Great planes: Tracer

Model Airplane News, Nov 2001 by Palmer, Keith

MODEL AIRPLANE NEWS

FIELD & BENCH

REVIEW

The Great Planes Tracer is a .46-size entry-level pattern airplane that will surely make learning how to fly pattern maneuvers much easier for the average sport flier.

TheTracer is almost as fun to build as it is to fly, and Great Planes supplies just about everything you need to frame it up. The kit includes high-quality balsa and lite ply and completet hardware package. You need only a .40 to .51 2-stroke or a .52 to .70 4-stroke engine, a 4- or 5- channel radio with six servos, wheels, a radio, covering and glue; retracts are available seperately. The Tracer also comes with a well-illustrated instruction manual.

CONSTRUCTION Begin construction with the tail feathers. Build the stab over the plans using die-cut center sections and a die-cut stab leading-edge (LE) support. Pin the center section and LE support over the plan then cut the center outer framework and ribs and pin them into place. Secure the framework in place with a few drops of thin CA. After the glue has dried, lightly sand the state top and bottom to remove any high spots and then sheet the framework.

To make the elevators, simply cut the tapered stock to match the plan, and sand a "V" on the LE.

The fin and rudder are constructed in much the same way as the stab. Simply cut the outer frame of the fin and teh rudder and the ribs and corner gussets, pin them to the plan and secure them with thin CA. I like to sand the fin and the rudder at the same time to ensure they're of the same thickness.

WING CONSTRUCTION

First, you must decide wherther you want to install retracts or fixed gear; the manual gives instructions for both. I decided to install the Hobbico retracts in my Tracer.

The first step is to punch out the diecut parts. The die cutting on the lite-ply doublers was not very crisp, and quite a bit of cutting with a no. 11 blade was required to free the parts. I also had a problem with four of the ribs; they had wavy airfoil contours from the main spar to the trailing edge (TE), and I had to make new ones.

The next step is to build up the spars by gluing four 1/8x3/8x14-1/2- inch long basswood spar doublers to four 1/8x3/8x30inch basswood spars. Because I built the retract version, the next step was to glue the 1/8-inch plywood retract rib doublers to the corresponding 3/32-inch balsa ribs, then frame up the wing over the plan upside-down, one panel at a time.

Place one aileron servo in each wing panel, then glue the 1/8-inch ply servo mount and servo-mount support into place. Each wing panel contains five shear webs, which are made from 1/16x 3x24-inch balsa sheet. The LEs are preshaped and must be cute apart before all the spars, LE and TE parts with the wing centerline before you glue them.

RETRACT INSTALLATION

The Hobbico main-gear retracts are very easy to install in the wing panels. Cut the gear legs to the length shown in the manual and attach Great Planes adjustable axles to the legs along with 2-inch wheels. Screw the completed unit to the basswood retract rails that are glued into the notches in the gear ribs. The plan shows a full-size template for bending the retract pushrods, which are made from two 12-inch Great Planes pushrods.

Attach the pushrod to the retract and make certain that nothing binds it or restricts its operation. Remove the retract from the wing panel, and glue the bottom LE and TE sheeting into place with thick CA. Unpin the wing panel and very carefully cut openings in the LE sheeting to accept the retract body. Lay the retract on the rails, draw around the wheel and gear leg with a pencil and carefully cut away the sheeting so that the unit fits in nicely; make sure there is ample clearance so the wheel and gear leg do not bind during operation.

The instructions show how to make a wheel well out of 1/32-inch ply wrapped around a soft-drink can. Center the wheel well around the wheel and glue it to the LE sheeting, spars and LE. Remove the retract again and trim the sheet flush with the inside of the wheel well, then block-- sand the top of the wheel well so it's flush with the ribs on each side of it. That's it! It isn't much more work than installing fixed gear, and it's well worth the extra time.

Join the framed-up wing panels with a wing joiner that is laminated together from three 1/8;-inch-ply die-cut pieces. Two wingtip jigs and a center-joint jig help keep the panel straight while the epoxy dries on the center joint. With the wing still on the jigs, glue the retract servo mount, the top sheeting and the capstrips into place. This will result in a perfectly straight wing.

When all of the sheeting has been trimmed, glue the forward dowel support into place with the two dowels. The ailerons, aileron-tip and aileron-center pieces are made from tapered aileron stock. Cap the wingtips with leftover 6-inch balsa sheet. Glue the aileron-center and aileron-tip pieces into place, and cut the ailerons so there is about 3/32-inch clearance on each end. Hinge the ailerons without gluing, and sand the entire wing smooth. The wing goes together very quickly; it probably took me less time to build it than to write about it.