Planes

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A plane is an engine, wings and control surfaces on a body. PlaneSettings describes it and PhysicsPlane flies it. Thrust, lift and drag are real forces. The control surfaces and the tail’s pull back into the airflow act on the spin, and fade with airspeed, so a plane too slow to fly cannot be steered and a stalled one drops its nose.

There is no sandbox command for planes yet, and I haven’t tuned the defaults in game.

Flying it

The throttle stays where you leave it. The stick returns to centre when you let go. With the stick centred, the wings level themselves at rollLevel.

The engine only runs with a player in the seat. Getting out closes the throttle and the plane glides.

Wheels and runways

A plane made with new GroupVehicle(new PlaneSettings(), ...) has no wheels and has to sit on its blocks. For a runway, start from a VehicleSettings with wheels and add the plane:

VehicleSettings gear = new VehicleSettings();
gear.engineTorque = 0f;            // the propeller moves it, not the wheels
gear.wheel(4f, 0.5f, 5f, true);    // nose or front pair
gear.wheel(0f, 0.5f, 5f, true);
gear.wheel(4f, 0.5f, 1f, false);
gear.wheel(0f, 0.5f, 1f, false);
GroupVehicle plane = new GroupVehicle(gear, 2f, 1.5f, 3f).plane(new PlaneSettings());

On a plane the wheels never get throttle. They roll free, steer with A and D, and brake when the throttle is closed and V is held. Give them no engine torque.

PlaneSettings

Forces are per tonne or a share of the weight, so a stone plane flies like a wooden one of the same shape.

How it works

Each tick, for the coming step:

1. Thrust along the nose: thrust × tonnes × throttle.
2. Lift, only with the air coming from ahead. The angle of attack is measured between the nose and the motion. The lift coefficient rises in a straight line from 0 to 1 at stallAngle (counting incidence), and past it falls off, but never below 0.3. Lift is weight × (airspeed / stallSpeed)² × coefficient, clamped to maxLoad × weight, and acts across the airflow over the wings.
3. Drag against the motion: the airframe’s, thrust × tonnes × (speed / topSpeed)², plus induced drag |lift × coefficient| × inducedDrag. Never more than stops it in a step.
4. Side drag against sideslip.
5. Controls and stability, faded by (airspeed / controlSpeed)² up to 1. Pitch and roll come from the stick, rudder from the roll input. The tail turns the nose toward the direction of motion at stability. With the stick centred, a roll toward level is added. The result is blended onto the body’s spin at attitudeResponse times that fade.

A plane sitting still has no control at all. It needs speed before the stick does anything, which is why it needs a runway.

Stalls

stalled() is true when the angle of attack plus incidence is past stallAngle and the airspeed is above 1 m/s. Past the stall the wings give less lift, and the tail keeps pulling the nose into the airflow, so a stalled plane drops its nose and picks up speed. Use stalled() and angleOfAttack() for a stall warning.

PhysicsPlane