How to link real 737 control columns/yokes for your simulator and add Active Control Loading:

5 min readJun 26, 2020

This article will be an insight into the process I used for building a motorized set of linked 737 control columns.

Parts used:

OEM 737 control columns
OEM 737 cross bar for elevator
OEM 737 aileron connectors
Servo motors: 750 watts AC motors and driver.
Parker linear actuator or Planetary Gear
Wire rope with end connectors
String potentiometers
Arduino mega card
Shock axel mount
Lots of wood and screws

WARNING: Working improperly with high voltage/high torque servo motors may cause body injury or damaged equipment. Please use caution. I’m not responsible for any damages caused by the information provided in this article.

Special thanks to Rob for coming out with this idea and providing all the guidance to build this.

Video: testing auto pilot

Platform:

The platform was built using 2x6 and 2x4 wood. It sits on top of 5” canisters. The total height with the floor is 12.5”

It was made of two 8’x4’ sections for a 8x8’ total.

Control columns:

The control columns (yokes) where sourced from Boy at Simzation in the Netherlands. They come for a real Boeing 737ng.

Aileron connectors:

I used OEM 737 aileron connectors. Sourced from Arif at FlyAB sim Parts in Indonesia. Having these connectors solves a lot of the technical challengers when linking the roll axis for the control wheels.

A few issues I had:

Too tall: as they come the aileron connectors would need a platform about 19” tall. To avoid this and be able to let the platform sit on wheels I decided to cut the bottom part off. This became very challenging as each part is used to hold the enclosure together. As you remove parts it all falls apart. I had to add additional screws to hold things in place. Hoping this holds overtime. Seems sturdy enough.

Second challenge was the wire rope that connects them together. I was not able to find connectors I could easily add to a Home Depot rope. I ended up getting them custom made.

LexcoCable.com. I used ST24–4 SS swaggers with 1/8” wire rope.

They came out perfect and match OEM exactly. About $50 for 4 of them.

Elevator connector

The elevator pitch is connected using an OEM crossbar. The crossbar came with the mounting brackets also from FlyAB sim parts. All I had to do was make a custom bracket to attach it to the platform.

Servo Motors

The servo motors are Nema 34, 750 watts 240v AC motors.

The drivers are AASD-15A Servo Driver with RS482/RS485 support (By default not included)

Works with 110 and 220 volts

A 12–24v power supply is also required to control the pulse.

I used a 24 Tooth 0.770" Aluminum Hub Mount Sprocket (SKU 615106) and a hub (SKU: 545560) from servo city . With a .25” pitch chain.

To mount the sprockets to the frame I used 0.750" 1/2" bore Hub Spacer SKU 545385). With a 1/2" pipe and 1/2" collar clamps.

UPDATE:
In the new version I kept the bottom small part of the aileron drums and used those wires to connect to the servo motor with a chain and small sprocket.

Linear actuator

The pitch axis is controlled using a Parker linear actuator for Nema 34 servos.

I connected the servo to the actuator using this coupler

The actuator is connected to the cross bar using this shock axel mount:

UPDATE:

For the new version instead of an actuator I used a long arm connected to the servo motor. I’m also using a 50:1 Planetary gear. This is a good alternative to using the actuator since they are hard to find a reasonable prices in the right size.

Make sure the planetary gear backslash precision is <12 arcmin or lower. (Lower the better)

Controlling the servo motors and software.

See here:
https://fabianb.medium.com/a-d862f927d0bf

Serve Noise

These high current servos can product a lot of noise interference which can affect the joystick axes.

Make sure to use toroid coils around the power cables, ground all your connections. I also added a Uxcell AC 115V 20A CW4L2–20A-S Noise Suppressor Power EMI Filter which helped a a lot