Lift off without receiver

Question

Can I make a small drone frame achieve lift using 4 coreless 3.7 v motors of 55000 rpm, 3.7 v lipo batteries having 40c without a receiver and remote. Motors are all alike. The propellers I have are marked L and R.

Looks like it could rise up. But for some reason it flips over .

I am just trying the basics before I later use a receiver and remote.

Edited and added: Additional things I will try. I will try changing direction of the motors by changing the polarity. I think motor direction is more important than just the propeller L & R. The propellor L and R must be just something that can either reinforce or work against the benefits of Motor direction.

What I understand is if motors spin all in same direction they will cause the whole system to spin over. So what seems best is to have diagonally opposite corner motors rotate in same direction. Adjacent motors will need to rotate in opposite directions. This I understand is enough for a basic vertical lift.

Let me know. Meanwhile will try later today and update.

Updating: adjusting motor rotation direction helped a bit. It now lifts on one side while another side drags. It also flips and turns down inverted in one arrangement.

I learnt from some other urls now that the L propellor must go on the CW motor. The R propellor on the CCW motor. I will try that. Also I learnt now that the distance between rotors should be 1/3 of the rotor rotation diameter. Will work on that next weekend and see.

Post weekend effort: I think problem is with my home made frame. I think the motors are not straight. They are at some angles. Will improve my frame and see.

The other thing I learnt is just try playing with the position of the propellers. As usual diagonally opposite same direction of rotation. Don't assume propeller lettered side should be on top. Depends on manufacturer. Main thing is to keep hand above and below the propellers when all four motors are running and get an idea if it's pushing wind below and not up.

If anyone has any suggestions pls advice.

R

Answer 1

What you are asking is not an easy task if you want to design everything on your own. I bet you can try to do it.

First of all there is no way to get a drone airborne without some sort of stabilising device, since those things are statically and dinamically unstable.

I offer two answers:

1. The long, steep way: Design your own stabiliser, with a minimum setup of a microcontroller, 4 motors and 4 ESC, one altimeter three gyroscopes and three accelerometers and write your own firmware to control it. starting from scratch, if you may have electronic design and programming skills, I estimate you will invest at least a few months and a few hundred bucks.

2.The easy way

Find a drone that supports Python programming. Using Python you are capable of controlling your drone without a 'proper receiver'. There is a lot to write here but this is maybe space for many other questions.

I would suggest to start programming your drones with simple Python programs, this is a simple example:

from djitellopy import tello
from time import sleep
me = tello.Tello()
me.connect()
print(me.get_battery())
sleep(10)
me.takeoff()
for i in range(5):
    sleep(2)
    me.send_rc_control(0,0,0,90)
    sleep(2)
    me.send_rc_control(0,0,0,0)
sleep(2)
me.send_rc_control(0,0,40,0)
for i in range(5):
    sleep(2)
    me.send_rc_control(0,0,0,90)
    sleep(2)
    me.send_rc_control(0,0,0,0)
sleep(2)
me.land()

Here the drone takes off, climbs and performs a few turns and lands as an example. This way you are programming your own drone without a receiver. Have fun

Answer 2

Do you mean "Lift off without a flight controller"? Quadcopters are inherently very unstable. A motor + propeller doesn't create an even amount of lift. For example, a tiny gust of wind hits one propeller more than the other three, which throws the balance off. Or because of turbulences in the air, one propeller might create a bit less thrust than the others. (Example: In forward flight, the front propellers create turbulences that then disturb the back propellers.) And the quadcopter isn't perfectly balanced, for example the battery is 1mm too far back and now the back motors have to create more thrust than the front motors to keep it in level flight.

Because of this instability, you need a flight controller to constantly measure what the quadcopter is doing (using at least a gyroscope), and then adjust the motor speeds to get the quadcopter to get it to do what you want it to do (be stable, or rotate slowly, and so on).

For example, my racing drone does this "measure what the quadcopter is doing" -> "compare that with what the pilot wants it to do" -> "calculate how fast each motor should spin" eight thousand times per second.

In case you mean "Lift off with a flight controller but without a receiver": That should absolutely be possible. Just have a device on the ground that is connected to the flight controller like a receiver and sends it a signal like a receiver would. For example, Betaflight flight controllers can understand a CPPM receiver signal. You could generate a CPPM signal using some microcontroller, and connect a long wire to the receiver pad of the flight controller.