2016-07-30 UteRC Swizzle Stick Build 1

These pictures are from the first of several Swizzle Stick build sessions at Ray Jones' home. Paul Jones helped Ray teach the class to the three students who attended. I have provided text to fill in some of what was taught that isn't shown in the photographs. I am sorry I was unable to stay to document the entire session.

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Ray Jones' bi-plane lawn ornament using early warped wing control and a (very) multi-bladed prop.

Rudder, elevator, and throttle servo tray in a partially complete Swizzle Stick.

Motor, tank, and servo tray, body has to be deep to clear aileron servos mounted on bottom center of the wing

Aileron servo linkage block before being cut for dihedral and installed on wing. This is made from a piece of trailing-edge stock separate from the wing so the straight groove can be easily made with an Exacto knife and rounded out using the threads of the push rod as a file.

Close-up of how an aileron linkage is made from bending aluminum pushrod material (threaded 2-56) with a brass tube bearing. These will be carefully greased before CA'ing to the trailing edge of the completed wing.

The right-angle bends in the 2-56 push rod material are at 90 degrees to each other. The threaded ends carry nylon connectors for the short linkage to the aileron servos. The short-bend end drives the aileron.

The joined wings and the aileron linkage block have been fiberglassed together for strength. Ray Jones shows how 150 grit sandpaper used along the corner edge of the 2-oz fiberglass will cut the fiberglass cleanly where a knife would leave a ragged edge.

The fiberglasssed center of the wing. Ray shows how to sand the edge of the fiberglass to both cut off the excess and feather the edge without digging into the unprotected balsa sheeting. He does this by applying a strip of masking tape at the desired edge to protect the balsa and then the excess fiberglass can be sanded away without cutting into the balsa.

Not shown is how 1/16" x 3" sheeting is held together with a strip of masking tape on one side, then bent open and ordinary wood glue applied, then laid back flat, and the excess glue wiped from the joint. Whatever width is needed can be easily made from less expensive narrow sheets. The tape is left in place and marks the side that will be glued to the foam core.

Ray demonstrates the following steps one would do to apply sheeting to the foam wing core, but uses the scrap foam and scrap sheeting to show how to apply spray contact cement and apply the sheeting.

Not shown, but Ray describes how to use 3M Super 77 spray contact cement to lightly coat both a foam core and the sheeting which are set aside for a few minutes until tacky to the touch. Once tacky, the sheeting is very carefully lined up with the notch made by the leading edge which has been CA'ed to the foam core. "Very carefully" means you only get ONE chance to touch the sticky sheeting to the sticky core and that has to be in exactly the right position. Once started correctly the sheeting is simply rolled out across the foam core toward, and over, the trailing edge. The scrap foam left from cutting out the wing core makes a fitting clamp that, with weights, will hold the sheeting tightly to the core until the contact cement completely dries.

Also not show is how the dihedral bevel is made on each sheeted wing half. Ray described how in hot weather, it is necessary to use slower setting epoxy to join the two wings together with the inserted 1/2" square plywood dihedral brace. The students were given a chance to practice fiberglassing by laying 2-oz fiberglass cloth over the dihedral joint on the wing bottom and how to avoid getting fiberglass resin in the aileron linkage. Ray emphasized using finish fiberglass resin which is thin and dries completely rather than lay-up resin which is a thicker liquid and remains tacky after curing.

Hinge slotting tools: The two pronged tool is for piercing into foam, the single point is for picking balsa out of a slot started with an Exacto knife so a hinge will slide in, the round nylon object will mark the center of the edge of any thickness it can span, and the black square thing is a parallelogram that will position a knife blade at the center of the edge of any thickness it can span. These tools are available at West Valley Hobbies.

A package of nylon pinned hinges made by Great Planes in just the right quantity; 4 for each aileron, 4 for the elevator, and 3 for the rudder.

The outer hinge position is marked as 3/4" in from the wing tip and on the center of the trailing edge of the wing. The two edges of the hinge are marked with dots that can be seen thru the slot in the parallelogram tool. In these photos, the tool is positioned to guide an Exacto knife blade, held parallel to the bottom of the wing, so it can be plunged thru the balsa trailing edge into the foam core at exactly where the hinge edges have been marked.

The foam plunge tool is inserted after the knife slot has been widened with the picking tool.

With an aileron held on the actuation pin at the center of the wing, fitting an outer hinge so the hinge positions can be marked on both the wing and aileron. It is a good idea to mark parts, as shown, so one doesn't get mixed up and make two left ailerons instead of a left and a right. The ailerons are trailing edge stock and have a bottom which is square with the wide edge of the stock. Incidentally, the forward edge of the aileron is left flat until all the hinge slots are marked and slotted to take the hinges because it is much easier to mark and cut on the center of a flat edge rather than on a beveled edge.

Using the picking tool to hollow out a hinge slot in an aileron.

Marking the remaining 3 hinge positions on both wing and aileron so matching hinge slots can be cut in both.

Ray using the center line tool to mark the center line along the trailing edge of the wing.

Gerhard Roos cutting a hinge slot in a wing with the parallelogram tool as a knife blade guide.

Joseph Lyman cutting a hinge slot in an aileron using the parallelogram tool as a knife blade guide.

Students left to right, Joseph (JoJo) Lyman, John Borer, Keith Hiatt holding partially completed planes after a hot afternoon, a cooling rain, and fiberglassing in a 9-hr long build session. Both Ray and Paul are happy to answer any questions you may have about building this plane. Catch them at a club meeting the second Thursday of the month. Photo courtesy of Paul Jones.

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