Thursday, November 28, 2019
Lawn Dart Rocketry SLAT/S Build, Part 4, Conduit Tunnel Shaping
While the balsa fairings dry, I worked on the Conduit Tunnel.
I don't have any half rounds, we'll carve one from a full dowel.
Draw a center line down both (opposite) sides of the dowel.
Carve off the back half of the dowel.
Notice on the right, I didn't carve all the way to the half center lines.
By the time you sand a curve into the flat back, you'll end up close to that center line.
On the left is the dowel before shaping the underside. You can see gaps on the side where it should fit the body tube curve.
On the right is the dowel after shaping the flat underside.
You could wrap sandpaper around the body tube but chances are the concave curve arc would be too shallow leaving a gap.
TIP: When shaping a part to fit a body tube, use a tube (or engine casing) that is smaller than the tube it has to fit on. You'll usually sand the inside curve wider than you intend to. Using a smaller tube or casing will give you a tighter fitting part.