Step 22 – Main Drive Gear

I’m now on page 16 in my TREX manual.

  1. Get bag 500HB and inside of it, bag 500HB2

  1. Ensure the self-tapping screws are tight, but do not over tighten.
  2. Put the nut in the hex hole in the gear.
  3. Ensure the holes line up.


  1. Put the gear into the frame
  2. Slide the Lock Collar onto the main shaft, but do not tighten the set screws.
  3. Slide the shaft down into the gear.
  4. Push in the “Jesus bolt” screw and tighten.

Now if you grab the head and frame, there is about a 1mm play.  You can move it up or down.  To prevent the main rotor assembly from sliding up/down, you need to position the collar and set the screws.

  1. Push the white gears up, pull the collar down and gently tighten one of the set screws.
  2. Loc-tite the 2nd set screw.
  3. Remove the original set screw, apply loc-tite and tighten.  You’re done.


Step 23 -  Servo Linkage Rods

  1. Make the last three servo linkage rods.
  2. I’m only going to attach them to head, not the servos yet.  The reason is that I still now to power the servos and make adjustments, without the linkage rods attached.


Step 24 – Anti-Rotation Bracket

Screw the Canopy Mounting brackets into anti-rotation bracket.

At this point, we are done page 16 in the TREX manual.


Step 25 – Motor

  1. Grab bag 500HZ5

  1. Put the pinion gear on the motor.  Do not loctite it.  We’ll do that later.
  2. Install the motor into the main helicopter frame.  Put the two mounting screws in to hold the motor.
  3. Slide the motor to the left, away from the main rotor gear.  The reason is that I don’t want the motor to engage the main rotor gear while I’m doing the heli set up.