Wing Tips

STRONG, LIGHT FORMERS
Harry Braunlich, Victor, NY
Published in Fly RC July 2008

After nearly 75 years of modeling, I prefer to design my own or build from plans. Naturally, I have developed a few favorite techniques of my own along the way. Here is a way to make very strong formers that are much lighter than plywood. Instead of using plywood, cut formers out of sheet balsa, or glue sticks with just butt joints; I use thinner balsa and laminate two layers, as shown. I use balsa of varied thicknesses, depending on the model’s size. Smaller sport models often call for 1/8-inch formers, so I use two layers of 1/16. For most 1/4-scale projects, I laminate forms of hard 1/8 balsa to give a 1/4-inch-thick structure. The key is to create a lap joint at every corner. By working around the formers in a pinwheel fashion, as shown, you’ll quickly create them without critically fitting any pieces. Trim and sand the excess wood flush with the outline after the glue has cured.

EASY MASKING
Steve Hillman, MD
Published in Fly RC May 2008

Here’s an easy way to mask a small area before you spray-paint it. Put the entire wing or fuselage into one or two large plastic drawstring garbage bags, and tie them so that the component is entirely covered. Now tear or cut the bag to make a hole that’s a little larger than the area to be painted. Mask the edges of your target area by using masking tape to hold the
plastic bag, and then paint without overspray!

CLOG-FREE FILING
Al Brooks, Lost Creek, WV
Published in Fly RC May 2008

When you file soft metals such as brass, aluminum and solder, they soon clog the file’s teeth and make it impossible to use and difficult to clean. To remedy this, fill between the teeth with regular blackboard chalk before you start, and repeat as needed. The chalk doesn’t degrade the file’s cutting action, and when you’ve finished your job, just tap the file to remove the chalk from between the teeth.

WORKBENCH PADDING
Don White, Houston, TX
Published in Fly RC September 2008

A small white sink mat that protects the bottom of a sink is perfect when you work on electric components. This one is white with waffle-pattern holes. Small screws get trapped in the holes, and servo arms stay where you put them. And who hasn’t lost an EZ connector screw? This pad works well and is also a place to put down tools and knives. I have not used it as a cutting pad yet!

TAPERED SANDING STICKS
Darvin Cloin, Elizabethtown, KY
Published in Fly RC November 2008

I sprayed 4 to 5 inches of a 9-inch-long piece of trailing-edge stock with 3M Super 77 adhesive. I laid that on a sheet of sandpaper and cut around the edges. I put 400-grit sandpaper on one side and 240 on the other. This simple tool gives me a handy way to sand the ends and tips of spars, ribs and anywhere else while I’m building, and the taper allows it to get into tight spaces, too.

STARTING A BOLT IN TIGHT QUARTERS
Robert Grossman, Swartz Creek, MI
Published in Fly RC June 2008

If you have trouble holding hex-head bolts and screws on the end of a ball-end wrench in tight quarters and you don’t like to magnetize your tools, try this. Shrink a piece of heat-shrink tubing down over the driver and the head of a bolt head. The tubing will allow a firm grip on the tool, and it will hold the fastener securely enough to get it started. The tubing can be used repeatedly. If it loosens, just re-shrink it around another fastener.

PORTABLE BUILDING BOARDS
Clark Duvall, La Quinta, CA
Published in Fly RC November 2008

I regularly work on more than one model at a time, and I use separate building boards for each project. I buy 4x8-foot 2-inch-thick sheets of pink or blue foam from a home-supply store and cut them into 2x4-foot panels. Next, I tape down the plans with blue painters tape, and I cover them with a wide clear stretch film. The film keeps the plans clean and resists glue, and the foam makes a light but firm work area that is easy to push pins into.

CONNECTOR MATCHING
Jerry Smith, Acworth, GA
Published in Fly RC October 2008

Have you ever tried to mate a male Futaba connector with a female JR connector? The spline on the Futaba connector will prevent you from making the connection. A secure way around this is to cut a slot in the JR connector to allow the spline in the Futaba connector to mate. Carefully cut the slot with a sharp X-Acto knife, as shown. Unlike simply trimming the spline, this is a quick and easy fix that maintains polarity protection.

RIVETING WINDSCREENS
William Foster, Bedford, Nova Scotia
Published in Fly RC October 2008

When thinking about attaching a windscreen to a Ryan model, I was faced with the problem of removing a thin strip of covering and getting canopy glue in there. Then I had a thought: I decided to “rivet” the windscreen to the fuselage with round wooden toothpicks that happen to be tapered. I drilled a few small holes in the windscreen and balsa decking. A drop or two of CA on the inside secures the toothpicks and their taper prevents the plastic windscreen from coming off. Once the glue cures, simply nip off the excess with some flush side cutters.

HARD CASE FOR WINGS
Eric Barry, Deep River, Ontario, Canada
Published in Fly RC September 2008

It can be hard to carry your plane to field in one piece, and I hate to put the wing down in the car, as it can easily be damaged. The solution is simple: a rifle case. These are available at many hardware stores for $20 to $30, and with a few modifications, they can be extremely useful. The hard cases come in many sizes and offer great protection for small to medium planes. They also have foam on the inside. I cut holes in the foam to accommodate my wing servos, and I notch the plastic for the plywood piece that sticks out of the wing. The foam and hard case offer great wing protection.

STURDY HARDPOINTS FOR ADJUSTABLE STRUTS
Gene Decook, Canandaigua, NY
Published in Fly RC August 2008

To make light, sturdy, wing-strut attachment points, you’ll need a 4-40 thumbscrew. Drill a suitable hole in the blade to accommodate a clevis, and then cut off the ears as shown. Mount the finished units in 4-40 blind nuts inset in plywood plates in the wing and fuselage. The studs’ lengths can be adjusted by 0.025-inch at a time by turning them in or out by half a turn.

EASY FIELD PLANE HOLD-DOWNS
Gary Lothridge, Weatherford, TX
Published in Fly RC July 2008

To secure my models when the breeze comes up a bit at the flying field, I use pairs of small beanbags tied together with string or light cord. Drape a pair over each wing or over the nose and tail on the fuselage to hold your model down.

INSTALLING WINDOWS
Lee Estingoy, Olathe, KS
Published in Fly RC August 2008

We often have to glue windows into holes where it is difficult to use conventional clamps. Tape is tough to use, as the plastic-window shape generally doesn’t fully conform to the hole, and tape can pull away before the glue sets. I use pairs of small, 1/2x1/4x1/8-inch, neodymium magnets from kjmagnetics.com to secure the window while the adhesive is setting. Put one magnet on the inside of the fuse and another on the outside. Use enough magnet pairs to hold the window securely in place. I use Goop-type adhesives for this application; clean-up is a breeze, since you can simply rub off the excess after it has cured.

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