This tutorial is about tuning Engine Performance, but the end result is to make our Flight Simulator aircraft perform as the actual aircraft did. There are factors in the simulator that we cannot control and there are also non-linear factors and interactions between parts of the aircraft that are not captured by a purely mathematical model.

So far we have been discussing Engine Output in Horsepower and I believe we have proven that we can tune that as precisely as we have patience for. One factor that we have not taken into account at all is the Engine's Exhaust Thrust which is shown at the bottom of the Jumo 213A graph.

This is usually on the order of several hundred pounds of extra thrust added to that of the propeller and is non trivial.

As an illustration, we can take the case of the Japanese Type Zero Fighter. The A6M3 Model 32 and A6M5 Model 52 have almost exactly the same airframe but for wing tips and minor details. The Engine is the same. The Model 32 uses an exhaust collector manifold while the Model 52 uses ejector stacks for exhaust thrust. The maximum speed of the Model 32 is about 335 mph. The maximum speed of the Model 52 is 350 mph or around 15 mph higher.

I don't know of a "correct" way to simulate exhaust thrust which has its greatest effect at high speeds.

The two ways I can see to do this are:

1. Decrease Airframe Drag which would have its greatest effect at high speeds.

2. Increase Engine Power.

In this case I chose to increase Engine Power.

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