A TOY SPACE SHUTTLE GROWS UP

GET INTO ORBIT WITH THIS $4 FLYER

ADMIT IT! Like me, you have seen this toy Space Shuttle from Guillow's in stores for years and have thought about converting it to RC. It took a dare from a friend-and the new, lightweight electronics and batteries-to spur me into action and make it happen.

The Space Shuttle is a durable, styrene-foam catapult glider. Its wing area is small, so don't expect it to be a floater. It is controllable in a baseball infield, though.

SHUTTLE CONSTRUCTION

Assemble the free-flight model, and try a few test glides to determine the center of gravity (CG). Mark the CG location, and balance the Shuttle to that CG after you have converted the model to RC. On my model, it was 7 inches behind the nose.

Foam-safe CA is used only for the control horns and the magnetic hold-downs (if you use them). First, sand the foam smooth and free of the mold flashing. Cut the "cargo bay" with a sharp hobby-knife blade that is at least 2 inches long. The rear cut should be ½ inch forward of the vertical fin, and the front cut should be 5 ¾ inches forward of the rear cut.

The horizontal cut for the bay is ¼ inch above the highest point of the wing. I used a ¼-inch piece of wood as a guide, keeping it parallel to the tabletop that the shuttle was sitting on. Mark a pencil-line guide for your cut, and use a sharp hobby knife that can cut through more than halfway. I used a long blade and cut all the way through to the marked guide on the other side of the bay.

Hollow out the cargo-bay lid to make room for the radio gear. Make small cuts with a sharp blade, and be careful not to cut too close to the exterior; an 1/8-inch wall thickness works well.

Place the servos so that the output shaft extends to the exterior, and trace the servos' dimensions. Cut the shape down into the foam to the thickness of the servo; this helps lower the weight below the midline. Larger servos may need to be fitted vertically. Apply thin tape across the servos to hold them securely (you could also use foam-safe CA). If you can get your hands on the new-generation, higher-output Li-poly cells, which are lighter but can deliver the amps needed by the IPS motor, be sure to move the servos farther forward to help maintain the proper CG.

Cut a recessed battery area from the cargo bay into the nose; be careful not to cut too far forward. Cut the rocket motor's nozzles down to a 1-inch angle; cut only the sides and top. This allows the prop to access calmer air than if you leave them stock.

The IPS motor has a 12mm diameter, so use a 10 to 12mm tube to cut a hole in the rocket nozzle that's half the length of the IPS motor. As before, keep the hole parallel to the tabletop; you can shim the motor to change the thrust angle later, if desired. I used a little right thrust, but this might not be necessary for your model. The snug fit holds the motor in place, and the motor does not overheat with the 7.4V Li-poly pack. Use a stiff wire to drill a hole from the back of the motor hole to the cargo bay. Thread some string from the cargo bay to the motor hole to assist in pulling the motor wires through to the cargo bay.

Cut the elevons out of foam food trays, and bevel the leading edges to allow free motion; then hinge them with thin, crystal-clear tape. The control horns are cut out of 1/64-inch ply (wood bonds well with the foam). Use 0.020-inch wire to connect the servo arms to the control horns. Half inch of control surface travel is all that's needed.

The cargo bay can be taped shut or secured with magnets. I pinned the radio gear down, as I was experimenting with different setups. A better, more stable method would be to use double-sided tape. To reduce clutter, I shortened the ESC's wire.

Originally, I routed the antenna out along the leading edge of the right wing. The antenna should be kept short to avoid its becoming tangled with the prop. A base-loaded micro-antenna is another way to do it, and this method adds a cool look.

The Space Shuttle comes with a nice set of decals. Foam-safe paint or a marking pen may be used to decorate the wing's leading edges. This is a lighter method that eliminates the possibility of your decals lifting off when they're placed over compound surfaces.

FLYING

As is common with many flying wings and deltas, launching can be a problem. The easiest method is to add a small skeg at the CG on the bottom of the shuttle. This gives a convenient surface to grip during launches as well as a little protection on landings. Alternatively, you can grasp the left wing in your right hand and give a sideways underhand toss; the large fin quickly straightens the flight.

The Space Shuttle is more stable than it looks. With the low aspect ratio wing, its roll rate is predictably fast, and it stalls quickly if too much up-control is used. The trick to sustained flight is to keep the airspeed up. Flying the Space Shuttle is a kick, but the look of awe from your field mates is even more enjoyable.

Copyright Air Age Publishing Aug 2005
Provided by ProQuest Information and Learning Company. All rights Reserved