reported by Karel Kališ on August 4, 2014

UNIT: Karel Kališ, Designer, Sandbox Design Dept.
TO: Arma 3 Dev-Branch Users
OPSUM: Bringing advanced helicopter flight dynamics to Arma 3.


Although Arma 3, at its core, focuses mainly on infantry combat, we continue to strive for deeper and more involving gameplay experiences for all kinds of players. With Arma 3 Helicopters DLC, we want to draw upon the knowledge we gained from Take On Helicopters (TKOH) and bring new content and gameplay for (although not limited to) helicopter enthusiasts. Alongside 'Sling Loading' and 'Firing from Vehicles' (outlined briefly in our Roadmap Blog) the central pillar of the incoming addition is an advanced helicopter flight dynamics model; a.k.a.: RotorLib.

This new functionality is composed of multiple layers. First and foremost, is the significantly different behaviour of helicopters in flight. Second, is a new set of optional helpers which you can use to tweak your flight experience according to taste, alongside the customisable new actions and keybinds made necessary by the sophisticated flight model. Last but not least, we've added new gauges and indicators.

Together, all these elements are essential for creating immersive gameplay. We'd like to explain them in more detail below.


Right now on the Development Branch, the advanced flight model (FM) is available for all existing helicopters and, naturally, will be part of all future helicopters In Arma 3, too. We'd like to stress that it's strictly optional functionality and is, by default, disabled. However, you can switch between the basic and advanced FMs at any time via the 'General' section of Game Options and determine which version suits you more. Of course, with our community content creators in mind, there will be the possibility to enforce RotorLib functionality in scenarios (both SP and MP). Do you want to level the playing field? Want to create a hardcore helicopter mission for fellow enthusiasts? Or do you prefer a simpler flight experience? It won't be a problem!

The new FM is more complex, taking into account things like a helicopter's construction, the weight of fuel/ammo, wind influence, stress damage and much more besides. If you ever played TKOH you might notice that we omitted certain functions like maintenance, which, in our view, were not within the scope of Arma 3's implementation. Instead, we focused on the core: challenging but really enjoyable helicopter flight. Additional game settings are associated with the new FM, which can help to tailor your flight experience according to your skills and preferences. Of course, you can make your flight as demanding as is possible: switch off all helpers accordingly and show everyone that you are the bloody best pilot on the whole of Altis (and Stratis too)! It's up to you.

Looking at the details, 'Show Gauges' displays/hides a new set of instruments like variometer, windage, plus and other indicators necessary for safe flight (more details below). Enabling 'Rough Landings' makes the job of landing a little less challenging, as your gear/skids can sustain more forceful impacts. A similar helper is 'Stress Damage'. When disabled, your helicopter can handle, let's say, more 'acrobatic' manoeuvres without damaging the helo. And if you disable the 'Wind Effects' option? Then you don't have to care about those strong Altisian gusts. The final new option is 'Auto Trim', which, if enabled, automatically compensates for the effect of torque upon a helicopter's behaviour in flight - very useful (although not essential) for mouse & keyboard pilots!


The advanced FM is naturally more demanding and requires additional control inputs. If you check the Controls settings, you'll discover that we significantly increased the number of bindings in the 'Helicopter Movement' section. Probably the most important aspect is the 'analogue collective', which offers much more precise control over the pitch angle of the rotor blades, which, essentially, controls the lift of the rotor-craft.

A number of the 'Helicopter Movement' keys are designated for manually setting trim, which should be welcomed by players that love to have full control when flying. Oh - and if you are using special controllers (like some kind of HOTAS system) - don't forget to check the 'Customize controller' section, where you can pick from list of predefined schemes and further tweak characteristics like sensitivity and dead zones. One word of warning, though, please understand that - although thanks to TKOH we have a fairly decent base of schemes and customizations - in this initial release we can't cover all possible hardware combinations, and you may encounter some issues. We kindly ask you to use our feedback tracker/forums and let us know about your experience with peripherals.

Another important part of RotorLib's integration is the new landing gear behaviour. Wheels move more realistically, which is related to a new function: wheel brakes (default keybind is 'Right Ctrl+W'). We also took another step and added the possibility to manually retract gear. That is, of course, valid only for helicopters with the applicable undercarriage: AH-99 Blackfoot, UH-80 Ghost Hawk and CH-49 Mohawk. And, okay, maybe we can tease some more - one of our new helicopters will have retractable gear, too. As a final note, be aware that manual gear is not restricted to the advanced FM; it also applies to the basic model!


Again, building on the strong foundation laid down by TKOH, we are bringing a new set of flight instruments and indicators. You can find information like ground speed, altitude, attitude, vertical speed, hover deviation, G-force and more. We also made some additional tweaks; for example, all gauges are now separate elements that can be moved around freely in layout settings.

We also added indicators related to new functionality, such as the wheel brake. This is only the first step, as we are planning additional improvements for the final release of Arma 3 Helicopters DLC. In future, we'd like to offer a distinctive new visual style of indicator for more modern helicopters, and also focus upon advanced HUDs. Don't forget, this is just the first step and we are working on a lot of more things related to Arma 3 Helicopters DLC. Over the next few weeks we hope to let you know more about the 'Sling Loading' and 'Firing from Vehicles' features, plus, you can look forward to another helic-OPREP, which will cover some more specifics of the FM in far greater detail. So, stay tuned!

By now, we hope that you have all the basic info about our new flight model - there is really only one thing left: to actually try it! This new gameplay experience is just a few clicks away via the dev-branch build of Arma 3. Don't forget to visit the 'General' section of Game Options and pick the advanced flight model. We'd love to hear about what you think of the handling, customization options, issues with controllers or anything else besides on our official forums and feedback tracker. Have fun, and share your impressions with us!