Flying through tunnels....

[NottsJules]

Has anyone had experience of flying or attempting to fly through tunnels... in particular disused railway tunnels...? An attempt was made and it responded and flew fine until after about 30m away when it failed to respond correctly and all it could do was drift sideways when trying to fly forward (in fact it clipped the tunnel wall). I had complete line of sight of it and as said was only 30m away. I tried disabling collision avoidance and got same effect. Obvioulsy it didn't have any GPS signal, but can't they fly indoors where GPS would be lacking too, or is it complete lack of GPS is where the issue is, and is there anyway round it? There's not much I can find on operating in tunnels, maybe I have answered my own question (lol)!

 

[dirkclod]

Seems you would be flying in ATTI.

 

[slup]

What makes you being able to fly your drone indoors without GPS reception is the VisualPositioningSensors under the drone ... those sensors will lock on to the pattern on ground & keep the drone horizontally stable. But if the ground is to monochrome without a clear pattern, reflective, the drone is height wise outside the reach of the sensors or if the light isn't enough ... they will not work.

If the VPS sensors can't work & the GPS reception isn't good enough the drone goes to ATTI mode ... this means that you will not have any horizontal positioning hold at all, the drone will drift freely from outside forces like wind ... furthermore the usual auto breaking when releasing the sticks will not work either, you yourself needs to break by carefully revert the stick inputs to make it stop.

Recommend you to read more about this in the full 53 pages manual ... get it here --> https://dl.djicdn.com/downloads/Mavic_Air_2/20200615/Mavic_Air_2_User_Manual_v1.2_en_.pdf

Unfortunately it isn't any way around this, to dark & shielded from the sky you face ATTI ... either learn how to master ATTI or carry the drone by hand through the tunnel while filming.

 

[MA2 317]

Has anyone had experience of flying or attempting to fly through tunnels... in particular disused railway tunnels...? An attempt was made and it responded and flew fine until after about 30m away when it failed to respond correctly and all it could do was drift sideways when trying to fly forward (in fact it clipped the tunnel wall). I had complete line of sight of it and as said was only 30m away. I tried disabling collision avoidance and got same effect. Obvioulsy it didn't have any GPS signal, but can't they fly indoors where GPS would be lacking too, or is it complete lack of GPS is where the issue is, and is there anyway round it? There's not much I can find on operating in tunnels, maybe I have answered my own question (lol)!

Turn the bottom LED light ON when in the tunnel.

This will help the VPS while in Atti-mode.

Fly in Tripod mode for slow movements.

Stay away from the rails, walls, and ceiling as they probably have a fair amount of rebar in the concrete that could effect the compass.

I have flown my Spark 1 foot from the rail and had no issues. The MA 2 might?

There will probably be a slight amount of air current though the tunnel so be ready for some drifting.

Good Luck.

 

[BigAl07]

What's happening is the aircraft is falling into ATTI mode (mentioned already here) and in this mode it's up to you, the operator, to control the aircraft since AUTO systems are now unavailable. It's a matter of being able to see and interpret movements and being able to counter-act them in a controlled manner but quickly.

Odds are it would have responded correctly if you had been giving the correct stick inputs etc. Flying in ATTI mode isn't easy until you get the hang of it and then it's 2nd nature. The problem is most of us don't know how to handle it or even RECOGNIZE it until we are in the middle of the situation and we think the aircraft is "out of control" when it's really just operator error.

Get yourself something like a Tiny Whoop and learn to fly it. Once you can fly that with precision flying through a tunnel in ATTI mode is a walk in the park.

 

[NottsJules]

Thanks guys.... you have described exactly what happened to it and some interesting responses. I shall read up further, practice gently, or avoid. Its not something I need to do.. more a "wonder if it will work kinda situation..." but not too bad if it didn't in terms of crashing/losing it etc. Cheers.

 

[Mazdaman323lx]

Your a man after my own heart . I spent a lot of hours trying to capture the videos below with my MA-2. You are correct in assuming that it is possible to fly in the tunnel without GPS but you will be in ATTI mode . My experience doing this is that your drone will act like a helium balloon. It will drift sideways unless your apply deliberate forward motion with the sticks .Slow but steady is my advice and land when you have travelled the required distance . It wont hover and will drift due to the slightest breeze or even its own downwash .This is caused both by the lack of gps, and the darkness ,causing the downward vision (responsible for stable hovering) system not to function.
Also like flying at night the lack of light will render the collision sensors useless so be prepared like me to sacrifice a couple of sets of propellors . I had no issues with connectivity inside the tunnels but be very very gentle with the stick inputs.

 

[Mossiback]

All of the above plus get some prop guards.

 

[BigAl07]

Do you tunnel fliers set your Signal Loss setting to "Hover in place" just in case?

 

[NottsJules]

Do you tunnel fliers set your Signal Loss setting to "Hover in place" just in case?

Interesting question....

 

[Mazdaman323lx]

No point really as it cant RTH because there is no gps , hence no home point is recorded. It would hover if it lost connection to the controller, but drift sideways into the walls .Also remember you'll have no braking action after you let up on the sticks. You'll have to use opposite inputs to stop .If its a dead straight tunnel this won't be as much as an issue as it was for me , as both tunnels i Flew in were curved . And ya , prop guards a must as Mossiback correctly pointed out if doing this. I would also recommend a strobe on top as the drone fades from view even with the leds after a hundred feet . Not a must do for me either ,but the challenge of doing something outside the norm makes it all the more interesting . Anybody can lift off an fly in a circle 100 feet up in the air . Hope you go for it and look forward to seeing what you capture . Best of luck with this adventure

 

[slup]

No point really as it cant RTH because there is no gps , hence no home point is recorded. It would hover if it lost connection to the controller, but drift sideways into the walls .Also remember you'll have no braking action after you let up on the sticks. You'll have to use opposite inputs to stop .If its a dead straight tunnel this won't be as much as an issue as it was for me , as both tunnels i Flew in were curved . And ya , prop guards a must as Mossiback correctly pointed out if doing this. I would also recommend a strobe on top as the drone fades from view even with the leds after a hundred feet . Not a must do for me either ,but the challenge of doing something outside the norm makes it all the more interesting . Anybody can lift off an fly in a circle 100 feet up in the air . Hope you go for it and look forward to seeing what you capture . Best of luck with this adventure

Well ... the thing is that if a DJI drone is in ATTI & looses the RC-AC connection it will not obey any set failsafe action, it will always land.

So if flying in an confined environment where it's a risk that the GPS reception can be intermittent it can be wise to either set the failsafe action to Hover or Land.

 

[RSDonovan]

Your a man after my own heart . I spent a lot of hours trying to capture the videos below with my MA-2. You are correct in assuming that it is possible to fly in the tunnel without GPS but you will be in ATTI mode . My experience doing this is that your drone will act like a helium balloon. It will drift sideways unless your apply deliberate forward motion with the sticks .Slow but steady is my advice and land when you have travelled the required distance . It wont hover and will drift due to the slightest breeze or even its own downwash .This is caused both by the lack of gps, and the darkness ,causing the downward vision (responsible for stable hovering) system not to function.
Also like flying at night the lack of light will render the collision sensors useless so be prepared like me to sacrifice a couple of sets of propellors . I had no issues with connectivity inside the tunnels but be very very gentle with the stick inputs.

OK Mazdaman Biggles ???

But seriously.. You sir are a [Language removed by Admin] legend! I wish I had the balls ? ? to do that - I was on the edge of my seat just watching it and my fingernails have vanished. If I had been the pilot I’d have needed fresh underwear after that! Long may you continue with your very impressive flying skills! ??? ✈

 

[DavidT_ NZ]

All of the above plus get some prop guards.

Prop guards for the Air 2 are about $30. A good insurance plan! And Tripod Mode after drinking some coffee .....

 

[Slade]

I have a tunnel in The Narrows, Poudre Canyon, that I want to fly through and film. That is, when things open up from our terrible fires. I’ll need to practice ATTI. BTW, if you can fly FPV you’re way ahead of ATTI wannabes. Good luck??

 

[Karl D]

Interesting question....

With out GPS it would just land

 

[NottsJules]

With out GPS it would just land

It didn't in my experience and from that video it didn't either.... depends on the settings too....

 

[Mazdaman323lx]

I think its a moot question as there little chance of losing signal in the tunnel. Your effectively shielded from all other external interference , and the signal is funneled down the tunnel anyway as long as your facing the drone.

 

[macfawlty]

Your a man after my own heart . I spent a lot of hours trying to capture the videos below with my MA-2. You are correct in assuming that it is possible to fly in the tunnel without GPS but you will be in ATTI mode . My experience doing this is that your drone will act like a helium balloon. It will drift sideways unless your apply deliberate forward motion with the sticks .Slow but steady is my advice and land when you have travelled the required distance . It wont hover and will drift due to the slightest breeze or even its own downwash .This is caused both by the lack of gps, and the darkness ,causing the downward vision (responsible for stable hovering) system not to function.
Also like flying at night the lack of light will render the collision sensors useless so be prepared like me to sacrifice a couple of sets of propellors . I had no issues with connectivity inside the tunnels but be very very gentle with the stick inputs.

Excellent examples of how to capture tunnel clips. You only need film from part way into a tunnel to capture the tunnel effect.
I like your choice of music. I really dig Ludovico Einaudi. Also, Olafur Arnaulds and Fabrizio Paterlini.

 

[Thomas B]

I think its a moot question as there little chance of losing signal in the tunnel. Your effectively shielded from all other external interference , and the signal is funneled down the tunnel anyway as long as your facing the drone.

Hmmmmm...