Subsections

• 3.1 Kit Parts Required
• 3.2 Additional Parts Required
• 3.3 Preparation notes
• 3.4 Build Notes
  • 3.4.1 Boom cutting
  • 3.4.2 Vertical Stabilizer and Rudder preparation
  • 3.4.3 Tape hinging the vertical stabilizer
  • 3.4.4 Horizontal stabilizer and elevator
  • 3.4.5 Horizontal stabilizer bonding to boom
  • 3.4.6 Vertical stabilizer bonding to boom

3. Tail

3.1 Kit Parts Required

• 1.5mm vertical stabilizer
• 1.5mm rudder
• 1.5mm horizontal stabilizer
• 1.5mm elevator
• 6~7mm CF boom

3.2 Additional Parts Required

• 6mm triangular stock
• 3~5mm x 6mm x 40mm grooved end-grain pylon mount for horizontal stab
• 3~5mm x 6mm x 50mm grooved end-grain pylon mount for vertical stab
• 12mm wide clear tape

3.3 Preparation notes

The tail feathers are made of very thin (1.5mm) balsa and subsequently can potentially be damaged very easily on rough landings. You can opt to cover them with very light glass (0.75oz or lighter) if you prefer, this will give greater durability and increase the potential maximum launch height.

3.4 Build Notes

3.4.1 Boom cutting

• Cut the CF boom to a length of 560mm (22'').
  • Wrap a couple of layers of masking tape around the boom at the point where it needs to be cut, this will help prevent the boom from splintering. Use an abrasive grinding wheel if possible. Strongly suggest avoid using a hacksaw as this will cause a lot of potential splits.
  • Keep off cut for using as a sanding guide later in the build process and potentially as the launch peg.

3.4.2 Vertical Stabilizer and Rudder preparation

• If desired, trim off a small amount of the rudder piece from the bottom to prevent snagging and subsequent tear off.

• (ADVANCED) Cover the tail surfaces with 25g/m.sq or similar finishing glass using preferred method (CA works well as a sealing agent providing you sand it back afterwards). Use this technique if you're planning on launching higher than 30m/100ft regularly.

• Bevel the join edge of the rudder using a balsa plane (or other tool) to approximately 45 degrees

• Finish off the surface of both pieces of the vertical stabilizer

• Round the leading edge of the vertical stabilizer
• Feather down the trailing edge of the rudder

3.4.3 Tape hinging the vertical stabilizer

• Hold together the two halves of the vertical stabilizer with the rudder's bevelled edge facing out

• Apply a full length of 12mm clear tape to the bevelled side of the two halves and fold it over the join

• Release the two halves from the clamping, the vertical stabilizer will tend to now fold up a little

• Hold the two halves down flat and apply a second piece of 12mm clear tape to the opposite side

• Your rudder is now hinged. There will be approximately a 1mm gap between the two halves, this is normal.

3.4.4 Horizontal stabilizer and elevator

• Perform the same tasks as with the vertical stabilizer/rudder to the vertical stabilizer/elevator.

3.4.5 Horizontal stabilizer bonding to boom

Bonding the tail feathers to the boom is an important task which must be done carefully to ensure maximum holding strength.

• Sand a suitable groove into a short length of 6mm end-grain medium balsa by placing sandpaper around a sample of boom and sliding the balsa block progressively against it

• Slice off a portion of the 6mm end-grain of approximately 5mm width. We do this using a balsa slicer set to 5mm + diameter of the boom (ie, 5 + 7mm = 12mm). To ensure a cleaner cut we progressively increase the depth of each cut rather than attempting to slice through the end-grain in one pass (typically requires at least 3 passes)

• Size up the length of the grooved balsa required for the horizontal stabilizer

• Mark the width of the interface on the tape hinge. We do this so we know where to cut away the tape. If we don't cut away the tape, when we bond the interface to the horizontal stab it won't stick in that area causing a potential weakness.

• Glue the interface down onto the horizontal stab with CA. Ensure there's a good bond and wicking. Try to avoid letting the CA wick too close to the top (where the boom will adhere) otherwise this may interfere with the boom/interface adhesion later.

• Due to the stresses involved on the tail feathers and the thin wood they're made of (1.5mm), it's important that the load between the boom and the horizontal stabilizer is spread out. To do this we add some 6x6mm triangular stock on either side of the exiting interface. Remember to cut away the tape hinge where required.

• Before attempting to bond the boom to the tail feathers it's important to lightly roughen up the boom using some 200 grit or finer sand paper up to 135mm from the end of the boom. Once you have done this, wash the boom under water and wipe dry, the boom should appear slightly more matt in appearance where the sandpaper was applied

• Finally, glue the horizontal stabilizer to the boom with the leading edge of the stabilizer at 135mm from the end of the boom. Make sure that the boom is resting evenly and horizontal in the groove. It's suggested that epoxy be used for the this bond. If you prefer to use CA provide at least a few minutes of bonding time even if the CA is ``fast''.

3.4.6 Vertical stabilizer bonding to boom

• Prepare a 6mm wide end grain balsa interface as with the horizontal stabilizer but instead of a 5~6mm wide piece we instead use a piece of 3~4mm. The reason why we have a thinner piece for the rudder is that we need it to be as close to the boom as possible so that the control rods / bell-cranks can remain aligned without requiring offsets.

• Mark the vertical stabilizer approximately 50mm from the base. Ensure that the line is perpendicular to the hinge join.

• Glue on the pylon interface
• Glue on some 2.4mm balsa strip scrap as reinforcement for the rudder

• When bonding the vertical stabilizer to the boom, it's very important that it is set up at 90 degrees to the existing horizontal stabilizer. There are many different ways that this can be done. We have used some right angle aluminium channelling to which we clamped on both the existing horizontal stabilizer and then the vertical stabilizer.

• Your tail feathers are now finished (until later when we add the radio control equipment).