Upscaling a Delta kite
by Dave Combs
(New Lebanon, OH, USA)
Greetings, Tim! I have a love-love relationship with the wind: If there isn't much of it, I launch model rockets. If there is, then I fly my rip-stop delta kite that I've had for a number of years.
I'd like to do some kite photography/cinematography, because I'd like to see what a REAL bird's eye view is like. I'm used to upscaling rockets; you multiply the dimensions by a scaling factor to determine what parts you'll need and what dimensions to make them. So, I want to see if this can be transferred to kites.
I'm interested in building a delta kite with a 10' tip-to-tip wingspan, based on upscaling my delta kite. I'm considering Tyvek for material for its good strength to weight ratio. One of my concerns of course is how to attach a keel to the kite (i.e. what can be used to glue Tyvek to itself). Also, I need to decide on what to use for the spars; whether wood would be sufficient, or if I need to consider woven carbon tubing to get a good bending resistance vs. weight ratio. But for now, I first need to know if the dimensions of my delta kite can be simply upscaled or if there are other factors to consider.
Thanks again for the input; I plan on buying the Delta kite book download as it may help with this project.
"I have a love-love relationship with the wind:"
Haha - ditto: except in my case I try to match the kite with the prevailing conditions. The Dowel Delta or Dowel Rokkaku for the zero-wind and thermals scenario right through to the Fresh Wind Box for 40kph sub-gales.
"I'd like to do some kite photography/cinematography"
I'm about to start doing this myself very soon, with a large dowel and plastic Rokkaku. Keep an eye out for the flight reports...
"I'm interested in building a delta kite with a 10' tip-to-tip wingspan, based on upscaling my delta kite."
As long as your current Delta is not less than about 4 feet in span, you should be able to scale up to 10 feet without changing anything. Your spar diameters (not circumference!) need to go up by the same factor as everything else. And Tyvek is a great sail material.
One area in which my Dowel Delta book would definitely be a help is the method for constructing and attaching the keel. Tyvek can be taped since it is paper-like and adheres well. The strain is actually taken by lines that are run along the surface of the keel on both sides. Hence the taping is not structural - it just keeps the base of the keel neatly against the center-line on the underside of the sail. For a big 10 footer, you'll probably want to use packing tape rather than sticky tape! This is what I do on the big (8 feet tall) 2-Dowel Sled.
So, one approach might be to scale up the MBK Dowel Delta using dowel / tyvek / packing tape to prove the concept. Then, substituting lighter and stiffer spars should make the kite even better for KAP (Kite Aerial Photography).
Feel free to share your big Delta experiences via this site. See the 'YOUR stories' link over there on the left. Plenty of people would admire your efforts, particularly in the first few days when it would be the latest thing on the site blog page as well.