What am I missing or doing wrong?

Hello guys,
So here is my story. Please, any answer it might help me fly the drone.
I am really new to drones.

I wanna build my own drone. It’s a F550 quad-copter frame. I am using Pixhawk PX4 PIX 2.4.8 as a flight controller, Radiolink M8N GPS SE100 as gps, AT10 II 2.4Ghz 10CH as transmitter, R12DS as receiver and a PPM Encoder as signal encoder from transmitter to Pixhawk. Also, brushless motors A2212/2700kv and 30A ESC with BEC.

I started by making some uploads to Pixhawk (making the accelerometer configuration, etc), about preferences as it seemed, turned controller on, in Stabilize mode, connecting and arming the motors. Everything connected, GPS, Pixhawk, battery, receiver and PPM Encoder, except Telemetry ( I am not sure if that is a MUST, although i just ordered one yesterday) and propellers. I removed propellers (1045) , I thought it would be safer for the first time.

Then I started put pushing the throttle to 10%. Motors started working fine, but they started accelerating on their own, without me changing the throttle. Throttle was still 10% and it kept turning faster and faster for the next 8-10 secs. As a result one of the 4 ESCs burned in fire ( no kidding). As soon as i was flames under the drone’s arm, i shut the throttle down. I changed that burnt ESC and placed a new one. And pretty much did the same. The first time i thought i had mis-connected something, but after i burned 2-3 more ESCs in the same way, i said it’s not about connections. Maybe it was about picking wrong ESCs (30A) but the motors had as suggested ESC 20A or 30A. So i had 30A ESC and i wondered why it burned so fast, only 8-10 secs working with motors. I am using a 3S 11.1v 4200mah LiPo battery 30c. So, the second thought was that the ESCs, were drawing so much power from the battery, and tehy couldn’t handle it and that was the reason that they kept burning on fire.

Then i came up with another possible explanation. Ever since i throttle up to 10%, GPS (which was connected) was sending to Pixhawk the information that the altitude is not increasing. So it was like keep saying to Pixhawk, “Hey, buddy, throttle up, we should have climb something at least”. And it was keep accelerating until it indeed drew so much power from the battery that it burnt. ( According to ESC suggestions, 30A ESC can draw up to 40A for only 10secs, otherwise it just burns, which by the way, is the actual time of my motors spinning… coincidence? maybe! That’s why i am asking for help :slight_smile: ) So, i figured if that possible explanation was actually the only explanation, that if I put back on the propellers, it could actually work, or If I made the drone blind to altitude by removing the GPS (will it work?).

Now, since I want to be sure, I ordered A2212/920kv and 40A ESC (better less rpm, it’s my 1st try for drone after all, and stronger ESCs just to be sure.

And another issue, is that my controller (RadioLink AT10 II) it can’t receive information about GPS (meaning in how many satellites it’s connected at that moment), and no YAW, LANG, LATI, ROLL, PITC, ALT, DIST. Everything is zeroed. How can i fix that? GPS seems to work just fine in Pixhawk.

Thank you for your time reading this, I hope you can help me.
Thanx in advance.

First with the radiolink you should rather be using SBUS and not a PPM encoder to connect to your pixhawk.

But apart from that what flight mode did you take off from? It is best to always start with stabilise first to make sure everything is working/ I also think it will be a good idea to look at your flight log and you should be able to see what the problem was.

So, you are saying that if connect them through SBUS, it should work properly in stabilize mode? And that’s my only mistake so far? I ll try that, hope it works. As for the take off, no, it didn’t take off. Since had the propellers removed for precautions. Will try to analyze the logs. Thanx for now.

I am not certain that will work, but in the past have had some issues with PPM encoders acting strange, particularly if they are not genuine/reputable manufacturers.

Let me know how it goes and if you need any more help

Meantime, limiting the maximum throttle might save some burnouts while you try to diagnose what’s wrong. You don’t have anything else mixed into that channel? Do you have a throttle cut out switch on the transmitter so you can quickly prevent extended runaway.

I’m not solving your problem but perhaps aiding diagnosis.