Snapper (oz14334)

About this Plan

Snapper. Radio control sport aerobatic model. Wingspan 50-1/2 in. Wing area 450 sq in. For OS .25 FSR engine.

Quote: "Snapper: It would be nice to take an airplane along when going somewhere on a trip, but models are inherently fragile and cumbersome. They just don't fit in the trunk along with luggage and things, and something is bound to poke a hole in the covering.

Snapper is designed with that in mind. It comes apart and can be assembled without tools in a minute or two, ready to fly. It fits in a 9 x 9 x 27 inch cardboard box for protection, with room to spare for a few odds and ends. A 25-size plane performs well and is small enough to be considered for travel.

Snapper is an easy-to-fly plain vanilla generic airplane, but is capable of satisfying performance. Everything snaps in place and latches, hence the name; beyond that, it is unremarkable. None of the latches are load-bearing members; they simply prevent random motion caused by vibration.

It has a box fuselage whose size was determined by available 3 x 36 in balsa sheets. The wing is of conventional construction except for the joiner, and the tail is 3/16 solid sheet balsa. All the controls are engaged using L-bends in the linkages.

The container would have to be a clumsy 40 inches long if the fuselage didn't come apart, but a system derived from piano hinges permits the fuselage to be separated for storage while retaining adequate structural integrity for flying. The wings and horizontal tail members push on and latch with ailerons and elevators engaged. The tricycle landing gear with steerable nose wheel is also easily removable, but structurally sound.

The center section of the wing normally stays in place as a part of the fuselage with the aileron servo connected, but it, too, can be removed without tools for access to the radio compartment. The sliding hatch cover has no visible latch, but can be removed to expose the fuel tank and battery compartment when the wing center section is off.

The wing has a semi-symmetrical NACA 1415 airfoil with minimal dihedral for quick take-offs and good inverted performance, while retaining forgiving characteristics.

Some of the unusual features require some patience for the necessary alignment and close fit, but otherwise the construction is straightforward. No machining is required for construction except with simple hand tools (Figure 1).

Fuselage: Build the whole fuselage first without the joiner. After it is finished, you will take a deep breath and saw it in two. Laminate the 1/16 plywood doublers to the 3/32 balsa sides, making a right and a left side. Glue the triangle stock along the edges, but spaced back to allow for the mating skins. Note that they are not all the same thickness and that provision must be made for the 1/8 ply landing gear mount.

Place the sides vertically over the plan and CA the two plywood bulkheads in place with the 1/16 plywood floor in position. Epoxy the aft ends of the fuselage sides together to assure perfect alignment, then carefully epoxy the firewall to the sides. When thoroughly cured, finish installing the floor forward of the aft bulkhead and mount the 3132" balsa fuselage top aft oldie wing. Glue the thick balsa dummy cowling on forward of the firewal I and provide support with more triangle stock. Do not install the bottom aft covering until after the pushrods are in place.

Hatch: Build the hatch cover and glue in 1/16 x 1/4 balsa strips on both sides that just clear the triangle stock on the top front of the fuselage. Next, glue in 1/16 x 3/8 balsa strips over the first ones so they are wider than the hatch opening. Sand these at an angle so the assembly slides over the triangle stock when inserted from the rear..."

Direct submission to Outerzone.

Scan by MarkD, cleanup by Circlip.

Supplementary file notes

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