Engines

An <Engine> drives one engine's nozzle: its petals open and close with the throttle, and its gimbal turns with the stick and the pedals. What it can do is read off the model.

<Airframe object={gltf.scene} animations={gltf.animations}>
  <Engine side="left">
    <Afterburner preset="afterburner" direction={[0, 0, -1]} />
  </Engine>
  <Engine side="right">
    <Afterburner preset="afterburner" direction={[0, 0, -1]} />
  </Engine>
</Airframe>

side picks the engine. Left out, an engine takes every nozzle part there is, for a single-engined aircraft.

The afterburner on itCopy Anchor Link

An <Afterburner> inside an <Engine> sits on the engine's exhaust anchor, turns with its nozzle and runs at its throttle. Its position and direction are then in the anchor's frame. See Engines in the core docs.

The throttleCopy Anchor Link

Each engine's throttle is the flight's by default. Give it its own:

// The left engine flamed out
<Engine side="left" throttle={() => 0} />

The petals follow a schedule: open at idle (0.45 of their travel), closed down at military power (0), wide open in full reheat (1). Change it with nozzle:

<Engine nozzle={{ nozzleIdle: 0.6, nozzleReheat: 0.9 }} />

A model that opens its nozzle with a clip, as ANIM_Nozzle_L_Open, has the clip scrubbed by the same schedule.

Thrust vectoringCopy Anchor Link

A model with a gimbal, nozzle parts of kind nozzle_pitch and nozzle_yaw, vectors by default. Nose up wants the exhaust up, so the stick aft turns it up; the right pedal turns it right.

• Limits are the gimbal parts' own. Cap them lower with numbers, in degrees: vectoring={{ pitch: 2, yaw: 5 }}.
• A round limit: when a gimbal part's extras say limit_shape: "ellipse", pitch and yaw share one round limit, as an axisymmetric nozzle's do. Full stick back and full pedal together reach the circle, not its corner.
• Off: vectoring={false} holds the nozzle straight.
• Its own command: pitch and yaw give what it vectors for, −1 to 1, the stick's and the pedals' by default.
• Its rate: rate, in degrees a second. The rig's for nozzle_pitch and nozzle_yaw is 40.

A model with no gimbalCopy Anchor Link

Give it vectoring and an exhaust anchor, and pivots are put in at the exhaust: a yaw pivot, a pitch pivot inside it, and a mount inside that, which the engine's anchor becomes. Whatever sits on the anchor, the afterburner included, turns with them. The limits are 10° each way unless given, in one round limit.

<Engine vectoring={{ pitch: 15, yaw: 15 }}>
  <Afterburner />
</Engine>

Where it pointsCopy Anchor Link

onVector is called in the frame the nozzle turns, with where the exhaust points, in degrees up and right of straight aft:

<Engine onVector={(pitch_deg, yaw_deg) => gauge.set(pitch_deg, yaw_deg)} />

useEngine() inside an engine gives the Engine itself: its parts, its anchor, its vectoring limits and shape, its extras, and pitchDeg and yawDeg as they are now.

With <ControlSurfaces>Copy Anchor Link

It makes an <Engine> for each side with a nozzle or an exhaust anchor. Its engine prop is given to each, and exhaust is put inside each:

<ControlSurfaces
  object={gltf.scene}
  animations={gltf.animations}
  engine={{ vectoring: { pitch: 3 } }}
  exhaust={<Afterburner preset="afterburner" direction={[0, 0, -1]} />}
/>

See it on the thrust vectoring example.

Next, how a model says what moves.