Step 10 – Building the Carbon Fiber Frame

I’m now on page 9 of the TREX 500 manual. Finally, something less complicated.

  1. Open bag 500 xxx. You’ll find:
    1. Carbon fiber main frame – left and frame-right.
    2. Bottom bracket

  1. Using 220-1000 grit sandpaper, sand down the sharp edges of the carbon fiber (CF) frame. This is done to prevent cutting your fingers and electrical wires.
  2. Open bag 500 HB and get out:
    1. Bearing blocks, black receiver tray, silver motor mount
  3. Open bag 500 HB1C – big bag
  4. Open bag 500 HB1D – small bag


  1. There seems to be a lot of parts to attach to the frame. So…I’m going to attach them all first, then loctite them later. Also, if I have problems lining up the left & right frames, I”ll want to be able to undo those screws.

Bearing Holder Blocks and Motor Mount

  1. The instructions show four M2x4mm screws coming up from the bottom of the bearing block that hold in a bearing cap. This was already done at the factory and loctited, so nothing to do here.

  1. Attach both BEARING BLOCKS to the right frame using the factory installed 6mm screws and specialty washer.

  1. Attach the MOTOR MOUNT using the factory installed M2.5x6mm screws.
    1. NOTE: there is no silver specialty washer with the motor mount.

Bottom Bracket

  1. attach the BOTTOM BRACKET and screw it in using the three M2.6x10mm socket button head self tapping screw.
    1. NOTE: I had problem pushing the bottom bracket onto the frame. See photo below.
    2. Using sandpaper, I sanded down the edge of the frame in order for the frame to fit snugly with the bottom brakcet.

Loctite all the screws that go into metal pieces.

Attach other Frame

  1. Loctite all the screws that screw into metal on the first frame.
  2. Snap on the second frame.
  3. Slide the main rotor shaft up and down to ensure you slides freely. Leave the shaft in place.

  1. Ensure the entire assembly sits flat on a table. That is, it does not rock.
  2. Screw in all the screws and loctite them.

At this point we are done page 9. I will attach the landing skids later since they get in the way.

Step 11 – Battery Mount and Canopy Spacers

Battery Mount and Canopy Spacers

  1. We are starting page 10 in the manual.
  2. Install the canopy spacers and the screws to hold in the battery mount.

Step 12 – Servos

Servo Installation:

  1. I am now on page 10 of the manual.
  2. In my box, I have three DS510 Coreless Digital Servos:
    1. Stall torque:
      1. (4.8v)
      2. (6.0v)
    2. Motion speed:
      1. 0.13sec / 60 (4.8v)
      2. 0.11sec / 60 (6.0v)
    3. Dimension: 35 x 15 x 29.2mm
    4. Weight: 25.9 g
  3. Each servo has a bag of servo horns and screws.

  1. Grab bag 500HZ6

  1. Install the two front servos. There is a bit of ‘play’ in that the servo can move side to side about 1/2 mm, so center the servo in the hole. Ensure both servos are straight across.

  1. Now install the elevator servo in the back, same thing, center it.
  2. NOTE:
    1. you need a spacer on both sides of the frame for . In my kit, I was not supplied any spacers so I had to make my own. The issue is without the servo spacer, the linkage ball at the end of the servo horn will not be centered in the middle of the helicopter frame.  In the servo bag, they supply lots of servo arms.  Using my trusty Dremel tool, I redrilled the holes and cut two spacers.  See the images below:

Now cut to fit.

Shown below is the servo with the spacers.  Note how the linkage ball from the servo is aligned with the linkage ball from the swash plate.

Servo Horn Installation:

  1. Using the supplied DS5 servo horn, screw the linkage balls into the horn at the 19.5mm hole.

NOTE: the linkage rods going from the DS510 servos are suppose to be 19.5 mm.  However, many people on the Internet believe this distance is based on another servo size OR it is a typo.  I found that at 19.5mm, the swash plate was slamming against the bottom of the blades.  I reduced the length of the linkage rods from 19.5 to ~17mm (6 full turns).  It still touches, but not as bad.