Rotorcraft Flight Model (RFM) is a physics framework that allows accurate representation of the physical flight characteristics of real-world helicopters.
This is a public TEST build. It flies, but there will be bugs, and I'm one person, so I can't find them all on my own. If something breaks, please report it (see the bottom).
Instead of vanilla's scripted handling, RFM flies off the forces the aircraft actually makes. Every rotor blade is simulated as it turns, the engines and gearbox actually drive the rotor, and the weight and balance change as you load up, burn fuel and fire.
DOCS
Player guide, modder guide and release notes: https://dice614.github.io/rfm-docs/
AIRCRAFT
RFM versions sit next to the vanilla helicopters in Game Master and the Conflict vehicle lists. Vanilla helicopters aren't changed.
- UH-1H: transport, armed, HE/HEDP gunships, shark-nose gunships, civilian
- Mi-8MT: transport, armed, HE/HEDP gunships, civilian (red/blue)
WHAT'S SIMULATED
- Rotor blades: lift, drag, stall and flapping on every blade. Teetering rotor on the UH-1, articulated rotor with lead-lag on the Mi-8.
- Tail rotor torque, translational lift, ground effect and retreating-blade stall.
- Engines, gearbox and governor: real start-ups, rotor RPM that can droop and overspeed, autorotation, single-engine flight and a rotor brake on the Mi-8.
- Weight and balance: fuel, crew, cargo, supplies and weapons all change the weight and CG live.
- Wind that changes with height, terrain and buildings, with gusts and thermals from the game's weather.
- Skids and wheels with suspension, and nose-wheel steering on the Mi-8.
- Damage uses the vanilla hit zones: engines, gearbox, drive shafts and rotors fail on their own, and repairs carry over.
- Rotor strikes on trees, buildings, terrain and water.
- Mi-8 AP-34B autopilot (attitude, heading and altitude hold).
CONTROLS
- Uses the vanilla helicopter keybinds. Pick your device in Settings > RFM (Auto by default).
- Keyboard, mouse and gamepad fly like vanilla: hold W/A/S/D to pitch or bank, let go and it holds that angle. Shift/Ctrl climb and descend, let go and it holds height.
- Autohover (C): slows you to a hover from any speed and holds you over that spot, even in wind. C again or the cyclic takes back control.
- Joystick/HOTAS flies the controls directly.
- Pedal helper handles the anti-torque pedal if you don't have rudder pedals.
- Bind "Force Trim Release" (Settings > Controls > RFM) before you fly. It sets where the cyclic rests and engages the Mi-8 autopilot.
SETTINGS (Settings > RFM)
Control device, flight assist, pedal helper, input tuning, camera shake, an RFM HUD and speed units.
MULTIPLAYER
Works on dedicated servers. The pilot's machine flies the aircraft and everyone else sees it smoothly. Multiplayer is the part I've been able to test the least, so server reports help a lot.
FOR MODDERS
You can put your own helicopters on RFM. The docs walk through a full conversion using the UH-1H and Mi-8MT as templates. Works with MFD Framework, AHC Fuel Systems and WCS-style mounts, no extra dependencies.
KNOWN LIMITATIONS
- Some Mi-8 data (blade airfoil, a few masses and dampers) are engineering estimates.
- I haven't confirmed Conflict refuel/repair or server save/restore work with RFM aircraft yet.
- The Mi-8 autopilot on/off is a stopgap for now (trim button: release to engage, double-press to turn it off).
REPORTING BUGS
Tell me which aircraft, what you were doing and what happened, and attach your log:
Documents/My Games/ArmaReforger/logs/<date>/console.log
If it happened on a dedicated server, the server's console log helps too.
LICENSE
Rotorcraft Flight Model (RFM) is released under the Arma Public License – No Derivatives (APL-ND).
Allowed:
- Using RFM in your missions, scenarios and servers.
- Making your own mods that list RFM as a Workshop dependency. That includes new aircraft built with RFM's components and variants of RFM's aircraft (liveries, loadouts, stations). Those mods can be open or closed.
Not allowed:
- Modifying RFM, or re-uploading or repacking it, in whole or in part.
- Copying RFM's scripts, prefabs, configs or other files into another mod. Use it as a dependency instead.
- Any commercial use (also forbidden by the Bohemia Interactive EULA).
Credit isn't required, but I'd appreciate it. If your mod uses RFM, please mention it on your Workshop page, since it changes how helicopters fly.
Full license text: https://www.bohemia.net/community/licenses/arma-public-license-nd
