UFO Construction Photos

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After receiving many questions about building a UFO, I present this guide to the construction of a ripstop UFO kite.

Construction Part List and Tools

[photo] First a summery of the parts you need to build this kite.
  • 2mm diameter solid fibreglass rods, 1meter long, × 2 (hoop rods)
  • 2mm inner diameter brass tubing (to join rods together into hoops)
  • 5.5mm diameter carbon fibre tube, 45cm long (inflexible axial)
  • 6mm inner thick plastic tubing (loose fit on axial)
  • 5mm inner thick plastic tubing (tight fit on axial)
  • 7mm inner diameter fiberglass washer, × 6 (bridle connections)
  • light weight nylon fish netting line (bridle line, flying line)
  • ripstop nylon fabric approx 30cm × 60cm × 2 (cover)
  • ripstop repair tape in appropriate colors
  • paper backed double sided tape, 6mm wide
  • scotch tape, super glue, thin single core telephone wire
  • pens, meter rule, scissors, sharp knife, sewing machine with zipper foot, cutting saws, for rods and brass tubing, etc., etc., etc..

Naming of the Parts of a UFO Kite

[diagram] Before we start, I need to ensure that you know what the various parts of the kite are called, so I can refer to them. The UFO is constructed from two ovals which will intersect each other.

One oval, called the 'wing', will have a rod attached along the longest axis of the oval. It is around this 'axle' that the kite spins. Bridle lines are tied to some fiberglass washers in which the 'axle' can spin freely, without wearing out.

The other oval, called the 'ear', is the vertical stabilizer for the kite. A slit is cut in this oval and the 'wing' which is build a little thinner, slides into this slit. The two oval surfaces are taped together, like a hinge on all four corners so the 'ear' can sit vertically when spinning in the air, or fold flat against the 'wing' for transport.

Make the Ovals Surfaces

[photo] Cut two lengths of 2mm diameter solid fibreglass rod, 1 meter long, and use a felt pen to mark quarters onto the rod (25 cm apart).

Actually only one rod needs to be marked on quarters (for the 'wing'). The other (the 'ear') only needs to have the half way mark, marked.

[photo] Once you have the rods marked, cut 2 lengths of 2mm internal diameter brass tubing about 2cm long. Sand the ends and remove any burrs of metal from the tubing.

On one end of each of the fiber glass rod, mark a point half the length of the brass tubing from the end of the rod. Make sure the brass tubing will slid on up to this mark.

When ready, put one drop of 'super glue' or 'crazy glue' on the end of the fiberglass, then push the brass tube ferule, onto the end, up to the 1cm mark, and hold a second or two, until the glue dries.

[photo] After a couple of minutes when the glue is dried, you can bend the 2mm into a circle, pushing the other end of the rod into the brass tube ferule.

You do not need to glue this end, though you can if you really want to.

If you look carefully at the photo (click on it to enlarge) you can see the marks I made earlier on the rods.

[photo] Next take the roll of scotch tape and attach one end to the middle of the brass ferule, looping the tape over the tube, and attaching it to itself glue side to glue side for about 2cm.

Cut off enough length of scotch tape, just short of reaching the other side of the circled rod.

Now push the fiberglass rod down the length of the scotch tape until it forms a oval. Take the end of the scotch tape and loop it around the fiberglass rod at the half way mark you made earlier, and let the tape stick to itself, glue side to glue side for about 2cm. Cut off the rest of the tape.

Repeat this for the other rod, but make the oval 1cm thiner or thicker than the first one you made.

The oval that is thicker will be the 'wing' of the UFO, and MUST have quarter marks marked on it.

The other thinner oval, is the 'ear' or vertical stabilizer.

[photo] At this point take a moment to think about what colors, and color arrangement you want for your UFO.

In the photo (right) I used some double sided tape to join two colors together for the 'ear'. The ripstop must cover the oval completely with 5cm or more extra material all around. This extra material is important, and while it will be cut off later, you should not skimp on it.

One point about joining the materials. Make sure any joins go from edge to edge, as this kite does not work well with applique techniques.

Also as the kite is spinning, you have a circling surface on the ear, and a surface which rabidly flips from one side to the other, as the kite spins. As such make your patterns bold and distinct, either highlighting the kites spin and flip, or de-emphasising it.

In this particular UFO, I chose two colors, yellow and red, and as shown for the ear chose to highlight the spinning ear surface by using different colors on each end.

Some designs can be added to the UFO after it is complete using strips or dots of colors made from stick on ripstop repair tape. consequently I commonly just make the UFO one color at this point, and add a design later.

[photo] After you have the material ready. Take the paper backed double-sided tape and stick it around the outside edge of your oval frame, as shown in the photo.

Once the tape is around the oval, fold it around the fiberglass rod, and carefully peel off the backing tape.
[photo] Now position the sticky oval over your ripstop cover, (sticky side of the scotch tape down), and press firmly. Don't worry about the ripstop not being very tight, it will tighten up in the next few steps.

At this time also mark the ripstop before the ripstop wraps around the spars and covers up that information.

On the wider 'ear' oval draw a pencil line across the short axis, from the middle of the ferule to the half way may. A slit will be cut along this line later.

On the 'wing' pencil a line along both the long axis, from the two quarter marks where the axle rod will be placed, and the short axis where the ear wing with be taped in place.

[photo] Now for the next step we need a lot of small pieces of double sided tape.

To make this easier get a wire shelf from the fridge or oven, and unroll the tape across the wires 3 to 4 times. Then use scissors to cut across all the multiple lengths of the paper backed tape to make lots and lots of 3 to 4 cm lengths of tape.

[photo] Pull off the short pieces of tape and stick to the ripstop, to form an oval 2 to 3 cm away from the inside edge of the fiberglass rod. Do not put it too close to the rod as you really don't want to sew through this stuff. If you do it will gum up the needle of your sewing machine.

If you are covering with mylar plastic instead of ripstop, put the double sided tape close to the fiberglass rod. In this case we don't sew the cover, just stick it down throughly, and cut the rest of the mylar plastic away.

[photo] Next use a sharp needle or pin and lift off the paper backing from the short pieces of double-sided tape to leave a ring of glue.
[photo] Now wrap the edge of the ripstop (or mylar) cover around the rod, and lightly stick it to the double sided tape glue. Now do the same on the other side, then at the quarter marks, then eights, so on. (see photo)

The goal here is to wrap the material evenly all the way around the fiberglass hoop so that it is even and not distorting the oval hoop. Easy to do if you are not careful.

[photo] Keep doing it until all the material is even and tight against the outside sticky fiberglass rod. You may have to un-stick a section of material, to make it tighter.

Once all the ripstop is wrapped well. press it down into the glue well. Especially remove as much air between the skin and the fiberglass rod.

[photo] With a mylar covering, skip this step. You can not sew mylar material as it will just tear from the pin pricks of the sewing needle.

For ripstop, however the double sided tape is not enough, as the double sided tape just does not bond to ripstop as well as it does to mylar. As such we need to sew the ripstop cover onto the fiberglass frame, but this is easy.

Attached a 'zipper foot' to your sewing machine, so that you can sew as close to the fiberglass rod as you possibily can. Then just sew all the way around the oval using a straight stitch with a long stitch 1/4 to 1/2 cm length) between stitches. Keep the needle as close to the frame as you can, without hitting the double sided tape on the frame itself.

[photo] When you have finished sewing the ripstop. Pull the ripstop from the inner ring of double sided tape and using a small sharp pair of scissors cut the ripstop about 3 to 5mm away from the sewn seam.

You can now also rub away the inner ring of double sided tape still attached to the surface of the oval, and the scotch tape can be removed as well.

With Mylar just cut the plastic as close to the inner ring of double sided tape. The tape sticks too well to mylar to attempt removal, not that their is any need, as you use the tape instead of sewing to keep the cover in place.

[photo] Repeat the above steps for the other oval.

[photo] Putting it all together

Along the long axis of the wing (marked with a pencil line earlier), stick down a line of double sided tape, and remove the paper backing.

[photo] Taking the carbon fiber rod (45cm long, which should be long enough to extend 3 to 4cm past both ends of the ovals long axis) mark its center point. I find using a dot of white liquid paper on the black rod good for this purpose, as pencil just isn't very visible.

Center the rod on along the long axis, over the double sided tape, and stick down. Roll it slightly back and forth to stick it good.

[photo] Cut lengths of colored ripstop repair tape, which either matches the ripstop of the 'wing', or is the opposite color to make it part of the design.

Stick the tape down good as it prevents dirt and sand getting into the kite.

[photo] Cut 10cm length of thin wire. I use single core telephone wire, but twist ties (with some of the extra plastic cut off) should work fine too.

With a sharp point punch a hole in the oval, on either side of the axial rod, at one end. Thread the wire though the holes and around both the fiberglass and carbon fiber rods, and twist to tie them together well. (See photo)

Cut off the excess wire and tuck the end down so that it can't hook on anything.

Repeat on the other end.

Warning don't tie the rods together too well or you can put too much stress on the fibreglass rod causing it to crack with time and use. It should be just tight enough to hold the two rods together well, preventing it from separating from the 'wing' oval.

[photo] Grab the 'ear' oval, and using a sharp craft knife, cut a slit into the 'ear' oval, along the pencil line across the short axis.

You may also like cut a piece out of the 'ear' on one side of the slit in the center. This provides some space for the axial rod to pass though, and let the ear fold neatly.

[photo] Slid the 'wing' oval into the slit you cut into the 'ear' oval. If you did not make the 'ear' oval a little wider than the 'wing', now would be the time you discovered you mistake.

As in the photo you can now see the rough final shape of the kite. You can also see the piece I cut out of the 'ear' for the axle rod.

Line up the pieces and using more ripstop repair tape, join the two ovals together, in all four corners. For this I cut the width of the ripstop repair tape into thirds.

[photo] Bridling

Cut two, 2cm lengths of the vinyl plastic tubing that fit loosely over the carbon fiber rod. These form spacers, to keep the bridle line from interfering with the spinning wing of the UFO.

Next cut two, 1/2cm lengths of a very tight fitting vinyl plastic tubing. These form a 'locking' end cap on the ends of the rods to stop the fiberglass washers coming off the kite.

Looking at the photo see how the vinyl tubing is added to the kite, leaving a generous gap between them. The locking cap should be very tight.

Using the light twisted nylon 'fish netting' line, cut at least a 2 meter length. The actual length does not matter, but be generous. On each end tie two loops, and 'larks head' that onto a fiberglass washer. (Enlarge the photo to see the line).

Slip the two fiberglass washers onto a nail or hook, and at the exact center of the bridle line, tie a overhand knot to make another loop. This is where the flying line is attached to the bridle.

[photo] Assemble the bearing for the kite to spin around. First the loose fitting spacing tube, three fiberglass washers (with the bridle line attached to the middle washer), and finally the locking tube on the end.

When finished lift the kite and give it a quick spin with your hand to make sure it spins freely, and the bridle point is properly centered.

Flying your UFO

[photo] Go fly your new kite. The kite likes a moderate to strong wind, with a good ground wind. You can NOT winch launch the kite, so the ground wind is essential.

Clip the flying line (the rest of the twisted nylon 'fish netting' line, with a fishing swivel clip on the end) to the bridle loop in the center of the flying line.

Let out at least 3 meters (or better still more), and while you have someone hold the flying line, give the kite an initial spin, while holding the 'ear' out from the 'wing'. The spin should be such the top of the kite moves with the wind.

The kite should quickly pickup speed and rise to a 35 to 45 degree angle on the flying line, and produce a strong pull. Let out line, and send to kite high.

You can now just relax, feel the vibrations, go for a walk along the beach with the kite following you, and wait for the inevitable questions... Good luck, and may your UFO spin well.

Anthony Thyssen

Leo Commandeur's UFO page

Leo Commandeur also published his own UFO Construction Notes with some excellent photos.

His UFO uses lighter 1mm carbon fibre instead of 2mm fiberglass, he did not mention the size of his carbon fiber axil. His photos are also somewhat confusing as one photo will show a grey ripstop, while the next a aluminized mylar (polyesterfoil), but if you ignore this his plan is correct. The bearings were made from nylon rings.


Ringed UFO by David Stirling (2003)

David Striling emailed me April 2003, with a few photos of his Mylar Ringed UFO. He said he has made 4 of these, but he keeps giving them away to friends and family.

The material is mylar from a space blanket, which as it did not come from a roll is very crinkly in appearance. This is actaully a bonus, as it makes any sunlight hitting the kite reflect in more directions, making it appear brighter to those not recieving a direct flash. I've actually purposely crinkled up my mylar on occasion for this very reason.

[photo] The hoops in his UFO, are 2mm fibreglass he mailed ordered from Pultron in New Zealand. These are feruled into circles with brass tubing, and the inside hoop of the ear is tied to the main wing.

The mylar is attached to the rings directly with scotch tape, rather than hidden double sided tape. It works and should not be visible when flying, though I like the neater appearence of double sided tape.

The outer 'ear ring' (sic!) is just tied with thread (nylon string) to the short axis of the main 'wing oval' of the ufo.
[photo] [photo]
[photo] The bridle bearings are made using cable ties, kepped loose on the 4mm carbon fibre axil, and kept in place with clear plastic vinal tubing (just as I do).

Created: 13 October 2004
Updated: 7 August 2005
Author: Anthony Thyssen, <anthony@cit.gu.edu.au>
WWW URL: http://www.cit.gu.edu.au/~anthony/kites/rotor/ufo_build/