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