Hi Steve,
Thanks for your input and thank you for keeping it civil.
I'm not assuming that all incidents are similar, of course they never are. But I am considering the worst possible scenario. In my line of work it is my job to consider 'failure modes' of the products that I work with, to consider ways in which to mitigate the fall-out of such events and implement them. In this particular instance we are considering just one type of event, that being the gimbal and camera assembly seperating from the airframe. The 'root cause' to such an event can be analysed extensively but you will most likely find that all such causes will be similar and only really fall into a couple of different categories - equipment failure or pilot error. You can then analyse these and open them up to reveal a lot more information in themselves.
The problem here is that however a failure manifests and whatever the result is, it can lead to a number of different outcomes for which it would be impossible to try and second guess how best to mitigate the results of a failure. Therefore, you are left with only one choice and that is to consider the 'worst case scenario'. You cannot possibly cover all the bases - if only for the simple fact in that you may not have even considered some of the types of failure, they may simply never have occured to you. Not only that but the different permutations, cause and effect and the random nature of these things make it impossible to predict. Reasonably, you can ONLY ever work to prevent the worst case scenario, which much of the time can indirectly or directly result in mitigating against other more minor things too. Anyway, I'm not intending to bore with the logic behind this since it's an entirely different and completely theorethical debate.
Boil it down to the basics - we are talking about people flying RC aircraft and the only constant is gravity directing all objects under it's influence downwards. Cameras, gimbals, etc, are largely irrelevant and we can simply consider them to be a payload of a variable nature but really whats the worst thing that can possibly happen when flying an RC anything ? It's not actually whether your model crashes or not, it's not even whether the root cause was down to you or an equipment failure - it is merely down to the simple factor of whether your model, if for whatever reason it's out of control, is the likelyhood of it causes injury to someone or damage property, or even death - the fact is that you are always present at take-off and so the answer to that always 'yes, it's possible'. How it happens is actually irrelevant because the various root causes can end up with the same outcome and you can practically guarantee that you will crash something at some time. It's those nasty outcomes that are the main thing to avoid. Your equipment can be replaced, a person cannot.
Well lets consider that statement for a moment. What does 'tethered' actually mean? You could tether something with any number of different materials with different properties, you can tie it loosely or tightly. In this particular instance we're talking about tethering around the vibration absorbing connectors, which suggests to me that you don't want to be tieing this stuff about too tightly without affecting the performance of the solution. If we take that as a given then you can only draw the conclusion that should the gimbal detatch itself for whatever reason that it's no longer going to be in the same static configuration that it started out in, in other words it will become loose and potentially moving seperately from the airframe - maybe not like a huge pendulum, but movement of any mass can result in some incredibly dynamic situations - a moving mass, even slightly, has much higher energy than one at rest. I'm kinda at a loss as to wondering how you could tie it to make sure it didn't move. If it became seperated without tieing it tightly it would therefore negate the performance of the solution in the first place.
OK, lets just clarify what it is that I was actually advocating - leaving the manufacturers solution unmodified and making a consious decision to not tethering the gimbal in any way. No more, no less, and in actual fact what I'm suggest is 'do nothing'. I'm not actually advocating a safe fall-away detachment of the gimbal and camera as an end-tp-end solution, as you are 100% correct in that you would need to engineer something to ensure it happens that way 100% of the time. My point was merely that the outcomes of literally doing nothing could be preferable to proactively doing something, and I ended that point by making a note on the legal implications of changing the manufacturers desgin.
Very true. But which is worse? - an object of a given mass dropping vertically straight down, or one that is potentially circling randomly above everyone's heads until it eventually and unpredictably comes to rest almost anywhere? You have to admit that if a gimbal was tethered (not necessarily using your method, but you have to consider that it could be tethered using any number of solutions, some effective and some not so) that there is a chance that it could lead to instability of the aircraft. The alternative of the item dropping straight down and on it's own has to be preferable to being still attached to a flying machine equipped with lots of chopping implements would could end up coming into contact with someone, even yourself. If you go and ask any professional in the field of risk assessment and present them with the two options then you already know which one they are going to take, and they won't give a moments thought for the cost of your equipment.
I would echo your sentiments completely. Everyone should always consider all the outcomes, but not to be too distracted by protecting their investment but rather should focus on protecting everyone else around them. It might not make for the most favourable outcomes for the RC operator but thats just a fact of life and is the basic ethos of responsible aero-modelling.
I see this debate popping up all the time, and I largely suspect it's due to this particular part of the aeromodelling hobby and the VTOL aspect being so appealing and so much more accessable to almost anyone, that a number of operators first exposure to aeromodelling is multirotors, and not the conventional introduction to RC flying that folks that have been in this hobby for more than 3 years will typically have.
The comments that the OP made to me in his last post did question my qualifications as an RC flyer and he seemed to think that I was giving the impression that I'd never crashed. The simple fact is that I have been examined (and passed) at various levels by my national governing body in this field, and so I have a qualification to fly this equipment and I have all the insurances in place by being a member of the BMFA and hold A and B certifications in all disciplines. Despite that I have crashed, lots of times, and I'm just as liable to do so as anyone else and always will be. As far as making my own potentially expensive paperweights I've spent thousands on gas turbine powered 200mph+ jets in the past and being involved in this hobby at the outset for more than 10 years via a local BMFA affiliated club (in fact the oldest recorded club in England) and even serving on it's commitee as it's 'Jets Officer' does give me an insight that people that just fly a Phantom in their back yard or down their street or over in some random field, will possibly never have. I've attended and flown at national events specifically for gas turbine models more times than I can remember and I've always had to be accountable to the safety personel at these events - thats how I qualify my experience and opinion in this matter, but none of that makes me an expert. This is merely my own opinion, and unfortunately for the OP I'm entitled to it even if he doesn't like it. He can call me all the names he like, it doesn't bother me and only serves to prove a point.
