for discussing about technics and applications of composite materials
in aeromodels.
Ossi Kilpelainen ( Wakefield F1B):
Ossi told about physics behind the strenghtness of aeromodel wings.
He introduced some thumb rules for determination of torque in wing bar:
- Torque increases to the second power of length when base of wing
is approached.
- if wings lenght is one meter the torque at 30 cm is half of torgue
at base ie. the material must be used as shown in figure 1.
Also the effect of joiner is shown in Fig1.
- If tube is used as bar the ratio a:b should be under 4. Fig 2
The bar is normally carbon fibre laminates up- and downsides with
balsa or carbon laminate filling. The balsa is best if it is cut
to 45° with two cross layers but 90° cut is almost as good.
The whole "packet" is tied with diagonal kevlar line to prevent
carbon laminates to separate from balsa filling. Typical layout
is seen in fig3.
