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

From: "bob_chiang2" <rhc3@...>
Date: Tuesday, July 30, 2002 4:10 PM
Subject: Re: Lightning Bug
Hi all, Thanks for the comments and suggestions: just the kind of feedback I was hoping for. 1) Almost as much as trying to decrease weight, I like how built up ribs can save wasted balsa. I always end up with odd bits of waste when I cut out ribs. The sliced rib top members all nest together so there's nothing lost there, and my bottom members are formed from sheet stock. Anyways, I like the open look when used with a transparent covering. 2) I've been thinking about how to extend the spar and tie it into a thumb and finger pad so the grip transfers directly to the spar. Maybe I could balance the wing tip grip with the radio antenna on the other side. 3) I think you're right and will use sheet for the tails. The Little Nipper even uses 3/32". 4) I hadn't thought about needing a curved spar to follow the high point. I once made a wing with tapered tips and cracked rib construction, so it just needed an angle point in the spar to follow the high point of the ribs. 5) I'm relatively new to using glass and carbon in models, so I don't know the comparative weights/strengths of using thicker balsa vs. composite reinforcement. As long as I was putting in the order for carbon tubes, I thought I'd buy some glass cloth and carbon matt to play with. I read some previous comment that the cruciform tail might be reduced in size, so I'll probably try that to reduce weight. Or, I may try a T-tail like the Little Nipper which seems to have a very small horizontal stab, I guess because it's full flying? And Steve, I don't take your comments as negative, just welcome advice. Thanks again, -Bob Chiang --- In BugHLG@y..., "no1steve2002" <stevew@h...> wrote: > Bob > A few points I would like to pick up on. > 1. I think built up ribs will or could end up being heavier than > contest grade 1/4 grain balsa. > 2. Laminated tips will save a few grams but you will then be > restricted to javlin launch only. I doubt you will have the strength > for SAL. > 3. A built up tail would I feel be weaker and heavier than the > 1/16th balsa. and will not take any hard landings if you use the + > tail. as a lighter V tail what about trying 2mm Depron? > 4. The spar Idea will not work unless it was bent to follow the high > point of each rib. For a lighter spar you could go for a carbon free > flight wing/tail spar of say 5mm these are real light. Check out > Free Flight Supplies website > http://www.freeflightsupplies.co.uk/ > 5. I feel that only by making a Kevlar pod would you be able to get > a fuz that is not expendable. I can not see the point of using > lighter wood then making it heavy again with glass cloth etc. Why > not use light thicker wood in the fist place that does not need the > cloth? > > Sorry to sound so negative IT'S only my opinion. Go ahead and try > your mod's and let us all know how you get on. The best way to > reduce the wing loadong would be to 1. increase the wing area 2. try > to get one of the new rx's that use 2 nicad cells for power 3. go > over to 1 lion cell. But bear in mind if you use lighter radio gear > and batteries you will have to lengthen the nose to get the CG > correct. No point in making all these savings then adding lead to > the nose. > > Good luck > Steve Wheeler > --- In BugHLG@y..., "bob_chiang2" <rhc3@c...> wrote: > > Hi all, > > > > I've finally ordered a bunch of carbon tubes and have begun > > construction of a Bug. I decided to go light: substituted 1/20" > balsa > > for the fuse sides, laminated my own ply using balsa, and I'm > making > > built-up wing ribs. Considering the material that goes into the > stock > > sheet ribs, it probably isn't worth the effort, and I hope they > are > > strong enough, but I'm far enough along that I don't want to > chicken > > out now. For ease of construction I made a template for the top > > surface of the wing, and have cut all of the rib top members using > > this same shape. > > > > I'm considering using laminated wing tips, and built up tail > surfaces > > if people think they'd be strong enough. I intend to use the > > cruciform tail that is posted in the photos section. Does anyone > have > > suggestions to modify the tail surface areas based on further > flying > > experience? > > > > What do people think of substituting a pair of 1/8" square balsa > spars > > with 1/32" shear webbing instead of the carbon spar? > > > > I also ordered some .53 ounce glass cloth, and light carbon mat. > I've > > read about using water based polyurethane instead of epoxy resin > or CA > > glue. Does anyone have comments about this process? > > > > Thanks in advance for any comments or suggestions.