My Pixhawk Setup

I was able to get 5 flights in today mostly in loiter and it's pretty rock solid. I am curious what it will do with a little wind. 

Here are my params for a Trex 550 stretched to a 700 running 1500 RPMs. 3691129941?profile=original


Trex 3.1.5 001.param

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  • Hey Sean, could you share your 3d printer files for the pixhawk mount and GPS mount with me as well. My email address is

    Thanks Robert

  • Hi Sean, I know this is an old post but any chance you could share your 3D printed files for the pixhawk mount and GPS?

    Thanks Kyle

  • Hi Sean,

    Thank you for the param file you had shared last time. It works great with the pixhawk. I had to make very little changes in it to get my 550L dominator flying. I could complete a waypoint mission as well.

    But the problem is with the battery. It hardly gives me 4-5 min of mission time. My headspeed is 1400. I want to go on longer missions. I tried to put up 2 x 6s x 5200mah x 25c batteries with Talon 90. But it reduced my flying time to 3 min. I guess the weight of the battery is too high compared to what it can offer.

    I had earlier read up Rob Lefebvre's comment that 550 is an inefficient machine unless it is stretched to a 600 or 700. I plan to stretch my 550L dominator to a 700 like you to get 30-40min of flying time. I plan to order the following parts:

    Tail boom - 700L size

    Torque tube - 700L size (with extra bearing)

    Rudder control rod - 700 size

    Tail boom supporting braces - 600 size (700 size braces have M4 bolts - not suitable for me)

    Tail blades - 105mm

    Main blades - align 700mm or 720mm

    My questions are:

    1. Do I have to change the rotor head completely for the 700 blades to fit properly? Or is it enough if I just order the main blade holder (would it fit on the stock main rotor head)?
    2. Do I have to elevate the vehicle by changing the landing skid so that the tail blades do not hit the ground?
    3. My motor is BL-730MX (850KV). I am not sure if this stock motor can take the load of the 700 or 720mm blades. Do I need to change the motor too, like you did?
    4. What batteries do you use to get this 35min flight time? Thunderpower 70c ?

    Can you please help me out with these questions? Thank you for your time.

    - Regards


    • Rish,  Are you sure about your head speed.  1400 with stock 520 or 550 blades is very low.  You should be able to get close to 10 minutes with a 5 amp pack and stock blades at 1800 ish headspeed. 


      David R. Boulanger

      • Hi David Boulanger,

        I had checked up your modification too :) . But I was keen on trying to stretch it to a 700.

        I fly with the 550 size blade. I do not practically have any extra payload other than a crossbar and the mounting for the pixhawk. But I suspect that my batteries are not up to it. With new batteries of the same specs I had mentioned in my previous reply, I used to get about 12-15 min on a 550E (flybarred) with 520 size blades at 1400 rpm. But with this dominator (550L) I am not able to replicate that. My battery weighs 800gm.

        I programmed Talon 90 for 1400 rpm and measured the rotor HS with the optical rpm measuring tool. . I don't have any reason to suspect either of them.

        The ambient temperature here is about 40-45 deg centigrade at this time of the year. So, I guess battery performance is effected. Even the motor heats up pretty quick.

        - Regards - HeliPal
        Buy / online at the lowest price. HeliPal is famous for their Fast Shipping, Low Price and Good Service. HeliPal is the best and the biggest rc hel…
  • Hi Sean / Anybody,
    I am an enthusiast trying to mount the pixhawk on a t-rex 550 dominator. I had earlier used the APM 2.6 on a quad and it is awesome. I wanted to try the parameter file mentioned here. But not able to download or view the images. Have they been taken down? Or is it a glitch. If you don't mind, can you please mail them to Thanks.

    - Rish

    • I haven't flown the Trex-550 in awhile. Attached is my most recent log file for the 550.

      Trex 3.1.5 004.param

      • Got it... Thank you !!

  • Thanks for posting.
    These helis, in my experience,are very resistant to wind.
    I have flown my helis in gusty winds up to 30mph. At those winds the pixhawk handled pretty well. They fly just as well as in calm winds.

    I like the braided wire covers. It helps the setup look really clean.
  • Can I ask where that GPS mast is from?    3d printed?

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