Bad Control for first 30 secs of flight

[John Casey]

Lately, my Inspire is almost out of control for about the first 30 seconds of flight, and then it is all OK. I always calibrate the compass (if I have moved locations from the previous flight) and after takeoff, it tends to move mostly backwards for a number of seconds and then all is pretty much OK. I now take off and ascent above tree height very quickly so if it moves off line, I won't hit anything. I also only take off in a very open area so if it moves offline, I am not in trouble. It doesn't always do it, and sometimes when it has, it's been quite windy (beach), so I wondered if it was the wind, but it seems a bit too often now for it not to be a short period of instability. When it does this, it does respond to controller stick movements, so I can move it around, but it appears fairly unstable. I don't know if the display is giving any warnings because I'm too busy watching the aircraft. I'm just wondering if anyone else has this problem, and/or if anyone knows what it is and a remedy.

 

[DaBone]

Could be that it has not locked up as many satellites yet and after a few seconds it has found some to stabilize.
Before it found satellites and stabilize it´s in ATTI and the wind can push it away..
I usually lift off and hover a few feet above the ground in 20-30 seconds, to be sure that it has found and locked satellites.

My Inspire once got that "toiletbowl-effect", where it spins around in circles. But it was after I hadn´t calibrated the compass in a new place.

 

[John Casey]

Thanks DaBone. It does say "Safe to Fly-GPS" at the top. I thought when it said that it had connected to enough sattelites, but I could be wrong. Also, it starts moving away as soon as it is off the ground, so I can't hover in one place straight away. However, after about 15 secs or so, it seems to stabilize and I can then hover in one place without any worries, and from then on during the flight it seems quite stable. It's just those first seconds after lift off that it seems to want to move away.

I always calibrate the compass after moving - even if it's just up the road 500 metres. I did read that it might be this constant re-calibration that could cause this type of trouble, but I'm not sure.

 

[huppe]

I say,give it a try.I went all over the place and I always check if calibration is needed.If app tells calibration is ok I don't do the "dance".I have calibrated once when I moved 70 miles away.Allthough my app showed calibration was not needed I did calibrate.And this was the first and only time my Inspire went into ATTI.So now I only calibrate when my app tells me to do.But do not forget to check that homepoint is set.

 

[DaBone]

The only time I had a problem was when I was not calibrated drone when I was in a new place.
Always calibrate the compass, when I change the location. This applies to all drones I have.
Maybe not 500m, but 1-2km away or more I do.

You have a satellite indicator in the upper left of the app, where you see how strong reception you have.

 

[huppe]

Sure I always wait 'till app shows enough satellite's and it's safe to fly,but I've never had any problems.But it's up to yourself to decide.But in the case of John Casey I say give it a try and stay close to starting point.
Another thing can be he's taking off too quickly.He's telling he is busy with looking at the Inspire so maybe slow down a bit when taking off.

 

[DaBone]

I answered "John Casey's" quote. Maybe he had not seen the indicator for satellites.
The app says "Safe to fly", even if it does not have full reception.

 

[worldsoutro]

I answered "John Casey's" quote. Maybe he had not seen the indicator for satellites.
The app says "Safe to fly", even if it does not have full reception.

There are two "safe to fly" One is green with gps and the other yellow without

 

[John Casey]

Thanks for all the replies. I always do the "dance" because the videos from DJI say to do so, but I don't check the controller menu to see if it is necessary. The thing that worries me is that it never used to do this until recently. It was always solid as a rock on takeoff - straight up to a few metres, hover in one place while I put the landing gear up, then up slowly and it wouldn't wander off being directly above where I took off by more than a foot or so, even in moderate winds. Now I take off and it looks like I am flying horizontally by 10-20 metres, usually backwards, but it does respond to the sticks on the controller, so when I take off, I start "flying" straight away, but I get it up high pretty quickly to avoid a problem if it does fly horizontally. But then it stabilizes and will hover happily from then on. I must admit I haven't checked how many sattellites I'm connected to, but it says "Safe to Fly (GPS) and is in green, not Yellow so it's not suggesting it is Safe to Fly but is in ATTI mode. I do wonder if I am calibrating the compass too much - I do it every time I change takeoff positions even if it's 1km away.

 

[John Casey]

I've been thinking about this problem, trying to see if there's anything that is common to the times that I've had this problem happen, and there's one thing that might be worth noting - most instances I can think of when this has happened, the takeoff "pad" has not been perfect in one or both of 2 ways.

1) The place I've taken off from is solid but uneven dirt surface and not really flat. ie. it is a dirt surface with small rocks embedded in it, and undulating, and the Inspire would not be quite level when taking off, and is on a slight slope.

2) A solid flat surface, but not level, like a roadway but on a slight slope.

I tried landing on an angled surface once, which had "stripes" on it and it didn't like it at all, to the point where I went back up and landed in an alternate spot some metres away which was flatter. This was a boat ramp, made of concrete and had "ruts" in it to provide grip for car tyres. The Inspire definitely drifted when trying to land on this, so I'm wondering if it is not acceptable to take off and land on less than perfect surfaces, or angled surfaces.

 

[Tahoe Ed]

This can also be caused by compass errors and that cause the Inspire to drop out of GPS mode. Once the data is restored the GPS comeback. This is being addressed in the next version of the firmware.

 

[John Casey]

Thanks, any idea when that next version of the firmware is being released. I read that it was going to be at the release the other day, along with the Inspire 1's hand-held camera mount etc, but only the Phantom 3 was released.

 

[Rob Suggs]

John, you might be experiencing the same effect I see. I have researched this a bit and the problem seems to be a difference between magnetic and true north (magnetic declination). It seems that the Inspire, and all of DJI' s products learn their declination as you fly. In my case, every time I launch the inspire it goes into a toilet bowl spin. The GPS tells the aircraft where it should be, but the compass tells it how to get there. Even if you do the compass calibration dance perfectly, the aircraft still needs to learn your declination. If I fly out and back a hundred feed or so, things stabilize quite a bit. Test to see if your aircraft always drifts I a circular motion in the same clockwise direction immediately after launch.

 

[John Casey]

Hi Rob, No I have never had the toilet bowl spin, or what I believe that to be. My Inspire was perfect for the first month or so, but I have noticed the erratic behaviour only recently. My problem just looks like I am flying away from the take off positon, usually backwards, but I am not flying off at all. I usually go straight up to give me more room if it takes a while to regain control, but the sticks on the controller do respond normally, and after I have quickly gained altitude, I then send the aircraft in the opposite direction to what it has decided to go which it does normally, and thereafter it flies quite normally with good response. I can hover with stability after this takeoff anomoly.