9.11:
Click the folder button '
Below a wing with two segments. The left segment shall be split.
After clicking button 'Split' the wing looks as shown below, now we have tree
segments.
Often it is desired, to split a segment at a
specific position. Enter the split position in the field 'Pos.Y [m] and then
click the Button 'Split Pos. Y'.
A geometric peculiarity occurs with twisted wings. All chord lines between the
both tip airfoils are shortened by the geometric twist. The stronger the twist,
the distinct is this effect.
The following reasoning shall clarify this.
Taken two wooden strips representing the both tip airfoils of wing and mounting
one thread each front side of the strips as leading and trailing edge of wing.
Now we fix one wooden strip on a table and use the other strip for simulating
geometric twist. With a twist of maximal180° the leading and trailing threads
will intersect and the length of chord line will become 0 at the intersection
point.
With a geometric twist between 0° and 15° - typical in aircraft construction –
the shortening of chord is not so serious, but still measurable. This effect
has consequences both for building the wing and for the aerodynamic.
By cutting Styrofoam this effect is hardly not to avoid, the airfoils between
the tips will shrink in chord length as well as in thickness.
With a rib wing one can make appropriate provisions to keep the chord length
constant, but then one builds a curve into the leading / trailing edge or both.
From the aerodynamic point of view this effect has impact above all on the
Reynolds number and the surface area, both will be shrinked by geometric twist.
This is the reason why you can find two radio buttons on the folder '