Doug, The standard procedure for bagging LEs is to cut the mylars short of the LE, feather the edge of the mylars, and then have an overlap layer like wax paper to conform the glass around the LE under pressure. When removed the paper peals off, the LE needs to be sanded, and the edge ridge left by the mylars has to be removed. That is the general idea. I have been trying to do it a different way and this was because I was trying alot of SMALL wings for micro HLGs and a small MHLG speed 280 wing. I use square mylars with no feathering because I want to keep a generic set of mylars, since I did not want to keep making specific mylars and then never use them again. (Save $, you know) Also I wanted to really reduce the amount of work I have to do. This method has one problem I am trying to figure out, that is buckling around compund curves. I prep the core as usual. I wrap the LE with FG. All other FG, CF is added as usual. I then take a strip of very light 0.5" wide FG and spray one side of it with 3M77. I apply it along the LE on the lower side of the wing, extending out about 1/4" or more from the LE, making a kind of ledge. I then mix up epoxy and microballoons (sometimes chopped cotton/cabosil (sp?)), relatively thick, and place this in a disposable syringe, plastic icing bag, or small sandwich bag. For the bags I cut a small bit of a corner out to make a exit for a bead of epoxy. I then apply a good sized bead of epoxy along the ledge of FG just prior to placing the top mylar over the core. I then apply the vacuum, and I have been using 16". The mylars contour to the LE as much as it can and the bead of epoxy/balloons fills the gap. I really rub and sweeze the mylars to get the bead of ballons to move and contour to the gap, filling it in. I then place the wing in the cores for the normal curing procedure. When I take off the mylars when cured and the LE is very nice. I can then sand the LE to shape and I have to do less work filling etc. I am still experimenting but this seems to be working. Now I have only tried this on small core wings, but feel that it is going to work for a new 3M ship I have been drawing. Again, the only problem is buckling along the compound LEs and this seems to be reduced when I keep the edge of the mylars near the compund transition point of the cores, and when the cores are thin. With the trend to go to thinner cores, I think it will work better and become popular. I am also trying to use this method for elipitical dihedral wings, like the Hobie Hawk. I have worked with bagging Hawk wings, made of plywood skins, with the MFDer, so I have seen that the thinner airfoils can have this work well. I cannot take credit for this method. I was at Visalia 2 years ago and had gaps (bubbles)in the Trailing Edge (TE) of the wings. Another manufacturer suggested I brush on some microballons/epoxy on the TE to eliminate the gaps during bagging. I just thought it would be more to my advantage to try it on my LE's. I have been trying to add molding stuff to my web site at http://www.scrollsander.com (under Soaring Goodies) and have not bagged wings recently, but will be. I have a digital camera and will be taking pictures of my next bagging with this method. I hope this helps. Thermals, Chris Adams -----Original Message----- From: Doug Turner <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Saturday, April 22, 2000 11:52 PM Subject: [RCSE] Bagging leading edges >I am trying to figure out how to vaccum bag a wing's leading edge. It seems >that as air is sucked out of the bag it leaves a void between the mylars at >the leading edge. So I guess that the leading edge really isn't under much >direct pressure. On my latest attempt, I added a strip of .75 oz glass to >the leading edge before bagging, but I didn't wet it out with resin. I >assumed that the mylars would squeeze together at the leading edge and wet >out the fiberglass that was on the wing.( I was pulling 15 inches by the >way) That didn't happen, in fact the entire leading edge was dry in the >majority of places. > Any hints or tips or website references? >BTW, the wing turned out beautiful otherwise. I have been bagging wings for >years but this was my first wet layup. My handlaunch wing weighs around 3.75 >oz. > >Thanks, >Doug 7B > >RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
