Canard Construction |
Date: 10 June 2002 - 16 June 2002 |
Chapter: 4.0 Canard/Elevators |
Section: Canard |
Section 4.1 Critical Dimensions
Prior to June 10, 2002 - Chapter
4.1.1
- "Reference List"
This section just outlines the critical dimensions for the Canard and Elevators and lists the parts and tools needed for this assembly.
Section 4.2 Canard Core Preparation
Prior to June 10, 2002 - Chapter
4.2.1
- "Installation of Lift Tabs" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.2.2
- "Foam Cores" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.2.3
- "Preparation for Skinning" FB
This section was completed as part of the Fast Build Wing kit.
Section 4.3 Glassing the Canard
Prior to June 10, 2002 - Chapter
4.3.1
- "Canard Lay-Up Schedule" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.3.2
- "Canard Lay-Up #1" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.3.3
- "Canard Lay-Up #2" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.3.4
- "Canard Lay-Up #3" FB
This section was completed as part of the Fast Build Wing kit.
Section 4.4 Elevator Construction
Prior to June 10, 2002 - Chapter
4.4.1
- "Assemble Cores" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.4.2
- "Lay-Up Procedure Side 1" FB
This section was completed as part of the Fast Build Wing kit.
Prior to June 10, 2002 - Chapter 4.4.3
- "Lay-Up Procedure Side 2" FB
This section was completed as part of the Fast Build Wing kit.
June 14, 2002 - Chapter 4.4.4 - "Elevator to Canard Fit"
This section starts off with instructions on how to find the centerline of the canard by marking the distance halfway between the lift tabs, and measuring and marking 90" outboard of this line to both ends and square off the canard. Although we made these marks while we were in Florida, due to time constraints we left it until we returned to actual cut the ends back. Next it has you trim the canard trailing edge 12 3/8" back from the leading edge, but fortunately ours was right on. Next we marked positions for the elevator hinges along the bottom surface of the canard and elevators at 23", 43-1/4", 64-1/2", and 85" (from the canard centerline). Finally we needed to mark the elevator torque tubes 89-5/8" from the outboard end and cut off the excess length. The elevator itself will be trimmed later when we place the canard on the fuselage.
June 14, 2002 - Chapter 4.4.5
- "Elevator Hinge Installation"
To install the elevator hinges, we aligned the vertical tabs to be flush with our marks from the previous section and verified that they were inline with each other with string. Also differing from what was stated in the manual, we received both left and right hinges, and aligned them with the vertical plated facing the outboard end so that the elevators can be removed later more easily.
Next we drilled pilot holes in the fore hinge hole for alignment. Then take a square and project the line square to the trailing edge and drill the aft pilot hole. We then sanded the mating surfaces and secured the hinges with structural adhesive, and fastened them down with 1/8" pop rivets while curing.
Once the hinges are attached, any circus training you might have had really comes into it's own, as you need to reach inside the elevator torque tubes and attach a MS21042-3 locknut to SM24693S-272 screws that you drill with a 3/16" bit as far aft as possible without going into the elevator foam, and countersunk it. A couple of extra hands are almost certainly required to accomplish this, as is a goodly bit of your preferred profanity, and 4' long 1/4" ignition wrench is handy too (the one at the factory was adequate, but it seemed to me someone had cut it about 4" shorter than would have been really preferable).
Hinge Arm Pockets - Marking Locations
Hinge Arm Pockets
June 14, 2002 - Chapter 4.4.6
- "Hinge Arm Installation"
Once the hinges have cured, we mounted the hinge arms to each hinge and placed the elevators in the trailing edge slot of the canard. The hinge arm locations were then transferred to the canard, and slots were carved out of the canard to accept them approximately 3/8" x 1 -1/4" all the way to the top skin.
Section 4.5 Canard Final Preparation for Elevators
June 15, 2002 - Chapter
4.5.1
- "Fixturing the Elevator Position"
The trailing edge of the canard was next tapered to about .03", and 4 straightedges were attached to the canard and elevators to hold them in alignment while the hinge arms were potted in. The elevators are checked to be in alignment with a string down the torque tubes, and the gap to the canard trailing edge is confirmed to be consistent (about .05", maintained by shimming tongue depressors underneath), and the pivot points are verified to be inline with the canard trailing edge. Next the hinge arms arm sanded and checked to see that the can all rotate completely to the canard upper skin. Finally the hinge arm pockets are filled with microglass and allowed to cure around the hinge arms (while filling the pockets it's important to agitate the micro to get it to fill all of the space inside the pocket). We also prepared the Center Hinge Arm with the rest of the arms rather than after as called for in the manual. The Center Hinge Arm is a double arm that is cut to fit into the supplied Center Bracket, and then drilled and tapped for 1/4"-28 screws. This is where we finished up our visit to the factory, and their Head Start program.
Potting the Hinge Arms into Canard
4 October, 2002
- Chapter 4.5.2 - "Positioning Torque/Counterweight arms"
There is simply a ton of work to do on the canard and elevators. This section talks about the center hinge are, but as you can see above we lined this out and installed it during Head Start week with the rest. Then we measured from the center hinge out 20 1/2" onto both elevators and trimmed the torque tubes to this length. Then the concentric torque tubes are installed inside the elevator torque tubes. The concentric torque alignment is checked, and then a 3/16" hole is drilled through it and countersunk for a MS24694S-59 (I actually had to order longer screws from AS&S) and locking nut.
Then the inboard counterweights can be installed on the center hinge arm. Note that my instructions and packaging didn't make it too clear that each outboard side of this arm gets 1 and 1/2 of the squared off counterweights with foremost holes getting a common 3 1/2" screw and space to hold them together. A call to the factory quickly clears this up.
On the outboard side of the elevators you get to use your creative thinking skills. Here you have multiple independent variables which are all important. You need to cut a notch in the canard for the counterweight to rest in all of the way to the inner skin (5 1/4" long, 1 1/4" wide), which will get fine BID glass later. You also need to cut just enough of the torque tube back to allow the thickness of the arm to rest flush once that notch accepts the counterweight. Except that you can't put the counterweight arm in yet, because it's so bloody tight of a fit that it will never come back out, and it's CRITICALLY important that the angle of the counterweight just stops the elevator travel at 28 degrees Down Elevator. Good luck. I fiddled and fitted and cajoled everything pretty close, then once I had the counterweights in still had to give it a few love taps to align things properly. Might be a better way, but it didn't come to me. Need to sign up for those patience lessons, perhaps.
Canard Inboard Counterweight (only 1 weight here)
Canard Outboard Counterwieght Recess
Once the weights are positioned, they get the same screw treatment as the concentric torque tubes. Then the elevators need to be finished off, and as I have the fast-build Brazilian elevators I need to cut some foam to fill the open ends of the elevators with, micro, and BID.
8 October, 2002
- Chapter 4.5.3 - "Elevator Balancing"
The last thing to do the canard (in this chapter at least) is the check the balance and travel. First you must connect the elevators at the center hinge/inboard counterweights, then fixture the trailing edges with your I-Beam. Then using 2 shorter section of I-Beam attached to trailing edge find neutral, and check for 28 degrees of down elevator travel and 24-26 degrees of up travel. Once this has been achieved, you check the balance. You can balance by running a string down the elevator hinges or brace the canard upside down. Either way, without paint they shoul0d hang slightly nose down. With paint they should be level, but nose down is OK, all to reduce flutter. The string method seems more precise to me, and mine seem OK so far, but we'll recheck after painting.
~ End of Chapter ~ End of Section ~