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

From: "Chris Lewis" <christopherlewis@...>
Date: Thursday, May 29, 2003 10:54 AM
Subject: Re: Help with rib production?
Henry - Are you building from the full size plans? Is so, there's a dihedral gauge that I copied and pasted to a scrap of balsa to get my R1 angle correct. I always install this rib last and make sure the angle is just right. For the LE notch, I bought a 1/8" rat-tail file and use it to form a perfect notch every time. Here's my wing building method. Keep in mind that I add an extra R3 every time, so none of the printed spar holes are in the right place except the first and last rib, so I drill them one at a time. 1. Photo copy the rib forms and cut out with scissors (Make an extra R3) 2. Spray with 3M 77 and attach to balsa sheet. 3. Rough cut each rib and sand to exact shape following photcopy lines. 4. Use file to make LE 1/2 round notch. 5. Mark trailing edge with rib spacing and attach to board w/tape. 6. Mark and drill spar hole in R2 and R7. Peel paper pattern off. 7. Glue R2 in place at TE and spar (I always run spar all the way to the end of the tip plate if you plan to SAL). 8. Slide R7 onto spar, do not glue. 9. For each internal rib, I lay it in place, mark the spar location, drill spar hole and then install (removing and reinstalling R7 each time). I glue the TE and the spar hole only, leaving the LE until the wing is built. Use a square gauge to make sure the ribs are staight. 10. Once the wing half is built, I glue on the tip plate. I use 1/8" balsa w/o lightening holes since I grab the tip for SAL. I usually have to file a groove for the spar at the tip so that the bottom surfaces of R7 and the tip plate line up. 11. Install R1 using the dihedral gauge. Remove from board and sand top and bottom of R1 flat to the other ribs w/sanding block. 12. Starting at R1, lay the 1/8" dowel LE into the notches and secure with CA. 13. Trim dowel at tip as shown and sand to fine bevel. Fill tip with light contest balsa and sand to match airfoil. This makes a good thumb grip for SAL. Do both sides for balance and leftie/rightie capability. 14. Install sheeting at R1-R2. 15. Harden edge of tip balsa with thin CA to prevent dings. 16. Repeat 1-15 for other wing. 17. Glue halves, reincorce w/FG 18. Cover. Different builders will have different methods, so take these steps as a guideline. I've built many of these wings and have had no problems at all (my first plane is still flying in it's second season with my kids learning to fly on this plane last year). They all turn out true and flat and any minor twists can be dealt with when covering. This is a great little plane. You'll enjoy it. I always use a cruciform tail and get nice straight launches w/o preset or mixing to 50-75 feet. I use a modified plastic pod and call mine a Lil' Bugger (1/2 Little Nipper, 1/2 Bug) translates wierdly from American to Kiwi but it's a fun plane (see LN photo section). http://photos.groups.yahoo.com/group/littlenipper/lst?.dir=/Lil% 27+Bugger&.src=gr&.order=&.view=t&.done=http%3a//briefcase.yahoo.com/ Enjoy! Chris in Seattle, USA --- In BugHLG@yahoogroups.com, "dimple_kwok" <henry.kwok@x> wrote: > I think I will try to make the parts myself, since this will be good > exercise anyway. I would appreciate it if you can give me some > pointers, since this is my 1st scratch built (I fly EPP slopers). > > I actually have made 1 set of wing but I am really unhappy about it > so I am going to remake it. The problems I have encountered are: > > 1. The notch for the LE dowel - how can I cut this accurately? > Inaccuracies have led to the dowel not sitting on the same horizontal > plane) with the spar (is this normal?) and one of the ribs needing > some lengthening for it to reach the LE. I presume if properly made > the LE, spar and TE will lie on the same horizontal plane? The crappy > wing set I have is obviously twisted. > > 2. The root rib dihedral angle. At first glance it appears simple but > once the two wing halves are made the two sides don't seem to meet > each other too well. I tried to sand the root rib with a block / bar > sander but really the results are not too good. I wonder what are the > tricks necessary to achieve a perfect wing joint with the right > dihedral. What's worst, when I was trying to sand the wing halves I > manage to damage them - hence new set of wings needed. > > 3. Related to 2 - I guess problem 2 can be solved if I can cut > correct bevels top and bottom of the root rib? But how can that be > achieved? > > 4. Wing center sheeting. Because of W1 being slanted the sheeting > does not want to sit flat esp in the front part. > > 5. It may sound silly but how do you keep the ribs parallel during > your construction, esp during the LE glueing? > > 6. What tool do you use to cut that perfect lightening hole in the > wing tip? Also would a laminate of 2 1/16" tip works better than a > single 1/8" tip? > > I think if I am not too picky most of the above problems will > probably be ok as long as they are symmetrical, except the center > wing joint which I just cannot get right! > > > Thanks for any suggestions > > Henry