Archive of the Yahoo! Groups mailing list for the Bug hand-launch glider 2002-2018

From: "Chris Lewis" <christopherlewis@...>
Date: Thursday, May 29, 2003 5:49 PM
Subject: Re: Help with rib production?
John - Sorry to hear that you didn't have folks come through for pod material. Next time send me a PM and I'm more than happy to help if I happen to have surplus material on hand. My first couple of pieces came through the mail, but I burned through them quickly while learning. It's just as well that you have a quantity since pod pulling is as much art as science. The pod is one piece of .060 PETG heated over a stove burner and pulled over a form. I use a piece about 6.5" x 6.5 to 8" and use a couple of spruce sticks 1/4"x1/2"x7" along with a couple of "binder clips" on each side to hold the plastic while heating. The key is to heat slowly until the PETG is droopy, but not until large bubbles start to form. Heat thouroughly from edge to edge by moving across the burner. I have a pod mold very similar to the one shown in Bruce Kimball's folder on the Little Nipper group. It has a carved, sanded and faired poplar fuse shaped to my liking and about 3" of wing shape attached to each side at the correct dihedral angle and LE shape. It has a 1/4" steel rod drilled into the TE side so that I can mount the form in a vise that is clamped right next to the stove. Once the plastic is floppy - Use gloves! you'll immediately want to pull it over the pod form and use your gloved hands to make sure it gets into the corners where the fuse and wing stubs meet. It takes work and practice. Pull to fast and the PETG gets too thin. Too slow and it cools and doesn't cover the pod mold. Be patient! Practice, Practice, Practice... Re-read my instructions and step 9 indicates the measure, mark and drill method for the intermediate rib spar holes. This extra wingspan is crucial to gaining more float time. I don't use pins. I just glue as I go with thin CA using a capillary tube to restrict glue application. Goes fast, works great. Keep in mind that going to the plastic pod means a total redesign of the airplane. The servos must be recessed in the wing, a boom mount must be fabricated, bolt anchors for the pod/boom mount must be added to the wing, servo linkages changed, pod form built and a pod pulled. Glassing the balsa pod, going to a cruciform tail (supergee style), WPU for tail finishes and extending the wing are simpler mod's if you are just looking to move up from the standard bug. It you like to tinker, go nuts. The Bug is an amazing platform to start from or fine just as it is. After talking with Dick Barker of DLG fame, I might try making this pod in two pieces using Vac-bag method and FG. But I've got a full sized Uplink to scratch build first. Hope that helps. Chris in Seattle