Prefab Setup

The reference airframe is Prefabs/Vehicles/Cessna172.et. This page walks its structure - the same recipe you'll follow to build a variant.

Inheritance & components

The prefab inherits the vanilla Wheeled_Base.et (62F416029692CE40) and adds:

Vehicle : Wheeled_Base.et
├── MeshObject                 → Models/Cessna172.xob
├── PFC_FlightController        (input smoothing, ground steering)
└── PFC_FlightModel             (the flight model + aero surface defs)
    └── m_aSurfaceDefs[]         (Wing, Aileron, Elevator, Rudder, ...)

Aero surface definitions

Surfaces live in PFC_FlightModel.m_aSurfaceDefs as PFC_AeroSurfaceDef entries. Set m_bMirror to spawn an X-mirrored counterpart automatically (the left/right wing, elevator halves, etc.); ailerons flip their deflection sign on the mirrored side so they act differentially.

The Cessna's main wing, for example:

PFC_AeroSurfaceDef "Wing" {
  m_vPosition 2.75 2 0.5      // local position (m); mirror negates X
  m_vRotation 0 0 0           // yaw pitch roll (deg) → resolves normal + forward axes
  m_bMirror 1
  m_iControlAxis NONE         // fixed surface
  m_fChord 1.47
  m_fSpan 5.5
  m_fLiftSlope 5.7
  m_fStallAngleHigh 16
  m_fStallAngleLow -16
  m_fAspectRatioOverride 7.4  // use the whole-wing AR for induced drag, not the per-panel value
}

See the Reference for every field. Use F6 → Prop Flight → Debug draw to see each surface's position, extent, and live force while tuning.

Aspect-ratio override

When a wing is split into several panels, the per-panel span/chord gives an unrealistically low aspect ratio and far too much induced drag. Set m_fAspectRatioOverride to the real full-wing AR so induced drag is computed correctly.

Neutralizing the wheeled sim

Flying on a car base only works if the wheeled simulation is properly defanged. These are the settings that matter:

• Power/torque ~0 - the car engine must not drive the wheels; all motion comes from the flight model.
• HasHandbrake 0 + low BrakeTorque - a flight model on Wheeled_Base otherwise sits stuck on the runway, because the handbrake stays engaged while CarThrust is 0. This is a handbrake problem, not a grip/friction problem.
• Reuse the vanilla wheeled-sim template GUIDs - the wheeled simulation's axle/suspension/wheel entries must reuse the vanilla template's GUIDs and override the wheels by name (Wheel_L01/R01/L02/R02). Giving them fresh GUIDs is a known cause of Game-Master crashes and a stiff/unflyable airframe.
• Runtime key zeroing (CarThrust/CarBrake/CarShift) is handled in script - see Input & Controls.

Procedural propeller animation

Configs/ProcAnims/PFC_Propeller.pap (+ .siga) drives the propeller bone from the PropellerAngle_1 signal that the flight model integrates from RPM each frame. Bind your prop bone to it in the model's procedural-animation setup.