For a helicopter that arrived as a freebie, the Nemeth Design EC135, which launched as Local Legend 21 last August, has attracted a surprisingly active third-party scene. After flight model mods and livery packs, a new developer is now tackling what many helicopter simmers consider the most immersive dimension of all: how the aircraft sounds and feels.
FWX Aviation, founded by real-world helicopter pilot Finn West (PPL(H) on R22 and R44), released two add-ons for the EC135. They can be bought separately or together as a bundle, and between them they cover both ears and body.
The FWX EC135 Sound Enhancement Pack is a full audio replacement for the Nemeth Design EC135. FWX is upfront about what motivated the project: the developer says the stock turbine sounds are “flat, simplistic, and completely unrealistic,” and that this pack replaces them entirely, inside and out.
The key features are a custom startup sequence mixed from real helicopter recordings, covering the turbine spool from ignition through to idle, and a full exterior replacement bringing the characteristic EC135 twin-turbine character to replays and external views. Pitch variation on torque transitions has been reduced to 20% of stock, which FWX says better reflects real-world behaviour. The pack is also specifically noted as ButtKicker and transducer-safe, with no internal bass rumble, which matters if you’re running the haptic engine alongside it.
Installation is a Community folder drag-and-drop with no third-party dependencies. FWX says there’s no FPS impact and that updates will be free as the sim evolves. Three demo videos are available on YouTube covering cockpit sound highlights, an external flyby, and a full interior walkthrough.
The FWX Rotor Haptic Engine takes a different approach entirely. Rather than audio, it uses SimConnect to send real-time rotor impulse data to ButtKicker, bass shaker, or transducer hardware. FWX’s argument against generic haptic tools is that constant RPM-scaled vibration feels like “sitting on a washing machine, not in a helicopter.” Their tool instead generates four distinct blade-pass impulses per rotor revolution, matching the EC135’s actual 4-blade main rotor.
The behaviour also changes across the RPM range in a way that’s worth spelling out. At low RPM during startup, the individual blade thumps are slow enough to count. Between 30 and 50% RPM, the tool simulates the irregular blade rattle of hanging blades at low speed. At full RPM, the individual hits merge into a smooth continuous bass pulse. There’s also rotor brake feedback, smart pause detection that stops the haptics in menus and loading screens, and a GUI with live RPM display and real-time controls for volume, bass, and impulse strength. While it was clearly built around the EC135, FWX states the basic RPM impulse function works with any helicopter in MSFS 2024.
Pricing and availability
Both products are available directly from the FWX Aviation website and on simMarket. Prices on the developer’s own site are slightly lower, though. From the FWX website: the Sound Enhancement Pack is €7.99, the Rotor Haptic Engine is €3.99, and the bundle combining both is €10.99 (saving €0.99 versus buying separately).
- FWX EC135 Sound Enhancement Pack on simMarket
- FWX Rotor Haptic Engine on simMarket
- FWX Sound + Haptic Bundle on simMarket
- FWX Aviation website | Discord
Obviously, the sound pack requires the Nemeth Design EC135 (Local Legend 21). The haptic engine requires compatible bass shaker hardware with an audio interface or amplifier, and a one-time SimConnect SDK install via MSFS Dev Mode. Both Steam and Microsoft Store versions of MSFS 2024 are supported.
