This has to be one of my favourite designs to date and is the second part of the heli controls to complement the cyclic. 
 
I have received a SPM (Small Printer Mod) from Petr, and now you can print all the parts on a 220 x220mm bed). A massive thanks to Petr for this. This mod is untested by myself. I still recommend a bed size of 300 x 300mm for maximum strength.
 
I have used a stepper motor (standard Nema 17) as the mag brake, Parallel actuator, Beep trim and later on the autopilot drive unit (series Actuator).
 
The Collective lever is based on AW139, and all the switches are mapped but not used currently.
 
The Force trim release button is used, and also the electric beep up and down is used. I would suggest the other buttons be mapped to other sim functions, such as the view orientation for the second top hat, etc.
 
This is NOT a force-feedback unit because helicopters do not operate like that. The control rods/cables are typically connected to servos. Due to the astronomical forces required to move the controls (between 3-20 tonnes), there are no feedback forces through the servos/controls. This is usually done by linear force feel units (springs) acting on a parallel actuator which can reset the datum point at any position. This is the purpose of the Stepper motor in this case. Most modern twin-engined rotorcraft is uncontrollable if full hydraulic servo power is lost. 
 
The forces on the collective are substantial; I would highly recommend using the trim release for take-off, landing and large movements. 
 
 
Currently, The collective can be repositioned in any neutral position using the trim release. Once the button is released, the collective will hold that position and force feel is enabled. Fine-tuning the collective position electrically can be used by trimming the Beep switch top hat in the direction required. 
 
I have included a highly detailed AW139 grip. If you have a resin printer, I recommend using this for a smooth finish. For those that do not have access to a resin printer, I might be able to produce them for you at a cost, but this will be a limited quantity due to the time they take.
 
Please note: I have made the collective fitting 25mm so it will fit most aircraft grips.
 
There is no complicated software involved, just Mobiflight, and I soon hope to issue the exact file, so you do not have to programme anything. This unit replicates a standard PC joystick, using a Leo Bodnar card to keep things simple. This means it can be used on XP, DCS, P3D and MSFS!
 
I hope this puts a smile on your face like it did so many at the EXPO in Lelystad, including real-life pilots! 
 
Pre-release right now while I construct the Build/Print and parts guide, which will be added here (if you want to start printing:
 
The build guide and components list can be found here.
 
 
This design requires a print build of 300 x 300mm (A Creality CR10 or similar)