Four Forces

The Four Forces tool shows a 3D aircraft with four labelled force arrows — lift, weight, thrust, and drag — that grow and shrink in real time as you adjust the controls. Two gauges show airspeed and rate of climb or descent.

There are two sliders:

• Power — increases or decreases engine thrust
• Attitude — pitches the aircraft nose up or down

As you move the sliders, the arrows and gauges update to show the new balance of forces and where the aircraft is headed.

For instructors

Use it during ground briefings to show concepts that are otherwise hard to describe:

• Straight and level flight — demonstrate that lift equals weight and thrust equals drag, and how changing one force disturbs the balance
• Climbing and descending — show how excess thrust produces a climb, and how reducing power causes a descent even with the same attitude
• The stall — if your aircraft’s stall speed is configured, the tool shows lift collapsing and the nose dropping when speed falls too low
• Turns — enable the bank control to show how lift must increase to maintain altitude in a turn, and how total drag rises as a result

The tool works in any modern browser — a laptop or tablet connected to a projector is all you need.

For trainees

Try it yourself between lessons to build intuition:

1. Set full power and watch the aircraft accelerate and climb
2. Reduce power gradually — notice how the rate of climb decreases, and what throttle setting holds level flight
3. Raise the nose at low speed and observe how the drag arrow grows relative to thrust
4. Lower the nose and add power — watch how quickly speed and lift recover

Experimenting here costs nothing and reinforces what you cover in the air.

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For source code and developer documentation, see open-aviation-solutions.github.io/open-aviation-components.