Complete TREX 550E Setup ( diagnostics )

This is here for diagnostics purposes. I’m not suggesting that these settings are correct.

Drive Train:

  • Battery: Hyperion 6S 35/65C 5000mah 
  • ESC: Kontroniks Jive 100+LV with heat sink
  • Motor:  NEU 1515 2.5DF   1650kv  
  • Pinion: 13T
  • Main Gear: 170T
  • Blades:  Edge 553mm FBL

Control System:

  • Electric Flybar/Receiver:  Skookum  SK-720
  • 2 x Spectrum DSMX satellites
  • Cyclic Servos: JR 8717’s
  • Tail  Servo: Futaba BLS 251

Control Power System:

  • BEC: Kontroniks Jive 100+LV   5A continuous / 15A peak 
  • twin 2 BEC cables
  • BEC Buffer Battery:  2000mah  4S NiMH  Eneloope pack
  • Powerbus:  SK-PWRB1

Orientation of SK-720 unit. The picture makes it look a bit crooked but it is parallel to the frame. The sub-trims in the SK-720 have the swash completely level from full negative to full positive.


This is a vibration log with the heli running at a governed 80% speed ( without blades) which is probably a lot faster than it should be. This log was generated after the most recent rebuild since the last crunch.



SK-720  Configuration  downloadable file, right click to save


I’m not using the SK governor, basically just a straight 80% throttle against the Kontroniks governor.


Orientation Check:  looking forward from the tail.
I added +20 to the Center and the rear jumped up.
I added +20 to the Left and the Left jumped up.
I added +20 to the Right and the Right jumped up.



The only change made to these settings since my last flight attempt is to check the Lock Cyclic Gain to 50% on both Cyclic tabs.


This video shows the SK-720 compensating for rocking the heli around

JR 11X Setup   downloadable file 550sk720.jrx

None of the controls are reversed in the Transmitter


All swash calculations in the TX are basically disabled.





The pitch adjustments of 82% and 92%  gave me +/- 10 degrees collective.


Very tame Expos to start with




Here is  the end result

A friend posted this video to show what happened.

I’ve built the following test rig to help me diagnose what is going on with this.flighttest

It has a bubble level centered over a Lazy Susan swivel under the top board, the main shaft will be centered over that. There are 4 latex covered hooks with wing nuts and lock washers holding the skids in place. There are 4 slots so the attachment points should allow a 450 up to a 700 sized heli to be mounted and centered.  The 4 PVC pipes allow the second board with swivel attached about 7” of vertical motion with only minor side to side  flexing allowed so the blades will never touch the ground. The 2×4 base under the  bottom board has replaceable wooden stakes screwed in to secure the platform to the ground.  I may replace them with metal stakes at a future time.  The total cost of the materials were less than one set of main blades.


  • 4  X  2’x2’ 1/4” Oak  plywood
  • 1 x   2”x4”x8’   ( cut 4’,  2 x 2’ )
  • scrap or  2x3x8’ ( cut  4 x 8” )
  • 12 x  PCV pipe connectors
  • 6’ of PVC pipe ( cut  4x 16”,   4x 1.25” )
  • PVC primer
  • PVC glue
  • 1 x lasy susan base
  • A pack of wooden stakes ( predrill  so they don’t split )
  • 3”  Wood screws to screws the base together
  • 1/5” Wood screws  to attach the plywood  to the base

The current plan is to test this on Wednesday Aug 24th. Hopefully the video and flight log will help diagnose what is going on.


2 Responses to “Complete TREX 550E Setup ( diagnostics )”

  1. 1 Brandon January 10, 2013 at 5:07 am

    Your flybarless unit is not setup properly. When you hold the helicopter and tilt it left, the swashplate should tilt right. In this video you clearly have it backwards. Good luck!

    • 2 mkovalcson January 10, 2013 at 5:28 am

      That was so long ago I don’t even remember how things were set, but suffice it to say it did fly and crash many times since then 🙂 Currently it has a JLog2 connected to it and in another week it will have an SK-GPS connected and in a couple weeks hopefully it will have Jeti receiver sending back full telemetry data. Then I will either rekit it as a Synergy E5 or Logo 600SX.

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