Instructions for Spring Solutions ADF/VOR Trainer

Instructions for Spring Solutions ADF/VOR Trainer

Version 3.6


This program simulates the movement of an aeroplane and some
instruments. You can program wind, position, control the movement of the aeroplane and change the way your track is displayed. If you want to practice intercepts, then it can also display the line that you should be intercepting if you want.

Note that for all text-entry fields prior to version 3.4, you had to press enter after typing in the updated value for it to be noticed. Now, the program notices every single character change and applies the new value after each key you press.


This page controls the simulated movement of the aeroplane. When you want to turn, there are four ways to do it. You can:

Turning Choose a rate 1 turn left or rate 1 turn right to specify a rated turn. Choose "Turn set by AOB" to specify the turn by angle of bank.
Angle of bank Specify your desired angle of bank. Note that the rate and radius of turn depends on your air speed as well as your angle of bank. The computation used is accurate, but valid only for level flight. You may find it instructive to increase the air speed and see what effect that has on the radius of turn for a given angle of bank.

The angle of bank is ignored if the "Turning" choice is set to a rate 1 turn left or right.

Air speed Specify your air speed in knots.
time scale If you want the simulation to run in real time, then enter a value of precisely 1. If you want to slow things down, enter a number between zero and 1. If you want to speed things up so you don't have to wait so long for something to happen, enter a number greater than one. For example, by entering a value of 10, for every second you experience, the simulation will move forwards 10 seconds. To see the effects of changing the time scale, you could turn on the stopwatch.
updates per second This specifies the number of times per second that the screen will be refreshed. Increasing this number will make the animation smoother, but may slow down your computer.
Pause Select the checkbox to stop the movement of the aeroplane. This holds simulated time still so you have time to think about things if required. Deselect the checkbox to continue the movement.
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Wind speed Allows you to specify the speed of the wind.
Wind direction Allows you to specify the direction that the wind is coming from.
Choose random wind Press this button to have the program randomly generate a wind setting.
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This page is used to select a line that you should intercept using your instruments. An intercept is always expressed in this program as the radial that should be intercepted and whether you should be inbound or outbound on that radial. To reduce confusion, the heading you would have in nil wind conditions is also displayed.

For example, if you were heading 090 inbound then you should be to the west, on the 270 radial.

Display Intercept Select the checkbox to draw the line to be intercepted.
Intercept specification Enter the radial to be intercepted and whether this is inbound or outbound. The heading indicator will show the heading you would have when on that radial and inbound/outbound. This will be the same as the radial when outbound and 180 degrees away from the radial direction when inbound.
Difficulty of current intercept This shows an estimate of how easy or hard this intercept is. This estimation of the difficulty is based mostly on the angle of intercept required to reach your desired track. If you can get onto your desired track using an intercept angle of 30 degrees or less, and if you start in the right "half" of the sky for being inbound or outbound then it is deemed to be easy. Unless you are very close to the station in which case things happen quickly and so it is then deemed to be of moderate difficulty.
Difficulty for random intercepts When producing random intercepts, this drop-down allows you to choose the difficulty level that you are willing to accept. Anyone who is new to learning how to do intercepts should stick to easy ones until they've got the hang of them.
Choose random intercept Press this button for the program to generate an intercept for you to practice.
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You can use this page both to find out your current position and set it.

Enter radial This allows you to change the radial that you are located on.
Enter distance By entering a value, you can change your distance from the station without changing the radial that you are on.
Enter heading Instead of flying the aeroplane to change the heading, you can "cheat" by directly entering a new heading here. This does not change your position.
Allow position by mouse When selected, mouse clicks in the track picture will change your location. This will either set the position of the aeroplane (standard view) or the location of the station (moving map view).
Get Current Position Press this button for the text fields to be filled with the current radial, distance and heading.
Choose random position Press this button to relocate the aeroplane at a random position somewhere within the visible area of the display.
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VOR OBS This lets you enter the Omni Bearing Selector for the VOR.
Instrument This drop-down lets you select which instrument is shown to the right of the direction indicator. The options are ADF, VOR and a "GPS" type display.
Add to DI This allows you to choose instruments to be displayed on top of the direction indicator. Your options are as follows:
ADF This superimposes the ADF needle onto the DI, making it an RMI.
Stopwatch This shows a stopwatch which can be reset to zero at any time by pressing the Reset button. Note that this shows simulated time so that if you change the time scale then you will see the stopwatch time change at a different rate.
GPS distance This displays the distance from the station as it would be measured by a GPS. This is not a DME because it does not take altitude into consideration. However, if you want to practice holds or approaches, the GPS distance may suffice.
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This page controls the display of the track made by the aeroplane.

Display size This sets the scale of the track diagram by specifying the distance across the width (and height) of the picture in nautical miles. If the aeroplane is off-screen because it is too far away, then increase this number to shrink the picture.
Display track When selected, the track picture will be displayed. Once a student understands things a little better, he/she can try intercepts or other exercises with the picture hidden.
Map type This allows the choice of the way the display is drawn. Your options are as follows:
Static map This provides a map that does not change, with the radio station fixed at the centre while the aeroplane moves around it. As the aeroplane turns, the drawing of the aeroplane will be seen to turn and nothing else.
Moving map This provides a view in which the aeroplane is fixed at the centre of the screen while everything else moves around it. So, for example, the radio station will appear to move. When the aeroplane turns, the picture shows no movement of the aeroplane, but everything else in the picture will change accordingly.
Show north When selected, this will display an arrow from the radio station pointing north. This is useful for the moving map display when it may become confusing which direction is which. Of course, determining which direction is which is an exercise that should be handled by looking at the instruments, and so you may wish to turn this off.
Erase track Pressing this erases the record of the track made by the aeroplane.
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Known Bugs

There are no known bugs.


The author retains full copyright to the software and grants a free license for personal, non-commercial use. You may not redistribute the software in any form apart from providing a link to For redistribution or commercial use, contact the author.

If you have any comments, let me know.

Paul Robinson

Last update: September 12th, 2009