What-Zit (oz14561)

About this Plan

What-Zit. Indoor microfilm soaring glider.

Direct submission to Outerzone.

Quote: "WHAT-ZIT & the Microfilm Game, by Bud Tenny.

What's a What-Zit? It's an indoor glider of variable design which can be flown anywhere indoors. Takes very little time to build, and teaches you a bit about indoor models. It's a change-of-pace fun model that is ideal for a club project and is fun to tinker with at home. Ready to start? Read the instructions completely before you start - then have fun!

PREPARATION: Make the microfilm first. Get some Sig Lite-Coat dope, the new low-shrink dope recently introduced by Sig Manufacturing. Take 20 parts of Lite-Coat, 4 parts of Acetone and 1 part of Amyl Acetate, (get last two items at a drug store), and mix them thoroughly.

Now find a place to pour the microfilm. The time-honored vessel is the bathtub, but you must be sure it is clean and absolutely free of soap. A thorough scrubbing followed by a rinse with scalding hot water will do the trick. The lady of the house may not like the idea at first, but point out you are going to clean it before and after! Otherwise, a plastic tablecloth laid in a frame of 1 x 2 in strips (See Fig.1) on a flat surface will do nicely. In either case, put about 3/4 in of cold water in the tank, or enough to cover the bottom of the tub.

Another necessity for making microfilm is a hoop to lift it off the water. A balsa hoop (Fig.1) is very little trouble to make and easy to work with. Be sure to glue the corners securely and put reinforcement blocks in each one. A single coat of dope sanded smooth will make the hoop easier to use and longer lasting. Make four or five hoops so you will have plenty of film to work with.

The basic idea in making microfilm is to spread the solution evenly on the water, let it 'set' a few minutes, and lift it off with the hoop. Old-timers use a bottle cap for pouring; this takes a lot of practice. A gadget to pour microfilm can be made from aluminum broiler foil molded around a small bottle, or from a plastic squeeze bottle and wooden or nylon rod drilled to the right size. A number 42 (3/32 in diameter) drill is about the proper size for this formula. Fig.3 shows a picture of the pouring gadget, and two pour nozzles.

HOW TO MAKE FILM: The procedure is to fill the gadget, then let the solution pour out while you swing your hand smoothly across just above the water. Start pouring about six inches from one end of the tank and stop about twelve inches from the other end. Fig. 4 shows how the squeeze bottle gadget is held. Note that the spout is stoppered with the little finger except when the pour is being made.

Once the film has been poured, the next step is to attach it to the hoop, remove the excess, and lift the film. First, coitt the hoop with Carter's Rubber Cement. Only that par t of the hoop which touches the film need be coated. Let the cement dry a moment, then place the hoop on the film carefully (see Fig. 5); tear the excess film from around the hoop carefully. Lift one edge of the hoop just a little, then slide the hoop forward and up in a slow, smooth motion (Fig. 6). Set the hoop up and let the water drain off. When the sheet is dry, it will show colors unless it is too light or too heavy to use. If the color ranges from a light straw brown to gold to blue, it is very light. Heavier film will range from blue through greens and reds. With practice you can see these colors while the film is still on the water.

As long as you have the set-up made, pour several sheets. Even if you plan to build only one or two What-Zits, you can use the best sheets and amaze your friends with the others; besides, you may goof a sheet and need another. Pouring microfilm is somewhat of an art, so if you have good results one time, keep pouring - it may not work as well the next time. One other word about materials, Sig Lite-Coat was specified because it (by some happy accident) is the only commercial dope which produces good microfilm with no special ingredients added.

Other dopes require extra ingredients which are hard to find. The microfilm should be aged after it has been poured. Let it rest on the hoops for 24 to 48 hours, then expose it to moving air from a fan for several hours. Fasten the hoops down so they won't blow around, and gradually move the fan closer until the film is agitated gently. Leave it this way until the film ripples freely on the hoop.

BUILD THE MODEL: Now that the hard part is over, let's build some What-Zits! Three strips of balsa cut from soft 1/32 sheet balsa (the lightest you can find) and three ribs make up the flying surfaces. After assembly and covering, these are glued to a piece of soft 1/16 square balsa which forms the fuselage. You will have to cut most of your indoor sticks to size, using a straightedge and a sharp knife. The straightedge should be aluminum or steel, but a school ruler with a metal edge will work. The knife should have a sharp thin blade with a point. An X-acto number 11 blade is almost ideal, as long as you take care to use only a sharp one.

Lay the straightedge on the wood near one edge and trim off the edge of the sheet so it will be smooth and straight. Now, align the straightedge with the previous cut, just a small distance away, and cut a strip. Don't try to cut it all in one grand slash; instead, take several very light cuts..."

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