A new addition to our shop, the Forstner bit set. This is a good tool for coring or drilling out large diameter holes. In balsa and soft woods, a tool made from brass tubing sometimes works better. We carefully used this set to drill plugs from the elevator assembly so dowel buttons could be glued in. We epoxied the buttons in the softer balsa and drilled the button to receive the threaded inserts.
	You can see the Forstner bit and the buttons are already glued in with epoxy. We used our band saw to make the buttons.
	These are the 4-40 threaded inserts used. The buttons are drilled for size and the threaded inserts are coated with epoxy and screwed into the button. This should help prevent the tail wheel assembly from coming loose which would normally happen over time, when mounting hardware to the softer balsa wood.
	We did a trial fit of the parts to make sure everything was positioned OK and that the mounting screws lined up with the threaded inserts. We were looking for interference between the elevator movement and the tail wheel. There is none.
	The tail wheel assembly was removed. Next we sealed the elevator hinge line gap. We used the same procedure that was used with the flaps and ailerons... Oracover was cut to 1-1/2 inches and then installed into the elevator hinge line using a covering iron. Also the dowel buttons are sealed before installing the tail wheel assembly.
	We used a piece of carbon arrow shaft for mounting the tail wheel springs to the rudder. This may look strange, but works very well. The normal control horn didn't fit with enough clearance for the springs and the elevator. We checked the clearance using this method and got good clearance with the elevator in the up position throughout the rudder travel.
	We used a HS85BB servo for the throttle, A hitec HS605BB for the elevator and a ACE 8109/S for the rudder. HS605BB servos are used for the flaps and ailerons. For reference the servo specs are: Servo   Speed Second   Torque in oz at 4.8 VDC   Weight hitec HS605BB   0.16   77   1.73 oz (49g) Ace 8109/S   0.18   47   2.58 oz (45g) hitec HS85BB   0.18   37.8   0.70 oz (20g) We opened the holes in the servo tray for the larger servos and modified the throttle servo opening with pieces of plywood. Plywood was also added under the ends of the elevator and rudder servo holes to give the mounting screws more wood to anchor to. The instructions were not followed in this sequence. We like to install the pushwires (pushrods in some cases) and servos FIRST and then mount the control horns. This provides the best alignment of the moving parts and the least friction.
	Another builder commented that the push rods were a tight fit on his model. He needed to sand the rods and then they seemed ok. We elected to use a welding rod and a ball joint connector instead of using the kit components. A 4-40 threaded end was silver soldered to the welding rod.
	Learning how to silver solder is a good thing to learn. Really rugged joints for landing gear, pushwires, interplane struts and fuel tank clunks can be fashioned from brass, steel, and copper pieces. We silver soldered the fuel Clunk and the elevator push wire parts. Make sure to wear eye protection as you solder components. We will use a Z-bend at the servo end and use the adjustable link at the elevator. This way, we can mechanically adjust the linkage with the wing on.
	We used the push rod from the kit for the rudder, but installed a different control horn. The control horns in the kit have holes too far from the control surface for the push wire to reach without binding. The replacement ones have more holes to choose from and are much closer to the elevator surface. Next we ground a point on the control horn mounting screws to make installation easier. We connected the push wires to the control horns, positioned the control horn for the lowest friction, while maintaining the control horn holes at the hinge line. We marked, checked, and rechecked the positioning, then installed the screws one at a time, drilling the hole for each screw separately. The control horns will not be at right angles to the hinge line, but slightly angled. This provides the lowest friction and still allows correct control surface movement and control.
	We connected the receiver and battery so we can verify the linkage installation. Turning on the transmitter, then the receiver will cause the servos to center. We moved the servo control horn to the position we needed it. Next the elevator was centered with the horizontal stabilizer. We marked the pushwire at the servo horn hole location. We used Z-bend pliers to put a Z-bend in the push wire. Then we used a vernier to measure the wire thickness, selected the same diameter drill bit, drilled out the servo control horn holes for this correct diameter (a tight fit is OK, loose is NOT!) Then the pushwire was installed into the servo control horn and everything checked for smooth operation. We needed to adjust the elevator linkage to make the elevator centered when the transmitter stick was centered while the trim was also centered. We preformed the same operation for the rudder and throttle servos. For the throttle servo, we fabricated a longer control horn from circuit board material, which makes setting the throttle end points easier. The control horns that came with the HS85BB servo are too short to get full range movement of the engine throttle arm.
	This is the complete tail control system. Not bad.
	The servo linkage to the aileron is being aligned. It is important to keep the pushwire at 90 degrees relative to the servo control arm. This will make sure the geometry of the four pushwires is the same. When the crow and coordinated aileron functions are switched on, the control surfaces must track with each other. We drilled one hole for one of the control horn's mounting hole and installed one screw through the aileron to hold the control horn's position. The control horn's other holes (used to connect the pushwire) must be in line with the hinge line, while the pushwire is held at 90 degrees to the servo control arm. An extra pair of hands sure helps out during this operation.
	These are some of the tools used to install the wing servos and linkages. Right angle, the z-bend pliers, screwdriver, as well as a dremel with a cutoff wheel and drill bit. We used a xacto blade to separate the control horn from its base and a grinder to grind a point on the end of each of the screws.
	All of the wing control surfaces are connected to their respective servos. We will have to set up the control throws, but we will do that when we get to the programming of the various control modes.
	Even though we have a lot left to do before the plane is finished, we wanted to take a look at the progress so far. The balance was checked and we are right on the money for the CG setting. We marked the CG location. The battery will need to be under the servo tray as far back as we can get it. (Another modeler added lead to his tail for balance, so apparently these models come out nose heavy) With all the stuff we have, the plane weighs 2838 grams (6.25 lbs) not too bad! The nicads we used are 4.8 volt 2000mah, so we can drop the weight somewhat by changing to lighter AA niMH cells. We'll weight it again when we've completed the plane. We are about 90% done now. Still remaining is the fuel tank installation, making, covering and installing the hatch, anchoring the tuned pipe, installing the receiver antenna and power switch and setting up the computer radio. We also need to run the engine and make sure it is reliable. We assembled a 14 oz fuel tank for this model, and will use it instead of the 11 ounce one that comes in the kit. With everything completed, the model weighs 6.1 lbs. No extra weight was used to balance the plane, the radio components were shifted within the fuselage to achieve the CG and lateral balance. A 1350 NIMH 5 cell pack was used for the radio. The plane is a great flyer at the 6 lb weight. The most difficult part of the building was the radio setup for the quad flaps, crow, etc. But, that is what makes this model worth the effort of building.

Last Updated: 11/12/01

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