“How did the zebra get it stripes?” and “Can lightning occur in space?” BBC Click Radio presenter Gareth Mitchell answers life's big questions
‘Kite-shaped’ normally means something that’s a stretched diamond, but kites can be almost any shape. To keep the weight down, most kites have two or three spars (the rigid poles that give a kite its structure) with ripstop nylon fabric stretched between them. Box kites arrange their sails in a ring so that they catch the wind from any angle, while many modern kites eschew a rigid frame altogether and use a parafoil design instead. Parafoils have pockets that are open at the front and as they fill with wind, they create a semi-rigid structure.
Single-line kites are limited by the wind direction, but ‘stunt kites’ use two (or sometimes four) control lines positioned to either side. Pulling the line on one side causes the kite to swoop in that direction. Pull harder and the kite will perform a complete 360° loop, but it remains steerable because the control lines can slide past each other, even when they’re twisted together.
The height of a kite is limited by the weight of the line it’s able to lift. Higher winds provide more thrust, but they also place more strain on the line, so it needs to be thicker and heavier. Single-line kites normally come with 45-60m of line, while stunt kites have much shorter lines because they’re harder to control. Also, short lines make it easier to avoid trees and anything else that might get in the way.
Parafoil kites are generally lighter than kites with spars and will fly with less wind, although too much can damage the kite or make it hard to control. Most kites are designed for winds between four and 20mph. That means from roughly a breeze you can feel on your face, up to the kind of wind that would make an umbrella impractical. Kites often have adjustable bridle attachment points that can compensate to some extent for higher wind speeds.
The trick is to keep the lines straight at all times. Kite flying twists the line, which stores energy that will try to tangle them into loops and knots. Once your kite is on the ground, wind the lines in as you walk towards it. Don’t disconnect the lines from the kite until they’re fully wound onto the spool.
Kites are essentially wind deflectors. The wind blows horizontally until it hits the angled surface of the kite wing and gets deflected downwards. The kite can’t move backwards because it is tethered to the line so the upward component of the reaction force pushes the kite higher. As the kite climbs along its arc, the angle between the kite and the wind becomes shallower and the vertical component of the thrust reduces. At a certain point for a given wind speed, the vertical thrust balances the weight of the kite and it hovers there. That’s where the fun begins.
Practicality: How small does the kite fold up? Are there any pieces that are fiddly to attach or can be easily lost? How fragile is it?
Flight control: Flying a kite is fun, constantly relaunching it after crashing is not. How easy is it to keep the thing in the air?
Wind range: A good kite will take off in a light breeze, but doesn’t become unstable or unmanageable if the wind picks up later on.
Fun factor: Once the kite is up in the air, is it fun to fly? Does it draw gasps of admiration from the crowd, or do they soon wander away?
Wing span: 150cm
This is a wonderfully bright and impressive delta wing (triangular) stunt kite. It takes just a few seconds to assemble and feels alive and responsive, even in quite modest winds. The rigid wing means you can fly at relatively large angles from the wind direction and this lets you make lovely swooping dives and spins. With a few minutes’ practice, we were able to make triple somersaults and recover before the kite hit the ground. The spine of the kite is held in place by a releasable tab that’s designed to reduce the impact force on the nose during a hard crash. We were never able to dive-bomb the kite hard enough for this to activate, but in higher winds, it should help protect your kite from damage.
A rigid frame and high flying speeds make this kite a little more dangerous if you accidentally hit children or pets. The spars that support the leading edges of the delta wing don’t fold in half so the kite stows away into a bag that’s 1.1m long. That’s fine for the boot of the car, but not really practical for a rucksack.
Wing span: 145cm
Since it uses a parasail-style wing, the Buzz folds away into a really small bag and there’s no assembly – you just shake it out and off you go. This makes it perfect for impatient children and the pull is light enough that even small kids can fly it quite easily. Crash landings are gentle and you can often relaunch it by yourself. Because it weighs almost nothing, the Buzz will get airborne on the lightest zephyr of wind and if the breeze suddenly drops, it will float gently down rather than thudding to the deck. Despite this, it’s very manoeuvrable and multiple somersaults are perfectly possible. What’s more, if you can hold it steady enough, the kite will climb higher and higher until it’s virtually overhead.
The wing only stays inflated as long as there’s air blowing into the front. Fly too far to one side and the wing tends to collapse on the outer edge. It also seems more susceptible to low-level turbulence. This limits its flying window more than a delta wing. The Buzz flies more slowly as you perform stunts, making it slightly less of a crowd pleaser.
Wing span: 66cm
This isn’t just a kite with a picture of a pirate ship on it – it’s an actual three-dimensional model with a hull, rigging and sails. This is guaranteed to draw gasps of admiration from everyone before you even get it in the air. Once it’s up, it flutters and darts like a corsair on the high seas. As a way to mark your territory on the beach, it’s hard to beat. In stronger winds, there’s a tail with three blue and purple streamers that you can attach to keep the kite stable, which even looks like the ship’s wake.
Unsurprisingly, this was the fiddliest kite to assemble. The rigging lines clip onto the hull using little rubber cups and you have to stretch them quite hard, making them easy to tear. The number of spars involved makes this kite very heavy for its sail area and it needed the most wind to get airborne. Once it was up, it needed a fairly steady breeze to fly properly. This often meant flying higher, to escape ground turbulence, which was a pity because it’s most impressive when it’s low enough for you to appreciate its shape.
Prism Stowaway Diamond
Wing span: 94cm
The classic diamond-shaped kite has been given a 21st-century makeover. The ripstop polyester fabric is vividly printed with an eye-catching geometric design and the spars collapse into sections held together with internal elastic connectors, like modern tent poles. There are no loose pieces to get lost, no complicated instructions to follow and the kite unfolds from a 35cm pouch that you could carry in your back pocket into an impressive kite almost a metre across. It’s light enough to launch in a 4mph breeze and there’s no need for a second person to act as a launcher – you can just hold the kite at arms length and let go, then pay out the line as it tugs earnestly upwards. With the tail attached, it draws a glance, even at its full height of 60m (200ft) and it has enough lift to fly at much steeper angles than the pirate ship. When you’re done flying, you can just reel the Stowaway back in and it will stay in the air until almost the last moment.
Precisely because it’s so stable, there’s much less to do with the Stowaway Diamond. Once it’s up, it stays up and it’s entirely feasible to tie it to the leg of a deck chair or a stake in the ground and then leave it unattended. If you need the constant adrenaline rush of fighting to keep your kite in the air, the Stowaway Diamond won’t offer enough of a challenge.
For younger children, the Flexifoil Buzz is an excellent beginner’s stunt kite, with very tolerant flight characteristics and little potential for injury. The Skydog Little Wing offers slightly more acrobatic flight, but it’s much less portable so it’s not something that will get taken along on family walks ‘just in case’.
The New Tech Pirate Ship has the biggest wow factor, but it’s also the most fragile and the fiddliest to assemble. Both of these factors will give this kite the shortest useful lifespan of those on test. Though the Prism Stowaway Diamond was initially the least impressive, it was the one we kept coming back to. It’s the easiest to take with you, the simplest to fly and the most dependable, making it the test winner.
Luis Villazon is one of the Focus Q&A experts