I know the Gnat, but not the answer! Soz....
Dan

The Folland Gnat was used by the Red Arrows display team for several years. It's a fine little aircraft.

You can change the track of the main gear by tweaking the Lateral Position in Aircraft.cfg. This is defined under the [contact_points] header. Here's an example from the default Lear45. The entries in Bold type are the Lateral Position. Note that the corresponding point.0 entry is 0.00 as it's the nosewheel. point.1 & point.2 are usually the main gear.

[contact_points]
point.0=1, -11.17,   0.00, -4.42, 1181.1, 0, 0.6349, 46.8, 0.4197, 2.5, 0.5878, 10.0, 10.0, 0, 0.0, 0.0
point.1=1, -37.25,  -4.75, -4.92, 1574.8, 1, 0.6349,  0.0, 0.4798, 2.5, 0.5456,  9.0,  9.0, 2, 0.0, 0.0
point.2=1, -37.25,   4.75, -4.92, 1574.8, 2, 0.6349,  0.0, 0.4798, 2.5, 0.5456,  9.0,  9.0, 3, 0.0, 0.0

thanks much  8)

got word over at CBFS that the designer is planing to update this particular model to 2k4 standards and that theres going to be a new build by somone else, which I may be involved in on a limited scale  8)