In this section we need to make a attachment point on the back side of the canard to accept the torsional load of the wing. In order to do this we made a jig out of 1″x4″ covered with aluminum foil tape to make 3″x3″ pads to later accept a bolt. First we sanded the canard where it will get glassed, bondoed the dog house to the canard in the proper position, then bondoed the 2 boards to the backside and the bottom of the doghouse as shown in these pictures. As a part of this installation, we sighted the concentric torque tube opening by shining a laser point light down the elevator hinge openings and opening a channel for these to slide down, and then we gradually cut the elevators back to clear the fuselage throughout their travel.

The canard attachment is made of 3 plys of 3″x12″ TRIAX, 2 sets on each side. The first layup is set on the canard and up 3″ to form a pad, the second is laid on the doghouse and overlays the 3″ pad. We foil taped the doghouse so that it can be removable for access to the avionics in the future. We plan to use a car hood latch to secure this later, and we prepared the surface with micro and BID to smooth the transition.

The canard attachment is made of 3 plys of 3″x12″ TRIAX, 2 sets on each side. The first layup is set on the canard and up 3″ to form a pad, the second is laid on the doghouse and overlays the 3″ pad. We foil taped the doghouse so that it can be removable for access to the avionics in the future. We plan to use a car hood latch to secure this later, and we prepared the surface with micro and BID to smooth the transition.

The mating surface on the fuselage is laid up against a jig that you have to make accept it, shown here.

You then need to layup 3 ply of 3″x12″ TRIAX horizontally against the jig, the 3 ply of 6″x12″ vertically to tie it all togther. This section is trimmed after curing to taper from the 3″x3″ pad to the fuselage side.

The only remaining thing for the aft canard tab then is to drill a 1/4″ hole through both pads and install a nutplate for to accept the bolt.

Canard Forward Tabs – In the newly (2/2003) revised manual, forward attachment tabs were called for, for additional support. After discussing the issue with the factory, we elected to install them even though it wasn’t required (this was not issued as a “KPC”, or kit-plans-change, that would indicate a mandatory fix). These were created in a similar manner to the front tabs, with the exception that the canard tab was made first, and the fuselage tab was laid up against the canard tab later. That’s because the front of the canard opening is angled, and it would be difficult to get a nice squared tab. As you see here, a (duct tape protected) board was bondo-ed across the front and underneath the canard with the doghouse on, and triax was laid up on both the canard top and doghouse side (which was also protected with aluminum tape). Once cured the doghouse and boards were easily removed from the lay up.

After the canard attach tabs and finished, you can finalize the attachment of the canard cover to the canard. I’d tried for several days to come up with a slick way to do this without any screws. This is the sort of thing that gets a builder into trouble, when vanity overcomes sense. What I tried to do was this, take a pair of automotive hood latches and turn them on their sides, and set the bolt into the doghouse. Then, when each side was lowered the bolt would be captured and BOTH hold the cover down, and pull it in side-to-side. There would be a release mechanism in the cockpit which would allow the cover to “spring” out of it’s fixtures. Where to start….

First let me say that there’s a lot of not-so-straightforward geometry here. The cover is curved up and down while the fuselage/canard are getting wider, and there’s not a lot of play in one of these latches. But I made groves for the bolt, and backing plates for the latches, and tapped hardpoints for the bolt to attach to the cover and started bondoing things into place to try and get the geometry just right. What I’ve come to know a few things hence, here are my top ten reasons YOU the potential Velocity builder SHOULD NOT DO THIS.

  1. Things in the manual are done for a reason, usually at the price of valuable previous experience.
  2. Once the geometry of this setup is right, you have to place an enormous amount of force onto the cover to get it latch flush with the fuselage (the second detent in the latch).
  3. Once so latched there is absolutely no incentive for the latch to open when the levered is pulled. I think they probably meant for these things to NOT have lateral loads imposed on them.
  4. You can’t really see the screws that hold these things on the factory planes further than 8 feet away.
  5. Bondo sets quickly when you’re trying to adjust something.
  6. Bondo sets slowly once you’ve got something perfect.
  7. Things in the manual are done for a reason.
  8. Once something is bondoed in place perfectly, the mere act of laying fiberglass over it inexplicably seems to alter the fit.
  9. No one, ever, anywhere, finds something that is “almost perfect” interesting, worthy of praise, nor complete…. and finally
  10. Getting something that is “almost perfect” to become perfect is almost as much fun as poking yourself in the eye with a pointed stick. It is generally painful, usually accomplishes nothing, and often leaves you with debilitating injury.

Here endith the lesson, but since a picture is worth a thousand words, here is my sorted tale of auto latches.

Needless to say, we reverted to 2 screws per side with two nutplates. Then the cover was sanded, and the canard was protected with duct tape while we laid a radius of FLOX and covered it with one ply of BID cloth to fair the cover to the canard.

After finishing up the canard fitting sequence of tasks, we went back and cleaned up the top of the canard where we’d sanded if during the work steps. Here we filled the void between the new doghouse junction and the canard with micro and contoured the canard in this area.

Another item that doesn’t really have a home is the seal from the canard/doghouse/fuselage. There is a gap on the rear of the canard from the doghouse to the top of the elevator torque tube that must be sealed. Since the fuselage needs to be open for the torque tube to side down into position while mounting the canard, we’ve mounted a piece of triax onto the bottom of the canard that will lay flat on the side of the fuselage and seal this opening.

OK, I didn’t like how I did the torque tube close-out after playing with it for awhile. It was flimsy, and it make it hard to get the canard in and out of the plane easily, so I went back to the more standard configuration. This has to you build the removed section back onto the canard. First a piece of scrape fuselage glass/foam board is carved to fit the opening (I made a cardboard cutout of the appropriate shape) and attached to the canard.

Next, the gap and the edge of the foam are sealed with micro. Finally, the torque tube hole is drilled, the elevators are installed, and the torque tube opening is closed with the same micro slurry mixture.

Sanding Canard Bonding area

Elevator Torque Tube Cutout

Setting Doghouse Position

Preparing to Glass Doghouse

Canard fore and aft tabs

Canard tab layups

Finished Attachment Tabs

Canard Aft Tab Jig

Canard Aft Tab Layups

Canard Front Attachment Tabs

Canard Doghouse

Canard Mounting

Canard Cover Finishing

Canard Cleanup

Torque Tube Seal Area

Torque Tube Gap with Canard

Torque Tube Seal Plate

Completed Torque Tube Cover

Attaching the plug to the canard

Closing gaps with micro

Closing the torque tube gap

Posted By: Brett Ferrell
Thursday October 10th, 2002 at 11:39 AM

Categories: Bulkheads Fuselage
Tags: Building Bulkheads Canard Fuselage

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