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REFLECTOR: From Al Gietzen



Forwarded message:
> 
> Dale Alexander recently pointed us to where we could get shims for things
> like canard alignment.  I did a writup on doing the canard mounts so no
> shims would be required which I planned to eventually submit to Velocity
> Views; but I'll post it here now in case it may be of help to someone doing
> canard installation.  Yeah, it's long.
> 
> A couple of relavant photos can be found at http://home.utm.net/alventur.
> Click on the "Al Gietzen" link, and then on "airplane"
> 
> The procedure for mounting the canard given in the manual leaves some blanks
> as to how the canard and mounting points are going to end up properly
> aligned.  Here's one way to do it that results in exact alignment.
> 
> After making the canard cutout in the fuselage sides down to the top of the
> canard bulkhead, tape off the bottom of the canard where it will rest on the
> fuselage sides.  Set the canard in place and fine tune the alignment
> (centered, level, incidence, tips equidistant from the ends of the CS spar).
> Since this will usually be done before the reinforcing triax from the canard
> to fuselage is installed, space the mounting tabs away from the bulkhead
> with two thickness' of stirring sticks (a.k.a., tongue depressors).  Use
> microglass to finish out the "saddle" under the canard.
> 
> Since there is likely to be some mismatch between the canard bulkhead and
> the canard, align it so at least one of the tabs is against the bulkhead
> (plus the two sticks), and at least one side flush with the top of the
> bulkhead. You might also at this time like to use some micro to form a nice
> fillet between the underside of the canard and the fuselage.  Once this
> saddle has cured your canard alignment is set by just setting it in.  Before
> removing the canard, mark (or drill) the 1/4" pilot holes for the mounting
> bushings cenetered in the holes on canard mounting tabs.
> 
> With the top of the fuselage on, triax reinforcements installed and trimmed
> to the canard saddle, drill out the 1" holes for the canard mounting
> bushings.  Sand the microglass "saddles" and finish with one ply of fine
> BID.  Put the canard in place and insure that the bolts will go through the
> mounting tabs and bushings.  Also note if any wide area washers are needed
> to shim between one of the tabs and the bulkhead.  Remove the canard and
> ream out the holes as necessary.
> 
> In order to get the bushings exactly aligned with the canard sitting nicely
> aligned in its "saddle"; put the microglassed bushing in just flush with the
> front side of the canard bulkhead, making sure that any space around the
> bushings in the bulkhead is filled with microglass.  Put the canard in
> place; get any washers needed between the tab and bushing into place, and
> put the bolts through (being careful, of course, to not push the bushings
> out).  Put the nuts on (with suitable spacers if your using the lock nuts)
> and snug them up.  This will pull the bushings against the tabs (and/or
> washers).  Let it cure.
> 
> Rather than grind down the bushings to be flush at the back of the bulkhead,
> you can sand one side of the wide area washer and fill any space between the
> washer and bulkhead with microglass; bonding the washer in place.  Be
> careful not to get microglass between the washer and the bushing. You can do
> the same for any spacer washers needed in front of the bulkhead.  Use the
> bolts to hold them snugly in place while the micro cures.  This gives good
> bearing area on the bulkhead and you don't have to handle any washers when
> removing and installing the canard.
> 
> For the torque mounts at the back of the canard, lay up the triax tabs onto
> the canard as described in the manual.  Let them cure.  Now put the canard
> in place and slip the bolts in the mounting bushings to insure alignment.
> Working from inside the fuselage (sorry, the panel can't be in to do this)
> bondo in a couple of 10" long pieces of 1 x 4 below and flush with the back
> of the triax tabs on the canard.  This can be done easily by clamping a
> small piece of plywood (or similar flat stock) to the tab and to the piece
> of board to hold it in place while putting on the bondo.  Tape off the board
> and tab and do the prescribed layups onto the fuselage and back of tabs.
> (see photo) Let cure, drill for the 1/4" mounting bolts, and shape the tabs.
> (see photo)
> 
> Now all the mounting points will match up exactly.  No spacers, no play, no
> stress due to misalignment.
> 
> Happy building,
> 
> Al Gietzen  RGE
> 


-- 
Brian Michalk  <http://www.awpi.com/michalk>
Life is what you make of it ... never wish you had done something.
Aviator, experimental aircraft builder, motorcyclist, SCUBA diver
musician, home-brewer, entrepenuer and SINGLE!