Vorherige Seite Inhaltsverzeichnis Nächste Seite
17.1: Flap Computations

The glider 'ASK21_EN.flz' shall now be used to explain the procedure with this function. Please open the file 'ASK21_EN.flz'.
Now the screen looks as shown below.



First we enter the settings and a functional description for each group of flaps. This eases later lucidity. Please select the horizontal stabilizer.



Switch to folder 'Wing' and select in the segment block the subfolder 'Flaps'. The horizontal stabilizer consist of two segments, please select for each segment the group of flaps 1 and enter in the input field 'Group of flaps / Functional Description' the text 'Elevator'.



We proceed in the same way for the wing, use for the left aileron e.g. the group of flaps 13 and enter the functional description 'Aileron left'. The right aileron gets the group number 10 and the functional description 'Aileron right'.

Please select the folder 'Total-Polars Computation' and the subfolder 'Flap Computations'. First we want to perform a polars computation for the elevator control. Therefore select the horizontal stabilizer as shown below.



In the list shown below one can enter a group of flaps, the elevator has the group number 1. So we enter in the top line '1' in column 'Grp. Flaps'. The flaps functional description is filled in automatically.
If one does not know the number of the group of flaps, one can drag and drop the flap from the 2D-graphic into the list. Therefore click the flap in the 2D-graphic with the right mouse button, keep mouse button pressed and pull the flap into the list. Lines with group number '0' are ignored.



Next we define the flap deflection angles for the elevator. The elevator shall be deflected from -10° to +10°. In the input field 'min. Angle[°]' we enter '-10' and in the field 'max. Angle[°]' we enter '10'. Next we have to define the number of steps in which the program shall solve the entered angles. We enter '20' into the input field 'Number of steps'. The deflection angles of the elevator will now be incremented by 1°-steps, so that we finally get 20 entries in our polars table / graphic. As a last resort before starting the polars computation, the program needs the information, if the angle of attack, the centre of gravity or the CL shall be fixed. Default is the centre of gravity, the values for centre of gravity and CL are taken from the folder 'Design Computation'. One has to control, that reasonable values are available, otherwise one should first perform a design computation.



The polars computation can now be started by click on the button 'Start Computations'. First a window will pop up, in which we can enter a remark about the computation, e.g. 'Test Horizontal Stabilizer'. After confirming the entry with clicking on button 'OK', the polars computation will be started.
The program first sets all flaps to 0°. The originally settings of the flaps are backed up, they will be restored after computation. In a loop the elevator is set step by step from +10° to -10° in 1° decrements.

After the computations one can examine the polars. See: 17.3: Viewing Polars as Table or Graphic

Computations with multiple Group of Flaps:
Up to now, we have only used one line of the list. It exists the opportunity to enter multiple groups of flaps, which is useful e.g. for computations with plain flaps. One can equip the both inner segments of the wing of the ASK21 with flaps. These flaps would form an own group of flaps with description.
See picture below:
The plain flaps are group of flaps 19 and the deflection angle is fixed to 5°. The computation is started like described above.



Vorherige Seite Inhaltsverzeichnis Nächste Seite