If a job is worth doing, it is worth doing well and making a circular nylon parachute will give you skills in cutting and sewing nylon as well as a good quality chute that will last (you can wash this one if you really want to).
Materials and equipment
For this parachute (and its drogue), you will need . . .
Lay the nylon fabric on the floor and then pick it up from a point that is halfway between the sides that are closest together and the same distance from one of the other two sides (where the green lines cross on the diagram). By doing this, you will get the largest area (outlined in blue) and have the most spare to make a drogue chute.Mark this point with a cross.
Then, use a piece of string, the same langth as your radius, to mark out sixteen points at equal intervals (on the imaginary blue line). Then, join them by drawing a straight line with a pen, using a ruler to make a regular, sixteen sided polygon. At each of the sixteen points, make sure that the line that you have drawn, extends around 1" towards the centre of the shroud. Next, put a mug in the centre of the shroud and draw around it. You now have a polygon, marked in ink and ready to cut.
Repeat the bove process on a smaller section - around 1.5 feet in diameter - for the drogue.
If you cut nylon with scissors, you will produce an edge that will fray given half a chance. Cutting nylon with something hot gives a good, seals edge that is very resistant to fraying - in addition, it is quicker and easier to cut nylon in this way.
Lay out the nylon shroud and run the hot soldering iron along the lines that you have drawn. If you make sure that the nylon is not in contact with a heat dissipating surface such as a metal sheet, it will cut quickly. If you press the nylon down so that it is in contact with a metal sheet, it will take ages to do it. When you have finished, you should have your main and drogue chutes ready to sew.
Take the nylon cord and cut off roughly 2½ metres - placing this to one side. To the remainder, fold it in half, then in half again and so on until you have 8 lengths, just over 2 metres long. Cut it into these lengths and seal the ends by melting in a flame for a second or two and then putting the melted end into the mug of cold water (left). Instead of using a knife or scissors, nylon can be cut by putting it in a small flame thus automaticaly sealing the ends.
Take one of the eight pieces and fold in two, forming a loop. Thread the loop through one of the plastic rings and then pass the two loose tails through this loop. Pull tight, tie a knot (not to stop it from coming undone but just to provide a bit of resistance) and repeat for the other seven lengths. You should now have sixteen ends coming from one plastic ring. Then tie the elastic to the ring (as in the photograph) - tying a knot in each end so as to stop fraying.
Now, make a smaller one with six or eight
cords around one foot long for the drogue.
Place the plastic ring in the middle of the shroud and lay out the cords so that they intersect the edge of the shroud at the sixteen corners. Make sure that the cords are in the order that they are on the plastic ring as this will make it easier to sort out any tangles that you may get into later on in the field.
At each corner, pinch about 1cm of the seam and tie a knot around it very tightly. Then, just to make sure, tie another. In the picture (right), you can see that the end of each cord is also tied in a knot.
Repeat a further fifteen times and then perform the same task on the drogue chute.