Crafting Aileron Test Piece for Primary Glider by No Mold only Sheet Work

Introduction

For building a primary glider, made an aileron piece to practice actual craft.

-materials-

・balsa wood sg 0.15 5mm*5mm for rib member

・birch plywood 1/32in for rib assy gusset

・GFRP plate consists of 2 ply #200 GF cloth ±45° angled for torque tube and trailing edge

・balsa plate sg 0.15 2mm thickness for torque tube rib

・Styrofoam 20mm thinkness for forming torque tube 

・PP shrink film 15μm thickness for skin

1200mm lenght and 450g weight. I feel it can make 350-400g weight by refining

subassembly

rib

fix wood blocks on the pinted drawing

Prastinc wrap and block's green tape are used to not glued rib assy with table or block.

birch plywood is so expensive in japan that some ribs used gfrp gusset for saving it

Gusset form is 18mm radius half circle for standardization and efficiency. GF plate gusset doesn't match to look of wood member.

Torque tube assy

making GFRP plate

GFRP plate is made from room temprature curing epoxy resin. Squeezed resin to make resin ratio 35-40%. Afeter curing, divide this for required size.

styroform is cut by hot wire

Innner tube rib is composed by 3ply 2mm thickness balsa wood that is angled 0/90/0° . At first I made it 2ply 0/90 but deformed. maybe by moisture.

Gluing them at the designed intervals and cutting styrofoam by hot wire using the both sides rib as guide line. Attach 3 side to rib first( torque tube has 4 side) like next picture back right. For getting torsional stiffness, each side panels must connect by strength member. So between these 3 side panels, making fillet made from epoxy resin with chopped glass fiber and thickener talc.

Be careful of the angle

the last side is attached after glued latter ribs.

this panel also connected by fillet. When assemble this tube, it is necessary to make each panel size slightly bigger or smaller so that assembly errors can be absorbed by epoxy fillet.

Lastly, making trailing edge by gf plate and Urethane foam and wraping by shrink film.

I actually wanted to install the hinges and horns but it is after the main wing assy is completed.

Conclusion

 I wanted to create 3 dimentional objects using sheet or plate work. Without using any mold as much as possible. But I noticed that making multiple pieces of same thing like split main wings, it makes more sense to avoid terrible work by paying the cost of maiking one mold.