Radar Simulation Help

Left-hand Display

compass

The left side of the simulation combines a Lightning attitude display and a compass into a single display (just to save space in the simulation). Above the compass rose there is a digital display of the fighter heading. A small gold-coloured triangle shows the target heading; this was often provided by the ground controller and could be set on the compass display as an aide-memoire to the pilot.

The controls on this display are as follows:

left = Turn left (toggles 45/60 degrees of bank). Keyboard shortcut: " ← "
right = Turn right. Keyboard shortcut: " → "
straight = Roll out. Keyboard shortcut: spacebar
auto = Auto, i.e. roll to hold target at current azimuth (shows "*" after fighter heading). Keyboard shortcut: A. This is just a convenient "fudge" for the simulation - to hold the target on the nose or at the current azimuth.

Right-hand Display

bscope bscope-view

The right side of the simulation represents the radar "b-scope" (first image above). This shows the target position in terms of range on the vertical axis and azimuth on the horizontal axis. By "azimuth" I mean the angle of the target to the left or right of the fighter's nose. At longer ranges this display is a reasonably undistorted view of the airspace ahead of the fighter. However, at shorter ranges the display is increasingly distorted. Compare the 2 images above; the image on the right shows an overhead view of the airspace being searched by the radar, while the image on the left shows how this block of airspace is presented to the pilot on the b-scope. At short range, the airspace is stretched out to fill the width of the b-scope display.

The single control on this display is:

range= Toggle range scale. Keyboard shortcut: R

Game Play

The fighter always starts on a heading of north. The target heading can be 90, 120, 150, 180, 210, 240 or 270 degrees - i.e. the target is always coming towards the fighter on a heading that is a multiple of 30 degrees. The target heading is shown on a gold-coloured "heading bug" on the compass. Fighter speed is 0.9 Mach and the target speed is slightly slower at 0.8 M.

The game is to manoeuvre the fighter to turn in behind the target and roll out between 1.5 and 2 miles astern. This allows the pilot to identify the target while keeping it within missile range.


Key Concepts

Although we know the heading of the target (from a ground-control-intercept radar), there is still some thinking to do before we can plan our moves.

The table below shows the ideal track down the radar display for each target heading.

Tgt HeadingRangeAzimuth
±902033
1531
1026
40key to turn
±1202518
2016
1513
106
80
6.25-8key to turn
±150253
220
20-1
15-6
10-16
9-22key to turn
1802520
2024
1532
1240key to turn

When a target moves down the "ideal" track on the radar, the fighter can just wait until the target reaches the "key" range and azimuth - and then start a turn at 45 degrees of bank towards the target, hopefully rolling out at about 1.5 to 2 miles astern.

If the target is not "ideal", it will be considered either "slack" or "tight". A "slack" target is one that has / will cross the nose at a greater range than the ideal. On the other hand a "tight" target will either cross the nose too close, or be on a "collision" course with the fighter, or may even be on a course to pass behind the fighter.

There are many rules-of-thumb for handling "non-ideal" geometries but a full exposition would exceed the purpose of this demonstration / game. Suffice it to say here that a "slack" intercept can be tightened-up by turning towards a point ahead of the target, "leading" the target - and a "tight" intercept can be slackened by pointing behind the target, "lagging" the target. In extremis for a very tight situation, put the target right to the edge of the radar (at 40 degrees azimuth) and hold it there.