How RFM works

Vanilla Reforger helicopters run on a simplified flight model. RFM turns that off and replaces it with a physics model. It simulates every blade of every rotor moving through the air, the engines and gearbox turning them, the fuselage and tail surfaces, the gear touching the ground, and the aircraft's weight and balance.

The normal Arma physics body is still there. RFM just pushes it around with the forces it works out.

The components

The RFM components on an aircraft in the Workbench inspector.

Component	Required?	What it does
RFM_FlightComponent	Always	The flight model itself. Almost everything in these docs lives on this one.
RFM_NetworkReplicationComponent	For multiplayer	Sends the pilot's motion to the server and everyone else.
RFM_VisualsComponent	Optional	Exact rotor spin and mast lean, gauges, sound loops, rotor blur and camera vibration.
RFM_ComponentDamageBridgeComponent	Optional	Turns normal hit-zone damage into engine, rotor and gearbox failures.
RFM_StoresMassComponent	Armed aircraft only	Weapon and ammo mass, drag and recoil.

The flight topology

A Flight Topology Config in the inspector: one power group, two rotor units and a wake link.

The most important field on the Flight component is Flight Topology Config. It's the mechanical layout of the aircraft: which engines drive which shafts, and which rotors sit on those shafts. This is the Mi-8's:

Power group "drivetrain.main"
   engine.left  ──freewheel──┐
                             ├──► combining gearbox ──► shaft.main (1 : 1)     ──► rotor.main  (lift)
   engine.right ──freewheel──┘                     └──► shaft.tail (× 5.854)  ──► rotor.tail  (anti-torque)

Wake link:  rotor.main ──downwash──► rotor.tail

What the pieces are:

• A power group is a set of engines geared together. Most aircraft only have one.
• A source is one engine.
• An output branch is a shaft coming off the gearbox, with its speed ratio.
• A rotor unit is one rotor. That's its blades, where the hub is, which shaft drives it, and how the pilot's controls get to it.
• A wake link means "this rotor's downwash blows through that rotor".

Everything gets hooked together by text IDs like "rotor.main" or "shaft.tail". The order things sit in a list doesn't matter, only the IDs do. They're case-sensitive, so watch your capitals.

Everything else on the Flight component covers the whole aircraft: mass and balance, ground contact, fuselage aerodynamics, controls and input.