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Ola posted:For the stability system, yes. But if you were trusting your life to it, it would be very much in your interest to know if one of the rotors failed, so you can abort the flight safely. Oh yeah, absolutely agree. I was only addressing it in the context of its integration into the control system and automatic compensation.
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Mar 15, 2018 09:05
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vessbot posted:Oh yeah, absolutely agree. I was only addressing it in the context of its integration into the control system and automatic compensation. The integration would be mostly invisible to the user, but the engineering of that automatic compensation and integration is interesting and definitely not a red herring. How would you build and maintain a passenger multirotor hybrid is a legit question. How does it fly is interesting too, but you ain't flying it until you figure out the answer to the first question!
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Mar 15, 2018 11:52
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For simple energy density reasons I can't see multirotors taking over the bread and butter of civilian helicopter operations like moving people back and forth from oil rigs. Surveillance and the like? Sure. The Channel 4 chopper doesn't need to be a big fancy helicopter if can just use a quadcopter drone with a telephoto camera.
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Mar 15, 2018 12:57
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vessbot posted:I think all this failure detection stuff for the multirotor is a red herring. Surely the control system for this craft would be fly by wire, automatically stabilizing around a commanded attitude or attitude rate (if not something even higher level than that, such as translation rate). So, it's already correcting for upsets regardless of the source, and a pitch and roll due to losing 1/3 of the thrust on one corner would be indistinguishable from the same pitch and roll due to, say, a strong gust; and automatically corrected for by the control system's natural behavior. The system should be able to, both just in purely technical terms and as a design goal for safety, be able to compensate for a dead/malfunctioning rotor that's reporting "no, everything's fine, we're all fine here." But you really want to know if a rotor is dead, because otherwise the system will keep trying to use that rotor in its efforts to compensate for the effects of the rotor failure. That will likely force the system to compensate, then compensate for the compensation, and then compensate for that - that's going to be very hard to control and may even cascade to the point that it brings the aircraft down. Heuristics can allow the system to figure out what happened on its own and develop an effective mitigation through trial and error, but that still takes some time to cycle and there are a lot of regimes where that time is the difference between crashing and not. Pitch and roll from losing thrust is and will always be distinctive from pitch and roll from external causes and has to be compensated for differently. Failure detection isn't a red herring, it's a core design problem for multirotors. That being said I don't think it's nearly as intractable or complex a problem as it's sometimes presented. "Keeping the wheels on" is a core design problem for cars that you have to get right, but it's not exactly hard in most cases.
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Mar 15, 2018 15:24
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The issue with scaled-up multirotors is that even if you disregard the above-mentioned control issues and assume that they are all solved problems, any motor or prop failure means that the computer will have to throttle down or shut down the opposing motor/prop pair as well to maintain control. If you want to be able to climb with a propulsion failure at MGTOW (which in a manned aircraft, you sure as hell are,) that means that you’re going to need an obscenely powerful vertical lift system, which will require heavier structure, and a lower payload fraction. At some point very soon, you realize that your scaled-up multirotor is now more expensive and less capable than something that Bell already builds. I do heartily agree that as soon as someone starts building an unmanned multi rotor big enough to reliably carry a TV camera and a transponder, and the FAA unfucks its regulatory structure regarding civilian UAS operation, that news helicopters are going away. That’s pretty much an ideal use-case for multicopters.
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Mar 15, 2018 15:36
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MrYenko posted:If you want to be able to climb with a propulsion failure at MGTOW (which in a manned aircraft, you sure as hell are,) This doesn't hold at all for the AS350, one of the most ubiquitous helicopters in the world. It reports the news, shoots film, transports people and heavy objects over populated areas every day. It even charges money for it. And it only has a single engine, single gearbox and a single rotor. Failure in any of those means it's coming down on the spot. And all aviation authorities thinks that's just fine and dandy, so long as you operate and maintain it a certain way. This will be true for manned multirotors as well. A twin engine helicopter loses half its lifting power when one engine fails, where as the Volocopter with 18 rotors only loses 1/9th, if you have to shut down the opposing engine. Which you don't, so somewhere between 1/9th and 1/18th. It depends on which motor and what maneuver you're trying to do. The computer will figure out how to vary thrust and it will hopefully tell the pilot what to do and what not to do in order to land safely. Jettisoning external sling loads should also be possible, as it is with helicopters.
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Mar 15, 2018 17:26
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Ola posted:This doesn't hold at all for the AS350, one of the most ubiquitous helicopters in the world. It reports the news, shoots film, transports people and heavy objects over populated areas every day. It even charges money for it. And it only has a single engine, single gearbox and a single rotor. Failure in any of those means it's coming down on the spot. And all aviation authorities thinks that's just fine and dandy, so long as you operate and maintain it a certain way. This will be true for manned multirotors as well. Just because you have 18 rotors doesn't mean you can afford to make them out of cheap Chinese horse glue, or have a maintenance program that consists of "eh, gently caress it, I ain't taking my boots off to count how many of these are still working". 18 rotors and gearboxes or motors vs. 1 rotor and one gearbox+motor = 18x the amount of inspections, parts, overhaul, tracking, etc. Yes the consequences of an individual unit failure are less, but the cost and complexity of maintaining the system goes up massively. Let's say you have a failed drivetrain component that points to a manufacturing defect which leads you to inspect and/or replace all the same part number components with upgraded parts. You've got to do that 18 times per aircraft now, vs once for the same failure on the single rotor helicopter. Regulations might permit a longer inspection interval due to the redundancy compared to the single rotor, but you're still going to have to do it.
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Mar 15, 2018 18:09
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Finger Prince posted:Just because you have 18 rotors doesn't mean you can afford to make them out of cheap Chinese horse glue, or have a maintenance program that consists of "eh, gently caress it, I ain't taking my boots off to count how many of these are still working". 18 rotors and gearboxes or motors vs. 1 rotor and one gearbox+motor = 18x the amount of inspections, parts, overhaul, tracking, etc. Yes the consequences of an individual unit failure are less, but the cost and complexity of maintaining the system goes up massively. Let's say you have a failed drivetrain component that points to a manufacturing defect which leads you to inspect and/or replace all the same part number components with upgraded parts. You've got to do that 18 times per aircraft now, vs once for the same failure on the single rotor helicopter. I bet 18 electric motors + rotors (no gearboxes), each with one moving part, contain two orders of magnitude fewer parts, serial numbers and inspection points than a turbine or piston powered helicopter.
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Mar 15, 2018 18:17
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Finger Prince posted:Just because you have 18 rotors doesn't mean you can afford to make them out of cheap Chinese horse glue, or have a maintenance program that consists of "eh, gently caress it, I ain't taking my boots off to count how many of these are still working". 18 rotors and gearboxes or motors vs. 1 rotor and one gearbox+motor = 18x the amount of inspections, parts, overhaul, tracking, etc. Yes the consequences of an individual unit failure are less, but the cost and complexity of maintaining the system goes up massively. Let's say you have a failed drivetrain component that points to a manufacturing defect which leads you to inspect and/or replace all the same part number components with upgraded parts. You've got to do that 18 times per aircraft now, vs once for the same failure on the single rotor helicopter. The simple fact is right now, no one actually knows where that breakpoint is, and more importantly if it's in a place that multirotor designs can compete with traditional designs, while remaining safe to operate. Right now the early designs fall into the grey area where it's tantalizing but far from guaranteed.
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Mar 15, 2018 18:19
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blugu64 posted:No no, just attach a big bag filled with a gas less dense then air, and attach the rotors around that. That way you get increased heavy lift capability to boot. You could use it to get lumber from hard to reach spots and everything.  If you could bring down the cost of tilt-rotors to something comparable to helicopters, I can see those becoming more popular. Please correct me if I'm wrong, but I think too the dual rotor setup is just a better setup than the single rotor and tail boom thing. If you wanted to make better helicopters, doing the scary thing and actually investing money in getting proficient at the new configuration would be the best way.
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Mar 15, 2018 18:41
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Firefly: E3-B landing (the smoke made me laugh)
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Mar 15, 2018 18:56
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Good ol fashioned TF33.
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Mar 15, 2018 19:08
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The problem with the multirotor is the specific energy of lithium batteries which is crap compared to jet fuel and not going to get sufficiently better to make up for it. Helicopters are already thin on payload. You could power it by some kind of turbo-electric deal but then you're back to square one; it's a single engine aircraft but way more complicated and it can't autorotate.Ola posted:I bet 18 electric motors + rotors (no gearboxes), each with one moving part, contain two orders of magnitude fewer parts, serial numbers and inspection points than a turbine or piston powered helicopter. OTOH I'm certain this is true. (Provided it is powered by batteries of course) Mortabis fucked around with this message at 20:14 on Mar 15, 2018 |
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Mar 15, 2018 20:10
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Finger Prince posted:Just because you have 18 rotors doesn't mean you can afford to make them out of cheap Chinese horse glue, or have a maintenance program that consists of "eh, gently caress it, I ain't taking my boots off to count how many of these are still working". "this is a bad design because if you make it out of inferior materials and don't maintain it, it will break" is not a valid argument.
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Mar 15, 2018 20:16
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I think that part of the problem with this argument is that we aren't even comparing apples to oranges, it's more like apples to potatoes. It's not even the same food group. We're looking at a Volocopter and trying to compare its operating cost and potential role to that of a jetranger or AStar, when it's much more realistic to compare it to a R22, which is dirt cheap and about as simple. Like, is something like a Volocopter or multirotor fixed wing hybrid going to be adopted for cattle mustering in the Australian outback due to its purported significantly lower cost of operation, maintenance requirements, and complexity? Maybe? Doubt it. Will they sell a bunch to rich men as toys? Sure. That's probably the market, but it's not going to replace workhorse helos. And my point is that if you're going to scale one up so that it can, it'll be too costly.
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Mar 15, 2018 20:38
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Sagebrush posted:"this is a bad design because if you make it out of inferior materials and don't maintain it, it will break" is not a valid argument. Did I say it was bad design? I said you can't cheap out just because there's more redundancy.
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Mar 15, 2018 20:55
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Finger Prince posted:I think that part of the problem with this argument is that we aren't even comparing apples to oranges, it's more like apples to potatoes. It's not even the same food group. We're looking at a Volocopter and trying to compare its operating cost and potential role to that of a jetranger or AStar, when it's much more realistic to compare it to a R22, which is dirt cheap and about as simple. I think you're just a tiny bit wrong now but you'll get more wrong as time passes. Scaling it up will be extremely costly today, but might not be so in the future. Helicopters too are extremely expensive today. They've been around for the better part of a century, yet they are privately owned only by rich people, or at best tiny hobby helicopters by very dedicated enthusiasts with income to spare. The operating costs of something like a workhorse AS350 are eye watering. But a lot of the things AS350s get hired for are done very inefficiently by them and can be done much more cheaply (and more environmentally friendly, safer, etc) by specialized tools. Think of aerial photography of a big building. A typical commission a museum or government building would do in the past. The price of an actual plane (rather than an AS350 I suppose) carrying an actual photographer vs a drone carrying just the camera. The full purchase price of a drone will hardly pay for a full tank of fuel, let alone pilot, photographer, landing fee, maintenance, etc etc. Cattle mustering, absolutely. Any sort of observation from altitude, easily. Communications relay, 10-4. Science, data retrieval, already happening. Sooner or later, precision lifting and cinema level set photography. People travel is further down the road, and it's a shame the startups and tech press are obsessing over this and forgetting all the lower hanging fruit. So replacing the vehicle 1-to-1 with an electric vehicle with similar performance is not the most likely way it will happen. It's more likely that specialized drones will pick away at the easy jobs before some big leap forward in energy storage, perhaps coupled with stricter regulations on fossil emissions, pulls the rug out.
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Mar 15, 2018 21:36
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Cool AI: Coming up out of a valley and seeing a ridge in the distance getting bombed with fire retardant. Not as cool AI: Noting that it's your ridge. (People, animals and structures are fine)
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Mar 15, 2018 22:43
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Ola posted:I think you're just a tiny bit wrong now but you'll get more wrong as time passes. Scaling it up will be extremely costly today, but might not be so in the future. Helicopters too are extremely expensive today. They've been around for the better part of a century, yet they are privately owned only by rich people, or at best tiny hobby helicopters by very dedicated enthusiasts with income to spare. The operating costs of something like a workhorse AS350 are eye watering. But a lot of the things AS350s get hired for are done very inefficiently by them and can be done much more cheaply (and more environmentally friendly, safer, etc) by specialized tools. But there you're arguing the difference between drone operations and manned flight. Hell before there were quadcopters my friend was doing aerial surveys for a mining company with his gas powered model single rotor helicopter. It was far cheaper to pay him a few hundred bucks than hire a chopper. Unmanned flight is definitely going to decimate the helicopter market in a lot of places, and it already is, whether it's multi rotor drones or blimps or whatever. But when you need to carry multiple humans and sensitive cargo and need to do it with vertical lift capability and greater range than a Tesla, it's going to be a big ask to do it cheaper than a helicopter, even with how monumentally expensive they are to operate.
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Mar 15, 2018 22:43
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joat mon posted:Cool AI: Coming up out of a valley and seeing a ridge in the distance getting bombed with fire retardant. My brother got bombed a lot as a hotshot and he said it was one of the coolest/most terrifying experiences of his life
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Mar 15, 2018 23:22
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Finger Prince posted:But there you're arguing the difference between drone operations and manned flight. But it's two fixed points on a path of development. The Volocopter already flies manned, does that mean it will never fly manned for money? Can't scale beyond point X? It took years and years before the first aircraft could match the payload of a horse. With so many potential benefits, why won't this technology improve like any other? Even horses were developed for better performance!
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Mar 15, 2018 23:25
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Mortabis posted:You could power it by some kind of turbo-electric deal but then you're back to square one; it's a single engine aircraft but way more complicated and it can't autorotate. A hybrid system could help here, both being able to take up the variations in load faster than the turbine-generator and to provide enough power for a safe landing. Of course that doesn't help the weight situation at all.
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Mar 15, 2018 23:33
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Look at the size of this thing! Sorry for FB link I’m on iPad and cant embed a video for some reason. It’s the new GE9X engine. https://l.facebook.com/l.php?u=http...umfZMkWfswmaR18
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Mar 15, 2018 23:46
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Spaced God posted:My brother got bombed a lot as a hotshot and he said it was one of the coolest/most terrifying experiences of his life Is that stuff toxic?
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Mar 15, 2018 23:47
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No, its mostly water and fertilizer. They're not trying to kill plant and animal life with it.
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Mar 15, 2018 23:51
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https://twitter.com/siberian_times/status/974219599397859330 Whaaaa If any of those bars had been wrapped with a slice of lemon there was a real chance of experiencing a pan galactic gargle blaster there.
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Mar 15, 2018 23:59
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Yeah, PhosChek is pretty much just glorified dish soap, dye and fertiliser.
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Mar 16, 2018 00:00
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monkeytennis posted:Look at the size of this thing! Sorry for FB link I’m on iPad and cant embed a video for some reason. It’s the new GE9X engine. That thing is just comically huge looking on that plane. Do they have to do some wierd computer control stuff on a test flight light that for the takeoff to prevent the (I assume) much higher thrust from that engine from causing issues, or do the test pilots just manually control it to keep it's thrust inline with the other engines?
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Mar 16, 2018 00:46
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Ola posted:But it's two fixed points on a path of development. The Volocopter already flies manned, does that mean it will never fly manned for money? Can't scale beyond point X? It took years and years before the first aircraft could match the payload of a horse. With so many potential benefits, why won't this technology improve like any other? Even horses were developed for better performance! I'm not arguing against evolution. Far from it. In fact the thing about evolution is that everything finds its niche, or changes to fit it. To me, "electric multirotors will replace everything" is just as absurd as dirigibles replacing everything. Could you make a search and rescue or air ambulance remote operated electric multicopter? Probably, eventually, with enough concentrated effort. Could you modernize single rotor flight using the same technology, while keeping the advantages of a single rotor and do it cheaper? You bet your rear end. Pie in the sky futurism is lovely, until someone has to foot the bill. Then they start asking how loving much, and can't we make the old stuff work better for cheaper? Cowboys still ride horses, right along side helicopters and ATVs.
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Mar 16, 2018 00:57
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Nah, the aviation industry will adopt new technology extremely quickly! * applies carb heat prior to commencing descent for NDB approach *
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Mar 16, 2018 01:11
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We had a spotter constantly orbiting over us and the property to our west:  A helo that was running for a couple hours, tanking up at the property to the east's pond and dropping on ours and the property to the west.     The closest were running about 250 meters from the house, and got a few sprinkles a couple times, But this little guy  Got within about 200m. Not allowed back to look at the damage yet because the firemen are still running dozers back there. joat mon fucked around with this message at 01:24 on Mar 16, 2018 |
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Mar 16, 2018 01:22
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monkeytennis posted:Look at the size of this thing! Sorry for FB link I’m on iPad and cant embed a video for some reason. It’s the new GE9X engine. https://www.youtube.com/watch?v=UsY5g3iV1rg
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Mar 16, 2018 01:22
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^  Nebakenezzer posted:Firefly: E3-B landing (the smoke made me laugh) 0578 was a Good Jet.
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Mar 16, 2018 02:43
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Nebakenezzer posted:Firefly: E3-B landing (the smoke made me laugh) Grew up within a mile of Tinker. This sound was every day. Took me right back to childhood.
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Mar 16, 2018 03:07
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  Fire retardant works!  S-61 King Air 250 AT-802 RJ-85 2 dozers A dozen or so fire vehicles (including an M715!) A couple dozen people. Makes me proud to be a taxpayer (and to buy $50 pies at VFD pie auctions)
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Mar 16, 2018 04:22
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Awesome, glad your place and animals didn’t get torched. Civic services often own.
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Mar 16, 2018 04:23
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I thought the first one was an old photo of Belleau Wood or something.
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Mar 16, 2018 04:46
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More like 
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Mar 16, 2018 05:12
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Ambihelical Hexnut posted:From what I can tell on google a BRS parachute system for a Cessna whatever weighs about 85lbs, will carry 3000lbs of airplane, and requires 260 feet of altitude for inflation. That last point might make the utility for hover recovery not super great, which means you really need to rely on the remaining props to arrest descent.
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Mar 16, 2018 14:09
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Hermsgervørden posted:https://twitter.com/siberian_times/status/974219599397859330 drat, is air salvage the same as sea salvage rules? siberiantimes.com/other/others/news/plane-loses-its-368-million-cargo-of-gold-platinum-and-diamonds-on-takeoff/?utm_source=fark&utm_medium=website&utm_content=link&ICID=ref_fark
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