| From slopeflyer.com Techniques 19. Pull the tape around the joiner tube slot and allow to cure. When you are happy with the wing alignment, are sure that the joiner tubes are aligned in the joiner tube slot, and have a nice goo crown over the joiner tube slot, pull the masking tape around the perimeter of the joiner tube slot and allow the goo to cure.
20. Sand the cured goo to profile. Carefully remove the clear tape on the bottom of the core, making sure that you get all the tape off the cores and cured goo. Sand the cured goo on the top and bottom of the joiner tube slot to profile with a Perma-Grit. If you find a void and need to fill a valley, use a Dremel tool with bur to roughen the area, tape the area off, fill with fresh goo, allow to cure, and then sand to profile.
Common Questions: 1. Q: Do you drill a hole in the sub-rib to pass the joiner tube through? A: No. The goo holds the joiner tube to the sub-rib. 2. Q: Would a plywood sub-rib or chordwise wider sub-rib be “better”? A: No. The balsa sub-rib in this system results in a robust wing structure and is faster and easier to install. 3. Q: Cutting the joiner tube slot, filling it with goo, and sanding it down, looks like a PITA. Is the good old plywood rib and sub-rib good enough? A: The plywood rib and sub-rib is good enough for small TWF planes, like the Shrike, Pica, and other small, light TWF designs. When you move to TWF planes that are bigger, heavier, and faster, like the Ultron, JARTeron, Rotor, Xica, I have found the plywood rib and sub-rib to be lacking in robustness. For example, 1) the plywood rib and sub-rib wings tend to sustain more damage at the LE and TE wing root on rough landings, 2) the plywood rib and sub-rib wing tend to develop “puncture” deformation around sub-rib from big air flying, and 3) the plywood rib and sub-rib wings are more susceptible to the joiner tube bending and binding on the joiner rod between the root and sub-rib after hitting the ground, cartwheels, and LE to LE mid-airs. 4. Q: Could I tack glue the joiner tubes in place then fill around the joiner tubes rather than filling the slot with goo and installing and aligning the tubes all in one operation? A: Yes. I use that technique with stab joiners, but for wings I found that once I developed a little experience with this technique, it is easier, much faster, and is more reliable, e.g., less prone to avoids. Once you get it down, you can do two or three sets of wings with one big batch of goo. 5. Q: Boy that sounds like more than a few hours work!?! A: It is like anything else, if you have not done anything like this before, it will take you longer than it takes me. But, as you develop knowledge, skill, and confidence you should be able to get the joiner tubes installed and sanded out for bagging with a couple hours of work. I tend to build wings is sets of three, I can now do three set of wings in 4 or 5 hours, if I don't make any mistakes. 6. Q: What about putting in some dihedral? A: Typically, I cut the foam cores so that the dihedral is built into the core bed. However, this technique works fine if you need to build in more dihedral as long as you can hold the core firmly against the core bed. © Copyright 2000-2007 by slopeflyer.com |
