Home Forums Everything about everything else Help with Kakute F4 V2 Unconventional Setup

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  • #59978
    GNM
    Participant

    Hello, this is my first post on this site and I’m not sure if this is the right place to post this, but I need some advice about a large scale heavy lift tricopter project I’m involved in that will potentially be using the Kakute F4 V2. The build is based around a 10S battery pack powering 3 Scorpion SII-4035-450KV motors via T-Motor Flame 80A HV ESCs. Yaw is achieved via BMS-385DMAX servo driving a set of vanes under the rear prop (similar to an airboat rudder), rather than tilting the rear motor.

    Previously we used a KK2, but due to being unable to reduce oscillations enough for sustained flight after repeated attempts at tuning the decision was made to move to a modern flight controller, and seeing as it seems the Kakute is being adopted as the new standard for RC Explorer we thought that’d be the way to go.

    However due to our power system we cannot simply wire the Kakute up to a PDB (as shown here: https://bit.ly/2EvvOdD) and route everything through that, as the voltage and current are much too high. I’ve drawn up a diagram of what as far as I can tell would be the way to set everything up, but I wanted to double check with people more experienced and knowledgeable than I to make sure I haven’t done anything dumb in my diagram.

    In particular I was wondering about whether it makes sense to use the BEC to power the board and servo as shown, and if the ESCs need to be grounded or not as it seems the Kakute F4 V2 doesn’t have dedicated ESC signal ground pads and I’m not sure if the T-Motor Flames are opto-isolated or not.

    Any input is much appreciated.

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    #59991
    GNM
    Participant

    Quick update, have bench tested the setup as per my wire diagram using betaflight 3.5 on the Kakute F4 V2, and almost everything seemed to be working, aside from a couple of issues:

    The left and back motors were swapped, as the rear motor is considered motor 1 in betaflight apparently. Seems to have been easily fixed by swapping the signal wires.

    Furthermore, pasting in the CLI code found on the setup tab of the Kakute F4 V2 store page here on RC Explorer to remap the resources needed for the tricopter setup resulted in an error and an inactive servo. As far as I can tell, the lines regarding the servo remapping were causing the issue:

    resource motor 1 B00
    resource motor 2 B01
    resource motor 3 A03
    resource motor 4 none
    resource motor LED A02
    resource servo 1 C04

    Changing ‘resource motor LED A02’ to ‘resource LED_STRIP none’
    and ‘resource servo 1 C04’ to ‘resource servo 1 C08’ (what LED_STRIP was previously assigned to) seems to have fixed the issue, as the servo now correctly reacts to movements on the bench, however I’m not sure if this is the correct approach or not, as I’m unfamiliar with resource re-mapping. If anyone has any input it would be much appreciated.

    #59995
    jihlein
    Participant

    resource LED_STRIP none
    resource servo 1 C08

    are correct. If you still want the LED strip function, then add

    resource LED_STRIP A02

    These three cli lines essentially swap the M4 (A02) and LED (C08) pin functions, which is necessary on the KakuteF4V2 to allow different PWM protocols for the motors and tail servo.

    Would love to see photos of your big bird!

    #60023
    GNM
    Participant

    Thanks for the response, good to know we are on the right track.

    The tricopter is part of a quarter-scale model of a vehicle being developed in a new venture by Glenn Martin https://www.facebook.com/martinjetpackinventor/
    and as it’s early days yet pictures and video of the craft are being kept under wraps for the next few months, but we hope to be able to disclose to everybody once our patent attorney says we can 🙂

    #60112
    vanbierstein
    Participant

    I am setting up a tricopter with the Kakute V2 and looks like only betaflight has support for the board. I mapped the resources according to the product page.

    resource motor 1 B00
    resource motor 2 B01
    resource motor 3 A03
    resource motor 4 none
    resource led_strip A02
    resource servo 1 C08

    Now when I power up the servo tilts 100% to one direction and betaflight doesn’t have the tailtune functionality. How do I setup and tune the tail in betaflight? Can I do this manually without tail tune?

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