Copyright 2001-2011 by Paul R. Jorgenson

SGS 2-33 Weight and Balance Calculator Program

by Paul R. Jorgenson -KE7HR

The Schweizer SGS 2-33 is a very popular two place trainer glider. It is also used extensively for giving the general public scenic rides. As a commercial glider pilot, I wanted to have current weight and balance information readily available to me for planning purposes. Using this program I can assure myself that I am operating in a safe and legal manner, with respect to the weight and balance limits of the aircraft.

Students that are learning to fly the aircraft can also gain valuable insight into the mechanics of glider 'weight and balance' issues without having to resort to manual calculations. The speed and ease with which students can visualize different loading conditions is very valuable.

The screen shot above shows a normally loaded glider.

As you can see on the form, there are boxes of information that look much like the weight and balance form in the SGS 2-33 manual. The sailplane registration number, empty weight, and empty arm, can be retrived by clicking a button in the 'Pick a specific glider' box. The boxes for Front Pilot Weight, Rear Pilot Weight, and Ballast are filled in by typing the number. The arm for these three things is fixed in the program, just as in the manual form. As the numbers are typed in, the program automatically does the calculation and displays the results below the respective column. The answer boxes are color coded. When they are green, the results are within the recommended limit. If they are red, then an out of limits condition exhists.

See the example below for an over gross weight condition.

Since the maximum gross weight has been exceeded in this calculation, the weight answer box is red. There is also a red warning box to point out that there is an Out of Limits condition. The pilot now has to decide to reduce the weight or possibly try another glider. A different glider button in the 'Pick a specific glider' box can be clicked to see the results without having to enter the pilot weights again. The calculation is automatic.

The screen shot below shows a condition where the center of gravity limits have been exceeded.

This lightweight pilot now has to decide to either add ballast or try another glider. The addition of weight (or subtraction, as well) is easily done by clicking the box where the desired number is to go and then type it in. The calculation is done automatically again.

Using this method, the placard weights can be checked. Just enter what the placard weights into the form and watch the calculation. If the placard is correct, the answer boxes should be green. By trying different weights, the pilot can watch the effects which will help in understanding the glider performance.

The buttons in the 'Pick a specific glider' box are set when the program starts by a data file. The data file is a text file that simply holds the registration number, the empty weight, and empty arm. This file is easily edited to be specific to any SGS 2-33 that you may fly - you are NOT limited to those shown here. The only limiting factor is that there are only 5 buttons. If you fly less than 5 different 2-33's, then those positions in the data file can be left blank. Those buttons will be blank and do nothing when clicked.

Example of the data file when opened with WordPad. It is easily edited.

This program is also fully accessable by standard Windows keyboard shortcuts - no mouse is required. Any shortcut is accessed by holding down the Alt key and the underlined letter or number on the form which you wish to use. For example, the number 4 glider (N1232S on the screen shots) information is to be used. Hold down the Alt key and press the 4 key. The information from the fourth glider is put into the Empty Weight boxes just as if the button was clicked by the mouse. If the desired shortcut is a data entry box, the Front Pilot Weight for example, then by holding down the Alt key and pressing the F key, the desired data entry box now has the flashing cursor. If there was information in the data entry box, it will be highlighted in blue. This means that you can just type in new data without having to use the delete key or the backspace. The Tab key works here just like all other Windows programs - pressing the Tab moves forward through the form, pressing the Shift key and the Tab key at the same time moves backward through the form.

If a printer is attached to the computer, the Print button at the bottom of the form will send an image of the form to the printer. If you only have a black and white printer, the form will not print in color.

The Clear button clears all of the boxes on the form, just as they are when the program starts. The Exit button closes the program.

SGS233WB is available from Paul R. Jorgenson via email delivery.
A Shareware fee of $25 is suggested and can be made via PayPal.

Please email ke7hr at for details on how you can get your copy today.
Replace the 'at' with the @. It is my attempt to stop email robot spam.

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Last updated 18 November 2011