Temporary Writeup on model for Whitehead number 21

11 July 2018

On wing construction using 1.8mm leading edge spars and polyethylene film:

1. Prepare paper template by first printing out the planform of the pair of wings. Fold it in half and fit it into the plastic bag. Tape to temporary secure the paper template.
2. Follow the lines on the template and draw on both sides of plastic bag using indelible pen or hot glue gun, the radial spars.
3. Glue the 2 root pieces and 2 leading edge spars to the bag.
4. Cut the bag as indicated on the template. The leading edge shall be rolled over the bamboo spars.
5. By curving the root pieces, the plastic film will be curved into an airfoil.

On fuselage construction using 2mm foam sheet:

1. Cut long rectangle piece of foam, put tape midpoint and fold in half.
2. Mark and cut out the required fuselage side length. The 2 remaining ends can be used for internal fuselage formers.
3. Cut one such piece to the width required and glue the top mast to it. The top mast is a length of 1.8mm bamboo dowel. This former assembly is used to space out the folded piece. Secure free end of fuselage with glue and tape.

Joining wing to fuselage:

1. Apply UHU glue to the areas where the root pieces of the wings will come into contact to the fuselage.
2. The free ends of the 2 leading edges are trimmed to length so that they can be turned up (wing turn down) along the fuselage former, against the top mast and forming the required dihedral angle.

Bowsprit, tail, wheels, rigging

1. Fabricate and install the 2 wheel pairs to formers and glue to fuselage.
2. Bowsprit is a length of 1.8mm bamboo dowel, glued to tip of fuselage and top mast (through the first former).
3. Glue remaining formers, clearing bowsprit.
4. Construct the tail using 2 pieces of 1.8mm bamboo dowel leading edges, spacers and plastic sheet. Set the decalage and glue to fuselage.
5. Glue motor mount to fuselage and then glue the twin motors to motor mount. Glue the control unit so that the CG balances at the desired place (test glide).

Flying

1. Test fly. Change CG location, decalage, thrust angles, vertical surfaces etc., wherever necessary, for powerless glide, power on trim, and turning trim.
2. Rig with cotton thread and add details and painting.