Chapter 12 - Canard Installation

Start:  12/30/06
Finish: 01/08/07
Total Time: 12 Hours

This chapter starts by pulling out the fuselage, which we've tucked away during the last couple of chapters.  We set up the up the sawhorses and proceeded to shim the fuselage until it was level fore-to-aft and side-to-side.  The first step in this chapter has us drill a couple of holes for the canard alignment pins, which we make by cutting the head off an AN3 bolt and grinding a pointed nose on it.

The second step is to is to shim the canard onto the F22 bulkhead such that it is level side to side, and that the incidence checks according to the jig made from the F template.  The canard must also be centered on the centerline of the fuselage and square to the centerline at the aft end.  In order to ensure that when the lift tabs were bolted tight to F22 they don't place a horizontal twisting force on the canard and alter the incidence, we placed flox pads on the surface of F22 and then clamped the canard into place with the correct incidence, level, square.  The lift tabs were covered with grey tape to insure they didn't stick to the flox.  After cure the flox pads will have the correct incidence built into them to insure no twisting force in placed on the tabs or canard when the lift tab bolts are tightened.

The next step is to install the alignment tabs onto the top surface of the canard.  Before doing this though, we wanted to modify our alignment pin system to a removable one.  Being able to completely remove the alignment pins will allow us to lift the canard straight up and off of the airplane should any servicing of the canard or elevators need to be performed.  Following the idea of a few other builders, we opened the alignment pin holes up to 3/8" and installed 3/8" O.D. / 3/16" I.D sleeves into the holes.  This will allow us to install an AN-3 bolt from the aft side of the F28 bulkhead through the sleeve and secure the alignment tab to it with a simple washer and nut.  After making that modification we proceeded to cut the alignment tabs from 1/2" plywood.  The plans calls for the tabs to made from 1/4" plywood, but because we placed a pad of flox behind the lift tabs to help set the incidence, and had trim the trailing edge of the canard to eliminate elevator interference, there was a 1/2" gap between the forward face of F28 and the trailing edge of our canard.  Upon shimming the canard into position, the alignment tabs are set in place with quick set epoxy, then the forward faces are glassed onto the canard.  After cure, the aft faces of the alignment tabs are glassed, and when all is cured, the canard is reinstalled and checked for correct incidence again.

Next we reinstalled the elevators to the canard and trial fit the canard/elevator assembly to the fuselage.  The inboard ends of the elevators needed to be trimmed slight, and the fuselage side needed to be notched for the elevator torque tubes.  After a few attempts we got enough clearance for full elevator travel while mounted to the fuselage.  With that fitted, we glassed the top edge of the fuselage sides between F22 and F28 bulkheads (just under the canard), and filled the remaining gap between this surface and the canard with flox.  Grey tape on the bottom of the canard will prevent it from sticking to the flox.

The last step is to create a foam filler piece to fill the gap between the elevator torque tube offset, and the bottom of the canard.