DJI FPV has flipped backwards on take-off

[John Gowland]

My DJI FPV has flipped backwards on take-off three times now damaging the props beyond repair.

I noticed that after putting on the props and pushing the props down they stick sometimes and don’t pop up. I only have one more set of props left and have to take off on a soft surface like a landing pad. Previously I have taken off on rocks or concreate surfaces.
The drone should not be doing this, can anyone tell me why this is happening and a solution?

Thanks

 

[JoostGT3]

A friend of mine had this happen to him as well. i was giving him (Mod Removed) that he probably had the left stick pushed all the way to the rear, but apparently there is something else going on... Did this happen while taking off in manual mode? He mentioned that was what he did. As for myself, I take off in N or S, then switch it into Manual when I am at altitude, and it never happened to me yet.

 

[Kilrah]

You probably swapped 2 props, there is nothing to prevent mounting them in the wrong location like on other DJI aircraft so you have to be real careful to match the red markings.
And yes I've done it once as well.

 

[msinger]

You probably swapped 2 props, there is nothing to prevent mounting them in the wrong location

Certainly a possibility.

Per the DJI FPV manual:

Previously I have taken off on rocks or concreate surfaces

Concrete surfaces like sidewalks? If so, you don't want to take off from them since they probably contain metal.

 

[John Gowland]

You probably swapped 2 props, there is nothing to prevent mounting them in the wrong location like on other DJI aircraft so you have to be real careful to match the red markings.
And yes I've done it once as well.

I am sure I put the red on red and black on black. I hope I have made a mistakes and it's just a question of putting the right one on the right place. Will try again tomorrow.

 

[John Gowland]

Certainly a possibility.

Per the DJI FPV manual:

View attachment 5112



Concrete surfaces like sidewalks? If so, you don't want to take off from them since they probably contain metal.

Maybe you are right.

 

[Phantomrain.org]

If is not switching the props .

It may be possible that you are taking off to slow off the ground , you need to throttle up much faster than you do a Regular DJI drone. These do end up Upside Down A lot more than any other drone and one of the Reason why we made the FPV Crash Jackets.

Phantomrain.org
Gear to protect you FPV in a Crash and fly in the Rain.

 

[JoostGT3]

With my mate it wasn't the props. Said he had been flying before without problem and didn't change them... Will be interesting to see if more of these cases turn up... Hope not!

 

[mrmund]

There's a Nurk video where it happens to his partner who's an experienced FPV pilot. It seems like it happens if you try to take off too slowly in M mode

 

[John Gowland]

I am nowhere near enough ready to go into M mode. A camera flyer with a passion for speed.
Today I am going to record putting on the props and taking off. I so hope I have made a stupid mistake and got the red and black props mixed. Which would mean I don't have to send it back. I don't think it is the gently take off because I have taken off gently many times.
By the way I have 6 batteries and used them all many, many times. Could be wear and tear most flyers not done so much with the DJI FPV. As I have mentioned, I have noticed after putting on the props and testing their security by pushing down to check the spring loaded mechanism they sometimes get stuck, ie don't come up again to be level with the metal pin (don't know the name of it) Again I hope I have made mistakes.
Keep you posted. Copying to DJI FORUM to get more help.
Thanks for your support guys.

 

[A.O.]

I am nowhere near enough ready to go into M mode. A camera flyer with a passion for speed.
Today I am going to record putting on the props and taking off. I so hope I have made a stupid mistake and got the red and black props mixed. Which would mean I don't have to send it back. I don't think it is the gently take off because I have taken off gently many times.
By the way I have 6 batteries and used them all many, many times. Could be wear and tear most flyers not done so much with the DJI FPV. As I have mentioned, I have noticed after putting on the props and testing their security by pushing down to check the spring loaded mechanism they sometimes get stuck, ie don't come up again to be level with the metal pin (don't know the name of it) Again I hope I have made mistakes.
Keep you posted. Copying to DJI FORUM to get more help.
Thanks for your support guys.

Let us know what you find out.

 

[John Gowland]

Well I took off 5 times today and without problem. So maybe I did put the props on incorrectly or did take off too gently. It seems to like aggression. or maybe there is a deeper long term issue. I do not know, but I know making sure you put your props on the correct way red on red..... and aggressively taking off, seems to work.
Thanks again for your support guys.

 

[venomoussvt]

Well I took off 5 times today and without problem. So maybe I did put the props on incorrectly or did take off too gently. It seems to like aggression. or maybe there is a deeper long term issue. I do not know, but I know making sure you put your props on the correct way red on red..... and aggressively taking off, seems to work.
Thanks again for your support guys.

it definitely sounds like the props are backwards, if you even put on one prop in the wrong direction (ie if you grabbed one from a second set of props and put on 3 red and 1 black) it will go nuts! Its also unbelievably immediate as well. its like pulling the rug out from under it, it flips over with fury.

 

[John Gowland]

I can not roll back history and see what I did. But it has not happened recently. I now think it was because I took off too gently. I now push the left stick full on and it takes off fine. I am not prepared to test this theory.

 

[jwahaus]

I can verify that taking off too slowly with the FPV can cause instability. I almost crashed mine indoors taking off from a bed in a small bedroom. I wanted to ease it up really slowly and the blowback from the props in addition to the tilt the FPV needs to make in order to be level (i.e. it's not level when landed) would sometimes cause for a very unstable take-off. I've done this several times now and it seems it's best not to be too slow on the assent.

 

[John Gowland]

Since I have never had a problem, since always taking off at max speed, I can only conclude that if you take of gently you will have problems.
There needs to be a software upgrade that forces a hard take off. Get it out DJI, please.

 

[jwahaus]

Since I have never had a problem, since always taking off at max speed, I can only conclude that if you take of gently you will have problems.
There needs to be a software upgrade that forces a hard take off. Get it out DJI, please.

Or better would be a software update that fixes the instability when taking off slowly.

 

[John Gowland]

True jwahaus.

 

[rktman]

I can verify that taking off too slowly with the FPV can cause instability. I almost crashed mine indoors taking off from a bed in a small bedroom.

Keep in mind DJI has not implemented anti-fool behavior in the flight controller. This very powerful drone can not stop itself from such idiotic flying conditions. It WILL let you hurt yourself with it if you are insistent.

 

[rktman]

I have no doubt the props were either mixed up, or the mode switch was in manual.

The FPV is not some odd, finicky platform. It's a fairly typical quad from the standpoint of flight characteristics.

Taking off in Normal mode with good light for VPS, a good GPS lock, and reasonably calm conditions (wind less than 5mph), it takes off with no trouble every time, no matter how slowly you ascend.

Use the auto takeoff feature, and it will successfully rise slowly every time. I prefer the CSC to start the motors, then leave the ground under my control, but the auto takeoff will show you what the engineers tested successfully. No aggression required..

Now, takeoff in Manual, and it's a completely different story, and everything said about controlling attitude, being more aggressive, and heading up and FORWARD right off the ground are spot-on. Hovering in-place just isn't something you do in manual, which is precisely what the Mavic pilot is going to try during takeoff.

Then, when the fundamental static instability of M mode rears its head, all their angle-mode skills and reflexes kick in, they react that way but the drone's in rate mode, and they flip it holding the pitch stick trying to get it to move where they want it to.

I went through exactly this early on, at about 20ft off the ground, and miraculously was able to have the reflex to hit the panic button and just barely save the situation as it was upside down heading for the ground.

The difference between angle and rate mode control is probably what results in most crashed FPVs. Since I fly about 75/25 N/S (angle) vs M (rate), it takes about a battery in M before I completely get my mind to switch my reflexive control behavior.

If you don't know what I'm referring to with angle vs. rate mode, don't try M mode until you do.