Hobby Shack's AirMaster40T Part 2

	The instructions cover aligning and gluing the tail feathers. A different method was used on this model. The main wing saddle and the horizontal stabilizer mounting platform were both sanded level. First, the main wing saddle was sanded flat. Next, the model was shimmed so that the saddle is level as indicated by the first level 1. Next the horizontal stabilizer mounting platform was sanded so that it is also level as indicated by the second level 2. Shown here are two levels, indicating that both surfaces are level. Shims can be glued into place to help get these aligned.
	This is a view of the horizontal stabilizer being glued to the fuselage. You can see the paper shim under the left main wheel used to level the main wing saddle. Steel weights were temporarily added to the front of the fuselage to offset the weight of the clamps, which are added during the gluing step. The levels can be seen in this photo, as well as the clamps used to hold the stabilizer in alignment. The screwdriver is being used as a weight to help hold the stabilizer in the desired position as the 30-minute epoxy sets.
	Once the horizontal stabilizer epoxy has set, the vertical stabilizer is glued into place. The original balsa reinforcement pieces of wood were replaced with longer hardwood pieces. This probably isn't necessary, but is lots stronger, without much weight gain. The vertical stabilizer and supports were glued onto the fuselage at the same time. Notice the covering material has been cut away from the glue areas on both the horizontal and vertical stabilizers.
	It is starting to get exciting now. The airframe is taking on a shape we can recognize. A square is used to verify that the angle between horizontal and vertical stabilizers is exactly 90 degrees. The control surfaces (elevator and rudder) will be glued onto the fuselage next. Then the servos and push rods will be installed. The radio of choice for this model is a JR X347. The radio was chosen because is the author's preferred radio vendor, has a buddy box setup, and we already own it.
	The control surface hinges are installed per the instructions. One change made was to widen the slot in the surfaces for the hinges using a razor knife handle. This keeps the gap between the surfaces to a minimum.
	All hinges were sanded with 220 grit sandpaper, as well as the control horn wires. 90-minute epoxy was used. The epoxy was spread thinly on the hinges and put into the control rod mounting hole. Waxed paper was taped on the wing behind the control rods. A drop of oil was put on all hinges at the hinge line. The hinges were installed on both the controlled surface and the stationary surface at the same time. Alcohol was used to clean up the excess epoxy. The movable surface was flexed several times during the epoxy curing period to make sure the control surfaces are still moveable.
	This is a view of the completed tail feathers. The gap between the movable and fixed surfaces is less than 1/16 of an inch. The gap should be kept to a minimum, while allowing full control surface deflection.
	The main wing is being modified for installing the servo. Since the covering material was removed to add the fiberglass reinforcement, this step is easy. The fiberglass and balsa are first scored with the razor knife, then the material is removed using pliers and the razor knife. The balsa in the center of the wing has to be removed to allow the servo to be installed. The existing epoxy was sanded and cleaned up with alcohol before the servo mount was glued into place.
	In this photo, you can see the Z-bend pliers used on the control rods.The control rods were cut to length using a dremel cutoff wheel. (Use eye protection!!!) Also shown in this photo are the fuel tubing "keepers" used to prevent the clevice from coming apart. The control rods were inserted into the nylon clevices using a variable speed drill. The rod is put into the drill just like a drill bit with the threaded portion out and then "screwed" into the clevice. Don't forget to put the servo horn (wheel in this case) screw back into the servo.. This is a commonly forgotten item and if forgotten, will eventually cause the airplane to crash! The wheel is drilled for two different differential throw positions (see next photo).
	Although this photo is pretty busy, we are connecting up the radio receiver, battery, and aileron servo. This allows adjustment of the center position and the amount of control throw. The aileron servo arm was a round wheel cut down using a jig saw and polished with a dremel. The control rods are not centered intentionally. The arrangement shown provides more up than down movement called a "differential throw". Aileron differential is best set up mechanically, but some computer radios can do this when two servos are used, one for each aileron. Using two servos (one for each aileron) will also allow the aileron to be used for spoilers (right and left aileron both up) and flaps (right and left aileron both down), at the same time allowing control of the model's roll rate using the normal aileron function.
	In the photo are the VK Cherokee and the AirMAster40T. The plane flies well and is an excellent trainer. It will fly inverted and tracks well in loops and rolls. The Fuji 40 provides plenty of power for the plane even in winds over 15 mph! This is a great buy for a kit that costs much less than $100.00 Total cost for assembling this plane was around $335.00 including the newly added JR radio.

Last Updated 11/19/00

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