Bug HLG

Another trick for re-inforcing thin balsa is to run thin CA into the edges, either before (if you want more CA penetration = stronger local hardening of the wood) or after the PU. Thats commonly used on the larger DHLGs round here. Otherwise you could use 1.5mil packing tape (with or without the PU/CA) on one side as a re-inforcement & control surface hinge. David H near Seattle

What Bob said... We've been building LN tails with waterborne polyurethane (Flecto Varathane Diamond Wood Finish in the blue can) with great success. Take your 1/16" sheet stock, drench a paper towel in poly and soak the sheet on both sides (important to avoid cupping). By the time you are done soaking take a clean paper towel and start rubbing the poly into the wood while rubbing the excess off at the same time. This forces the poly into the wood fibers and creates a composite material. When both sides are wiped down stand the sheet on one edge to dry. It should dry straight every time in only a couple of hours. If there is some cupping, press under books between some plastic wrap overnight. The water evaporates leaving only the poly molecules and adds little weight. You can then cut out your parts and sand to shape. Here's the great part. The poly changes the balsa fibers enough that they are now attracted to the bench instead of floating into the air! I then take .75 oz glass and just lay it over the finished piece. I take my thin CA or thinned wood glue and just drip it onto the surface. The glass wets out and you can wipe off any excess with a paper towel. Instant sandwich! You can even reduce glass coverage to the high stress areas and then treat the balsa edges with CA or Elmer's for a nice hard edge. You can try this for the cost of a small can of WATER BASED poly at the home enter. You'll love it. Chris --- In BugHLG@y..., "bob_chiang2" <rhc3@c...> wrote: > --- In BugHLG@y..., "Dan" <danstrider@a...> wrote: > > I'm curious about creating really light and stong tail feathers. > > > > For what it's worth, I just used relatively light 1/16" balsa treated > with water based polyurethane (per the Little Nipper model) for my > Bug. With the cruciform tail, I have only broken the vertical fin > once: when I missed a catch and the model fell straight back onto the > fin. I was skeptical of using 1/16", but it has been plenty strong > enough without reinforcement (except where it joins the fuselage > boom).

--- In BugHLG@y..., "Dan" <danstrider@a...> wrote: > I'm curious about creating really light and stong tail feathers. > For what it's worth, I just used relatively light 1/16" balsa treated with water based polyurethane (per the Little Nipper model) for my Bug. With the cruciform tail, I have only broken the vertical fin once: when I missed a catch and the model fell straight back onto the fin. I was skeptical of using 1/16", but it has been plenty strong enough without reinforcement (except where it joins the fuselage boom).

I made some wing tiplets for a Zagi using 3/4 oz cloth over balsa. For flat things, it's easy enough to weight with books, I just put saran wrap between the layup and the books. Note that whatever texture is in the book cover will transfer, so pick something smooth. Might try some mylar instead. Be sure to get as much excess resin off as you can to avoid weight. I used Zpoxy finishing resin with good results. You should be able to go at least 1/32" thinner on the balsa with this sandwich approach. I'm certain it will be heavier, though, than lightweight covering over the thicker balsa, but it will be much stronger. --- In BugHLG@y..., "Dan" <danstrider@a...> wrote: > I'm curious about creating really light and stong tail feathers. > > I have looked at Dr. Drela's Apogee tail surfaces, but I'm looking > for something a modeler without access to a vacuum bagger or CNC > molding equipment could build. I'm also shying away from foam due > to an accute shortage of foam cutting equipment here. > > I expiromented with using .75 oz FG and CyA with mixed results. My > surfaces warped, presumably due to the moisture in the glue. With > one layer on each side, however, I do get strong pieces. > > Is there any way I can sheet 1/16" balsa feathers with fiberglass to > get more accurate and rigid surfaces? I'm curious, must I go to vac > bagging to get straight and light tail feathers? If so, what resins > work well for this application? Is there any furture with my FG and > CyA approach? > > Thanks again, > Dan

I'm curious about creating really light and stong tail feathers. I have looked at Dr. Drela's Apogee tail surfaces, but I'm looking for something a modeler without access to a vacuum bagger or CNC molding equipment could build. I'm also shying away from foam due to an accute shortage of foam cutting equipment here. I expiromented with using .75 oz FG and CyA with mixed results. My surfaces warped, presumably due to the moisture in the glue. With one layer on each side, however, I do get strong pieces. Is there any way I can sheet 1/16" balsa feathers with fiberglass to get more accurate and rigid surfaces? I'm curious, must I go to vac bagging to get straight and light tail feathers? If so, what resins work well for this application? Is there any furture with my FG and CyA approach? Thanks again, Dan