This lever is now outdated because both single and twin current levers feel as good as this one now, but also support switch panels (heads).

Single lever:
https://github.com/hc625ma/simchair_models/tree/master/Components/Peripherals/Single%20collective

Twin lever:
https://github.com/hc625ma/simchair_models/tree/master/Components/Peripherals/Twin%20collective

This is a mark III version of a collective lever (https://www.thingiverse.com/thing:1578566).

It looks, feels and works better than mark II version. Just like its predecessor, it is based on the same SS495A hall sensor. This time you wouldn't need to adjust anything though. Just print everything, press fit an SS495A sensor, a magnet, throttle handle resistor, and two 608 bearings to their corresponding mount places, assemble everything with some m3 and m8 bolts and nuts, add some glue where needed (I used some cyanoacrylate to secure SS495A and its wires, also glued the decorative cover with the back plate of the throttle handle), and plug it into your joystick controller (I still use UnoJoy).

This is intended to be printed in PLA. Use 0,1mm layer on the main frame part. If you have any questions, regarding the lever, Simchair, or UnoJoy setup, please feel free to contact me. Comments, suggestions, remixes and improvements are always welcome!)

You will need:

1 x 250x10x10mm aluminum square pipe
1 x 20x10 aluminum rectangular pipe for chair mounting (the mount for the IKEA GUNDE chair is included)
1 x SS495A hall sensor
1 x 10KOhm LINEAR potentiometer
(https://goo.gl/vbi1Zh)
1 x 6x6x4mm square magnet
4 x 3x40mm screws and nyloc nuts to connect the frame to its enclosure
1 x 3x40mm screw for lever connector axis strengthening
4 x 3x45mm screws for tensioner halves contraction
4 x m8x75 bolts, spring washers, and nuts
2 x 608 bearings (standard skateboard bearings)
cyanoacrylate

You can plug this lever into your favorite joystick controller. If you don't have one, no worries, the software for Arduino UNO is included. Note that you will need an original Arduino UNO or its exact clone with atmega16u2 onboard.

How to use UnoJoy software:

1. Upload the "simchair.ino" sketch to your Arduino with an Arduino IDE.
2. Install Atmel FLIP.
3. Turn your Arduino into DFU mode.
4. Your board should come up as an atmega16u2.
5. Run "Turn into a joystick.bat"
6. Replug your board and it will show up as a joystick.

Note that ALL analog inputs MUST be either connected to potentiometers or grounded.

If you need two throttle grips and the collective head switch panel, you can use this twin throttle, 200 degrees travel version: https://www.thingiverse.com/thing:2747131.

The video below should give you the general idea of how it is built, though it covers the twin-throttle version as it is more complex.

---- UPDATE 30.01.2018
Noticed that some STLs were missing, so uploaded them and oriented everything in the correct position to print. Also made minor adjustments to throttle wedge part for an easier fit.
---- UPDATE 18.04.2018
Uploaded a missing STL file of the resistor mount.

---- UPDATE 19.05.2018
I2C upgrade! Connect an Arduino Pro Mini as follows:

PIN10 - SS495A/potentiometer VCC
GND - SS495A/potentiometer GND
RAW or VCC - orange-white ethernet cable wire (+5V)
GND - orange ethernet cable wire
SDA - blue ethernet cable wire
SCL - green-white ethernet cable wire
A0, A1 SS495A and potentiometer signal wires (A0 - throttle, A1 - collective, or change this in the ino file)

Flash it with the provided ino file and fly with a filtered 10-bit resolution!

---- UPDATE 23.05.2018
Collective assembly manual added!
http://hc625ma.org/simple-collective/