NPW 5 F (with Frame), an experiment.


Draw the bare forms of the NPW 5 (2 triangles and a square, forget the rest) on paper and add some letters.
 
Put a nail at both A's and both B's. Bend a glasfibre 4 mm rod from B via A-A to the other B.
 
The new form of the triangle and square includes the darker coloured area's.
 
Draw a horizontal line at approx. 1/3 to 2/5 of the top and add letter D. At both crossings of line D-D with A-C put letter X
 
Draw a line from A to E at the middle of D-X. Draw a Line from A to F at 1/3 of the distance X-X from X.
 
Optional (cosmetics): draw a triangle B-C-X from 3 equal lines (use distance C-X). Make line A-F longer until it crosses B-X.
Consider: draw line F-G. Start coupe at A with maximum at 1/3 A-F from A BUT ending in F.
 
  1. Cut the drawing along the lines into pieces and assemble them (glue on cardboard or thick paper) again when reading (doing) the numbers 2 - 8.
  2. Add coupe's (up to 3 cm, see book) at A-E (2x, red and green coloured part) and A-F (1x, only green coloured part). Maximum coupe always at 1/3 from the top. Measure the length along A-F along the coupe.
  3. Part A-F-F-A (aqua) is without coupe. Make sure that it is elongate (vertically), along A-F, to the length of couped A-F. The length of A-A and F-F remains as was before.
  4. Add 1.6 cm hem (for a double folded one) at each side of the lines A-E, X-B, A-F, X-D, X-F and F-F (all D-D).
  5. Replace line A-X and X-C (or A-C) with one single 1.6 cm wide strip. This strip, folded double, will be used to sew a tunnel in between.
  6. Optional: curve B-C, C-B and C-C.
  7. Add 2.0 cm for a double 1 cm wide hem on B-C, C-C and C-B.
  8. Each colour is cut as one part (red, aqua, yellow!! and green!!) above and below line D-D.
  9. When sewing first sew the parts above line D-D and then below D-D together. Then starting from the middle of F-F or X-X sew the upper and lower part together.
  10. Add tunnels for glasfibre rods (all 3 or 4 mm) first at A-C (2x) then at B-D-A-A-D-B. See Speedwing in the book. I used a backside opening to slide the rod in. The A-C tunnels end 8 to 9 cm before they reach A but you must continue sewing the folded strip until you reach A. You need this space to connect the C-A rod to the B-D-A-A-D-B rod with flexible connectors. The A-C tunnel is sewn in between the folded double strip of A-C. The A-C tunnels are made from Dacron, the B-D-A-A-D-B tunnel from soft webbing (gives better shape).
  11. Bridle points (melt nail through tunnel or push needle with bridle through it) start at 5 cm from B or C and go from B -> A and C -> A. They are repeated every 25 to 30 cm such that they end nicely in A. Between A-A is also every 25-30 cm a bridle point (at least 1 point).
  12. The bridle is simular to any normal kite. Take for each bridle line the average length, as used for the NPW 5, plus 30-40 cm extra. All bridles are knotted together as done for the NPW5 with B1-B6 and A1-A12 bridle. Lift the kite by its upper bridle (use 2 hooks -'distance X-X'- attached to the ceiling). Add the turbo-bridle, from the book, to the bridle lines connected at A. From the outside to the inside adjust the bridle such that the kite hangs almost horizontal and all bridle lines are stretched (tight) equally. (On foto: bridle lines at C and B not connected, 4-liner.) Check on one of your kites what the angle should be (approx.). A pro knows how to make the bridle adjustable so that the angle with the horizontal plane can be adjusted easy.
  13. For a 4-liner only the 1st bridle line at B and C are used for the lower bridle.
  14. I think it is not wise to make C-C and A-A wider then 75 - 80 cm. And C-B maximal 120 cm wide. Remember the kite must be flatter compared to the NPW 5.
  15. Think about repeating the square A-A-C-C several times left to right and up to a heigth (A-C) of 165 cm or 200 cm. Make shure that B-D-A-A-D-B rod keeps its round shape AND make sure that each rod towards the middle increase in length (top at least +7.5cm, bottom +2.5 cm) compared to the first or previous rod.
Findings:
  • 5-4-99: Up to now: None, but I am starting to build one today.
  • 6-4-99: Up to the point where one continues with the frame, took me 8 hours.
  • 7-4-99: The sail with frame is rather flat and stretched so be generous with the coupe's. Maybe a 3 mm frame is better then 4 mm frame for a LK=1 kite.
  • 8-4-99: Frame and bridle took 3 hours.
  • 10-4-99: First flight impression, bridle: kites hangs horizontal, wind: 2-3 beaufort
    1. Wind window 160 degrees and more.
    2. Steering: very indirect, little reaction. The turbo-bridle is needed at A-A and maybe more. Steering must mainly be done with the lower kite lines (4-liner), then all seams normal.
    3. It makes much noise. Don't put a coupe at E-B as I did. Bypass: sew 3 cm wide dacron over the area.
  • 11-4-99: Added some photo's. Click on the underlined text. Doesn't it work ? Update your browser. Or use this foto page.
  • 12-4-99: Retune bridle, turbo bridle and tilting position.
  • 18-4-99: Testing with winds between 1 .. 3 beaufort. Improved steering. Discovered a dent in A-A. Assumed solution: loosen bridle lines at the middle of A-A.
  • 20-4-99: Changed bridle between A-A and put ripstop-tape on the back against the noise.
  • 25-6-99: Dent is gone. Noise remains. Don't coupe E-B or B-X.The E-B coupe causes the noise.
  • 26-6-99: Used it to buggy but forgot to compare it with the standard NPW5 in the same wind.
  • 27-6-99: Crash landed during start. 1 rod broken (A-C), 1 rod pushed through the tunnel at B.
Think about:
  • the coupe's must stop at D-D.
  • instead of using coupe's add a part of a foil profile at A-X or A-C. This will be my next 2 experiments.
  • changing the design so that the transport surface in m2 becomes less or equalto your average delta. And with the same size NPW's so I can compare.
  • drawing a horizontal line B-B and removing anything beneath it. Is it a ...?