dr_wogz
Posts: 2006
Joined: 7/17/2002
From: Pointe Claire,
QC, CANADA
Status: offline
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Here's how I had to do it on my RCM plan spit Mk I With foam wings (about 65" span)
The tip 6" will be a sandwich of balsa and 1/16 ply, with teh rest of the wing being foam. Or there abouts. I beileve I had the balsa tips starting at teh end of teh ailerons (from the aileron to teh wing tip was balsa). The ply had 'fingers' that would help join it to the rest of teh wing; additional strength. Or, leave these off, for a 'clipped wing' spit..
The aleading edge was a layered series of balsa strips. You'll need one one was you build, and the others afterwards. 3 x 1/8" sounds about right..
Make 2 'root' templates, and one 'tip' template. You'll be using the templates twice for your 'hot wire' so, make them 'heat resistant'. Mark thier centetr lines, both horizontal and vertical. Also, make two 'bottom skins'. make them from a fairly hard balsa. Mark the datum (center line) on the skins (trace the plan)
The center section is a simple, constant cord section. Two root templates.
The 'tapered wing panel are the tricky part:
With the block cut to width, fasten the two root templates to each end, ensureing teh correct 'washout' on the tip. Cut core. Yeah, it'll be a constant chord whing at this point, with washout.
Save teh blanks that the core was cut from (the top & bottiom of the foam block). You'll need them to glue teh skins on, to ensure no twists.
Glue the bottom skin to the block, aligning the datum line on the skin with the center marks on the tip and root. Glue, place in teh blanks, and secure, and set aside. cut the other one.
Cut a leading edge strip, one end teh as thick as teh root template, the other as the tip template. You should have a long strip the length of the wing panel (plus a little extra due to curavature) that tapers form the root to the tip. 1/8" balsa worked for me, if I remember. Don't worry too much if it's a little under or orversized, as it's more of a sanding guide at this point.
Now the fun part.. Secure teh 'tip' template to the tip of teh core. Aling the bottom edge with the skin, and the center line should align with the datum line on teh skin. Flip over, and remove all foam outside teh balsa skin. So, you'll have that lovely eliptical wing shape. Glue the leading edge strip in place. Now, with a long sanding bar, sand teh crap out of the top portion of the foam core. [lots of styro dust!! do it ourside!!] You want to sand to the tops of both the root and tip tremplates, and the LE strip. The trailing esdge should nicely feather to the balsa skin.
Sheet the top, and add moer leading edge pieces, and sand. Cut out the ailerons. Cut out 1/4" x 4" slots at teh root for 1/4" balsa spars / stiffeners. Ditto for teh wing center section. Sand in the required dehidral angle (sand after, or cut in as you cut the cores)Glyue all three parts togehter. Add spars...
Cut a groove for the aileron control line (golden rods), then fille with balsa.
Cut holes for retracts, lines, servos, etc..
hope that helps, and hope I haven't confudsed you!!
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How do you cut foam wing cores for a Spitfire? - 
