Maiden Flight of Ranger EX 757-3


I completed the maiden flight of my Ranger EX 757-3 today, with mixed results.  The flying weight today was 6lbs, using a standard rule of thumb, the power requirements would be 450 - 600W.  The supplied 3715/1000KV outrunner brushless motor only provides 300W.


  • Initial parameter selection flew the aircraft safely and successfully in Manual and FBWA! 
  • The build was good (no bits flew off)!
  • All the systems checked out
    • Pixhawk
    • GPS/Compass
    • Power monitor
    • LIDARlite V3
    • Airspeed sensor
  • Modes checked
    • FBWA
    • Manual - now have a good trim

The Mediocre:

  • Under powered, with the current motor and 6lbs flying weight takeoff and climb out were sluggish
    • Batteries 2 x 5100mah 3S 8C batteries in parallel - which should deliver 40A each 
    • 40A ESC
    • 25A motor (~300W)
    • Looking to upgraded the motor to 450W plus and may need 60A ESC for 600W motor
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  • From initial inspection it should be repairable. I figured it was the voltage issue not the motor. I'll have to look around and see what motor I can find. Thanks for your calculations. Maybe next time with a better motor my results will be better. Make sure you keep us up to date on your progress.

  • Sorry to hear your flight ended abruptly. Hopefully the damage is repairable? The stock motor is underpowered for my 6 lbs takeoff weight, I have ordered a 500w motor to replace the stock 300w.

    Once the airframe made a cruising altitude it flew very stable and landing soft but positive.

    The original post has a plot of power vs airspeed/altitude
  • I flew my Ranger last weekend. Woefully underpowered with stock setup on 3s. Unfortunatly my flight had an abrupt ending. I love the idea of the platform but have yet to ever feel comfortable with it in the air.

  • Try 6S and a Tiger MN4012-9 with a Tiger 80A ESC. Bit pricey I know. I have one in this spec that I purchased lightly used from a person who had multiple rangers. I have yet to fly it but I have seen it fly well on a Vector but I am adding a Pixhawk 2 to it. 

    Better still -- ask on this thread. This is where you need to be.

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    Forward equipment bay:

    • Pixhawk - on vibration mount
    • 3DR telemetry transmitter starboard side
    • Pixhawk power module port side
    • 2 x 5100mah 3S 8C LiPo battery packs
    • Digital L2C airspeed sensor
    • FrSky RC receiver/telemetry transceiver 

    Not visible:

    • LIDARlite V3 - bottom of airframe
    • 40A ESC - port side below wing saddle 
  • Nice!

    Any photos from the internal setup?

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