Building my first fibreglass & styrofoam model

[Richard H.]

I am building my first fibreglass & styro foam model. It will be a 61. version of Carl Goldberg. Any recommendation on how to build the fuselage from fibre ?. Where can I find articles - in the internet - on this issue ?
The wing will be made from styro foam. Ooops, and after enlarging the plans. the wingspan is now 2 M,. The plans is enlarge by 27 % from the original 25 - 45. version. Is this Ok ?.

[BrokenChild]

You can make your wings by building a jig with a patern on the wing airfoil on each end. Make your wing outline on a piece of 1/8" ply, use a scrol saw to cut the exact outline out on your patern, then make another one just like it. What you would be doing here is making a thin line through this sheet of 1/8" ply for your *hot wire* to go through after you build your jig. If you have tapered wings, then obviously, you would have a diffrent pattern on each end of your jig. The jig will need to be a few inches longer than the length of the pannel of your wing. The patterns are then built onto the jig, 90* from horizontal. I always used one of them red lazor lights fixed onto a square to make sure after you get your jig built, that your root, and tip incidence's were at 0*'s, or to set the washout. Also remember with a tapered wing...to mark off several marks on the paterns, in percentages of each other...(EXAMPLE; If I wanted to build a foam wing with a 10" center root chord, and a 5" tip chord, I would mark off every 2 inches on the center patern and every inch on the tip paters, then remember when I was cutting the wing halves out, to cut evenly, and make sure each end of the wire hit the marks at the same time. This would keep the wing from being made incorrectly) A thin wire of any kind will work, as long as you can run enough voltage through the wire to melt or actually to cut the foam. Something like a gituar string...one of them that has the smaller wire wrapped around the center cord...un wrap about 5 inches more of this smaller diameter stuff than the length of half your desired span. I dont know if you can visualize this in your mind or not, but I'm trying. Here is what i did.

I cut slots in my old building table and braced my pattern's in these slots. I made about 8 or 9 wings exactly alike, so I just glued them in there 90*'s offset from the table. I wanted to make one adjustable, but then I had to mess with the length of the wire, so I didnt. I then places a block of foam between these two patterns, and ran my wire through the slots in the patterns, and fixed them to where I could slide them back and forth, but at all times were kept tight. I had a small wire, so I could run the foam cutter off of my 12V 7A. flight box battery (for sports/glow models)... Them would hold a handmade handle on each side and slide the wire evenly through the wings...then removed the waste, and sheeted the wings with thin ply.

As for the fuse... I would carve or cut with a hand made foam cutter until you got the design just right, and then take a lot of fiberglass and epoxy resin and get after it. After you have several layers of some really thick fiberglas, let it completely dry for a good 24 or so hours, coat with another layer of expoy, then let it dry again for another 24-36 hours. Then what I would do it carve out a hole in the foam through out the whole fuse... fill with acitone, and watch it eat the foam away... now all you are left with is the hollow fiberglass fuse....and a foam wing... remember to reinforce the inside of the fuse, and cut you a strip of foam out of the wing at around 33% of the M.A.C, the complete length of the wing, on bottom... then build you a brace to hold the spars together, and glue the spars and the brace in.. If you take your time, you end up with a strong wing... Remember to reinforce this, or it isnt worth your time messing with it... Plain foam works well for smaller models, without much reinforcement (ie... reinforcement tape, packing tape) but a larger model wont fly very long without some plywood...

Hope I helped...

A .61 model of a CGM what? A chipmunk? I would really suggest you build this out of ply and balsa...so that you dont have to build you a whole nother plane if you accidently land wrong...


~broken

[BrokenChild]

http://members.aol.com/davthacker/radicalrcfoamcutting.htm

I wouldnt pay high money for something you wont use much...me being a 'hand's on' kind of person build almost everything myself... My own flight boxed, airplanes... I even rewired my old radios to make a buddy box to train my friend to fly with a homemade cardboard airplane... It was something I should have had a camera for!

~broken