My Innapropriate plan for short tunnel exploration??

[Keerev]

I want you all to think of my "Mission Impossible" attempt to photograph an unstable small tunnel.
It's of great historical importance and was built into a walled embankment somewhere about 1795-1805.
It may collapse within a few years and could be related to the World Heritage Site near Llangollen in North Wales, UK.
Neglect of the entire site has resulted in increasing cracking of the entire structure, including small falls of building stone stone from the structure.
The story of the tunnel is lost in time, but poses more questions than you have room for here, but would be happy to expand on elsewhere.
The elevated embankment carried a single track railway, and is of a size that varies from 8 to10 m (25 to 30ft) wide, and runs for 1.2km (1/2 mile).
The tunnel runs at an angle through this embankment and has been blocked off at one end by a stone wall that is now failing.
Rubbish has been dumped, to half-fill this 2m x 2m tunnel, leaving little flying room.
Come on, chaps. Persuade me against the stupid, but desperate plan to record this before it falls down, or some authority makes it safe with a bull dozer.
If there are alternative approaches for an mere amateur, such as myself, please don't hesitate to tell me what you think as I know most of you know more than this new user.
I am on my 9th flight, the last 4 of which have been practising with kids toy tunnel tent, and brick pillars in my back garden.
I am flying a Mavic Pro Platinum, using "Tripod Mode", but struggling.
I have a thick skin, so just say your piece and I will not be offended.
Thanks for all of the great information that you all provide on this forum.
keerev.

 

[Meta4]

I am on my 9th flight, the last 4 of which have been practising with kids toy tunnel tent, and brick pillars in my back garden.
I am flying a Mavic Pro Platinum, using "Tripod Mode", but struggling.

Your testing isn't going to be much help because it's not at all like the actual proposed flight would be.
Fly in a real tunnel and there are two serious issues you will have to deal with:
1. It's going to be dark in there and you won't be able to see where obstacles and tunnel walls are relative to the Mavic.
2. You will lose GPS quickly after entering the tunnel. Without GPS, your drone will also lose position holding and braking ability .
Imagine driving your car in a tunnel, without headlights and without brakes.
Just to make it more fun, the floor of the tunnel is smooth ice.
That's what the tunnel venture would be like.

 

[Keerev]

Thanks
Meta4
You provide a very visual description of what I suspected.
Perhaps I need to go back to the drawing board on this one, as I love this kit too much to risk loosing it.
I thought that "Tripod Mode" would help to give better, more precise control, and in slow motion too?
Your answer was just what I needed, so thanks again. keerev.

 

[dirkclod]

If I had a hankering to do it I would just spend the money
and buy thr Osmo Pocket and not take a chance flying mine.If I didn’t have the money then I would just go for it but
keep the outter bubble protector on it and walk right behind it. Is what I would do . And keep in mind what meta said .
Not really, all I would need is for someone say it can’t be done then I would go for it.

 

[Mossiback]

Don't do it.

• It will be dark.
• If you lose contact for any reason (RTH set to hover) you will have to enter the tunnel to retrieve or leave it behind.
• It will be in atti mode so will be susceptible to drifting. Don't do it without prop guards.
• Steel in the tracks or the rubbish or even the composition of the rock could cause compass errors.

 

[Mikero]

I thought that "Tripod Mode" would help to give better, more precise control, and in slow motion too?

Tripod Mode requires GPS.

 

[dirkclod]

Yes but set it to hover wouldn’t that work. Like flying in a house.

 

[Keerev]

If I had a hankering to do it I would just spend the money
and buy thr Osmo Pocket and not take a chance flying mine.If I didn’t have the money then I would just go for it but
keep the outter bubble protector on it and walk right behind it. Is what I would do . And keep in mind what meta said .
Not really, all I would need is for someone say it can’t be done then I would go for it.

Thanks
dirkclod
You are more courageous than I. The tunnel is the "Dodgy" bit as the roof is really cracked, and after 225 years of poor maintenance, I dont think that I, a mere 73years, have the strength to hold it up as I make my escape, MPP in hand! I have realised that the tunnel length is only 8m (25ft) long and I managed to obtain the attached picture standing in the entrance.
My cameras lack the ability of the MPP and I was really hoping to obtain the best photo that I can. Light is going to be easier this time, as I have a new Cree Spotlight that should throw 100 times the lux that the old one did.
What do you all think of using the Mavic as a hand-held unit from the entrance just once? Minus props, of course.
All ideas gratefully received. PDF's of tunnel entrance & interior from the entrance.
keerev

 

[Keerev]

Don't do it.

• It will be dark.
• If you lose contact for any reason (RTH set to hover) you will have to enter the tunnel to retrieve or leave it behind.
• It will be in atti mode so will be susceptible to drifting. Don't do it without prop guards.
• Steel in the tracks or the rubbish or even the composition of the rock could cause compass errors.

Hi
Mossiback
You state it so clearly, and if you see my reply to dirclod you will see photos of the tunnel that I have taken, so far. I just won't risk it.
Thanks, keerev

 

[Keerev]

Tripod Mode requires GPS.

Hi
Mikero
Thanks for that info. I misunderstood the Mode, thinking that it only relied on the sensors. That and the slowing of the Mavic actions I hoped would give more stability, but I was clearly wrong.
Incidentally, as a UK'er, you may be familiar with the site's famous neighbour? It's Telford's Pontcysyllte Aqueduct, near Llangollen. This tunnel may have supplied the water during construction and to fill it for the opening ceremony.
keerev

 

[Keerev]

Yes but set it to hover wouldn’t that work. Like flying in a house.

Thanks dirkclod, judging by the really helpful comments, ideas and concerned warnings, i think that it would be more like flying a house into the tunnel!!
thanks anyway,
keerev

 

[Splashy]

Unless there is likely to be something of interest in there I don't think I would bother. BUT if you did want to try it then strap a couple of Lume Cubes to the Pro and point one forward and one down and forward. This should provide enough light for the visual positioning to work. I believe that this would be enough to hold position but then you would have to be aware that if there was rubble and you flew over it then the drone would rise. If it is only 8m then you could set up a torch to illuminate it and then send a Tello down there.

 

[Bigglesfliesundone]

I think the DJI Osmo Pocket set to 4K 50p would render the best results with someone carrying a small video light. I think your drone method is fraught with too many problems, especially loosing GPS.

 

[Jackcutrone]

There are a number of YouTube videos on using a mavic as a handheld stabilized camera. Didn’t check them out myself but you may want to as it may solve your issue and give you the benefit without the danger of flying it in the tunnel.

 

[packnrat]

i did not read any about just the vibes from the props could bring down the celing.
if it is too dangers for you to walk in it is too dangers for a drone to fly in.
maybe a tethered four ( or more) wheel unit?

 

[SCK]

What about trying it with a small toy camera drone. No the video will not be "great" but you can see what is there and determine if it is actually worth risking the $$. Practice flying inside then give it a shot. the only downside would be the limited flight time but it the tunnel is straight through and only 25' long you should be able to maintain connection and they are not a apt to be affected by the metal in the tunnel. thoughts??

 

[Peter Hughes]

Thanks
dirkclod
You are more courageous than I. The tunnel is the "Dodgy" bit as the roof is really cracked, and after 225 years of poor maintenance, I dont think that I, a mere 73years, have the strength to hold it up as I make my escape, MPP in hand! I have realised that the tunnel length is only 8m (25ft) long and I managed to obtain the attached picture standing in the entrance.
My cameras lack the ability of the MPP and I was really hoping to obtain the best photo that I can. Light is going to be easier this time, as I have a new Cree Spotlight that should throw 100 times the lux that the old one did.
What do you all think of using the Mavic as a hand-held unit from the entrance just once? Minus props, of course.
All ideas gratefully received. PDF's of tunnel entrance & interior from the entrance.
keerev

To be honest, whilst I applaud your sentiments, I would earnestly advise against it for all the reasons given above.
Looking at the photos, I would say the second one is pretty good and shows most of the tunnel without the inherent risks.
IF you do go ahead I wish you the best of luck and would love to see the results.
Take care. Peter

 

[AMann]

I want you all to think of my "Mission Impossible" attempt to photograph an unstable small tunnel.
It's of great historical importance and was built into a walled embankment somewhere about 1795-1805.
It may collapse within a few years and could be related to the World Heritage Site near Llangollen in North Wales, UK.
Neglect of the entire site has resulted in increasing cracking of the entire structure, including small falls of building stone stone from the structure.
The story of the tunnel is lost in time, but poses more questions than you have room for here, but would be happy to expand on elsewhere.
The elevated embankment carried a single track railway, and is of a size that varies from 8 to10 m (25 to 30ft) wide, and runs for 1.2km (1/2 mile).
The tunnel runs at an angle through this embankment and has been blocked off at one end by a stone wall that is now failing.
Rubbish has been dumped, to half-fill this 2m x 2m tunnel, leaving little flying room.
Come on, chaps. Persuade me against the stupid, but desperate plan to record this before it falls down, or some authority makes it safe with a bull dozer.
If there are alternative approaches for an mere amateur, such as myself, please don't hesitate to tell me what you think as I know most of you know more than this new user.
I am on my 9th flight, the last 4 of which have been practising with kids toy tunnel tent, and brick pillars in my back garden.
I am flying a Mavic Pro Platinum, using "Tripod Mode", but struggling.
I have a thick skin, so just say your piece and I will not be offended.
Thanks for all of the great information that you all provide on this forum.
keerev.

I used to do mine survey work for evaluation of bat roosting sites, we used a rc toy tank on a long wire to explore dangerous adits and lowered it into shafts with bad cribbing. You will not be able to use radio remote control nor video feeds very far underground nor GPS.

 

[Idealhobbies]

If I wanted to do something like what you propose, I think that I would try it with a cheap drone. “Captain Drone” on YouTube does many reviews on inexpensive drones. Maybe one will suit your needs better. While losing a $150 drone would sting, losing a $1100 drone would break my heart. That way you could have a throw away drone that you could afford to take greater risks with. My 2 cents (or pence).

 

[Mossiback]

The OP describes an "unstable" tunnel "including small falls of building stone". This makes going inside with any hand held option unwise. Looking at the pictures from post #8 it looks like all he needs is more light and a decent telephoto lens.