Building a Sports Model – Part 5

The root  ribs are cut from 1.5mm ply and glued to the foam wing cores.  Also included are a 5mm bolt for mounting to the fuselage and two locator lugs made from leftover carbon-fibre rods.

The wings are now ready for sheeting with 1.5mm balsa.  First the sheets need to be glued together along their edges.  They are taped together, flipped over and yellow glue applied along the joins, then weighted down while they dry.

Gluing the sheets to the foam wings can be tricky, as it’s very important to get a consistent bond.  But with the right tools it’s actually very easy.  

Yellow glue is spread with scrap balsa like butter to cover every bit of foam.  The balsa is laid in place hard up against the leading edge, and now for the tricky part.  The wing is inserted into a giant vacuum bag from Bunnings, and the air sucked out and left to dry overnight.  Clever eh?  Perfect results every time.

Do that with the other three sides, trim the edges, and the wings are now super strong and light.

 

That was the easy part.  Now the aileron servo cutouts have to be made, lined with balsa, and the servos mounted on hardwood blocks. 

Then the ailerons need to be carefully measured and cut out.  12mm balsa spars are added to the trailing edge cutout and the aileron leading edge, then sanded to shape.  Hinges are installed and balsa blocks glued in for the aileron horns, which are then fitted.  A quick check with the receiver connected to make sure everything works, then pull it apart again.

The blurred photo below shows the end ribs being glued on.  Note the small cross on the wing for the servo cutout.  The ailerons process was so involved that I forgot to take photos.  

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