Windshark (oz10752)


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About this Plan

Windshark. Radio control sailplane model.

Quote: "Excellent sailplane good for slope or thermal contesting, simple, basic design that can do everything that's required. Windshark, by Fred Koval and Alan Kicks.

I was first introduced to the Windshark in August 1975. Trying to qualify in a club contest, I totally destroyed my Todi because of a poor launch. It seems I became a little greedy and pulled the nose up a bit too far during the initial stage of the launch hoping to get maximum altitude. Instead of maximum altitude, the glider rolled over and went straight in.

I needed one more flight to qualify and there was just no way the Todi was going to fly again that day. Fortunately for me, Mr Kicks was in the process of test flying his prototype version of the Windshark. He graciously offered to allow me to fly my last official flight with his plane. Naturally, I was a bit reluctant to take the controls of an aircraft with only three or four prior flights, let alone one which was a prototype version of a new design. My options were quickly reduced when Mr Kicks thrust the transmitter into my hands and released the Windshark on the hi-start. To make a long story short, that was my best flight of the day, and I ended up with third place in Standard Class. I had to build the Windshark after that.

The Windshark was designed in two versions, a 72-inch span training version, which is the prototype I flew in August, and a 96-inch span competition version. It has several features which make it an excellent choice for the relative beginner at scratch building as well as glider flying:

a) The wing is a constant chord design which reduces the chore of cutting wing ribs. You simply make a template out of 1/16" plywood and hack the ribs out.
b) The aircraft is strongly constructed with four spruce spars in the wing and a 1/16 plywood nose on the fuselage. It will withstand the rigors of a novice flyer.
c) The construction is straight forward in nature - flat bottom wing, simple box fuselage, and sheet balsa tail.

Since the Windshark is designed with the beginner in mind, a rather detailed con-struction sequence follows:

WINGS: I prefer to begin construction of any project with the most difficult component first. We will start with the wing, dealing primarily with the 72-inch span wing since both wings are nearly identical except for the outer panels.

1. Make a plywood template of 1/16 plywood and cut the necessary number of ribs out of 3/32 balsa. Stack the ribs together, sand, and cut the spar slots.
2. Working on a flat building board free of warps, tape down the plan and cover with Saran Wrap or equivalent. I would suggest building a center and an outer panel at the same time.
3. Pin down the 3/8 leading edge to the board.
4. Glue the bottom leading edge sheeting to the leading edge.
5. Pin down the trailing edge bottom sheet.
6. Place the bottom 1/16 x 3/8 cap strips between the rear edge of the leading edge sheeting and the forward edge of the trailing edge sheet.
7. Using several ribs as a guide, glue the forward 1/8 x 3/8 spruce spar to the leading edge sheeting.
8. Pin down the rear 1/8 x 3/8 spruce spar.
9. Glue in all ribs, making sure to set the inboard ribs at the correct angle using the proper dihedral gauge. Let dry.
10. Glue in both top spars.
11. Install 1/16 webbing (grain vertical) between forward spars.
12. Install top trailing edge sheet.
13. Join center and outer panels using 1/16 plywood doublers on all spars.
14. Install 1/16 leading edge top sheeting and cap strips on outer panels. Do not install top sheeting on center panel at this time since you will have to join the center panels first.
15. Using the same procedure, build the opposite set of wing panels. You now have two sets of center panels with outer panels joined and sheeted.
16. Join center panels using 1/16 plywood doublers on all spars.
17. Install leading edge sheeting, cap strips and center section sheeting. Shape leading edge.
18. Reinforce center section joint with a strip of 3 to 4 in wide fiberglass at the too and bottom... "

Windshark, MAN, June 1977.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.


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