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Roy Mueller, et al.

Rotary Arch Kite [ Skybow ]







An extreme sport application of the Magnus Effect -- with apparent potential for power-generation --


 

Videos -

http://www.youtube.com/watch?v=4ZIW-Ypkymk

200 foot Blue and Pink Skybows wereTested in Winds ~10-12 MPH. Rotation speed is at ~5000 RPM's

http://www.youtube.com/watch?v=oYN4zV4_B_c

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 high.
http://www.youtube.com/watch?v=PbwseVyXkts

A Pair of New Rotary Skybow Electro-Pro Kites

The New Skybow-PRO Electro Kite 75M/250'. By WindMueller Aerology Lab. Boca Raton Florida.

http://www.youtube.com/watch?v=-CfV77GWmfM

Skybow Kite... 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

What's a skybow?

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 skybows?

Kite enthusiasts worldwide are experimenting with skybows, improving flying techniques, design and materials.

How does it work?

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. If 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 ends?

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 your experiments.)

How do you launch them?

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

Construction Materials

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 were damaged.

Construction 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 permanent way.

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 from bearclaw.net.

There are apparently no retail sources for the 3M #863 tape---you have to order a carton of 36 from a tape wholesaler.

Centerweighting

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 delaminate.

Other stabilization methods

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 same end:

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.

Weight

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 is better.

Stiffness

A skybow does need a certain stiffness across its width so that when twisted under tension it will not buckle and twist up like twine.

Swivels

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 dirt.

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.

Length

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



http://stores.ebay.com/The-Skybow-Store

Skybow Information

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 : SkyBow Results

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



USPA 2010270432    
ROTARY ARCH KITE AND SWIVEL SYSTEM

Inventor:  MUELLER ROY
IPC:   B64C31/06; F16B7/00

Abstract -- 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 and lift.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to kites and, more particularly, to a rotary arch kite and swivel systems for operating rotary arch kites.

[0003] 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.

[0004] 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

[0005] 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 kite.

[0006] 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 bearing.

[0007] 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.

[0008] 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

FIG. 1 is a perspective view of an aerial swivel connector according to an embodiment of the present invention;


FIG. 2 is a side view of the aerial swivel connector of FIG. 1;

FIG. 3 is a top view of the aerial swivel connector of FIG. 1;

FIG. 4 is an exploded perspective view of the aerial swivel connector of FIG. 1;


FIG. 5 is a perspective view of a ground swivel according to an embodiment of the present invention;


FIG. 6 is an exploded perspective view of the ground swivel of FIG. 5;

FIG. 7 is a perspective view of a handle being inserted into the ground swivel of FIG. 5;


FIG. 8 is a perspective view of a static connector according to an embodiment of the present invention;

FIG. 9 is a perspective partially taken-apart view of a rotary arch kite according to an embodiment of the present invention;

FIG. 10 is a perspective view of an end of the kite of FIG. 9; and

FIG. 11 is a top view of an end seam of the kite of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

[0020] 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.

[0021] Various inventive features are described below that can each be used independently of one another or in combination with other features.

[0022] 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.

[0023] 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.

[0024] 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 be used.

[0025] 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 be used.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.




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