28% Edge 540T Assembly Manual
Step 6.
Install control horns on all surfaces
We recommend Rocket City or similar control horns with a 8-32 screw used for the horn.
Rocket city #69D is the one I prefer because of the snap-together assembly. Each package
has hardware so that you get either 2 control horns or 1 rudder tiller. There will be hardware
left over no matter what you do.
There are a couple ways to do this. You should decide whether you care if the screw head
shows on the upper surface. The hard points are already pilot drilled, but need to be made
larger for the 8-32 stud. I have found that grinding a small flat on one side of the tip of the 8-
32 stud makes it thread into the hard point more easily.
IMPORTANT NOTE: Do not drill the hardpoints larger than 9/64. The screws must
thread snugly into the hardpoints. If you drill it larger the screw can wobble in the hole
and allow the control surface to flutter with disastrous results.
If you don’t care about the screw head showing, drill all the way through the hard point in
the aileron and elevator with a 9/64 drill. Also drill the upper hard point in the rudder with
the 9/64 drill, save the lower one for later. Countersink the drilled holes in elevators and ai-
lerons on the top.
On ailerons and elevators install the 8-32 stud from the top, screw it all the way in until it is
snug. Install the rest of the horn assembly from the bottom.
Or;
Another way to do it does not allow anything to show on top.
Very carefully and slowly
drill from the bottom side with a 9/64 drill, following the pilot hole so you don’t change the
angle. I use a hex drive quick change bit and put it in my power screwdriver which turns
slowly and is easy to handle. Pull the bit out every 1/8” or so and blow out the shavings.
While drilling observe the top surface of the hardpoint visually. When the drill reaches the
covering on top you should be able to see it bulge before the covering is pierced. As soon as
you see it, stop drilling and withdraw the drill, blow out all the shavings.
Now take your 8-32 stud and thread it into the hole from the bottom. Screw it in by hand or
with a power screwdriver, again observing the other end, until you can see the tip of the
screw through the covering.
