Skin tension

In the Skin tension window you can define the parameters from the 5th section of the lep file.

Raw data:

*************************************************************
*           5. SKIN TENSION                                 *
*************************************************************
Extrados
0.              0.      0.              0.
7.5             1.3     10.             1.33
15.             2.5     20.             2.5
80.             2.5     80.             2.5
90.             1.33    90.             1.33
100.            0.0     100.            0.
0.0114
1000    1.0

The tension of the top surface and lower surface panels is achieved by creating tapers in the panels. The program allows you to define “over-wides” in 6 points along the edge of the panels. The transition between basis points of overwide is linear.

Top dist LE

Distance from Leading Edge in [% chord]

Top widening

Over widening in [% chord]

Bott dist TE

Distance from Trailing Edge in [% chord]

Bott widening

Over widening in [% chord]

Strain mini ribs

The background here is to deal with the extension of the canvas.

In case of doubt put the default value of 0.0114

Num Points and Coeff

There are two different inperpretations of these parameters. Recommended for all designs is the setup described below.

Set the parameters of the line to the values:

1000 1.0

First number “1000” is only a convention than signifies force the program to use maximal precision, reformating panels to achieve accuraccy better than 0.1 mm (lengths differences beetween rib and panels located at left and right).

Second number is a coefficient between 0.0 and 1.0 that sets the intensity of the correction. If coefficient is set to “0.0” then no correction applies. If the coefficient is set to “1.0” the accuracy is maximal, aprox < 0.01 mm.

A more detailed description you can find here Laboratori d'envol website.