P-51B

There is a T/W rule right now for turbines. The new rules, that are in abeyance, have no T/W rule. It was designed to keep the speed below 200 mph. It was that or a speed limiter that are required in the old rules.

With the new rules, as they stand right now, there is a 200 mph limit, but no way to enforce it. No T/W and no speed limiter. Some of the jets will not exceed 200, period. The guys that fly those planes want additional thrust to add to the manuverability of the plane.

This is the issue stopping implementation of the new rules, at the moment.

The T/W rule calls for a .9 to 1 T/W ratio. Unlike other engines, the thrust of a turbine can be adjusted to meet the rule.

The airframes for the jets generally have a VNE (velocity not to exceed) that the jet guys pretty well follow. The prop planes have recommended engine ranges from the manufacturer, but, as you can see, many people exceed them. There is no rule keeping the non-turbine pilot from bolting on whatever he wants or flying as fast as he can.