[Spaceships] Calculating Climb Rate

[Anaraxes]

The aircraft's thrust has to counter drag to keep the plane in the air. Excess thrust can be used to climb. Divide that by the weight of the plane. ((T - D) / W).

The complexity really kicks in if you want an accurate answer to pop out of the calculations. For real aircraft, "thrust" isn't a constant you find on a spec sheet. It varies with the speed of the plane and with altitude (and other atmosphere conditions like temperature and humidity). Drag also varies with altitude, and with speed, especially once you start talking transonic and supersonic speeds. The way prop planes change with these factors varies from turboprops which vary from jets (and presumably from other high-tech sources of thrust in Spaceships).

You could also look at it from the point of view of energy. Subtract drag from the power output of the engine, and then use that power to add potential energy in the form of altitude. But again, drag and how much power you need to counter it while maintaining lift is going to vary how much excess power you have to work with.