I explained in the Overview section of this chapter how I am using the Cozy Girls elevator torque tube offsets.
So I decided to have 0.5" clearance between the fuselage wall and the outboard end of the offset...
After taking a few measurements... I took the center spool piece to the bandsaw, cut it... deburred it.. popped the offsets in.. and prayed to the canard gods all went well! Perfect length!
Here's a good shot showing 0.5" between the fuselage wall and the outboard end of the offset...
And the other side... perfect!
The Cozy Girls plans now say to place this assembly on your bench and drill through the center spool piece and through the offsets to "lock" them in with respect to each other. BUT I had other plans.
While doing my recon in the early stages of the build, one of the reoccurring warnings I would hear was: "Be careful when installing the elevators.. watch the clearances, else you will not get the full 15 degrees trailing edge up that is required!!"
So I gave my elevator install procedure a very hard look. Rather than lock the offsets in place now (on my bench), I wanted to lock them in place when the elevators are on the jigs. This way, if there is any twist on my workbench, it will not be transferred over to having an elevator mismatch.
So per my "Ary's elevator install plans", I decided to prep the jigs and lock the elevators later.
First, I wanted to make sure the canard's trailing edge didn't have any rough areas... so I sanded it smooth..
With the canard upside down on my workbench, I placed all my "L" jigs on the canard.. and then placed a heavy straight iron square beam onto of the jigs. I then clamped the square beam to the canard to keep the jigs from tipping over. This did an outstanding job at not only keeping the jigs in place, but making sure the canard and jigs were perfectly straight.
I then clamped the elevators to the jigs... lining up the outboard ends.
Per plans, I made sure I had 0.1" spacing between the canard outboard end and the elevator outboard end... this is so that the elevators won't rub up against the canard tips later on.
0.1" clearance! Perfect!
I then double checked that all my elevator slots lined up with the canard hard points (this had already been done prior to glassing the elevator outboard ends)... but just wanted to double check.
It was now time to trim the elevator inboard ends... so I took a 90 degree square.. placed it up against the elevator's trailing edge....
The important thing to note here is that the fuselage walls determine the location of the center spool piece (not the elevator). I had marked the fuselage walls onto the canard before removing the canard. This allowed me to place the center spool piece exactly where it needed to be... and then slide the 90 degree square along the trailing edge until it hit the elevator offset.
Having both elevators marked... it was time to take them to the bandsaw!
No pressure... just slicing my elevators away!
Deburred the elevator torque tube so that the offset would slide in...
I then dry fitted everything up... and verified the cut lengths... looking goooood!
Since I wanted to "lock" the elevators with respect to each other while they are in the jigs, I needed to install the offsets to the elevators first. So I made a tick mark at the 12 o'clock....
Measured 0.55" aft of the elevator's leading edge...
And made a mark at the bottom..
I then measured where the AN3-13A bolt hole needed to be drilled... this is 0.6" from the inboard end... at the leading edge..
Drilled the leading edge hole (using a #30 pilot)...
I then slid the offset into the torque tube...
And rotated it such that the 12 o'clock tick mark lined up with the 0.55" mark on the elevator bottom...
Here's a closer shot...
I then removed some foam aft of the torque tube...
And then drilled through the offset and through the opposite side of the torque tube. I then opened the hole up to a #12 size hole and passed the AN3-13A bolt through...
I did the same thing for the other elevator, except instead of using the 12 o'clock trick... I lined them up on the bench and rotated the offset until it formed a perfect mirror image with the other elevator.
With the offsets attached to the elevators, I rebuilt the assembly on the jigs... keep in mind that the offsets were still not yet attached to the center spool, so each elevator was still free to move independently.
Double-checking my 0.1" clearance... perfect!
Double-checking my offset location with respect to the fuselage wall marks... perfect!
Everything looking great!
I think one of the main reasons builders in the past failed at getting 15 degrees of up travel is because the "L" jigs do a poor job of maintaining a precise gap between the canard's trailing edge and the elevator. The plans say this gap should be approximately 0.2".
I've heard so many horror stories in the past that I wanted to make sure I got this right - the first time.
So to make sure my canard/elevator gap was consistent, I used precise shims.. look close, here is a shot showing the shims between the canard and elevator..
I placed old water jugs as weight on top of the elevators to press the elevators down onto the shims... it was amazing to see how even though the "L" jigs were perfectly flush with the canard, I could still control the gap spacing with shims with precise control.. in the order of a few thou at a time. So what gap spacing should I use? 0.2"? What if that's not enough? What if that's too much and I create a large step? I needed a way to test the gap!! Keep reading - this gets good!
In order to test the elevator travel, I needed hinges! So I marked the slots...
And used a drill as a mill...
I then removed the elevators and test fitted the hinges to see if they went deep enough. Here is when I asked the question "is it possible for the hinges to go in too deep?" And the answer is yes! The reason is because if the hinges go in too deep, the NC2 insert that is embedded inside the elevator torque tube will come in contact with the hinge - perhaps another reason why builders in the past have had trouble obtaining 15 degrees of up travel! But I came up with a solution to that as well! Keep reading!
I wanted a way to test the elevator travel BEFORE floxing the hinges in place. So I made six of these adjustable jigs out of 1x2's with a slot just wide enough for the hinge to pass through and a hole running through it.
I used bondo to lock the jigs for each hinge location. This allowed me to crimp the hinge onto the 2x1 and test the elevator travel. If I needed to adjust the gap, I could easily loosen up the bolts, readjust the gap between the canard and the elevator, and try again - without having to re-bondo everything!
For the inboard jigs, I had to cut a small 45 on the 2x1 lip so that it would not come in contact with the belhorn when I rotated the elevators...
I started with 8 cards for each deck, which gave me a 0.242" gap between the canard and elevator. (I later had to re-adjust to 7 cards for a .211" gap.. keep reading!).
But before I could pivot the elevator, I had to "lock" them with respect to each other. That meant drilling through the center spool piece and through the elevator offsets. With both elevators on the jigs, I measured where I needed to drill through.
I placed a deck of cards on the backside to protect the canard from getting drilled!
With both offsets drilled, I inserted AN3-13A bolts and locked both elevators with respect to each other!
But the AN3-13A bolt had to be inserted from the other side (else the nut and remaining threads would come in contact with the canard). So I had to remove the elevator.. insert the AN3-13A bolts, and reinstall the elevators...
With the elevators locked in, I checked for elevator up travel. At first, I got 18 deg trailing edge up! That meant I had too large of a gap. I then removed a card from each deck (7 cards total now for each deck giving me a 0.211" gap)... retested the elevators and presto! 15 degrees on the money!
Happy with the elevator travel, it was time to flox these hinges in! BUT, I wanted to do two at a time.. this way, I could check the elevator travel, make sure I was still getting 15.. and move on.
So I removed the left inboard jig and right middle jig first (to minimize any potential slop). If I had removed both inboard jigs first, the entire middle span might have sagged a bit.
Before floxing the hinges in, I installed the AN960-10L washers on each side of the hinges. (Tip: if using "hot stuff" glue, it helps to moisten the washer a tad before applying the glue. The glue reacts to the moisture and cures instantly!) I used a bolt to hold the washer in position while it cured.
One washer on each side...
Back to my bag of tricks... in order to keep the hinge from over-rotating... I cut these cards to form a "U"... these will hold the hinges in the correct depth later on... keep reading and you'll see what I mean...
So I had my gap spacing set with the correct number of cards... water jug to bear down on it...
With everything set... we mixed up flox and began filling in the pockets... using a toothpick to help the flox in on the sides... and continuing to rock the hinge up and down until the pocket filled up..
Here is the "U".. I used a bit of hot glue gun to tack the card in place. This held the hinge exactly where I wanted. Without this, the hinge would have cured too low, and possibly cause the NC2 insert to bottom-out onto the hinge - resulting in lesser travel than 15 degrees.
This one cured perfectly!
After those two hinges cured, we checked elevator travel and still got 15 degrees! So we moved on to flox the other inboard hinge and other middle hinge.
When those cured, we checked travel again, and proceeded to do the outboard most hinges.
Finally, all six hinges were completed and the elevators were installed!
And checking one last time...
Woooohoooo!!! 15 degrees of up travel!
And there you have it! Elevators are installed! Up next, canard tips!