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QuickTalk 14 - BUILDING THE NEW Q2 CANARD

Do not cut the top and bottom indention in the canard slot cores until the spar slot and elevator slot have been hotwired. This stiffens the 'tails' on the templates and prevents distortion or breakage.

The spars are not smooth, so careful sanding is required to remove the shiny surface from both the 'hills' and the 'valleys'. Do not sand the glass layer down to the carbon as you will need to lightly sand the spars at least three more times prior to layups. It may be necessary to sand off part of the glass layer to adequately sand the entire surface.

Locate the BL15 and BL100 canard jigging templates on the table. The BL100 template may need to be moved inboard 1/2" to 3/4" in order for the spars and foam cores to reach the template. I also moved BL15 inboard the same amount to maintain the proper anhedral. I did not slant the templates as shown in the plans because I hotwired the cores so that the joints would be parallel to BL00.

Trial fit the spars in the templates and grind the spars to get a rough fit at BL00. Then measure the aft sweep along the centerline of the spars, which should be about 6" of sweep from BL00 to BL100 or 0.06" of sweep per inch. This same amount of skew should be put on the canard core blocks prior to hot-wiring if you want the joints between the cores to be parallel to BL00. The spar centerline marks on the hotwire templates should be used to align the templates at each end of the foam blocks.

You will notice on both the canard hot-wiring templates and the canard foam cores that if the top surface of the canard is extended to the spar cutout, it will be 0.05" to 0.10" away from the spar. This can also be checked by fitting the hot-wiring templates into the jigging templates. This means that the spars should NOT rest on the jigging templates when the cores are fitted to the spar. In order to raise the spars above the jigging templates, I modified the spar cutout so that the aft portion was a vertical surface tangent to the spar. I then trial fit the cores against the spar in the templates (with the 'tails' sanded off the cores at BL15 and BL100) and bonded wood shims to the templates under the spars to hold the spars at the proper position.

Now to join the spars. The picture at the top of page 2 in the new plans is WRONG. The spars must be sanded and the 3 BID layup made before the bottom spar cap layup. Hold the spars against the templates with string. Grind on the spars to get a good match at BL00. Temporarily bond the spars together with small dabs of 5-Minute around the circumference at BL00. Make alignment marks on the spars at BL00. Now carefully remove the spars from the templates and lay them flat on the table. Place 2" blocks at BL15 on each side and let BL00 hang off the side of the table. This should give enough room to sand down the apex at BL00. It is NOT necessary to sand down to the foam in order to remove the joggle at the apex. Now put the spars back into the templates and 5-Minute one of the spars to the templates. Dremel off the 5-Minute which is holding the spars together. If you did not sand the apex down to the foam, you may wish to do as I did and put a small flox corner in the foam around the circumference of each spar at BL00. Join the spars as per the plans using the alignment marks at BL00.

The 3-ply BID layup to join the spars is rather difficult due to the sweep and anhedral of the spars. The easiest method is probably to lay up the three plies (small ply first) on Handi-Wrap and then transfer it to the spars. Place one edge of the layup along the top of the spars. Lay the glass around the spars, keeping the glass against the spar at BL00 and away from the spar at BL6. Butt splice the two edges at BL00. Now carefully remove the Handi-Wrap, and work the bulge out of the glass while moving in the same direction as before.

Allow the 3-ply BID layup to cure to the 'tacky' stage before laying up the spar caps. I cut the spanwise UNI skin for the canard layup 27" wide. This leaves a long piece 11" wide, which can be cut for the spar caps. I cut the spar caps 1/4" wider to allow for fraying. I wet out two sets of spar caps on auto masking paper. One set was 3-ply and the other set was 2-ply. The caps can be cut to the proper size and stippled in place. Another builder was able to layup each set of 5 plies at one time. A word of caution. The resulting layup is quite thick and can start a heat buildup by exotherm, so you may wish to lower the temperature in your workshop after completing the layup. Also, I peel-plied the entire 3-ply BID and 25-ply UNI layup.

Now comes the important part - aligning the canard cores. This is made easier than the main wing because of the spar. First, sand down the 'tails' at BL48.8 on all four outboard cores. I made a set of 'outside' templates from the BL15 and BL48.8 hot-wiring templates so that I could check the level at these points after the cores are joined. Mark hotwire numbers 2, 5, 8, 12 and 15 on the outside of each core and template. These marks are used to run string lines and straight edges for core alignment. Sand a 1/2" wide slot off of the 'tails' on the top and bottom of all cores every 12". These locations can be used to check the alignment of the cores with the spar after the cores are joined. Insert small finishing nails into the 'flash' left on the L.E. after hot-wiring the cores. You can sight down these nails or run a string line to align the L.E. IMPORTANT - Do not align the 'top' side of the cores without also checking the alignment of the 'bottom' side. If you place a straight edge on each side of a core, you will notice that there will be about 0.05" of burndown in the center portion out to within 6" of each end. If you were to 'push up' the center of the core to match the ends, you would have a 0.1" dip in the core when you turned the canard over to layup the top surface. You would be forced to make a 0.1" change to one side of the airfoil at BL15, BL48.8 and BL100 in order to obtain a smooth surface. I used the following method. At hotwire number 8 in the BL15 and BL100 jigging templates; make a saw cut just large enough to tightly hold a string line. Dremel out a large slot in the other templates so that the string will move freely. Trial fit the cores on the spar using the hotwire templates to level the cores. Run a string line across the top of the cores at hotwire number 8. The string lines should just touch the cores at BL15, BL48.8 and BL100. There should be the same distance between the top and bottom strings and the center of the cores. A straight edge placed on the canard through the slots made in the 'tails' should indicate the cores are aligned with the spar. The nails on the L.E. should line up. When everything looks good, bond the templates to the table and bond the spar to the templates. Additional supports may be needed to align the cores.

We're now ready to join the cores to the spar and to each other. This is really a two-person operation. You can do one side at a time by dry fitting one side while bonding the other. I beveled the BL00 joint for a micro bond. This works just fine as long as you position the BL00-BL15 core first and work outboard. The important thing here is to avoid air pockets between the cores and the spars. To accomplish this, I microed the spar slot and then put a 'mound' of wet micro in the slot. This is where things get complicated. You want this micro wet enough so that it will flow when the core is pressed against the spar, but not so wet that it will drain down and leave voids at the top part of the cores. If the micro flows to the bottom of the slot before you can position it on the spar, then it's too wet. You can determine how much micro is needed by dry fitting the core to the spar and estimating the amount of void space. It's better to use too much than too little. The micro will flow down much easier than up, so either position the micro 'mound' in the top portion of the slot, or press the core onto the spar at a 45 degree angle and rotate the core down. Since the end of one of the cores should also have a micro 'mound' on it, you should press the core on the spar 1/4" away from the other core, rotate the core on the spar to squeeze out the micro, and then slide the core against the other core. Holding the cores against the spar with rubber bands is a good idea, but you cannot check the top core alignment with a string line or straight edge. The core alignment will change due to the micro! I put the rubber bands on and checked the alignment of the cores with the spar. After the micro squeeze-out had stopped, I used 5-Minute to hold the cores to the spar and removed the rubber bands. I then used a string line to align the top surface and used the nails to align the L.E. When everything looked good, I used 5-Minute to bond the cores to the templates. You need to seal the gap between the spar and the bottom of the cores to prevent too much micro from running out. I did not put micro on the outer 3/8" of the BL15 joint since it gets removed for the flox joint later on.

After curing, sand the 'tails' off the top surface. If any foam is not bonded to the spar, cut out the foam and fill the void with micro, or with foam pieces and micro. You will now need to sand the cores at BL15, BL48.8 and BL100 to obtain a smooth surface. I have found that it is easiest to sand foam around a micro joint by first using a Dremel tool to sand the micro down below the foam surface, and then sand the foam with a sanding block. Repeat, if necessary. If, at the end, the micro is below the surface of the foam, it can be filled with micro before glassing. Some builders may consider the above steps a lot of overkill, but the canard shape and surface warrants the additional construction time.

The flox in the BL15 flox joints will 'sag' before it cures which leaves a low area. I overfilled the trough with flox and Dremelled off the excess after it cured. Masking tape can be used to protect the foam while sanding.

After glassing, Peel-Ply the wheel pant area, the trailing edge, slot core attachment area, the leading edge, 3" on either side of BL15 and the firewall attachment area. Locate leveling blocks at BL00 and BL50.

After the canard is turned over, it is leveled by using the leveling blocks and the hotwire templates at BL100. I sanded a 0.05" joggle from BL92 to BL100 to allow for the eventual wheel pant attachment glass plies. The high spots at BL15 and BL48.8 are sanded down until the surface of the canard is smooth. After the layup of the top canard skins, Peel-Ply can be put down on the spar, the slot core attachment area, 3" on either side of BL15, the firewall attachment area and the wheel pant attachment area from BL92 to BL100.

The short leveling lines on the canard slot core hotwire templates make alignment of the cores subject to error. The alignment can be checked by making an 'outside' template at BL15, BL48.8 and BL100. This is done by positioning the slot core hotwire template against the canard core hotwire template and tracing the outline on a piece of Masonite. You should of course allow for three plies of UNI cloth on the canard. Remember that this is only a second check. You should first check the level line on the slot core template.



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