balsa glider construction balsa wood very high strength to weight ratio. easy to cut and sand grainy...

Balsa Glider Construction

Balsa Wood

• Very high strength to weight ratio.

• Easy to cut and sand• Grainy• Available in strips,

sheets, or blocks• Not very durable for a

fuselage… spruce is better.

Glider Components

• Fuselage• Wings• Horizontal Stabilizer• Vertical Tail (or

Stabilizer)• Nose Weight

Familiarize yourself with the plan

• Components• Dimensions• Materials• Outlines vs. Cuts

Building on a single sheet

WingHorizontalStabilizer

VerticalTail

Notice the grain direction:Always spanwise!

Leave extra space at these locations if material allows.

Marking the fuselage

WingLocation

Centerof

Gravity NeutralPoint

HorizontalStabilizer

VerticalTail

Cut for Length

Choosing a Wing Planform

• Elliptical wings might be great for full size aircraft, but they are very challenging for small gliders.

• Straight leading edges tend to work well for small gliders.

Cut out all of the pieces

• Cut the wing with extra span if material allows. (See later note for reason)

• Cut out stabilizers and sand leading and trailing edges with minimal rounding.

Shaping the Wing Profile

• The leading edge should have minimal rounding.

• The trailing edge needs to have a taper on the top only.

• Use a sanding block and the edge of a surface for uniform sanding.

Adding the wing

• Center the wing on the fuselage.

• Glue it on straight and square to the fuselage… this is critical.

Making a strong bond

• Traditional method of lots of glue on an edge then stick it together is weak.

• Light bond with reinforcing fillets increases the glue surface area and thus the strength of the bond.

One Piece Stabilizer

• Cut out the wedge from the glider plan.

• Trace on to and cut out the wedge from a scrap of fuselage.

• Glue the wedge (not the stabilizer) to the top of the fuselage.

• Direction depends on tail or canard mount.

Front Back

Side of FuselageHS

WedgeStabilizer

Canard PositionHS

Frontback

Tail PositionHS

Add the horizontal stabilizer

• One piece stabilizer– Stronger– Only possible if

mounted somewhere away from the vertical stabilizer.

• Two piece stabilizer– Weaker– Mount anywhere else

Check alignment

• Hold the stabilizer on the wedge and check from the front or back that it is parallel to the wing.

• If not, sand the wedge slightly and recheck.

Glue the Stabilizer

• Glue to the TOP of the fuselage.

• Align the lowest edge with the end of the wedge so it contacts the fuselage.

Canard PositionHS

Wedge

Two Piece Stabilizer

• Cut out the wedge from the glider plan.

• Trace an angled line onto the side of the fuselage.

• Direction depends on tail or canard mount.

Front Back

Side of FuselageHS

Tail PositionHS

Check alignment

• Cut the stabilizer in two.

• Doing one side at a time…– Glue one half to each

side.Canard PositionHS

Tail PositionHS

Glue the Stabilizer

• Glue to the SIDE of the fuselage.

• Make certain that each half is straight and square to the fuselage.

Balance the Glider

• Place a pencil on the table top and put the glider on top of it with the C.G. directly over the pencil.

• Add clay to the nose until the glider balances at the C.G.

Balance the Glider

• Hold the glider on fingertips placed at the nose and the tail.

• Add clay to the wingtips until the glider balances at the fuselage.