arch as high as you want to
go. There is no known limit. The longest we have gone
is 1000', creating an arch approximately 350-400 feet high in the
center. An Incredible 33 Pounds of Pull on each end of the
1000' Skybow was recorded. The Turbo-Jet Skybow now also
comes with our Latest High Performance MEGA-Velocity Ground
Swivel's, rated at 85 Pounds/85,000 RPM's. In a Light Wind,
the Skybow Ribbon can spin at an incredible 4000 rpm's. With
Higher Dead-Smooth Winds (16-22 MPH), 7000-10,000 rpm's are now
possible... A hum will begin to sound once the Skybow Pops
Up Into the Air, which is the loudest from beneath the Center of
the arch. Like the sweeping motion of a (Rotary Wing
Aircraft) Helicopter Blade, the Skybow Airfoil Ribbon has a
Sweeping Lateral Rotation. This creates an Incredible Low
Pressure towards the direction of the oncoming wind, which
magically lifts the Skybow high into the air, based on the Magnus
Effect Principle. (Named after the German Physicist and Chemist
Heinrich Gustav Magnus (Photo below)). Although Heinrich
Magnus Published his papers of this Discovered Effect in the Mid
1800's, there has never been an apparatus to Demonstrate this
Effect and Principle until Now.
The Turbo-Jet Skybow is the perfect tool for High School and
College Mathematic & Science Projects. You can now move a
Class of Students Momentarily Outdoors to an open area and
demonstrate in real time, the Mathematical and Scientific Concepts
of Angular Momentum, Angular Velocity and Witness first hand, just
how powerful The Aerodynamic Principle of the Magnus Effect
is. The Basic Skybow Unit Now includes... A Pair
MEGA-Velocity Ground Swivel's, A 60M/200' Skybow Airfoil Ribbon,
and A 10" Yo-Yo Winder... which all fit into 2 special drawstring
pouches to keep everything together in, with the
instructions. It is possible to obtain an arch past 90
degrees perpendicular tilted into the direction of the wind Using
Micro Aerial Swivels. With longer bows, a horseshoe type
arch, shaped like the St. Louis Arch in Missouri is
possible. Find a friend or two, to help you hold the ends so
you can hear the noise it makes from underneath the center. With a
good wind it can sound like A Thundering Waterfall or an
Oscillating Turbo-Jet Engine
Chart Based on using 85,000 rpm
rated swivels with a 17 mm/200' Rip-Stop Skybow Airfoil Ribbon.
The Highest Velocity ever Recorded was 10,625 rpm's, July of 2009.
Wind Speed -- ~ RPM Range :
8 MPH --3000 : Parallel to Ground
10 MPH -- 4000 : Low Wavy Arch
12 MPH/10 Knots -- 5000 : Minimal Arch
14 MPH -- 6000 : Good Arch
16 MPH -- 7000 : Great Arch
18 MPH -- 8000 : Strong Arch
20 MPH -- 9000 : Very Strong Arch
22 Mph -- 10,000 : Super Strong Arch
24 MPH/20 Knots -- 11,000 : Maximum Lifting Arch
26 MPH & Above -- Above 12,000 : Instability Range
ROTARY ARCH KITE AND SWIVEL
Inventor: MUELLER ROY
IPC: B64C31/06; F16B7/00
-- A rotary arch
kite kit may include a rotary arch kite and a system for
connecting various segments of the kite. The connecting system may
include ground swivels, aerial swivel connectors and static
connectors. The ground swivels may be single independent swivels
for attaching a handle to the rotary arch kite. The aerial swivel
connectors may be double independent swivels for, for example,
attaching two lengths of rotary arch kite together. The static
connectors may also be used for joining two lengths of rotary arch
kite together. The rotary arch kite of the present may include a
unique folding and stitching design to permit enhanced rotation
BACKGROUND OF THE INVENTION
 The present invention relates to kites and, more
particularly, to a rotary arch kite and swivel systems for
operating rotary arch kites.
 Rotary arch kites may produce a pulling force in excess of
50-60 pounds. These kites may also rotate at high velocities,
often upwards of 20,000 revolutions per minute (rpm) or greater.
Current swivel systems may not be able to work with these pulling
forces and rotational velocities.
 As can be seen, there is a need for a rotary arch kite and
swivel system that may allow operation of the rotary arch kite at
typical pulling forces and high rotational velocities.
SUMMARY OF THE INVENTION
 In one aspect of the present invention, a rotary arch kite
kit comprises a rotary arch kite; a ground swivel adapted to
provide a handle for the kite; and an aerial swivel connector
optionally connecting the rotary arch kite to a second rotary arch
 In another aspect of the present invention, a ground swivel
comprises a strap having a tube rotationally attached to the
strap; a monofilament extending from a body of the ground swivel,
the tube attaching to one end of the monofilament; an end casing
permitting another end of the monofilament to pass through into
the body of the ground swivel a spacer ring within the end casing,
the monofilament passing through the spacer ring; and a bearing,
wherein the monofilament fits into an inner bore hole of the
 In a further aspect of the present invention, a rotary arch
kite comprises a strip of material, wherein the strip of material
is from 1 to 4 inches wide and from 100 to 300 feet long, wherein
the kite is formed by folding the strip of material in thirds and
stitching the folded material along its length at one side of the
strip; and an end of the folded material being folded and stitched
to itself to form a loop in one end of the kite; and a slit cut in
the end of the kite.
 These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
is a perspective
view of an aerial swivel connector according to an embodiment of
the present invention;
is a side view of
the aerial swivel connector of FIG. 1;
is a top view of
the aerial swivel connector of FIG. 1;
is an exploded
perspective view of the aerial swivel connector of FIG. 1;
is a perspective
view of a ground swivel according to an embodiment of the present
is an exploded
perspective view of the ground swivel of FIG. 5;
is a perspective
view of a handle being inserted into the ground swivel of FIG. 5;
is a perspective
view of a static connector according to an embodiment of the
is a perspective
partially taken-apart view of a rotary arch kite according to an
embodiment of the present invention;
is a perspective
view of an end of the kite of FIG. 9; and
is a top view of
an end seam of the kite of FIG. 9.
DETAILED DESCRIPTION OF THE
 The following detailed description is of the best currently
contemplated modes of carrying out exemplary embodiments of the
invention. The description is not to be taken in a limiting sense,
but is made merely for the purpose of illustrating the general
principles of the invention, since the scope of the invention is
best defined by the appended claims.
 Various inventive features are described below that can
each be used independently of one another or in combination with
 Broadly, an embodiment of the present invention provides a
rotary arch kite and system for connecting various segments of the
kite. The connecting system may include ground swivels, aerial
swivel connectors and static connectors. The ground swivels may be
single independent swivels (that is, a first end may rotate
relative to a fixed second end) for attaching a handle to the
rotary arch kite. The aerial swivel connectors may be double
independent swivels (that is, each end may independently rotate)
for, for example, attaching multiple lengths of rotary arch kite
together. The static connectors may also be used for joining two
lengths of rotary arch kite together. The rotary arch kite of the
present may include a unique folding and stitching design to
permit enhanced rotation and lift.
 Referring to FIGS. 1 through 4, an aerial swivel connector
10 may include tube casing 12 having end casings 28 attached to
each end thereof. A monofilament 20 may extend from each end
casing 28. The extending end of the monofilament 20 may attach to
a tube 22. The tube 22 may attach a first rotary arch kite 24 with
a second rotary arch kite 26. Typically, two aerial swivel
connectors 10 may attach to each end of a central rotary arch
kite, with two additional rotary arch kites attached to each of
these aerial swivel connectors 10. In an alternate embodiment, the
tube from one end casing 28 may attach to a strap handle and the
tube from the other end casing 28 may attach to the rotary arch
kite. Within the tube casing 12, each monofilament 20 may pass
through a bushing 14 and fit into an inner bore hole of a bearing
16. Each monofilament 20 may have different diameters, as shown in
FIG. 4. Alternatively, each monofilament 20 may have the same
diameter. A bushing 18 may fit between adjacent bearings 16. The
tube casing 12, end casings 28, and bushings 14, 18 may be made of
any suitable material, such as PVC, CPVC, ABS, carbon composite,
metal, and the like. The bearing 16 may be a high RPM rated
bearing, such as a bearing rated at 10,000-500,000 RPMs.
 Referring now to FIGS. 5 through 7, a ground swivel 30 may
include a strap 32 having a tube 34 rotationally attached to the
strap 32 to allow the tube 34 to spin freely at high velocities. A
monofilament 36 may extend from a body 38 of the ground swivel 30.
The tube 34 may attach to one end of the monofilament 36. The
other end of the monofilament 36 may pass through an end casing
40, a spacer ring 42 and fit into an inner bore hole of a bearing
44. A first spacer 46 may attach to the end casing 40. A tube 48
may fit over and attach to the first spacer 46. A second spacer 50
may fit into and attach to the tube 48. As discussed below, the
strap 32 may attach within the second spacer 50. A heat shrink
tubing 52 may be used to cover and protect the components of the
body 38 of the ground swivel 30. The end casing 40, tube 48, and
spacers 46, 50 may be made of any suitable material, such as PVC,
CPVC, ABS, carbon composite, metal, and the like. The bearing 44
may be a shielded high RPM rated bearing, such as a bearing rated
for at least about 85,000 RPMs, however other bearing ratings may
 According to one embodiment of the present invention, the
strap 32 may be folded in as shown in FIG. 7. The resulting four
layers of strap 32 may be inserted into the second spacer 50. A
hole (not shown) may be drilled in either the second spacer 50
and/or the tube 48. The hole may also pass through the four layers
of strap 32. A pin (not shown) may be inserted into the hole to
hold the strap 32. Optionally, a monofilament may be inserted
through the pin to reinforce the strap 32 onto the body 38 of the
ground swivel 30. Other means, as may be known in the art, for
connecting the strap 32 to the body 38 of the ground swivel 30 may
 The tube 34 of the ground swivel 30 may attach to one end
of a rotary arch kite. The ground swivel 30 of the present
invention may allow the rotary arch kite to rotate at high
velocities, even while a pulling force is applied from the ground
swivel 30. The spacers 46, 50 may be, for example [1/2] inch pipe
and the tube 48 may be a [1/2] inch coupling and the end casing 40
may be a [1/2] inch cap.
 The ground swivel 30 may have other uses where a swivel
handle may be desirable. For example, the ground swivel 30 may be
used to connect a dog collar to a leash, thereby preventing
twisting of the leash.
 Referring to FIG. 8, a static connector 80 may be used join
ends of a rotary arch kite. The static connector 80 may be used,
for example, in place of the aerial swivel connector 10, described
above. The static connector 80 may have first and second tubes 82
attached by a monofilament 84. In one embodiment, three rotary
arch kites may be part of a kite package, wherein the ends of the
middle rotary arch kite connect with the other two rotary arch
kites with two aerial swivel connectors. In another embodiment, a
first and a second rotary arch kite may be joined with the static
connector 80. A fourth and fifth rotary arch kite may also be
joined with the static connector 80. A third rotary arch kite may
have the aerial swivel connector at each end to connect to the
first/second rotary arch kites at one end, and to the fourth/fifth
rotary arch kites at the other end. The ground swivel 30 may be
used as a handle for the first rotary arch kite. Such a package
may incorporate several features of the present invention into a
single rotary arch kite package or kit.
 Referring now to FIGS. 9 through 11, a rotary arch kite 90
may be an airfoil ribbon formed from, for example, ripstop nylon
that is folded in thirds, as shown in FIG. 9. An exterior third 92
may be attached with stitching 100 for the length of the kite 90.
The length of the kite 90 may be from about 100 to about 300 feet,
typically about 200 feet. The unfolded kite 90 may have a width
from about 1 to about 4 inches, typically about 2 inches. Each
kite end 94 may have a slit 96 cut therein. The slit 96 may be use
to retain a tube of, for example, the ground swivel 30, the aerial
swivel connector 10 or the static connector 80. The kite end 94 of
the kite may be formed by folding about 6 inches of a material end
98 of the kite onto itself. This material end 98 is then folded
under itself (back toward the kite end 94) for about two inches to
create a fold 106, resulting in a three-layer thickness 102. This
three layer thickness may be joined with stitching 104 as an
interior, elongated X, as shown in FIG. 11. The stitching 104 may
not extend across the width of the kite 90, as such stitching may
provide a perforation in the kite capable of tearing. The
stitching 104 may extend beyond the fold 106, as shown in FIG. 11.