Inside Heli #33: Basic CCPM Setup

We've got a full house this episode! Join the James' (Northern and Southern), Eeeeky, and Chris as they chat about CCPM setup basics. Also hear Eeeeky's thoughts about IRCHA and the MSH Protos.

Stuff We Talked About:
Video of the Week
MS Heli
Esprit Model
Eeeeky's Protos Vid
Newspaper article about Eeeeky

Direct download: InsideHeli_33_-_Basic_CCPM_Setup.mp3

Setting up flybarless with the HeliCommand RIGID, part 2: Physical setup and trimming

The next step is getting your physical setup correct.

The first thing you should note is that servo horns will make a huge difference to your setup - I'm using the Mikado CF horns (#4021 for Futaba servos, #4022 for JR) on the outer-most (20mm) holes. What you want is nice rigid horns, with very little flex - any slop in your control system is going to turn up as quirks in your flight behaviour. The VStabi Wiki has a great article giving general advice for converting your head to flybarless.

The next step is to trim your Helicommand unit. The best way to do this is using a swash leveling tool. This is the advice I gave in my "More Logo 500 Fun" entry:

Here's what I did. Turn on your transmitter and set your pitch stick in the middle (or wherever you have 0 degree's set on your curves). Power on your machine's avionics (it's a good idea to disconnect the motor), this is a good time to double-check that both of your blades are exactly at 0 degrees with a pitch gauge, because if they are then you will have no problems with tracking. You can use a swash levelling tool or something else to check that the swash is sitting perpendicular to the main shaft, if it is not you can adjust the aileron and elevator trims using the Internal autotrim settings in the RC & trim tab of the Helicommand setup software.



Unlike the VStabi software, changes made in the Helicommand software do not instantly update the unit, so you need to adjust each a few clicks and then click write on the right hand side, which sends your changes to the unit. You will probably have to rinse & repeat a few times until you get it right.

The complete RC & trim tab looks like this:



The transmitter neutral fields are automatically learned by the Helicommand during the initialisation phase, after powering the unit it. This is why it's really important not to fiddle with the sticks while it's intialising.

The only things you are likely to need to change is the stick reverse options if you are finding that your swash is moving in the wrong direction to stick input. This is different to servo reversing! Remember you need the swash to move the correct way when you move the cyclic stick or the heli. ie:

• Moving the cyclic stick to the left should tilt your swash to the left, tipping your heli to the left should tilt your swash to the right (for a moment, then it will move back to center).
• Moving the cyclic stick to aft should tilt your swash to aft, tipping your heli aft should tilt your swash towards the front (for a moment, then it will move back to center).

In the next part we will cover configuring the RIGID mode for flybarless stabilisation.

Setting up flybarless with the HeliCommand RIGID, part 1: Swash mixing.

The first thing is to make sure that you have the latest software (currently 1.34.3). Next, you need to make sure you have your servos connected correctly to the HeliCommand RC module - the manual, sparse as it is covers this step. If you get this wrong then you will not be able to set the mixer to do anything.

The next thing is to get your Mixer tab set up to match your particular swash type - on my Logo 500, which is a 120° CCPM swash this is how I have it configured:



Things you will need to change:

• Mounting orientation: This refers to the way you have your HeliCommand sensor unit mounted on the frame. This is an old screenshot, and I actually have mine facing to the right now.
• Main rotor direction: This is pretty obvious, mostly it's "right" unless you are building a scale machine or have something particularly exotic.
• Control travel: The control travel sliders are used to eliminate binding of each servo, they are your end-points, essentially.
• Swashplate: Choose the swash type that matches your machine.
• Servo reverse: Note that this is not about matching your swash to the movements of your stick, but to the output of the gyros. For example, tilting the heli forward should result in the swash tilting to aft for a moment, then slowly moving back to center, tilting the heli left should tilt the swash to the right for a moment, then slowly move back to center.
  
• Virtual swashplate rotation: This allows you to rotate the control inputs to your swash, this is probably of most use on flybarless heads that don't handle your 90° phasing in their design - this is most multi-bladed heads and maybe some conversions. If your head looks like these (ie with the control rods 90° to the blade grips), then you don't need to worry. If you don't understand why we need 90° phasing in the rotorhead then read this very informative Wikipedia article.