February 2013 newsletter February 2013 newsletter March 2013 newsletter April Comming Soon April Comming Soon


Whatever it is; writing novels, playing golf, computer programming, motor racing, politics, marriage (same game), maybe even tiddly winks and pooh sticks, learning how to do something well takes 10,000 hours of practice. Or so we're told.
And I believe this: To get really good at doing anything takes more than just natural talent. In fact it's less and less accepted now that having an initial 'gift' for something has much if any bearing on the skill level that can eventually be achieved by focus and practice. (Except perhaps for activities like long distance running and quantum physics, for which who you've chosen as your parents makes a big difference.)

There's probably no particular genetic pre-requisite for kite making though, so I rather thought that just focus , practice and endless stuffing around would eventually lead to mastery.

But it hasn't yet, so either I'm wrong (again), or I haven't worked at it for long enough.

Ray Number 1 1988
Ray Number 1 1988
Ram air rays are the type of kite I've done most of my stuffing around with- more hours than for every other type in total, not excluding traction kites and pilots.

I picked on the ray shape (though lately it's been picking on me), because of it's similarity to so many framed kites that are excellent fliers- especially various diamond shaped fighter kites- figuring that all I would need to do is get the profiles, bridling and inflation right and it should work.
This still seems likely to be correct, though it has taken longer than I expected.

Origional Ray at Dieppe.
Origional Ray at Dieppe.
The first stickless ray I built was a patchwork style for the Dieppe Festival in 1988. After cutting, sewing, bridling, and a few weeks stuffing around to get it sort-of flying, I had it laid out in our drive way to dry before packing when my father caught one of it's bridles under his car while driving out. He dragged it a km or so townward with me in futile pursuit (on foot) before it was drawn to his attention by passing cars. Repaired in time though (slept on the plane). In hindsight I should perhaps have recognised this as a premonition of all the grief still to come.

Mark Sommerville with the 2nd Ray style, about 1991
Mark Sommerville with the 2nd Ray style, about 1991.
The second style I tried (blunter nose, drogue-ended tail), 1991 or thereabouts, was relatively successful, especially in smaller sizes, but as a maxi, wouldn't always recover from the edges of the wind.
And this was another ignored augury of frustrations to follow, because I'm still struggling to control this particular form of misbehaviour 22 years and two new styles later, and after thousands more hours of stuffing around (yes really). Grrrrr!

Harlequin Bucket Cervia 2005
Harlequin Bucket Cervia 2005
The next style was the harlequin/bucket tail versions from about the mid 1990's which has become the most successful single line maxi kite (by sales and usefulness) that Peter Lynn Kites have had to date. But even after 19 years of incremental development, in maxi form, they will still only fly reliably without a pilot in smooth mid-range winds. Their success has come instead from excellent graphics (various designers), their usefulness as the top kite in maxi kite stacks (lots of lift, high angle), and because the now ubiquitous pilot kites cure occasional wanders. This style is also made in various plain colour selections and midi versions are near perfect fly- alones. The original Mega Ray (650sq.m) is a development from this series.

Mega Ray Nelson 2003
Mega Ray Nelson 2003.jpg.
My current love/hate relationship with rays really kicked in (and mostly without the love bit- on either side) about 2005, when I started working on a higher aspect ratio smooth tailed version (from which the latest Mega Ray derives). This development was driven by the annoying propensity that bucket tails have for catching on things - like small children- which rips them to shreds (the tails that is), and the belated insight that stronger wind hunting/looping tendencies are a function of aspect ratio (Wider but shorter kites are less subject to strong wind instabilities, reducing their need for draggy tails).

Maxi ray light wind misbehaviour always has the same overt characteristic: The leading edge on one side or the other becomes slightly compressed (appears to lose inflation), pulling the kite to that side. It then either crashes or recovers and repeats the performance to the opposite side. As wind speed increases, instabilities caused by leading edge compression reduces until the kite flies straight and this form of misbehavior ceases.

Mega Ray Nelson 2003
Another shot at the Mega Ray Nelson 2003
The first remedy was optimal inflation- by working on the position and shape of the mouth and conical throat. This wasn't completely accomplished until quite recently, but did then cure most of the problem.
But not quite all of it; and that these kites are so inflation sensitive suggests a problem for older porous kites.

The main cause of the remaining problem was loose fabric along the leading edges. To visualise how this gets there, think of a plain paper envelope when it's blown up like a balloon. The crinkles on the envelope's longest edges have the same cause as the looseness along the leading edge of a bucket tailed, or earlier smooth tailed ray. To get this most sensitive region of a soft kite tight and smooth, careful panel shaping is required. That looseness along the leading edges is only a problem in light winds is because in stronger winds there is enough internal pressure for the kite to maintain it's shape against aerodynamic and bridle forces. In lighter winds, some fabric stiffness is an essential element- but unless it is stretched smooth, it doesn't. Unfortunately, neither computer modelling (of the sophistication that is generally available) nor inflating with a blower is adequate for determining the required shaping- because when a kite is flying, the net pressure on the skin at each point varies according to external aeodynamic flow patterns.
For the smooth tailed style, by sporadic attempts over a few years, by last week I had finally achieved a satisfactory leading edge; when the kite is flying straight, it's now smooth and tight even in light winds.
But even this hasn't completely cured the problem. In very light winds, especially if it's turbulent, the leading edges still alternately wrinkle up a little, causing minor (but annoying) instability.

Two Line Satun 2013
Two Line Satun 2013
Smooth Tailed Ray, de-power mode, Elwyn, Satun 2013
De Power Mode
Ray Smooth Tail Satun 2013
Smooth Tail Satun 2013
Ray Smooth Tail Satun 2013.
Smooth Tail
Satun 2013.
Ray Smooth Tail Pasir Gudang 2013
Smooth Tail
Pasir Gudang 2013

A reason for this residual effect is compressive loads in the kite's leading edge imposed by spanwise angles between the bridles . Using longer bridles would reduce this- but at about their current lengths (pretty long), they are themselves beginning to interfere with the kite's ability to recover from the edge of the window.
Stiffening struts along the leading edges would also work- but then the kite wouldn't be stickless.
A solution may be to increase the leading edge sweep-back so that spanwise components of wing bridle tension are taken more through the body of the kite and less along the leading edge. Unfortunately, as for aspect ratio changes, changing sweep back requires the building of a completely new kite- which is why changes to shape (such as sweep back) and aspect ratio are less often used in the search for stability as compared to changing angle of attack and profile-both of which are to a large extent a function of bridling. Doubly unfortunately, all this development has to be done on maxi and larger size prototypes because almost none of the things that effect kite stability are scalable.

But though not yet as good as it needs to be, the current maxi smooth tail ray version is performing rather well. When the wind provides even half a chance, it flies steadily at a high angle with good lift- equal to bucket tailed rays in most conditions and superior in some. Haven't tried a midi yet.

And it's arch type bridle makes it steerable. In this traction kite mode it's definitely kite-boardable.

The Boy Who Was Followed Home.
The Boy Who Was Followed Home.
And, from development done for the mega ray version, it has substantial de-power via a nose line with a single attachment point (from which it will fly stably at a low angle).

And that magical 10,000 hours must be about to roll up soon; when everything that currently confuses me about these kites (which is just about everything) will become simple and straightforward.

Yeah right.


Peter Lynn Kites Ltd
105 Alford Forest Rd
Ashburton 8300
Ph: +64 (0) 3 308 4538
Fax: + 64 (0)3 308 1905
Email: peter@peterlynnhimself.com
Website :www.peterlynnhimself.com

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