KITE PLAN - MODIFIED BROGDEN

John Maxworthy, Long Island, NY
Date: January 13, '97

BACKGROUND / MATERIALS

I first built a Brogden 6 Wing to scale using the diagram in the book "Kites" and then built this version to proportions that were taller and narrower at 9+ ft. high x 6 ft. wide. Brogden's original kite was 17 ft. high x 16 ft. wide. This kite is easy to hand launch and is steady in the sky. Well, almost steady; it slowly slides side to side about 6" in a sea breeze.

The materials needed for construction include:
Ripstop nylon, 3/4 oz. -- 3 yds @ 40 in. wide
Fiberglass tubing, .317" dia. -- 4 pcs x 39 1/2" lg.
Fiberglass tubing, .370" dia. -- 2 pcs. x 54" lg.
Fiberglass tubing, .248" dia. -- 2 pcs x 32 1/2" lg.
(An alternate would be 1/4" dia. x 48" lg. wood dowel.)
Misc. -- arrow nocks, 1/4" fg rod for internal ferrules, barrel beads, 1/2" dia. metal slip rings, 1/8" & 3/8" dia. grommets, line tensions, and 30 ft. of line for the bridle and some of the connection points.

PANEL ID AND SEWING STEPS


Before the panel cutting and sewing steps would be the planning of the graphics or panel colors. As suggested in the Kite Plan Index, this planning could use Paint Shop Pro or Windows Paintbrush.

FITTINGS AND CONNECTIONS

I use line tensioners to create an adjustable bow at the top of each of the panels instead of using 1/2 length spars and a center fitting to have a dihedrhal angle as Borgden originally used. The line tensioners are connected thru the slip rings at each end of the spar sleeves for A, B, and C.

Also the 12 cord connections between panels could probably be just as easy to tie off both ends, instead of the way I show one end tied off at the ripstop loop and then the cord passing thru a small grommet hole and then tied off to a bead in the back of the panel. I thought the appearance might be cleaner with the bead arrangement.

The 2 permanent cord connections at the bottom sides had the original purpose to Borgden of being able to create a front/ back "bow" in the spline if pulled tight. I originally tried this using line tensioners. Yes, it worked well, but I saw no difference when flying the kite; changed it back to 2 permanent cord connections to reduce the weight and eliminate the 2 adjustments needed at setup.

SPAR/ SPLINE ID AND DETAILS

Both the spars and spline have arrow nocks at their ends. The nocks are installed on the kite thru the slip rings on one end and tensioned with the bead tensioners on the opposite ends.

SPAR DESCRIPTION
A .317" dia. x 73" lg. fg tubing w/ arrow nocks on both ends & internal ferrule of 1/4" dia. fg rod or tubing
B .317" dia. x 54" lg. fg tubing w/ arrow nocks on both ends. An option would be to use .248" dia fg tubing
C .248" dia. x 35" lg. fiberglass tubing w/ arrow nocks on both ends. An option would be to use a 1/4" dia. wood dowel
D .370" dia. x 108" lg. fg tubing w/ arrow nocks on both ends & removable ferrule

Determine exact lengths at time of rigging. Probably could reduce diameters one size for all parts.

BRIDLE & SETUP

Line A is 120" lg. and line B is 120" lg. Line A is connected at point #1 (thru the panel grommet and onto Spar A) and to the shown metal slip ring. Line B is connected at Points #2 (thru the panel grommet and onto Spar C) & #3 (on the bottom slip ring for the bead tensioner) and passes freely thru the metal slip ring, adjusting each leg length depending where the towpoint is selected on Line A.

Setup only requires installing the spline and adjusting the 3 line tensioners to create the bow. You might want to also remove 1/2 of the top spar #A for making it more compact. (Its curious that the width of my car truck is a key dimension when I determine spar/spline lengths between ferrule connections. The choice is aways, "will this fit in the car boot or diagonally across the back seat?".)


You can reach me by e-mail at: [email protected]
http://home.sprynet.com/sprynet/jmaxworthy/brogden.html