There aren't any detailed instructions on building Delta kites on this page. For that, you might like to try the downloadable books over there on the right. If you are on a mobile device, check out my book catalog.
However, this page is worth a browse if you are thinking about knocking together a cheap Delta kite from your own ideas. You might avoid a few pitfalls! This information is just a collection of thoughts, observations and experiences from building Delta kites from my Skewer and Dowel series of designs.
All 3 designs...
By the time I had got around to making and flying all the Delta designs mentioned here, I standardized on using a Template for the sail. This gets construction off to an accurate start by transferring the Template shape to one side of a plastic bag, with the bag edge being the center-line of the kite. It's easy to get the sail shape very symmetrical this way. This means that later, the spars are fitted to the sail, rather than the other way around!
A quick overview of these kites now...
The 1-Skewer Delta is really for small kids, or adults with limited patience :-). As far as Delta kites go, it's quite a quick build and therefore a good workshop kite for kids. With enough tail, this little kite provides plenty of fun in light to moderate winds, on 50 meters (150 feet) of line or less.
The 2-Skewer Delta is a bit trickier to make due to the slightly more gluing involved. This design looks and performs well enough to engage an adult for as long as they want to watch a kite fly! It's quite capable of flying at 100s of feet in the air, and will readily respond to any thermal lift around.
The Dowel Delta is a nice big 'floater', which exerts a satisfying pull on the line due to its significant wing area. As long as it is accurately constructed, this kite easily flies at the legal ceiling which is 400 feet above ground here in Australia. Your country might be 500 feet or 150 meters. Or perhaps you are in the Third World somewhere, where there aren't any Altitude Police to spoil the fun as you fly right up to 3 or 4 thousand feet!
For the following sections on building Delta kites, I'm assuming you are familiar with the basic geometry of the Delta wing and keel...
I use 30cm (1 foot) bamboo skewers, which come in packs of 100. At this scale, a tail is usually necessary to take care of stability. There's minimal gluing, just the 3 points where the spars touch each other. My original design was glued at the nose too, but there are 2 reasons to leave some space between the upper tip of the vertical spar and the leading edge spars...
If the kite tends to loop around in one direction, it's possible to tweak it straight by adding a tiny amount of tail to one wing tip. Just experiment, so the extra drag on one side is just enough to correct the looping. Mind you, if the wind is just too strong, nothing will stop the little Delta from going unstable!
It's easy to double the size of the 1-Skewer Delta just by making each spar from 2 skewers end-to-end. Short reinforcers need to be glued on to make the joins strong enough. This adds a little extra weight, but with 4 times the surface area of the 1-Skewer kite, that's not at all a problem. In fact, I've found building Delta kites this way gives an almost perfect combination of strength and weight.
The original 2-Skewer design was a bit marginal without a tail, so a short tail was added to give enough stability for long flights. In windier conditions, adding even more tail is sometimes necessary.
The attaching of the spar skewers together with short reinforcers has 2 advantages...
The 'small tail on the wing-tip' idea would probably work fine, but I found this unnecessary for building Delta kites with 2-skewer spars. Since it's twice as big as a 1-Skewer kite, it's so much easier to end up with required build accuracy.
A tip: Try to match the horizontal spar skewers though. If one is much stiffer than the other, there could be problems near the top of this kite's wind range. By the way, with both skewer designs, gluing alone seemed fine to hold the bamboo together. I can't remember a single in-flight failure due to a weak glue joint. So, don't bother wasting time with binding the spars with anything. Also, my instructions and plans specify the right length of reinforcers so that the final joint won't fail.
Where I'm from, Tasmanian Oak is the only type of dowel readily available in hardware stores. However, any sort of hard-wood dowel should be fine. The exact density of the wood might make small changes to the kite's characteristics. The heavier woods will result in less light-wind capability and so on.
The MBK Dowel Delta has quite a lot of leading edge between the upper tip of the vertical spar and the upper tip of each leading edge spar. The trailing edge of the kite is swept forwards just a little. The end result of this arrangement is a Delta which is well-balanced from nose to tail.
When allowed to sink though the air in nearly calm
conditions, a Delta comes down vertically. Sort of an aerial belly-flop!
With a small amount of tension in the line, you can pull down the kite's nose a touch and get it to fly around like a model plane!
Dowel is not as strong as bamboo! Hence, it's quite possible to snap the spreader if the kite is flown in fresh wind. It also might be the case that the kite simply has too much area for the size of dowel you are using. In any case, I've come to the conclusion that dowel Deltas really need reinforcement over 20% or so of the horizontal spar. Right in the middle, where flight loads cause the most bending. It's easy to do this by simply placing a length of the same size dowel right next to the horizontal spar, and running some glue down the entire length of the join. When dry, flip over and glue the other side also.
A tip-tail can look a bit weird, but does work, just as it does for the smallest MBK Delta kite. Before you do that though...
The standard way of trimming a Delta left or right is to trim down the diameter of one leading edge spar or the other. Reduced diameter means more flexibility, which can allow you to balance the amount of flexibility on both sides.
Also ensure that the vertical spar, or spine, is as straight as possible. A slight curve one way or the other will tend to steer the kite, with the effect getting worse with increasing wind speed.
That's it for this page on building Delta kites. Hope you found something handy here, and if you end up making an MBK Delta - Good Winds! as they say...
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