17.3: Viewing Polars as Table or Graphic
After performing a total polars calculation as described in chapter 17.1 and
17.2 one can examine the results. This chapter shows how to do so. Click the
button 'Display Total-Polars' to open a new window.
The new window shows by default the folder 'Table-Output' which outputs the
computed polars data in text form. The File menu offers the options to save and
to delete this data, or to load additional polars from other computations. The
most important polar data from previously done computations shown in this table
are:
1) The angle of attack alpha in degree
2) the two flap deflection angles and the two wing angles of incident in
degree, as entered into the list in folder 'Total-Polars Computation'
3) The lift coefficient CL of the whole airplane
4) The drag coefficient CD of the whole airplane
5) The airspeed in m/s
6) The settling velocity in m/s
7) The glide ratio LD
8) The ascent ratio epsilon
9) The sliding angle in degree
10) The centre of gravity measured from the leading edge in m
11) The stability measure in % of aerodynamic chord of wing
12) An information line
In the information line e.g. a separation warning is shown, together with the
number of wing and the size of the involved surface in %.
Negative values apply only to inverted flight. If one would put the airplane
upside down, one had to multiply these values with -1.
The second folder shows the polars graphic. The polars are shown in the
graphic, while bottom left the appropriate values for X and Y at the position
of the mouse cursor are visible. The radio buttons bottom right can be used to
select the desired units. Every unit can be put on either the X- or the Y-axis.
Select the check-box 'Crosshairs' to display crosshairs in the graphic.
In the graphic below, one can see points with different shapes.
1) A quadrate indicates health flow.
2) A triangle with apex up indicates flow separation anywhere on an upper
surface of a wing.
3) A triangle with apex down indicates flow separation anywhere on a lower
surface of a wing.
If the mouse cursor is directly on a polar point, one can get in info-box with
explanatory text by pressing the left mouse button.
In the check list bottom left are the actual available polars recorded. They
can be made visible by selecting the check-box left of the text.
If you want to delete a line of polars, click first with the left mouse button
on the desired entry and than press the right mouse button. A pop-up button
'Delete marked polars' appears. Click it, to delete the line of polars.