Weight and Balance

When was the last time you did a weight and balance? Are you absolutely sure that your c.g. will be within limits 4 hours into the flight?

WandB is a tk program to draw a W and B plot. The parameters for the airplane are entered into a graphical window, and then you can experiment with various configurations, fuel loads etc. to see how your total weight and C.G. location change. Fuel is specified with a slider so the effect of fuel burn on CG may be observed.


WandB [-D datafile-directory] [config-name]

The config files are stored in datafile-directory (the user's home directory by default) and the string .wnb is appended to the config name. If run without a config name, WandB will bring up the data entry window where you can enter the W and B information and then save it as a config file. Some sample .wnb files are provided.

The main window

You enter the weights of the front (and rear, if applicable) pax, the baggage; and move the fuel slider. The c.g. location and total weight will be displayed by the red dot. It is also displayed on the line at the bottom of the window.

Entering (or editing) an airplane's parameters

For a single-seat airplane (or a two-seat side-by-side one, like a 152 or Grob 115) the rear seat station can be disabled. That's the red button to the right of the "Rear pax" data entry fields.

Obtaining WandB

Complete source code (which is also the executable) is available. This is a gzipped tar archive.

To run WandB you must have tcl/tk installed. tcl-7.4 and tk-4.0 are required, but tcl-7.5 and tk-4.1 are strongly recommended. Source code is freely available; and pre-compiled binaries for Unix systems may be purchased. MS-Windows binaries may be obtained from ftp.sunlabs.com. Mac executables are also available.

No warranty of any sort is offered! I wrote the program for myself, and am distributing it in the hope that someone else might find it useful. For entertainment purposes only! Batteries not included.


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