CARF F100 - Build Guide

The drop tanks connect to the wing using the two 10mm OD carbon tubes (glued to the wing) that slides into the 12mm OD carbon tubes (glued to the mount and tank). Two M3 bolts screwed from the side of the mounts into the carbon tubes holds the tank in place.

Mark the CENTER of the hole where you want the carbon tubes to be placed on the mount from both sides of the mount (the wing side and the tank side).

To make sure these holes are parallel, draw the center line of the holes to the side of the mount and make sure the two lines (one for each tube) are parallel using a caliper.

Drill the holes you marked on the mount (12mm).
Roughen the surface and glue the mount to the drop tank using thickened epoxy.

Then, using the holes you created in the mount, drill through the drop tank so the 12mm carbon tube will protrude it.

The tricky part is to glue those 12mm tubes perfectly parallel to each other and with enough glueing surface between the tube and the inside of the skin to hold firmly. Here's how I do it:

Don't cut the 12mm carbon tubes to length. The longer they are easier to accurately align them.

Using a vinyl cutter I cut a 12mm hole in some tape.
I increase the hole size of the mount on the side where it meets the wing (only) to about 13-14mm.

I use thicken epoxy around the edge of the 12mm carbon tube and position it in place. Then I'm able to put thickened epoxy through the 1-2mm gaps around the tube from the outside due to the increased size of the hole. I then put the piece of take with the 12mm hole through the tube to prevent the glue from spreading out and put hold the entire setup up side down so the glue can spread nicely inside. I align the rods and make sure they are parallel by measuring the distance between them in several places.

After the epoxy hardened, you'll remove the tape and end up with a beautiful flush seem with lots of glueing surface between the tube and the inside of the mount. you can now cut the rods to size to make them flush.

Even though the carbon tubes in the wing are 10mm OD, drill 12mm holes in the wing. We'll be using a similar method as we did in the tanks/mounts to glue those tubes in the wing.

Cut the 10mm carbon tube to stick out about 2cm (while touching the bottom of the upper wing skin. it should be about 6-7cm if i'm not wrong).

Slide the 10mm tube into the 12mm tubes in the mounts and drill and tap the hole for the 3M bolts from the side of the mounts.

Then, put a generous amount of thickened epoxy on the bottom of the 10mm tubes (inside and outside) where it meets the bottom of the upper skin and position it. we want the glue to spread about 5mm around the tube for strength. Don't put glue in the holes of the wing (bottom skin).

After the epoxy cured, carefully remove the 3M bolts and the tank.

Using a vinyl cutter, cut 10mm holes in some tape. put glue around the hole of the bottom wing skin, put the tape through the tube and flip the wing right side up so the glue will spread nicely on the inside of the skin.

Wiring the wings:

Since I wanted to use a large size AMP connected and I didn't want to compromise the area on the fuselage next to the wing screw, I decided to make a hole in the middle of the spar where the flaps servo is. I don't know if this is recommended or not, but for me, it works great and after hundreds of flights there's no signs of weakness.

I had to carve some space for the pushrod to allow it to come to the up position.