How to make a kite using Hangtime.

The following settings may be edited:

Span

Enter the required span in metres. The span is the distance over the canopy from tip to tip.

Chord

Enter the required centre chord for the kite.

Tip Chord

The tip chord ratio defines the width of the tip as a percentage of the centre chord. Enter a number from 1 to 99. Anything outside these values may give strange results. The combination of span, chord and tip chord ratio defines the surface area and aspect ratio of the kite. The surface area displayed is the flat canopy area.

PAP (Profile Alignment Point)

This defines a line along which all the profiles that make up the kite's shape line up. Again a number between 1 and 99 is good. Change the numbers and see what happens.

Tip Profile Depth

This defines the profile depth at the tip as a ratio of the profile depth at the center, and so allows the kite to have a fuller aerofoil in the center. This appears to be a good thing, a flatter profile in the tips can have some advantages. Again use 1 - 99.

AOA Centre

The Angle of Attack of the kite in degrees, at the centre.

AOA Tip

Obvious really...

No. of Panels

The number of panels making up the canopy of the kite. One of my aims with hangtime was to make a kite using just a few panels that would have good performance. Change the number in the box to see the effect (this part of the application is not very smooth and you may have to save your changes and then open the Kite Settings window again). More panels gives a smoother aerofoil but remember the material you will use to make the kite will stretch and (hopefully) conform to a nice smooth aerofoil section. Drag the yellow squares in the profile window to adjust the shape of the profile. Remember most commercial kites use a profile with the rear 70% or so absolutely flat...

No Profile at Tip

Check this box if the tips should have no profile (definitely tick it if using batten tips)

Leading Edge Diameter

Enter the required LE tube diameter as a percentage of the chord if you are making a tube kite, or enter 0 for no tube..

Sail Angle

Sets the angle at which the sail (canopy) is attached to the LE tube. Change the value to see the yellow square move. When using this option (only for tube kites of course) the first canopy panel is not used, and the front edge of the second canopy panel is attached to the LE tube. I will indicate the line where the panel should attach to the tube in a later release :-)

Profile Smoothing

Hangtime prints out the rib panels to the shape of the smoothed profile you specify. The smoothed profile should be the profile that you expect the canopy to deform to in flight, and should follow the panel shapes fairly closely. The lengths of the smoothed and unsmoothed profiles are indicated, and these should be more or less the same. (If they are slightly different I don't think it will matter, the extra will be at the trailing edge where both profiles are pretty straight)

The DXF output option prints 40 rib sections - use as many as you need when building the kite. If printing directly to the printer five ribs will be printed, and their position on the canopy is marked with a line. Later versions will include an option to select which ribs to print.

To specify the shape of the smoothed profiles, drag the red handles in the profile window.

Canopy Curve

To adjust the canopy curve, click the 'canopy' button, and drag the yellow squares. The canopy shape should match the shape you expect the kite to naturally take in the air, and should NOT be the shape you would LIKE it to take - at the minute Hangtime does not have bridling option... I am working on FEM (Finite element Modelling) code to predict the canopy shape, and I will release a version with this functionality as soon as possible.

 

Once you have entered all the settings to your satisfaction, click 'ok' to close the settings window and go back to the 4-view of the kite.

To print the patterns directly to a printer, click 'File>Print Preview', select the paper size you need and click 'Print'

I am making some changes to the way the printing is handled, so there may be some differences between the print preview and the actualt printout (such as page orientation etc.)

If you have access to a big printer then export the plans to a CAD file and print them out.

Trace the panel shapes onto ripstop or whatever you are using and cut out the panels, remembering to add a seam allowance of about 10mm on every size.

Sew the canopy panels together. The panels are laid out in the CAD file in the correct positions relative to one another, with the center of the kite to the left, and the tip to the right. The trailing edge is upper most.

Hem the tips, and make a batten pocket if you are using tip battens. Make line attachments front and rear of each tip using nylon webbing.

Trace the shapes of the ribs onto your fabric, again leaving a seam allowance on each side. Starting an inch or two back from the leading edge, sew each rib (use as many or as few as you need...) in position. The rib positions are marked by the circles printed along the front and rear edge of each canopy panel, and by lines on the canopy panels if you are using the paper printout.

Sew the curved edge of the rib to the canopy, not the straight edge!

When the ribs panels are in position, make a pocket for the leading edge spar by folding a strip of fabric in half lengthwise and stiching it to the front of the forward canopy panel. The strip of material should be long enough to go from tip to tip and wide enough to make a pocket that is big enough for your leading edge spar.

Make a similar pocket along the bottom edge of each rib panel (it may be easier to make these pockets before attaching the ribs to the canopy...)

To reinforce the front of the rib where it joins the leading edge, use two strips of webbing about 2 - 3 inches long, and at least as wide as the spar pockets.

Stitch the two pieces of webbing together as shown below:

The 'T' junction is then used to attach the leading edge spar tube to the rib spar tube by stitching the webbing in place. Only stich through the top and bottom edges of the webbing to avoid closing the spar tubes! The webbing effectively forms an outer sleeve over the spar tube.

Fold the trailing edge of the canopy twice ans stitch to avoid fraying

Insert the battens into the trailing edge of each spar tube, and then close the end of the tube with another piece of webbing. If I am using carbon battens I just sew them in - they rarely break!

Insert the leading edge batten, and either sew each end shut of make some arrangement so that one end can be opened to remove the batten.

Attach lines, find a big windy field...

I'll post some construction pictures here when I have them... I'll also add some instructions on making tube kites soon :-)