Architecture

PFC is a custom flight model layered on top of Enfusion's rigid-body simulation. The engine integrates the rigid body; PFC's scripts apply per-surface lift/drag and thrust via Physics.ApplyImpulseAt, plus angular-rate damping to keep the airframe stable.

Built on Wheeled_Base.et

The reference Cessna inherits the vanilla Wheeled_Base.et. The wheeled simulation is neutralized - only the suspension and wheel-bone visuals remain - so the inherited SCR_CarControllerComponent still handles ownership transfer and grants the input context (CarContext) that the flight controller reads.

Flying on a car base has sharp edges

The vanilla car controls share keys with flight: the handbrake stays engaged because CarThrust is 0, CarBrake is on S (= pitch back), and CarShift is on Q/E (= yaw). PFC neutralizes all of these every frame. See Prefab Setup for the full list of wheeled-sim settings that must be right, and Input & Controls for the key de-conflicting.

Components

Component	Responsibility
PFC_FlightModel	The flight model. Builds aero surfaces, applies per-surface lift/drag + thrust impulses, spools engine RPM, angular damping, wind/gusts, publishes instrument signals, debug draw. Runs on owner + server.
PFC_FlightController	Reads pilot input from CarContext, smooths it (slew-rate limited), exposes pitch/roll/yaw/throttle to the flight model, relays input to the server, and injects ground steering.
PFC_NwkMovementComponent	Replicates owner→proxy movement state (transform + velocity) so remote viewers see smooth motion.
PFC_AeroSurface	A single aerodynamic panel: given local airflow + air density, returns the lift+drag force. Pure math, no engine state.
PFC_AeroSurfaceConfig	Runtime aero parameters for one surface (chord, span, lift slope, stall, etc.).
PFC_AeroSurfaceDef	The editable surface definition placed in the prefab; builds a config and resolves its axes, handles X-mirroring.
PFC_PilotUtil	Helper to determine the local active pilot.

Execution flow (per simulation tick)

EOnSimulate (owner / server only)
 ├─ PFC_FlightController.PollInput()      → smoothed pitch/roll/yaw/throttle
 ├─ set each surface's flap deflection from its control axis
 ├─ guard against NaN / teleport-spike velocity (reset or clamp)
 ├─ RefreshWind()                          → steady wind + gradient + gusts
 ├─ for each surface: CalculateForce() → ApplyImpulseAt(surfacePos, force·dt)
 ├─ fuselage drag impulse
 ├─ spool engine RPM, apply thrust impulse at the centre of mass
 ├─ speed-scaled angular-rate damping
 ├─ compute normal G-load
 └─ (owner, once registered) UpdateSignals() → instrument MP signals

EOnFrame (all peers)
 ├─ PFC_FlightController.ApplyGroundSteering()  (also zeroes CarThrust/CarBrake/CarShift)
 ├─ UpdatePropellerVisuals()   (owner/server from local RPM; proxies from replicated RPM signal)
 └─ DrawDebug()                (F6)

Authority model

• EOnSimulate returns immediately on a peer that is neither the owner nor the server, so the aerodynamic simulation only ever runs on the authoritative peer.
• The owner publishes instrument signals; they replicate to everyone for free.
• Proxies receive replicated movement via PFC_NwkMovementComponent and drive their own propeller spin from the replicated, normalized engine-RPM signal.
• OnTicksOnRemoteProxy() returns true so the component keeps ticking on proxies (needed for the local visual updates).

See Networking & MP for the replication and signal details, including the compression and boot-window pitfalls.