General

What sets AccuRC apart from other simulators?

AccuRC is the world’s first aerodynamically and physically accurate RC simulator, designed to simulate the entire model from the servos to the blades and control surfaces, with control geometries and components accurately affecting the way things feel– it’s not just simply a picture of a model. Your models can be set up to individual tastes and requirements, simply by swapping electrical and mechanical components and adjusting settings as you would do with your own model. We have worked and are working with many large companies in the hobby like BK Designs LLC, GAUI TSH, Minicopter, MSH USA, SAB Heli Division, Synergy RC, VTX Designs, XLPower and many, many more, to have their models and components represented as accurately as possible in our simulator.

In AccuRC, everything is physics- and kinematics driven. When you move your cyclic stick, we’re not telling the model to rotate. We’re telling our FBL the requested rate input, our FBL moves the servos correspondingly, the linkages connected to the servo arms move the swash plate. The swash plate the transfers the control input as the angle of incidence of the blade grips, the blades fly through virtual air, from which we calculate their angle of attack and resulting lift. No two different models in AccuRC will fly the same, as each model precisely resembles its real world counterpart’s geometry determined control feel. A Goblin will precisely fly like a Goblin, a LOGO will have the very distinct LOGO feel, and a Synergy will be just as locked in as a real life Synergy. Same goes for swappable rotor blades, servos, motors, batteries… You name it. All components are modeled as closely to their real life counterparts as possible, servos have real life torque and speed specs, rotor blades use their actual airfoils, weight, CGs and planforms, motors come with their corresponding resistances, velocity constants, heat losses.

No other simulator on the market offers the true-to-life customizability of AccuRC- which our users trust enough to base their decision for their next IRL model on.



Distribution

Why is AccuRC so priced so aggressively?

Don’t let the price fool you, AccuRC is a accurate, realistic simulator, no toy physics and graphics here.

Traditionally, sims are sold through a dealer network with proprietary hardware. That dealer network all want to make their markup, this pushes the prices up plus DVDs, boxes, shipping also increase the costs substantially.

We are a small but dedicated team working from our homes, this goes further to reduce costs as we have no overheads of having offices etc. Working from homes also means we can recruit the best people for us from anywhere in the world. Currently the team is spread over 2 continents and 3 countries but still work closely to bring you the best product we can.

The upshot is that we can provide a class leading product for less money and less environmental impact, plus we don’t have to participate in the daily slog in rush hour traffic to an office! The downside (for us at least!) is that your support email that you sent at 10pm will probably get answered almost immidiately!


Why do I need Steam?

Steam is a gaming platform for PC and Mac. Think of it as a platform that roughly works like the Google Play Store or Apple AppStore, but for games and other software.

For AccuRC it means that we can push updates very quickly without you needing to download the full sim over and over again. If you leave the Steam client running in the background, it will even keep the sim up to date automatically for you when you arent even using the PC.

Furthermore, Steam allows us to make beta versions available to everyone keen to test. Developing software as complex as AccuRC is hard, but with your feedback we can ensure that AccuRC can be the best product possible.

Steam also allows online model sharing through the Steam Workshop integrated with AccuRC, where you can publish your setups or try others’.

Steam will synchronize your settings and models across all your computers. This means that once you have set it up a model, it will automatically sync to your other computers/laptops, or if you get a new computer, you can just login and all your models are there ready and waiting for you.

Lastly, Steam’s licensing is cross platform, so if you own AccuRC on Steam, you can install it on either a Mac or a PC or both if you wish.


Community & Betas

Is there a community hub for AccuRC users?

Yes! Happily join our Discord server using the link below. Via Discord you’ll always get notified about the latest updates and news first, you can discuss the sim with other users, efficiently report and discuss bugs in the latest development builds, schedule online flying sessions with other users and just have a great time overall.

AccuRC Discord Server


How do I access the latest Alpha/Beta?

To get access to the latest development builds of AccuRC, all you need to do is to switch one option in Steam.

•Open your Steam client

•Click on “Library” in the top menu bar, select “Games”

•Right-click AccuRC 2 in your games list on the left

•Select “Properties”

•Open the “BETAS” tab

•From the dropdown, select “alpha – bleeding edge development” or “beta – beta build”

That’s it! There’s no password required, simply close the Properties window and Steam should automatically start the Update process.

Make sure to join the AccuRC Discord Server when using the beta, that way you can immediately report bugs to the developers.

Check the latest change log to see what ‘s new: AccuRC Change Log


 


Transmitters

Does my Transmitter work with AccuRC?

The short answer is yes. There almost always is at least one method to connect your transmitter to your PC. There are numerous USB dongles on the market that work with the vast majority of transmitters and many transmitter brand that support direct USB.

If your Tx has a trainer port, then, for example, the HobbyKing 9-in-1 dongle will work with.

Some manufacturers like Spektrum and FrSky have their own wireless dongles that allows you to use your transmitter wirelessly, or you can purchase the OrangeRX equivalent.

•Setting up Spektrum transmitters to use with AccuRC

Some transmitters don’t even need a dongle. FrSky, Jeti, VControl and Devo (with the right firmware) will work with just a USB cable from the Transmitter to the PC.

The golden rule is that if it appears in Windows as a USB Game Controller (joy.cpl) (not just a HID device), it will work with AccuRC.

There are also various dedicated USB transmitters like the RealFlight Interlink transmitters that will work with AccuRC.

The 2 main dongles that will NOT work with AccuRC, as they are proprietary devices, are the Phoenix dongle and the Realflight Interface that connects to your transmitter.

We are maintaining a document that lists numerous dongles that work with accurc here.


How do I configure my transmitter to work with AccuRC?

For some dongle and transmitter combinations we presets for instance the real flight controller all you need to do is select the preset and calibrate in AccuRC and Windows.

We have a number of Youtube videos to help with setting up your transmitter and its switches with AccuRC check out the playlist on Youtube

https://www.youtube.com/channel/UC4Wr8Vnd-K1mzd328s0pQRQ/playlists


I am experiencing input lag, what can I do?

We have done extensive analysis on input lag and identified main components contributing to it as follows:

•Inherent USB lag, this in unavoidable and depends on your mainboard/USB hub. It typically ranges from 80-100ms.

•Transmission lag, especially using wireless connections. While convenient, they can introduce an additional delay of appx. 30-40ms.

•Conversion lag, especially in USB dongles having to convert a PPM signal from the trainer port to a USB game controller signal. Induced lag can vary greatly here, appx. 10-30ms over a direct USB connection from transmitter to PC are normal.

•Frame timing, the time it takes your PC to render the next frame after your input. The higher your monitor’s refresh rate, the lower this delay is.  At 60Hz, this equates to 16.67ms.

•VSync, the vertical synchronisation of the sim’s frame output to your monitor’s refresh rate can add one frame of delay. At 60Hz, this equates to 16.67ms.

We found up to appx. 130ms of input lag to be very flyable in 3D, up to 150ms we were fine to sport fly with. Above that, the delay becomes very noticeable very quickly. Older computers with slower USB connections naturally have less overhead in what additional lag can be taken without affecting the flying experience too much.

If you feel like the input lag on your system is excessive, review the above contributors. The simplest thing to do is to turn off VSync, this will save one frame in exchange for slightly reduced smoothness. If you’re using a wireless connection, consider changing that to a direct USB cable, saving 30-40ms. While we’re absolutely in love with high refresh rate monitors (120…144Hz), this is likely the most expensive solution, but reduces input lag greatly as the time between both frame and VSync delay are reduced greatly.


I am seeing drift on some axis even with my sticks neutral.

Make sure your transmitter is calibrated correctly and all axes are centered at 0. If that’s the case and you’re still seeing drift, try increasing the deadband in transmitter configuration, it’s set rather low by default.


I can’t get my VControl Touch to work as a Game Controller.

Typically you should be able to just plug your VControl Touch in and it will work as a game controller, however sometimes it will mount as a USB drive instead, If this happens, simply eject the drive on your PC/Mac and it will then reconnect automatically as a Game Controller.


 


Simulation

Why are autorotation difficulty and collective feel different compared to my real helicopter?

Short answer, they arent, you probably just haven’t taken advantage of all settings yet. AccuRC simulates pretty much every aerodynamic aspect of a helicopter, of which many directly correlate to the properties of the air you’re flying in. Collective feel and autorotation energy management are two of the most apparent things to change with atmospheric conditions, which makes it important to match the simulated air in AccuRC to the atmosphere you’re flying in normally.

The main parameters to adjust for this purpose are air density and temperature in flight mode weather settings. Setting these to your usual flying conditions can make quite a difference already as they directly affect reynolds nubers, lift and drag of the very airfoils flying your model.

Additionally, we recommend to always select the blades you would also use in real life to have the correct airfoils/chords simulated. A rectangular NACA0014 blade, for example, will never autorotate even similarly to a VTX blade with its specially engineered airfoil and planform.


What does “Full Control System Simulation” do?

To understand what this setting does, we need to take a quick dive into how AccuRC’s control system works. One of the key features that makes AccuRC so accurate is that we simulate the model’s entire control system with all its individual pieces like linkages, bell cranks, servo arms, blade grips, as bodies with a mass, a moment of inertia and an axis they rotate about, translate about and/or multiple hinges they are connected to. Doing this allows us to accurately simulate how the blade angles correspond to servo positions, we pretty much move the servos, the control system reacts in between like the mechanics of a real heli would react, and we just read the blade grips’ angles of incidence and calculate the angle of attack on the blades with it in correspondence to current airflow which allows us to calculate the lift generated by the blade.

Furthermore it’s important to understand that both the physics engine and the control system run at framerate that depends on your computer’s power. The higher your computing power, the higher those framerates, and the more often physics and control system position get calculated per second. You can display these numbers by pressing Q in flight mode.

Assuming a computer can achieve high enough physics/control FPS, the simulator would perform just as expected. The magic number up until 2.0.7 was ~420 physics FPS, above which the sim remained perfectly flyable. Below that, the framerate would be too low to accurately simulate the highly dynamic tail rotor system. With a very fast servo, very large deflections in a very short amount of time, the mechanics at some point wouldn’t be able to follow anymore, which was below that magic 420PFPS number, where users would experience tail wag, regardless of gain.

This is why with 2.0.7, we introduced Full Control System Simulation toggle. If you switch this toggle off, the tail rotor essentially skips the entire tail mechanics and translates the servo position into a tail rotor pitch angle via pre-cached values. This allows the sim to fly just fine down to the minimum PFPS possible (300 is the lower cap), with no issues on the tail whatsoever. For the user there virtually are no downsides to this, it saves computing power, feels pretty much just like the actual control system and allows the simulator to run on machines with low computing power.


Does AccuRC have a “Style” setting like VBar?

In short: No, but you can emulate it.

To understand why AccuRC doesn’t have a Style setting, we first need to understand what Style on VBar does. All FBLs use PID (Proportional-Integral-Derivative) control loops to control the helicopter’s angular rate. The tune of the three gains P, I and D, largely determines how the helicopter’s cyclic system response feels. P gain outputs a signal proportional to the rate error, I gain sums up the rate error over time and grows the longer the error persists, D looks at the error’s rate of change and makes corrections proportional to how quickly the error changes. Inherently, this renders D the most sensitive and “harshest” parameter of the control loop.

On VBar, the Style slider varies the ratio of P and D gain. The lower the style, the higher P and the lower D, and vice versa. A high P gain with a low D gain will, upon rate request, yield a general control output proportional to the rate error (read: requested rate), and generally respond to the same error with the same control output each time. It doesn’t matter how quickly you move the stick, P will dictate mostly the same acceleration in all cases.

Setting VBar style to a high, “robotic” value, yields a high D gain. As D looks at the rate of change of the rate error, this also takes into consideration how quickly the stick is moved and how quickly the helicopter accelerates and approaches the target rate. To put it in simple terms, more D gain will allow the helicopter to reach the target rate quicker and more precisely, and will also make stops harder and more precise.

AccuRC in turn uses pre-tuned control loops, which have been adjusted using industrial methods to achieve aperiodic boundary condition for the helicopter’s cyclic system response as precisely as possible, setting a fixed ratio of P, I and D, which generally just works. Messing with the individual gains would mess with the stability of the control loop, which is why we decided to not make these gains user-adjustable.

You can, however, adjust the cyclic passthrough to emulate how VBar feels, by manually overriding the control loop’s aperiodic boundary condition. Increasing cyclic passthrough past the sweet spot will make the heli feel more vivid, similar to how low Style on VBar feels, and slightly reducing it will yield a more precise reaction as the control loop takes over and dictates the heli’s acceleration to target rate.


 


Troubleshooting

It can happen that AccuRC stops working as expected, may it be Antivirus falsely quarantining files, a failed download through Steam, accidentally deleting an important game file, gamma rays flipping bits before they’re written to your database, etc. Worry not, you’re not facing a reinstall- Steam has you covered.

Verifying the integrity of your AccuRC files // “Doing a verify”

This is by far the simplest way to check if your sim is corrupted. Simply follow these steps:

•Open your Steam client

•Click on “Library” in the top menu bar, select “Games”

•Right-click AccuRC 2 in your games list on the left

•Select “Properties”

•Open the “LOCAL FILES” tab

•Click the “VERIFY INTEGRITY OF GAME FILES…” Buttom

Steam will start going through your AccuRC file system and check its contents against the latest build and replace any file that is corrupt.

Note: Due to several files holding user generated model information, Steam may return a small number of failed files, which is nothing to worry about. Only if Steam starts and automatic download after the verification is done, files actually needed replacement.

 

Resetting your sim

Sometimes it can be necessary to reset your sim to factory settings if a verify doesn’t help.

WARNING: Resetting AccuRC will result in loss of all configured models, transmitters and settings. This process is permanent.

To reset AccuRC to default settings, follow these steps:

•Open your Steam client

•Click on “Library” in the top menu bar, select “Games”

•Right-click AccuRC 2 in your games list on the left

•Select “Properties”

•Open the “UPDATES” tab

•Under Steam Cloud, disable “Enable Steam Cloud synchronization for AccuRC 2”

•Open the “LOCAL FILES” tab

•Select “BROWSE LOCAL FILES…”

•A Windows Explorer window will open. Navigate to …\AccuRC 2\Docs\Data

•Delete or rename the file saracen.db, which is the database holding all user data. If you have disabled file extensions in Windows, the file will simply be called “saracen” of type “Data Base File”.

•Return to Steam, in Properties>LOCAL FILES now select “VERIFY INTEGRITY OF GAME FILES…”

•Steam will now scan your file system as described above, will find that your saracen.db is missing and replace it with a fresh copy of said file.

Next time you open AccuRC, you should be greeted by the initial setup wizard. Your sim has been successfully reset and you can start over.

 

If those measures don’t help, please contact us through one of the ways listed under Contact.

 


 


Compatibility

Does AccuRC work on a Mac?

Yes! Although it is currently a Beta. We are working out some final bugs we want to fix before we make it an official release.

If you would like to provide feedback, feel free to join our Discord server.


Why are there no fixed wing aircraft on Mac?

We are currently working on an update to the fixed wing physics and a whole lot of new fixed wing models. It would have been a lot of work port the old physics working to Mac, so we decided to hold off and just put the new physics engine in to the Mac version when its ready. That means we have more time to iron out bugs, which we decided is worth skipping FW for now for.


I have version 1, how do I upgrade?

We offered AccuRC 2 as a free upgrade all the way back in 2017 with the intention to migrate our loyal user base. If you didn’t upgrade in 2017, then unfortunately you are going to need to head to our web store and purchase AccuRC 2 there, due to the fact we are running on Steam now we have been able to greatly reduce the price compared to other simulators.


Is there a manual?

We have a manual that is work in progress, we are updating it regularly. It is available here.

If you see any errors or parts you don’t understand please use the google docs commenting system.


 


Contact

I need help, how can I contact you?

We are active in many places spread around the internet, these include:

support@accurc.com

AccuRC Discord Server

AccuRC Facebook community

HeliFreak AccuRC sub forum

rcgroups.com simulators sub forum

rcheliaddict AccuRC sub forum

CP Helis Facebook group

German language rc-heli.de Simulators sub forum