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Quadcopters as they exist in RC today will never see use carrying humans. They still rely on absolute motor reliability, and have failure modes that either result in loss of control, or in the very best case, a loss of half of its lift, and loss of almost all control. You'd have to engineer a quad with transmissions to transmit power from one motor to another rotor whose drive motor has failed. At that point, just stick the motors together, put the rotor on top, and build a helicopter. It's cheaper. Octocopters have a little bit more promise for this, but still have controllability and lift reserve issues during a motor-out event. And then there's the aforementioned battery issues. I don't think they hobbyist/DIY crowd fully appreciate what FAA regulation could do to them, either. I've seen views ranging from guarded optimism to raging, hard-boner enthusiasm, because the thinking is that FAA regulation will bring legitimacy to their hobby/industry. FAA regulations for RC past what already exist will be crippling to the industry, full stop. The FAA isn't going to make changes to the current FARs to incorporate RC powered lift, and have everyone living in harmony. They're going to regulate RC powered lift into irrelevance, to protect manned flight, and the National Airspace System.
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Mar 23, 2014 17:02
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Is there any reason a man-rated quad/octorotor couldn't use gas engines instead of electric motors? And I imagine if they have large enough blades to lift a human payload like helicopters do, they should be able to land safely; if the engines run at constant throttle and use cyclic to vary the lift at each corner, you're a set of clutches away from being able to autorotate, which I'm sure sufficiently robust software could easily handle.
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Mar 23, 2014 17:15
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Quads will never be man-rated, period. If you lose one corner, you're dead unless your controller software recognizes it in milliseconds or you will overturn; you'd still need enough lift on two rotors to keep you airborne. In that scenario, you are spinning uncontrollably because the rotors keeping you up turn the same direction, eliminating any yaw control. The other problem with only having two rotors is that you've lost orientation control, so you can't react to crosswinds or obstacles. In short, any kind of drive failure on a quad carrying humans is going to result in death. EightBit fucked around with this message at 17:33 on Mar 23, 2014 |
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Mar 23, 2014 17:29
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EightBit posted:Quads will never be man-rated, period. If you lose one corner, you're dead unless your controller software recognizes it in milliseconds or you will overturn; you'd still need enough lift on two rotors to keep you airborne. In that scenario, you are spinning uncontrollably because the rotors keeping you up turn the same direction, eliminating any yaw control. The other problem with only having two rotors is that you've lost orientation control, so you can't react to crosswinds or obstacles. http://diydrones.com/profiles/blogs/new-algorithm-can-save-a-quadcopter-after-one-motor-prop-failure To be fair: Helicopters are still in common use despite the fact that a single rotor loss will KILL you. CommieGIR fucked around with this message at 17:37 on Mar 23, 2014 |
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Mar 23, 2014 17:34
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MrYenko posted:Quadcopters as they exist in RC today will never see use carrying humans. They still rely on absolute motor reliability, and have failure modes that either result in loss of control, or in the very best case, a loss of half of its lift, and loss of almost all control. You'd have to engineer a quad with transmissions to transmit power from one motor to another rotor whose drive motor has failed. At that point, just stick the motors together, put the rotor on top, and build a helicopter. It's cheaper. Failure mode control is improving rapidly, but agreed that quads are unsuited for passenger transportation. https://www.youtube.com/watch?v=ek0FrCaogcs
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Mar 23, 2014 17:35
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Several quads tied together and you have your very own vertical aircraft! https://www.youtube.com/watch?v=L75ESD9PBOw
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Mar 23, 2014 17:40
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Ambihelical Hexnut posted:Several quads tied together and you have your very own vertical aircraft! Don't forget Atlas, the human powered quadcopter! http://www.youtube.com/watch?v=syJq10EQkog
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Mar 23, 2014 17:42
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Multis are also very inefficient. You will use a lot more fuel and create a lot more noise than a helicopter, without being safer of better. The reason is disk loading. Imagine the area swept by a helicopter's rotor. It is force distributed over that area that carries the weight. Now imagine this weight needs to be carried by four to six tiny rotors that fit within the hull. They need to push a lot more thrust per area of lifting surface so they will create a lot more noise and more downwash. It would be more similar to a Harrier than a helicopter. And if you are controlling it with complex computers, why not just control a regular helicopter with computers?
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Mar 23, 2014 17:45
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Edit: ^^^^ Modern helicopters do use computers for stability. The reason for going to a multirotor is to vastly reduce mechanical complexity. In a conventional helicopter there are a large number of single point vulnerabilities that result in a total loss of control. This is why they are such maintenance hogs. As for noise you can optimise a fixed pitch prop far more easily than a typical helicopter rotor. Go listen to a multirotor and compare it to a similar sized single rotor and you will find the multi is quieter because you gt rid of the tail rotor to main rotor interference. EightBit posted:Quads will never be man-rated, period. Not sure why anyone would limit themselves to only 4 motors. Modern helicopters are in the same boat as quads and tricopters loss of any one rotor means you are basically hosed. As soon as you get into the higher numbers of motors the loss of a single motor becomes less and less important. With the high reliability of electric motors you can reduce the odds of a total failure to a very low level compared with the mechanical nightmare that is the modern single rotor helicopter. And has everyone already forgotten this. Done in 2011 with off the shelf R/C components. https://www.youtube.com/watch?v=L75ESD9PBOw This is the newest bit of work from these guys. https://www.youtube.com/watch?v=tNulEa8LTHI The idea is to have a very limited range supplied purely from batteries with main power supplied by a turbine generator set. In the event of a generator failure you can still land on battery power. helno fucked around with this message at 17:55 on Mar 23, 2014 |
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Mar 23, 2014 17:47
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MrYenko posted:I don't think they hobbyist/DIY crowd fully appreciate what FAA regulation could do to them, either. I've seen views ranging from guarded optimism to raging, hard-boner enthusiasm, because the thinking is that FAA regulation will bring legitimacy to their hobby/industry. FAA regulations for RC past what already exist will be crippling to the industry, full stop. The FAA isn't going to make changes to the current FARs to incorporate RC powered lift, and have everyone living in harmony. They're going to regulate RC powered lift into irrelevance, to protect manned flight, and the National Airspace System. Agreeing with this. http://online.wsj.com/news/articles/SB10001424052702304256404579453120221666910?mod=WSJ_Opinion_LEADTop&mg=reno64-wsj quote:Now the field is wide open for private drone flight—at least until regulators promulgate binding standards. Trade groups say that some 100,000 U.S. jobs and $80 billion in business over the next decade are on the line, but Mr. Pirker isn't optimistic. The FAA's current policy "road map," he notes, envisions as strict a licensing system for operators of small remote-controlled drones as for pilots of private passenger planes. The regulation trend is to be extremely conservative; you can argue whether that's to protect entrenched industries, etc. Same thing that's holding back the driverless car and is currently trying to strangle stuff like Uber and even AirBNB in the crib for the flimsiest public safety reasons.
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Mar 23, 2014 22:00
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First off, when I say flying car, I don't mean like jetsons car or Moller sky car. We need to drop that idea and think outside the box. Second, when I say within a year, I don't mean a commercial offering or even prototype. This will be a youtube video of someone that took the guts of a sharper image quad copter and attached them to a scaled up model that they can effortlessly fly. Third, this is a long way from a commercial offering. I expect to see this fit more into a personal flying vehicle category similar to experimentals and ultralights that hobbyists use more than anything.
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Mar 23, 2014 22:05
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kmcormick9 posted:First off, when I say flying car, I don't mean like jetsons car or Moller sky car. We need to drop that idea and think outside the box. 'Thinking outside the box' would be telecommuting and unmanned communal delivery systems (like the joke Amazon quadcopter.) Physically moving human bodies through the sky essentially just to look at things in person and go home is one of those hilariously inefficient '60s ideas people just can't drop
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Mar 23, 2014 22:09
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EightBit posted:Quads will never be man-rated, period. If you lose one corner, you're dead unless your controller software recognizes it in milliseconds or you will overturn; you'd still need enough lift on two rotors to keep you airborne. In that scenario, you are spinning uncontrollably because the rotors keeping you up turn the same direction, eliminating any yaw control. The other problem with only having two rotors is that you've lost orientation control, so you can't react to crosswinds or obstacles. Quads perhaps, but people have already solved that by having lots of redundant motors. FYI, it's a manned prototype (which has already flown with a passenger in an earlier version). Like people have mentioned the limitation is still the battery tech, but it would still allow the pilot to fly for ~10 mins. Extend that and you've got your flying car. https://www.youtube.com/watch?v=6rK2Url7UBQ Blah I'm slow. Barnsy fucked around with this message at 22:20 on Mar 23, 2014 |
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Mar 23, 2014 22:18
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Barnsy posted:Quads perhaps, but people have already solved that by having lots of redundant motors. FYI, it's a manned prototype (which has already flown with a passenger in an earlier version). Like people have mentioned the limitation is still the battery tech, but it would still allow the pilot to fly for ~10 mins. Extend that and you've got your flying car. At that point, you might as well just have a goddamn helicopter. They also come with a hell of a lot more than 10 minutes' worth of endurance.
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Mar 23, 2014 22:25
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Snowdens Secret posted:
The regulation trend is to protect people in manned aircraft from being killed by a yahoo with a toy helicopter and zero training. It's really nothing like Uber.
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Mar 23, 2014 22:29
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FrozenVent posted:At that point, you might as well just have a goddamn helicopter. They also come with a hell of a lot more than 10 minutes' worth of endurance. Except you have a lot less maintenance, redundancy on engines, and you don't have the crazy torque failure issues that are so common in helis. That cable that downed the heli in a second? It would have just stopped one motor and nothing would have happened. From a flying perspective it's also a piece of cake because the software does all the correcting for you. For the layman they'll be miles more easy to fly than a traditional heli. As stated before, they're thinking of sticking a turbine generator to power the motors. There's your endurance issue solved. And there's still going to be a small battery backup for if the turbine fails.
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Mar 23, 2014 22:39
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Prop Wash posted:The regulation trend is to protect people in manned aircraft from being killed by a yahoo with a toy helicopter and zero training. It's really nothing like Uber. There's an argument that, in the envelopes they operate in, you're as likely to be killed by a five pound bird as you are by a five pound copter. And collision avoidance is a simple matter of sensors and software. But you're reinforcing my point, if the Fed mindset think a phone app that assists with carpooling is a danger to the very fabric of society, it's pretty obvious widespread unmanned rotorcraft are an immediate no-go. E: removed 'this idea will never get off the ground' and 'app for when you need a lift' puns for n4i's sake
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Mar 23, 2014 22:57
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Snowdens Secret posted:There's an argument that, in the envelopes they operate in, you're as likely to be killed by a five pound bird as you are by a five pound copter. And collision avoidance is a simple matter of sensors and software. But you're reinforcing my point, if the Fed mindset think a phone app that assists with carpooling is a danger to the very fabric of society, it's pretty obvious widespread unmanned rotorcraft are an immediate no-go. The federal government does not regulate car sharing applications. They do require a license for certain interstate trucking however and most states require you to have additional insurance and training if you are operating a vehicle for hire. Also interesting you mention birds because there are FAA regulations requiring airports to ensure that birds will not interfere with aircraft at low altitudes. I guess since drones aren't afraid of owls, falcons or blank rounds we should require the installation of ADA at all airports? I'm sure Grover could recommend a laser based battery.
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Mar 23, 2014 23:15
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You're right, I should've said 'the general government mindset' instead of just the Fed, since the crackdowns on Uber/AirBNB etc aren't at the Fed level. Nevertheless there's worlds of distance between saying 'don't fly drones near an active airport' (if that's what that weird grover tie-in meant) and 'drone pilots must be licensed the same as manned aircraft pilots'. Bobby Joe putting a GoPro over the 50 yard line of his local high school football game to throw the footage on the Youtubes isn't going to be taking down airliner traffic, but that kind of use is still what the FAA is going to swat down.
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Mar 24, 2014 00:04
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Snowdens Secret posted:You're right, I should've said 'the general government mindset' instead of just the Fed, since the crackdowns on Uber/AirBNB etc aren't at the Fed level. I'm sure life flights will just love having those drones everywhere.
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Mar 24, 2014 00:18
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hobbesmaster posted:I'm sure life flights will just love having those drones everywhere. TCAS overload!
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Mar 24, 2014 00:36
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Snowdens Secret posted:There's an argument that, in the envelopes they operate in, you're as likely to be killed by a five pound bird as you are by a five pound copter. And collision avoidance is a simple matter of sensors and software. But you're reinforcing my point, if the Fed mindset think a phone app that assists with carpooling is a danger to the very fabric of society, it's pretty obvious widespread unmanned rotorcraft are an immediate no-go. I will rescind my comments if it turns out that the average drone user is aware of the existence of SR routes and can readily identify the related potential hazard areas and altitudes. Also birds are a pretty bad comparison considering we actually have fairly good bird prediction models whereas the only warning we would have for unmanned rotorcraft activity would be if the operator put a NOTAM into the system, which would be excellent if they knew what a NOTAM was.
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Mar 24, 2014 02:17
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Snowdens Secret posted:'Thinking outside the box' would be telecommuting and unmanned communal delivery systems (like the joke Amazon quadcopter.) Physically moving human bodies through the sky essentially just to look at things in person and go home is one of those hilariously inefficient '60s ideas people just can't drop This is what's going to kill the "flying car" once and for all: http://www.doublerobotics.com/
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Mar 24, 2014 02:46
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Prop Wash posted:I will rescind my comments if it turns out that the average drone user is aware of the existence of SR routes and can readily identify the related potential hazard areas and altitudes. Also birds are a pretty bad comparison considering we actually have fairly good bird prediction models whereas the only warning we would have for unmanned rotorcraft activity would be if the operator put a NOTAM into the system, which would be excellent if they knew what a NOTAM was. Look, why don't you just limit the height, leave in the current requirements for light and noise, and add in a transponder? They already make transponders for drones, if it's lit up, screaming, and sending out a signal at 200 feet in the air, the only person you have to blame for hitting it is your own drat self. Requiring a NOTAM or a Private Pilot's License is just stupid. It's taking the two major selling points of UAV technology and stepping on them. (It's cheap! It's quick! Not anymore..) If a brush fire starts, I want the fire department to be able to have an eye in the sky within minutes, not be stuck on the phone with the FAA, or be putting Firefighter Joe through goddamned flight training so he can pilot a device that works through his iPhone.
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Mar 24, 2014 03:10
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Captain Bravo posted:Look, why don't you just limit the height, leave in the current requirements for light and noise, and add in a transponder? They already make transponders for drones, if it's lit up, screaming, and sending out a signal at 200 feet in the air, the only person you have to blame for hitting it is your own drat self. It doesn't have to make sense. It's the federal government. The idea that the FAA won't smack down the drones JUST BECAUSE is preposterous. They might not, but it should definitely be a careful-what-you-wish-for type of situation.
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Mar 24, 2014 03:39
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Captain Bravo posted:Look, why don't you just limit the height, leave in the current requirements for light and noise, and add in a transponder? They already make transponders for drones, if it's lit up, screaming, and sending out a signal at 200 feet in the air, the only person you have to blame for hitting it is your own drat self. If you want a transponder you'll need to talk to ATC and have a FCC license for the transmitter (a PPL counts as an FCC license for properly certified aircraft radios)
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Mar 24, 2014 03:45
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I feel like this is the second or third time in this thread's lengthy posts that I've been reminded of the multiple times I've almost had a midair with a UAS while flying. Something that weighs a few hundred pounds, does 50+kts, and has no regard for its own survival can be very difficult to see and avoid, and these are ones where the operators are talking to ATC. There's no reason that something of model size and weight shouldn't be fast and easy to put up vmc, just like any r/c airplane, but if you're going to send it out of visual range of the operator without so much as a notam then you're just asking for an incident. It's going to suck if there's no standard in place when someone's hobbyking-sourced fpv cross country project shits a servo and crashes 10 pounds of lipos into a school or a government building or whatever, then you'll really see some reactionary lawmaking. The need to submit a notification to the FAA prior to launches hasn't killed high power rockets, and those guys are putting 10-100 pounds up 20k+ at mach speeds. It can be done.
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Mar 24, 2014 03:51
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Fucknag posted:Is there any reason a man-rated quad/octorotor couldn't use gas engines instead of electric motors? And I imagine if they have large enough blades to lift a human payload like helicopters do, they should be able to land safely; if the engines run at constant throttle and use cyclic to vary the lift at each corner, you're a set of clutches away from being able to autorotate, which I'm sure sufficiently robust software could easily handle. You probably pieced this together from the other replies, but the main advantage of a multirotor is the elimination of all the mechanical complexity that comes with a single. If you add back in combustion engines and cylic pitch, you're sort of defeating the purpose. I have wondered if it would be a fun toy to have cyclic pitch on the rotors, though. It would make for some very interesting aerobatic capability. Otherwise, multirotors are worse in just about every other way. The flight envelope doesn't even compare. For example, there isn't really such thing as a controlled rapid descent on a multicopter. You accelerate downward by reducing the speed of all the rotors - without rotors spinning you have no control. Likewise, if you've ever seen a quad drop altitude quickly, you'll see just how unstable they are in what amounts to a constant prop stall on 4 rotors. I've crashed mine this way before. Helicopters also have a larger spinning mass, which gyroscopically stabilizes the craft. I know that the electronics solve this on a multi, but there's something to be said for inherent stability. As mentioned already, a single rotor is also more efficient. The redundancy of >4 rotors does sound promising, but it seems mostly theoretical at this point. Multirotors are great because they're cheap, cheap to operate, easy to maintain, easy to fly. You would choose a multirotor for doing camera work for the same reason golf carts are electric. Best tool for the job. The volocopter does look interesting. If the turbine fails, you still have some reserve on battery. If a single rotor fails, you have redundancy. It's not clear to me if the loss of efficiency is worth it, but they seem to be pretty serious about it.
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Mar 24, 2014 05:15
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Powercube posted:And then, one lands at the wrong airport: http://www.nbcnews.com/storyline/missing-jet/china-plane-sea-search-lands-wrong-australia-airport-n59406 I thought I heard something loud on Saturday.
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Mar 24, 2014 06:35
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Captain Bravo posted:Look, why don't you just limit the height, leave in the current requirements for light and noise, and add in a transponder? They already make transponders for drones, if it's lit up, screaming, and sending out a signal at 200 feet in the air, the only person you have to blame for hitting it is your own drat self. I'm sorry, but not even CLOSE to everyone flying today has a traffic avoidance system. The transponder would only be helpful to aircraft such equipped. quote:If a brush fire starts, I want the fire department to be able to have an eye in the sky within minutes, not be stuck on the phone with the FAA, or be putting Firefighter Joe through goddamned flight training so he can pilot a device that works through his iPhone. There are already automatic Temporary Flight Restriction areas set up around any wildfire/firefighting operation. This would be redundant in the US.
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Mar 24, 2014 11:16
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Same in Australia... If you go bumbling into a fire grounds airspace in your news chopper or your light plane, you WILL be intercepted by the air attack supervisor in his chopper and you WILL get told in no uncertain terms to gently caress off before your hit by a fire bomber. Although our fixed wing bombers get so drat close to the ground that a quad copter would be a serious risk to them
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Mar 24, 2014 11:31
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Drones with transponders would pretty much totally require a full redesign of the current system. So much of the TCAS system is inhibited below 1700' which just so happens to be where drones will be flying.
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Mar 24, 2014 13:26
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SCOTLAND posted:Drones with transponders would pretty much totally require a full redesign of the current system. So much of the TCAS system is inhibited below 1700' which just so happens to be where drones will be flying. Wait, TCAS doesn't work below 1700'? I thought the entire point of TCAS was to increase SA in busy terminal areas.
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Mar 24, 2014 14:17
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Bob A Feet posted:Wait, TCAS doesn't work below 1700'? I thought the entire point of TCAS was to increase SA in busy terminal areas. Certain portions are inhibited, at varying altitudes and configurations. For example, on the 787 TCAS RAs are inhibited below 1000' radio altitude while in the landing regime, until the go around at 900 feet (for a TCAS climb) or 1200 feet for a (TCAS Descend). There are different rules for take-off and also non-normals from what I understand
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Mar 24, 2014 14:26
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It seems like it would make more sense to mandate drones above some specified weight have sensors to pick up whatever presence signal manned aircraft are required to broadcast and programming to auto-flee in an opposite direction. Recievers presumably take a lot less size/weight/power than transmitters, this avoids any FCC broadcasting concerns, etc. You could also put similar beacons for repulsion around active airports (if there's not an essentially equivalent signal already.) Also the concerns here (and hexnut's anecdote) are all about mid-air collision, which isn't addressed at all with (ground-based) pilot licensing, which sounds like what the FAA wants to implement. Licensing in particular makes less and less sense as the drones become more autonomous / pre-programmed.
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Mar 24, 2014 14:26
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CommieGIR posted:http://diydrones.com/profiles/blogs/new-algorithm-can-save-a-quadcopter-after-one-motor-prop-failure If you mean a single main rotor, okay, but tail rotor losses are frequently survivable, and main rotor loss is one hell of a lot less common than engine losses, which helicopters frequently survive. Semi-related datapoint of pure crazy: https://en.wikipedia.org/wiki/Piasecki_PA-97
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Mar 24, 2014 14:27
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Snowdens Secret posted:It seems like it would make more sense to mandate drones above some specified weight have sensors to pick up whatever presence signal manned aircraft are required to broadcast and programming to auto-flee in an opposite direction. Recievers presumably take a lot less size/weight/power than transmitters, this avoids any FCC broadcasting concerns, etc. You could also put similar beacons for repulsion around active airports (if there's not an essentially equivalent signal already.) So what you're saying is no drones until everyone has ads-b?
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Mar 24, 2014 14:37
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I think some folks are vastly overestimating the amount of positive control and avoidance tools that exist below Class A airspace.
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Mar 24, 2014 14:44
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Godholio posted:I think some folks are vastly overestimating the amount of positive control and avoidance tools that exist below Class A airspace. Its about time someone taught those cessna's buzzing around private fields with their radios and transponders off a lesson. Glad the drones can fill that role.
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Mar 24, 2014 14:59
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Snowdens Secret posted:It seems like it would make more sense to mandate drones above some specified weight have sensors to pick up whatever presence signal manned aircraft are required to broadcast There is no such signal requirement in the US that applies to all manned aifcraft.
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Mar 24, 2014 15:02
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