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

From: "John" <gldrgidr@...>
Date: Monday, March 15, 2004 12:01 AM
Subject: Re: 1.8 oz/ft2 BUG
Thanks for your reply, Jason. The trees at my field are over 65 feet tall measured by a phone lineman's pole and I launch my bug to just higher than the treetops (I estimate 68 - 70 foot launches). I've done this hundreds of times without any breakage. A shoulder injury prevents javelin launching so SAL is necessary for me. When I built my bug, I didn't order the contest grade balsa but I used the lightest balsa I had (about 7-8), and a lightweight wrapped tail boom. This boom weighs about the same as the 1/8" pultruded CF tube but is stiffer and larger in diamater. The boom diameter is large enough that you can put holes in the boom to allow the pushrods to exit the boom in front of the tail, making pushrod hookup easy. The link for this boom is posted in the Links section (replacement for Skyshark 2P). I did fiberglass the fuse for strength adding more weight. All radio components are forward of the wing LE. I used Hitec HS-50 servos because they are lighter than the Pico BB's. The weight of my x-tail pieces are not near as light as your v-tail. The original flying weight of my bug was about 3.8 ounces but it is strong enough for 70 foot launches. Light with incredible thermalling ability but doesn't launch high VS heavier with decent thermalling ability but launches high. Two schools of thought with positive points for both. For me, the answer is somewhere between your 2.6 ounces and my 3.8 ounces, but with the strength to launch high. I'd be satisfied with 3.25 ounces and the ability to SAL launch to about 60 feet. The weight of my x-tail pieces for coming Bug #2 is 6.7 grams with CF reinforcement and fiberglassed fin/rudder. Already have the 250 mah lipoly (Etech) 5.5 grams. More to come but another project first. John Gallagher --- In BugHLG@yahoogroups.com, "jason_wasylyk" <thetoothdoc@s...> wrote: > --- In BugHLG@yahoogroups.com, "John" <gldrgidr@m...> wrote: > > Jason, > > That's incredible!! How did you do it? Give us some more details. > > How about some photos? > > > > John > > > > > > Photos will follow later this week (left the digicam at the office). > > Well, 'cuz you asked.... here are some (hopefully controversial > enough to spawn some discuusion)details: > > First let me say that I differ from the popular notion that the way > to improve on the BUG's performance is to add a DLG style x-tail and > chuck it higher. While this is UNQUESTIONABLY the way to maximize > dead air time in a 60" competion class DLG contest, I don't think > this style of building or flying makes maximum use of the BUG's most > desirable qualities which are its LIGHT WEIGHT (if built "correclty") > and RADICAL manouverablilty (again if built "correctly"). > > I concede that a 60" DLG launched to 100 feet is going to outfly a > 60" DLG launched to 40 feet, But I contend that a 2.5 oz BUG launched > to 20 feet will outfly a 3.5 to 4oz BUG launched to 60 feet (which I > can't see anybody launching a BUG to without blowing it apart). So, > I prefer to leave the v-tail for maximum tail lightness and to allow > the use of a light (4g) Kokam 145mAh cell for juice. Most > importantly, the use of the v tail and a gentle javelin or side-arm > (NOT DLG) launch allows the use of smaller dimeter (LIGHTER) tailbooms > which is where the MAJOR weight savings is to be had. I've already > posted on this in the past and stirred the pot a bit. Many others > contend that the 1/8" CF tube I favor is too sloppy--maybe if your > trying to full force discus launch. Anyway, you can look up details > of this discussion in previous posts. > > So, the fun of the BUG is in my opinion building lite and > manouverable and having fun down to 10 and 20 feet altitude where > thermals form tight and fast. I suspect that not even a top of the > line 60" DLG can work the bubbles this gem can at 10 feet off the > deck. > > So, the major departurs in the way I build my BUGS are: > > 1. Contest wood only. > 2. Use of Modelairtech Clearfilm for covering and WBPU on bare > wood. No Color. > 3. Use of CST's 1/8" cf for tailbooms > 4. single cell Kokam 145 cell from www.b-p-p.com > 5. positioning all gear forward of foremost bulkhead for balance. > 6. GWS pico rx and pico BB servos > 7. extended wing as described in other posts > 8. Vtail (NO DLG style tails-- I built one and the lightest i could > do is 6g compared to the 2g vtail. That 4g diff takes about 12-15g > more weight in the nose to balance. > 9. don't cover any part of the fuselage with f/glass. It's too > heavy. Try this-- 3M-77 forward of the wing LE, then apply 3M > tartan crystal clear packing tape (1mil thick). Then iron down. > VERY Strong and on ly adds 1g. Cover the nose forward to the EPP > block (see below), then coat with goop. > > A point of interest is that in order to get her to balance with the > single Kokam 145 cell, I had to put the Rx, batery and both GWS pico > BB servos forward of the foremost bulkhead. That leaves the entire > compartment under the wing empty (except of course for the pushrods). > As this compartment is right under the CG it'll make a perfect > ballast box should I wish to fly at the more usual wingloads of 3-4 > oz/sq. ft. > > Another GREAT innovation has been the replacement of the nose balsa > block with EPP foam sanded to shape, spackled and coated with marine > GOOP thinned with toluene. VERY smooth and resilient. This cushions > MAJOR landing impact and never chips and dents like the balsa block > does. Try it-- you'll never go back. I'll post photos later. > > For the time being, I'm going to have fun seeing what a tip- > launchable, extremely nimble glider can do at under 2oz/sq/ft. > > Should be lots of fun