Tethered MR Flights - does anyone use this technique

[Mojave]

Does anyone fly their multirotor using a tether or know of another person using this technique? I understand there are situations where the tether can supply power and that FAA rules are different for tethered flight.

Thanks

 

[Benjamin Kenobi]

I have seen a tethered system. It just follows the chap around like a dog on a lead. Quite clever but limited also. And yes, it does negate the regulations but I believe if you get paid for it you would likely need some licensing (don't quote me on that).

 

[FerdinandK]

For 20m (height, 30m wire) I had to play all tricks to get the needed power though the wire (to supply the copter from ground only). Of course it is much easier to take a multirotor (with Lipos on board) and put it on a line.

best regards
Feridnand

 

[pj1967]

this would be ideal for me i have looked into getting the application working on my Rig as i dont need to fly around and all i need it to do is go up and down, although i need it to go up to 4OOft to make it worth my while.

 

[Mojave]

Tethered Power Details

For 20m (height, 30m wire) I had to play all tricks to get the needed power though the wire (to supply the copter from ground only). Of course it is much easier to take a multirotor (with Lipos on board) and put it on a line.

best regards
Feridnand

Feridnand - a couple of questions:
1) Why did you decide to use a tether?
2) What gauge of wire did you use?
3) Lastly, what did you use as a power supply?

 

[FerdinandK]

1) It had to be done.
2) 30m 16AWG (this was a really lightweight copter)
3) A standard power supply (that can be regulated) this is the one I use for charging.

The copter is hovering at about 7A at 15 V (so something like 100W)

From my point of view 400ft is impossible (I do not use this word very often). But with current energy transport technology (copper) there is no chance (with the typical safe DC-voltage range we use for MC)

best regards
Ferdinand

 

[Scott Drysdale]

Just this a.m. I was assisting a colleague by helping with tethered flight. But in our case, the tether was to ensure the MR height was aligned with the client's specific height requests in taking panorama shots of some new condo development. The intent is to show potential clients precisely what view they could expect from the various storey balconies. Panoramic shots were later stitched together for the full 360 deg view. Here is photo.View attachment 18581

 

[jes1111]

The irony is that such a technique is possibly just as dangerous to nearby people/property, if not more so, than free flight.

 

[Bartman]

have tethered my heli's on a number of occasions, mostly when the location of the shoot required zero possibility of a flyaway. to tether I've used a tennis ball about twenty feet below the helicopter to keep the line centered below the helicopter and to make the tether more visible. the tether was 20 lb. fishing line spooled out from a short, heavy duty ocean fishing pole/reel operated by a friend of mine. both Mikrokopter and Hoverfly heli's seemed unfazed by the tether being there.

 

[Bartman]

The irony is that such a technique is possibly just as dangerous to nearby people/property, if not more so, than free flight.

and you've got how many flights to your credit with this technique?

 

[Stacky]

Hoverfly have a setup for sale thats tethered. http://www.hoverflytech.com/

 

[jes1111]

and you've got how many flights to your credit with this technique?

Score zero for comprehension.

My remark was a dig at the FAA - not you or anyone else who employs this technique. Please also note that I qualified my proposition with the word "possibly", in acknowledgement of the fact that I haven't tried this myself. Nevertheless, it's not difficult to imagine the range of additional complications and unwanted outcomes that this technique could add. The "irony" is that the FAA would (allegedly) deem your flight as "safe", i.e. outside the scope of their safety-centric control.

I thought you started this forum as a place for friendly, non-RCG-like exchange.

 

[Bartman]

Score zero for comprehension.

My remark was a dig at the FAA - not you or anyone else who employs this technique. Please also note that I qualified my proposition with the word "possibly", in acknowledgement of the fact that I haven't tried this myself. Nevertheless, it's not difficult to imagine the range of additional complications and unwanted outcomes that this technique could add. The "irony" is that the FAA would (allegedly) deem your flight as "safe", i.e. outside the scope of their safety-centric control.

I thought you started this forum as a place for friendly, non-RCG-like exchange.

jes, your approach to friendly, non RCG exchanges is difficult for me to understand. "Zero for comprehension" is a stretch as your post was without any reference to a specific person/group/post and as such could only be connected to the post immediately preceding it. in that context it was dramatically overstating a danger unknown to you because, as i guessed, you hadn't actually tried it. as such, i could only roll my eyes and wonder why you'd make such a pronouncement.

maybe you should ask a few questions before you tell us your opinions.

 

[pj1967]

Could you please explain/elaborate why the technique is more dangerous if the Rotorcopter is going straight up with no need to move around.

 

[Bartman]

..........................that FAA rules are different for tethered flight.

Thanks

it has been suggested that the tether makes the heli into a kite and that kite operations for hire aren't prohibited and are legal to 150 ft, per FAA guidance on the topic of kites.

 

[jes1111]

jes, your approach to friendly, non RCG exchanges is difficult for me to understand. "Zero for comprehension" is a stretch as your post was without any reference to a specific person/group/post and as such could only be connected to the post immediately preceding it. in that context it was dramatically overstating a danger unknown to you because, as i guessed, you hadn't actually tried it. as such, i could only roll my eyes and wonder why you'd make such a pronouncement.

maybe you should ask a few questions before you tell us your opinions.

Score double zero for comprehension.

It's your approach that's hard to understand, bart - from several angles. Firstly, your response to my post was unnecessarily aggressive, particularly since you failed to understand what I'd actually written. Secondly, you claim to be a trained engineer and yet you persist in the approach that only real-world testing is relevant to multirotor operations. Safety requires the standard Scientific Method: hypothesis followed by trial. You can't skip on the hypothesis stage - and that's all I was doing in my post: hypothesising (hence the word "possibly"). The Scientific Method is embodied in the UK Health & Safety Executive's requirements for Risk Assessment as an exercise. (You'll have similar legislation in the US, I'm sure.) Simply put, you are required to list what could go wrong and demonstrate planning to eliminate or mitigate all possible unsafe outcomes.

Straight off the top of my head I can think of a number of possible problems:
- what might happen if you suffer a motor-out?
- what might happen if you need to descend rapidly - is it possible to catch up with, and therefore get tangled in, your own tether?
- what might happen if you lose control over the aircraft (a fly-away)?
- what might happen if your tether breaks?
- what are the possible risks in deploying the tether to the target height?

Each of these (and more) needs to be considered and planned for. I'm not saying that tethering can't or shouldn't be done, just that it introduces additional safety considerations over and above those of normal free flight. I can't write in my Flight Operations Manual "Bart tried it and says it's safe, so no further consideration is required"

 

[Bartman]

i hypothesized and then i tested and then i went out and did it, and did it again, and did it again, etc., etc., etc.

i don't generally inject my unfounded over-dramatized opinions into conversations where it is almost always inappropriate.

engineering is a discipline that uses the middle ground to apply scientific gains to everyday life. as an engineering enthusiast you seem to miss the middle ground part and instead take things to extremes. science explores the extremes and the engineers then utilize the best compromise to make science useful. balance, it's about balance.

 

[Bartman]

1) It had to be done.
2) 30m 16AWG (this was a really lightweight copter)
3) A standard power supply (that can be regulated) this is the one I use for charging.

The copter is hovering at about 7A at 15 V (so something like 100W)

From my point of view 400ft is impossible (I do not use this word very often). But with current energy transport technology (copper) there is no chance (with the typical safe DC-voltage range we use for MC)

best regards
Ferdinand

It's been suggested that if you run a higher voltage supply through the wires (allowing for lower current and smaller wire requirements) you could then use a regulator at the heli to step the voltage down to the desired level. higher voltage motors would require less of a step from supply voltage to motor voltage.

Graphene is a new material that has much better conductivity (superconductive I think at ambient temps) and it will be very interesting to see if it is adapted to this use as it should allow for motor voltage to be passed to the heli up to higher altitudes. It's also much lighter than copper so it will help in that respect as well.

I briefly consulted with a fiber-optics company about a tethered heli with a secure video feed but didn't remain with the project so can't say how far along it's come.

 

[Benjamin Kenobi]

I think the tethered approach does negate many of the safety issues of untethered flight. The chap I saw demonstrating his system had it literally on a retractable dog lead. To bring it down he just pushes the switch and down it comes. He still used a transmitter on the ground to increase/decrease the throttle as needed and then walked around with it.

The safety case certainly seems much easier to work out. The multi is restricted to the length of the tether. There's no chance of a flyaway as it is attached to the tether, and you can still kill the throttle if you need to bring it down quickly.

I can see why the CAA/FAA is far less concerned by this kind of system. Much more control if something goes wrong and a very defined radius of operation.

 

[jes1111]

i hypothesized and then i tested and then i went out and did it, and did it again, and did it again, etc., etc., etc.

i don't generally inject my unfounded over-dramatized opinions into conversations where it is almost always inappropriate.

engineering is a discipline that uses the middle ground to apply scientific gains to everyday life. as an engineering enthusiast you seem to miss the middle ground part and instead take things to extremes. science explores the extremes and the engineers then utilize the best compromise to make science useful. balance, it's about balance.

Unfounded? Over-dramatized? Inappropriate? Let me paste in here the words that seem to have got you so riled:

The irony is that such a technique is possibly just as dangerous to nearby people/property, if not more so, than free flight.

Please point out precisely what is unfounded, what is over-dramatized and what is inappropriate in there. Note also that it does not express an opinion, per se - it's only a hypothesis. Furthermore, it is only pointing out an irony - one that's remarkably similar to the recreation/commercial distinction that the FAA makes whilst claiming their sole motivation is safety.

I wish you would stop jumping on everything I write - it's tiresome for all. If you don't agree or feel the need to refute, then go ahead - but stop with the snide put-downs, will you? It seems you can't see it but you are coming across very "RCG".