Demoiselle (oz14333)

About this Plan

Demoiselle. Radio control scale model for electric power. Wingspan 30 in, wing area 288 sq in.

Quote: "Demoiselle: These small planes might be considered the first ultra-lights: they were intended to transport people from one estate to another. Santos even published the design in Popular Mechanics so that everyone could share in the Demoiselle.

My RC micro model is designed after the Santos-Dumont no.20, which was built in 1909. If you've seen the movie 'Those Magnificent Men in Their Flying Machines,' you know what a charismatic little airplane the Demoiselle was (if you haven't seen it, rent it right now; it will surely inspire you!).

The Demoiselle is fairly straightforward to build: it consists mostly of bamboo sticks and aluminum tubes in place of the bamboo and steel tubes that were used in the original. Balsa is used for the wing ribs and in a few of the details. I found 0.1-inch-diameter bamboo in a sushi mat and 0.125-inch-diameter bamboo in a package of meat skewers. Weigh your bamboo, and try to use the lighter sticks.

The fuselage is based on five triangular formers that are made of K&S 1/8-inch-diameter aluminum tube. You must set several angles and bevels into each tube used in the formers. To do this accurately, you will need to make the jigs shown on the plan. I made mine out of 2x4 scrap lumber.

Start by building the smallest triangle. Use the template shown on the plan to cut the aluminum tubes to length. You will need two long, one short and three 1/2-inch-long end pieces for each triangle, except for the largest triangle, which has /16-inch-long ends. After you cut each 1/2-inch piece, use a hobby knife to flute the inside. This will make it much easier to fit the bamboo sticks later.

To shape the tubes for the sides of the triangular formers, place one of the long tubes in the hole on top of the jig. Using a green permanent ink marker, draw a line along the length of the tube that lines up with the index mark on the top of the jig. Keeping the first mark aligned with the index mark, push the tube into the jig until it is flush with the top. Use an 1/8-inch-diameter round file to remove material until you have gone deep enough to come even with the sides of the tube. Turn the jig over, and line up the mark with the index mark on the bottom of the jig (note: the index is offset at a bit of an angle). Again file the tube until you come even with its sides. Keep track of which end is the top, and put the tube aside. Repeat the process for the second side of the triangle, but use a red pen, and line up the mark with the red line on the bottom of the jig. Now that both sides have been grooved, we'll use another jig to bevel the angle where the sides will meet to form the top of the triangle.

The bevel jig is made out of two pieces of 1/8-inch-thick pressboard. Both pieces have the outline shown on the plan. The base is simply a solid rectangle cut to the outline.The second part is glued on top of the base and has the slots for the 1/8-inch tubes cut out. Place the tube into the bevel jig with its index line facing up. Now rotate the tube 90 degrees clockwise as viewed from the bottom of the tube. Line up the top end of the tube so that when it is filed flush with the edge of the jig, only 1/2 of the groove you filed in previously will remain. Repeat the process for the second tube (it also rotates clockwise). You now have two sides to your former.

The bottom tube is done much the same way as the sides. Use a permanent marker to place an index mark on the tube that lines up with the groove in the top of the jig. File out the groove, remove the tube, flip it over and return the index mark to the same location, then file again... "

Direct submission to Outerzone.

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