controlling the throttle of a quadcopter using ultrasonic sensor

Other Hardware 3rd Party Boards
1

I want to control the throttle of my quadcopter using my HC-SR04 Ultrasonic Sensor & consist of KK 2.1.5 Flight controller, I successfully can arm and disarm the board by my sketch But unable to map the throttle with HC-SR04.

I want to map the range 0-50 Cm of HC-SR04 with bldc_Throttle.writeMicroseconds(1100) - bldc_Throttle.writeMicroseconds(2390)

that means if the range increase throttle should also increase

#include <Servo.h>

int 55;
int senseval;

#define echoPin 7
#define trigPin 8
#define LEDPin 13

int maximumRange = 200;
int minimumRange = 0;
long duration, distance;

Servo bldc_Aileron;
Servo bldc_Elevator;
Servo bldc_Throttle;
Servo bldc_Rudder;
Servo bldc_Aux;


Servo Aileron;
Servo Elevator;
Servo Throttle;
Servo Rudder;
Servo Aux;


int defAileron = 1500;
int defElevator = 1500;
int defThrottle = 1100;
int defRudder = 1500;

int deffThrottle = 2300;

int auxOn = 2018;
int auxOff = 1015;

void setup()
{
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);

  bldc_Aileron.attach(5);
  bldc_Elevator.attach(6);
  bldc_Throttle.attach(9);
  bldc_Rudder.attach(10);
  bldc_Aux.attach(11);

  Serial.begin(9600);
  delay(100);
}

void loop()
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);

  distance = duration / 58.2;

  Serial.println(distance);
  
  delay (100);

  senseval = constrain(distance, 0, 50);
  
 
  
  

  if (Serial.available() > 0) {
    int	incomingByte = Serial.read();
    if (incomingByte == 43) { // plus sign
      bldc_Throttle.writeMicroseconds(defThrottle);
      bldc_Rudder.writeMicroseconds(1100);
      delay(2000);
      bldc_Rudder.writeMicroseconds(defRudder);
      Serial.println("Model Armed and Ready to Fly");
      delay(1000);
    }

    else if (incomingByte == 45) { // minus sign
      bldc_Throttle.writeMicroseconds(defThrottle);
      bldc_Rudder.writeMicroseconds(1900);
      delay(2000);
      bldc_Rudder.writeMicroseconds(defRudder);

      Serial.println("Model Disarmed");
      delay(1000);
    }




  }
}

Thanks in advance