Kite Making - The Black Deca part 1
In the beginning....
View of the black decaI like the Synergy Deca kites. So I made one. This worked better than expected, so I decided to make another - one which was larger than the original and with lighter spars. The idea was, so my thinking went, to have a Deca I could use for those light wind days.
I got out the templates for the Deca I had knocked up in May 2003 and started redrawing them. I decided to leave the Deca wingtips the same length, but increase the length of the main sail by 10cm, and the height by 5cm. This would give a greater surface area to the wind and if I use lighter 4mm carbon spars throughout I would reduce the weight & hence be able to fly in lighter winds.
I originally wanted some white Icarex fabric to do this (ooh a nice white kite), however I had the offer of some black Ventex very cheap so I quickly changed my mind (ohh a nice black kite). I also wanted it to be a single colour, even if it had a number of panels. There is something very striking about a single coloured kite flying. At least to me.
So armed with a couple of meters of second hand Ventex (which is pretty much the same as Icarex in that it is lightweight polyester fabric), a few 1.5m 4mm spars from Decathlon, 1m of 5mm internal diameter white plastic tubing from B&Q, and some cheap nylon line of I went.
The construction
A 'real' Deca 6 has 6 separate sail panels sewn in such a way to make a more 3D shape (i.e. you can't flatten the sail completely) and a 'real' Deca 1 has a single piece of fabric stretched into the 3D shape. I decided to make a pseudo-Deca 5 - where I had 5 panels to the sail, but sewn so it stays flat and is stretched into shape by the tension in the lines/spars. I hoped that the sail panels would 'aid' the formation of the 3D shape.
My first problem - the 5 panel design needs curved seams and drawing/cutting/stitching curved seams is hard! I plotted the shape on cardboard templates (made out of cereal packets by the way), sometimes drawing freehand, sometimes plotting points, then joining the points up with straight lines. In then drew the seam allowance (8mm I think) around and cut it all out. To make it easier to draw the actual kite outline I cut out bits of the template near the edge (see photo) that allowed me to mark the edge in yellow chalk on the sail.
Hot cutting the curves was very difficult as I had to do it freehand - and as everything in a Deca is a curve it quite an undertaking!
Eventually I was left with the slightly ragged panels which were simply overlapped, glued (using Bostick), stitched together with two lines of parallel straight stitch. The end result wasn't bad but wasn't great either. I seemed to have huge problems sewing the hem around the kite as well - very wonky stitching - again because everything is curved. But trying to stitch black fabric to another piece of black fabric using black thread is, lets say, challenging!
Once the sail was complete and made end caps out the plastic tubing and fitted them to the sail, then made the spars out of the 4mm carbon and lashed the whole lot together with the bridle line. I proudly stepped back to admire my handiwork only to realise it was rubbish! In a read Deca the wing tips are swept back at an angle, on my Black Deca they weren't swept back at all - the whole thing was flat!
The Back Deca was then consigned to the top of the shelves for a couple of weeks until I could think of something.
Fixing it (part 1)
Taking the kite off it's shelf again I decided the problem was a) the central bow spar was too long and b) all the bridles were wrong. Nothing major then.
First thing was to remove all the bridles and retie - but as I realised that there would be a large amount of fiddling around with knots and stuff in order to work out the rights length using slip knots to easily adjust the lengths would speed up development.
Once all the bridles had been retied the kite looked a lot better - at least the wingtips were swept back. There was a lot of adjusting each one by eye (no point looking at the original Deca since I had altered an number of dimensions) but in the end I had a kite that looked a Deca.
I decided to leave the central bow spar the way it was until I had test flown the kite - I could always tape the central spar to the end of the bow spar in order to shorten it until I found the right length.