I want to controll my drone from esp32 without reciever. I have connect esp32 by UART (RX to TX, TX to RX). And Use this code:

#include <Arduino.h>
#include <HardwareSerial.h>
#include <MAVLink.h>

#define SERIAL_PORT Serial1 

void setup() {
  Serial.begin(115200); 
  SERIAL_PORT.begin(115200); 
  delay(1000); 
  }

void loop() {
   uint16_t throttle_value = 1500;

   mavlink_message_t msg;
   mavlink_msg_command_long_pack(1, MAV_COMP_ID_AUTOPILOT1, &msg, 
                            MAV_CMD_NAV_TAKEOFF, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            throttle_value, 
                            0, 
                            0, 
                            0); 


    uint8_t buf[MAVLINK_MAX_PACKET_LEN];
    uint16_t len = mavlink_msg_to_send_buffer(buf, &msg);


    SERIAL_PORT.write(buf, len);

    delay(1000);
    }

But this code dont start the motors. On the betaflight i have setting that UART3, mavlink. But motors dont start. Si thank you for any help.