If your Microjet is approx. 4 meter long/length IRL, then on the grid^ one square means approx: 0.37*0.37m.
Should be calculated in meters from origo:
Approx.:
Nose wheel touch (lowest) point: 1.776, -0.74, 0.0
Main wheel touch points: -0.18, -0.66 -0.5? and -0.18, -0.66, 0.5?
I think the most important part is:
Lowered wheels touch points, should be out of (under) the bounding box.
Lowest ends of segments nodes of wheel touch points must be loll out from the box (box of collision model)