Zip (oz12531)

About this Plan

Zip. Rubber sport model. All-sheet design.

Direct submission to Outerzone.

Quote: "Hi there, I'm attaching a plan for the 14 inch 'Zip' rubber powered model, together with a few pics of my own build."

Update 15/10/2020: Added article thanks to skyraider as posted on HPA, see https://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=5851

Quote: "The Zip. By Ed Lidgard ans Bob Bienenstein. Realistic appearance, all sheet wood and simple construction make Zip an ideal project for new corners and oldtimers alike. This 'cutie' is capable of 1-minute plus flights if built according to instructions with light quarter grain wood.

Your first glance at Zip is bound to bring back memories, as it does resemble many old-type designs. The original concept was to have a small, all sheet-wood model that looked like an airplane and a model both, with pleasant, simple lines that a sub-junior would want to build and fly. ZIP has proved to be a successful model on all counts. It's just fun to build and fly.

For best performance, ZIP should be built with light quarter grain wood. By keeping it light and building a wood prop, you can get consistent flights of over one minute.

CONSTRUCTION: The first thing to do is to accumulate the materials needed. When building a part, it will often be necessary to let something dry and go on to some odd bit of sanding or gluing.

Start with the fuselage by transferring the side pattern on to the 1/32 balsa wood. It's a good idea to make all pieces before starting the project. Glue the nose brace and rubber anchor reinforcements to the insides of the fuselage sides and main formers (those under the wing) to the inside of one fuselage side. Be sure they are square. When dry, glue the same formers to the inside of the other fuselage side. When dry, glue the nose former in place. It's best to hold this in your hands until dry.

Sand the inside edges of the rear ends of the fuselage until they are only 1/32 thick together. Apply glue and hold with a clothes pin or small clamp. You can get a very crooked fuselage if you aren't careful at this point.

Glue the landing gear to former #3 and glue sections of 1/32 balsa to the top and bottom of the fuselage with grain crosswise, hold until glue sets. When dry, trim flush to the fuselage sides with a sharp razor. The top of the nose should be wet with water when glued on, so it will bend; hold with rubber bands.

Sand wing and tail balsa parts with fine sandpaper so that the trailing edges are thin and leading edges round.

Shape the wing airfoil by carefully tacking or pinning the leading and trailing edge to the work board. Under the center of the wing, place a piece of 1/16 balsa; this curves the wood to an airfoil shape.

Wing tips are carefully curved in the fingers; blowing your breath while bending helps. Glue the tips to the center section making sure the joint matches, and that the tip is exactly 1-3/16 in above the work surface.

Carefully fit that portion of the nose block that fits into the fuselage nose and then glue it to the main nose block. Glue the male portion of dress snaps onto the front and rear. Spin the entire assembly on a wire to see if the snaps provide a square bushed hole for the prop shaft.

When dry, shape and sand block to match body. Wing and tail are glued on carefully; be sure they are square and not twisted.

Sketch out proposed color scheme be-fore applying it to the model. Using a spray can of lacquer, fog a base color all over the model. Then add any other trim with a steady brush.

Cut the celluloid windshield and carefully fit it to the model. Hold the windshield in place and neatly glue it in place around its edge. Bend a prop shaft as shown on the plans. Don't be disappointed if you need to bend several times to get it right. Don't forget the washers and put a dab of grease or oil on them.

FLYING: Test glide before winding the propeller. The model should turn to the right a bit. Do this by bending the rudder. Wind the propeller about 50 times and launch level but don't expect too much climb at this time; trim to a 50 foot diameter right circle. If the model tends to drop the right wing, warp the right wing down about 1/16 or more.

Wind again about 50 more times. Concentrate on developing an almost level right turn. Sometimes a 1/32 sliver of wood between the fuselage and nose block will help get a nice turn. If the model tends to wave the tail right and left (dutch roll) during the climb, add a bit of weight to the nose because the dutch roll is an indication of the approach to a stall. Do not fly when the wind is over 8 to 10 mph. To fly the model in a gym, use slightly smaller rubber and a longer length.

Good luck with your Zip, it's easy to build and even easier to fly and should lead you to the fun that can be found in this wonderful world of free-flight."

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