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Flying Models Centerfold Plan - February 2013

The Poly-Wog

Teach kids to build this fun model and
they’ll learn a new hobby to last a lifetime!

By Bill Warner/Photos by the author

When I began teaching in junior high in 1960, all teachers were requested to start a club. Having built models as a kid, I jumped at the chance. Little did I know then that model airplanes would become one of the most important things in my life!

One of the first things I had to do was to find appropriate projects, and I literally tried everything I could find that was suitable for beginners. I was learning a lot as I went, getting involved with people who knew what they were doing such as Bill Hannan, Walt Mooney, and Frank Zaic, and spending every chance I could get designing and building new projects.

Soon we were using winders and better rubber, adding polyhedral, and stretching the fuselages to those 29-cent wonders. From there, I designed a 1⁄32-inch balsa sheet model of my own called the Mini-Wog, using a flat wing with raised tips. It flew pretty well, and turned in 1–2 minute flights in thermals. In the mid-’60s the Poly-Wog was born of the Mini, having a more pleasing shape and polyhedral. It flew so well that one of my Balsa Butchers even made one with a wingspan of several feet, which he flew on rubber power in a contest at Taft.

The Poly-Wog was not designed as just a beginner’s model, but as a high-performance, simple transition from a really super-simple anyone-can-build-without-supervision to a stick and tissue plane. It was, and is, best built with a small group, led by an experienced modeler building and demonstrating each step before the students take it. Learning is twofold: First: reading a plan, following directions, and learning building skills and secondly learning the basics of aerodynamics and aeronautics.

Poly-Wog

Use a steel straightedge to guide fuselage cuts (above). An unused telephone book works well as a cutting surface. Watch your fingers! Glue the patterns to the balsa (below) with a “repositionable” glue stick. When cutting out parts, make several light cuts when crossing the grain. Flip the pattern over and re-use for the opposite wing.

Poly-Wog

The model is built of balsa. Light “B/C” grain 1⁄32-inch sheet for the wing and tail is best, and 1⁄8-inch hard balsa for the fuselage. Make two photocopies of the plan, and cut one up for patterns, which can be either stuck down on the balsa using an “Elmer’s Repositionable Glue Stick” or just traced around with a ball-point pen. I use a phone book to cut on, and also for using the glue stick. You can tear off the sticky page, or hacked-up pages and have a fresh working surface.

Balsa wood is porous, so put a light coat of glue on each surface you are going to join and allow to dry. Then put on a second coat, and assemble, holding the parts together for a couple minutes until set. When dry, smearing a thin coat of glue on the joints is a good idea. Walmart’s “Multi-Purpose Cement” is great. I strongly recommend not using “instant” glue.

Getting it together
You can use a ready-made Sleek-Streek type prop hanger assembly from Easy Built Models or Peck Polymer, with a 5- or 6-inch plastic prop. If you use a ready-made assembly, it helps to cut out a bit of the plastic hanger (glue and bind with thread to get a bit more rubber clearance). Cutting this can be dangerous, so be careful. Sometimes the knife slips or the plastic can break.

Another way to make a front end is to use a short length of 1⁄32-inch aluminum tubing and a spacer block, which is worth the extra work. The spacer block needs to be angled for downthrust (see picture), and the roughed-up so- the-glue-will-stick tube should be glued on pointing slightly to the right as seen from the top. Glue and bind with thread. A glass bead goes between the prop and the bearing block. Buy or make a prop shaft of 1⁄32-inch music wire.

The empennage (tail): Glue the stab on the underside of the fuselage. Gluing the rudder to the side of the fuselage, instead of on top, keeps it nice and straight.

Rear rubber hook: Bend a straight pin for the rear rubber motor attachment point and glue and bind. Note: the position on the fuselage is not optional.

Rubber motors: 1⁄8-inch flight rubber works fine. If you do not have a rubber winder, a loop of 1⁄8-inch about the same length as the distance between the prop and rear hooks will work best for finger winding. For high performance, make the loop as long as the fuselage and use a winder.

Poly-Wog

Note how the wing will be cambered (curved). If you cut out the wing parts per plan, the little curves should fit together like this.

Building the wing: The wing has three sections which meet at angles. Note that where they glue together the edges are curved in a bit to allow for them to be put together while cambered. Sanding each joint a little with an angled sanding block makes for a better fit. See the dihedral sketch and photos for a rough idea as to the angles. This is not critical, but should be close.

Lick the top surface with your tongue, (swells the wood fibers on top and gives you a dandy camber). Glue the curved wing formers underneath using the double-gluing technique. When dry, applying a light coat of glue at each join is good.

The pylon is cut from fuselage material and glued under the center of the wing. The front (higher) end of the pylon creates the front of the wing.

Balancing and wing position: Hang a rubber motor on the fuselage as shown, balancing level using your finger as a balance point. Mark the spot where your finger is. The wing and pylon assembly should be centered over that point. Make sure the thicker end of the pylon is facing forward.

Pre-flight: Hold your model out, close one eye, and sight to make sure you see no warps in the wings. If you do, you can heat the warped wing with a hair dryer or with tea kettle steam and twist in the opposite direction of the warp. Hold it that way until it cools. Check again. It is crucial that you don’t try to fly with twisted wings! Keep at it until you get it right. Put a drop of oil on the prop shaft. If you get to the field and have forgotten to do this, use the oil dipstick from a car.

Poly-Wog

Double glue! Formers will hold the camber. Let dry before attaching at tips and center.

Make up a few rubber motors of different sizes. Tie the ends with a square knot, chewing some saliva into it as you pull it tight. Bind the loose ends together with thread if you want. Put the motors in a baggie with a little silicone grease, ready-made rubber lube, or a 50-50 mixture of glycerin and green soap and squoosh ’em around until they are coated. Wipe off the excess lube with a paper towel.

Take your model(s) to the field in a box to prevent damage in transit, with your glue, balsa scraps, flight rubber, a winder, a bit of modeling clay in a separate box.

Poly-Wog

Tail feathers. Rudder glues to side for straightness (above). Sand airfoils if you wish. Move your finger under the fuselage (below) with all parts attached, including rubber loop. Mark the balance point.

Poly-Wog

Flying the Poly-Wog
Find a big field with no trees and deep grass on a day with no wind. (Okay, so I’m a dreamer.) If the breeze is coming from the north, fly from the north end of the field, otherwise use the center. You have no idea how far a well adjusted Poly-Wog will fly!

Double-check for warps, and you are ready to wind. On the field, breathing heavily on a warp and twisting in the opposite direction sometimes works.

For winding, always grip the fuselage as far forward as possible. Let’s not break it before you get airborne! Use a short motor if finger-winding, and start with a low number of turns until you see what the model wants to do in flight. If you are using a winder, have a helper hold the prop and the rubber on the prop shaft up front, with the tail well away from the line of winding. Stretch it out about three lengths and put in test winds.

Hold the model with the nose about 30 degrees above the horizon. Lightly launch it straight ahead into the light wind, if there is any.

Thanks for Moses Ortiz, ten and future President of the U.S., for building and flying his first model aeroplane (which flew beautifully); to Joel Reiman who, as a member of the Sepulveda Junior High Balsa Butchers built about ten of these in 1971 and flew in for the picture shoot; and to my lovely wife, Jeanie, without whose help, this article would still be sitting, uncorrected, on my dead computer.

Need help getting off the ground? Try these Troubleshooting Tips (PDF)!

This article originally appeared in the February 2013 Flying Models.

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