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zoux posted:That's crazy. Are there any natural conditions under which that kind of stress is even possible? Also, what does "154" mean in that context? No not really, they're required to meet a certain stress limit and then they keep going past that to see where the point of failure is. 154 is 154% of design limit load (design limit load is the most extreme forces ever expected to be seen in service).
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Mar 20, 2014 16:01
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zoux posted:That's crazy. Are there any natural conditions under which that kind of stress is even possible? Also, what does "154" mean in that context? It's a percentage, they show it on the camera at the end. Probably "154% of the strain we're required to withstand" or something. E: beaten.
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Mar 20, 2014 16:01
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zoux posted:That's crazy. Are there any natural conditions under which that kind of stress is even possible? Also, what does "154" mean in that context? Someone with more knowledge will likely have a better answer, but I believe the 154% here means if the wing is designed to bear X amount of force, in application the wing can actual bear 154% of that X force. The X force it was designed to withstand is something like 1.5x maximum possible conditions too, or something wild like that. e: way beaten, drat. e2: to actually add something to the train talk - in a former job I worked a lot with the Union Pacific, and remember hearing stories about how they pretty much never let their container trains stop outside of their massive yard in Memphis, TN (techincally marion, ar, but whatever) because if they do, they tend to get broken into real fast. onezero fucked around with this message at 16:08 on Mar 20, 2014 |
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Mar 20, 2014 16:03
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zoux posted:That's crazy. Are there any natural conditions under which that kind of stress is even possible? Also, what does "154" mean in that context? Hopefully not, but the test is to make sure that the wings are way overengineered for safety purposes (aluminum becomes brittle and weakens as it is cyclically loaded, so you have to overengineer things made from it that are life-critical). 154 is the percentage of design load that the wings break at.
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Mar 20, 2014 16:03
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SeaborneClink posted:(Blue?) R22 if memory serves. Red R22, or if I have a friend along- it's a white or yellow R44. The blue R22 has janky seats.
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Mar 20, 2014 16:04
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zoux posted:That's crazy. Are there any natural conditions under which that kind of stress is even possible? Also, what does "154" mean in that context? 154% of the design maximum wing loading.
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Mar 20, 2014 16:20
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What percentage of the maximum load is an airplane under during normal flight, usually?
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Mar 20, 2014 16:30
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zoux posted:Hey guys, big fan of the thread. Saw this on imgur titled "787 wing stress test". Nice, I can see several parts that I (theoretically) inspected on that plane.
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Mar 20, 2014 16:31
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zoux posted:What percentage of the maximum load is an airplane under during normal flight, usually? IIRC, airliners are rated to roughly 2.5g, which means in level flight, at MGTOW, you're looking at about a 40% load factor, if my math is right.
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Mar 20, 2014 16:45
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Shampoo posted:Isn't that....expensive? Basically everything in the US military runs on JP8, from kitchen stoves and space heaters to main battle tanks, ground vehicles with diesel engines, generators, and so on. The DoD justifies the cost because it simplifies logistics a lot. Instead of having to get ten or twenty kinds of fuel to a unit through god knows how many pipelines and keeping track of all of them, you just throw a whole bunch of JP8 at it.
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Mar 20, 2014 21:00
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onezero posted:See for yourself: https://www.youtube.com/watch?v=H8N7gOe4bCI I guess the video is mislabeled, the footage is from 1995 and some commenter says its a 777. I wonder what the 787's wings can do.
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Mar 20, 2014 21:39
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VERTiG0 posted:I guess the video is mislabeled, the footage is from 1995 and some commenter says its a 777. I wonder what the 787's wings can do. The picture looks like a 787, video is definitely not. Cockpit windows look like a match to a 787. Alighieri fucked around with this message at 21:51 on Mar 20, 2014 |
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Mar 20, 2014 21:48
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Alighieri posted:The picture looks like a 787, video is definitely not. That picture is definitely a 787, the video is for a 777.
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Mar 20, 2014 22:14
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E4C85D38 posted:Basically everything in the US military runs on JP8, from kitchen stoves and space heaters to main battle tanks, ground vehicles with diesel engines, generators, and so on. The DoD justifies the cost because it simplifies logistics a lot. Instead of having to get ten or twenty kinds of fuel to a unit through god knows how many pipelines and keeping track of all of them, you just throw a whole bunch of JP8 at it. It also got a diesel KLR dirtbike made, which is coo.
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Mar 20, 2014 22:22
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DJ Commie posted:It also got a diesel KLR dirtbike made, which is coo. Which I'd kill for.
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Mar 20, 2014 22:34
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Terrible day at work. Found a great big crack in the pax door.
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Mar 20, 2014 23:16
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E4C85D38 posted:Basically everything in the US military runs on JP8, from kitchen stoves and space heaters to main battle tanks, ground vehicles with diesel engines, generators, and so on. The DoD justifies the cost because it simplifies logistics a lot. Instead of having to get ten or twenty kinds of fuel to a unit through god knows how many pipelines and keeping track of all of them, you just throw a whole bunch of JP8 at it. You're all talking like jet fuel is expensive or something? Apart from bunker fuel, jet fuel is about as cheap a petroleum fuel as there is.
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Mar 20, 2014 23:54
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goons posted:154 Yay! Something I can talk about! I'm an engineer and I'm here to help! The FARs relevant to the aircraft's structure dictate that the wings (and most of the structure) be able to withstand a "Margin of Safety" of 1.5. That is, as was explained, the aircraft must be able to withstand 150% of "worst case scenario" profiles, depending on the mission profile set by the manufacturer and as regulated by the FAA. You literally cannot register or fly an aircraft in US air space if it has not been proven to meet this number. This was a huge issue with the A380, because although it failed where they predicted (location on wing), it failed at 1.49. I don't think there are too many aircraft that exceed this number by more than .1 as you start to get too heavy for general aviation and flying (the weight in making the aircraft tougher begins to really take a toll on it's flying capabilities). zoux posted:What percentage of the maximum load is an airplane under during normal flight, usually? Depends on weight, speed, weather, wind, etc. I can't give you a solid number, but generally speaking, if the pilot is flying at 100%, he's in the poo poo. If the pilot somehow pushes the aircraft past that without breaking it, and manages to survive, the airframe is pretty well hosed. If a pilot manages 150% while operating that aircraft, you get 24 hour news channels running with every conspiracy shy of lizard men for a month solid.
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Mar 21, 2014 00:32
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YF19pilot posted:Yay! Something I can talk about! I'm an engineer and I'm here to help! As I understand it the 2.5G maximum would get a pilot fired on the spot, bar some sort of in-flight emergency.
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Mar 21, 2014 00:42
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Barnsy posted:As I understand it the 2.5G maximum would get a pilot fired on the spot, bar some sort of in-flight emergency. You'd answer for excessive G well below 2.5G. There are book limits in place for specific areas of flight. In AWACS, it was kind of common to get G waivers for aerial refueling due to excessive aircraft weight. Operational necessity drove those and the number not to be exceeded like was 1.2G or something near there.
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Mar 21, 2014 00:45
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I'd imagine flying in a 777 pulling 2.5g would be  as gently caress. (Actually, I'd probably be making GBS threads myself.)
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Mar 21, 2014 01:03
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CommieGIR posted:The USAF uses JP8 in everything diesel. So yeah, Jet Fuel is largely Kerosene with additives anyways. They burn that poo poo in diesel generators even. 10% power derating.
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Mar 21, 2014 01:05
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TotalLossBrain posted:They burn that poo poo in diesel generators even. 10% power derating. Yeah, our ACE (Air conditioning) and Gensets for the JSTARS are JP8 fueled.
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Mar 21, 2014 01:09
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Passengers start screaming at about 1.5 g, so it's adventageous to keep it below that. That works out to a ~45ish degree level, banked turn. Most airlines will yell at you for exceeding 30-40 degrees bank angle without good reason to do so, and ~20-25 degrees pitch angle as well. The big driving factor for aircraft limit loads are wind gusts; the 2.5g certified load factor for an airliner corresponds to an 80 foot-per-second wind gust (with ultimate load factor corresponding to a 120 fps wind gust). 80 fps is really high, but not uncommon in something like a thunderstorm.
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Mar 21, 2014 01:10
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Acid Reflux posted:Terrible day at work. Found a great big crack in the pax door. well, you got a chuckle out of me so... did you have to do a butt splice? FullMetalJacket fucked around with this message at 01:44 on Mar 21, 2014 |
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Mar 21, 2014 01:14
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Barnsy posted:As I understand it the 2.5G maximum would get a pilot fired on the spot, bar some sort of in-flight emergency. It's been a while since I've had a good run through of the relevant FARs, but I think with wide body aircraft the G loading is dependent on direction, with 2.5G being the lowest number, iirc. Basically, internal equipment in the aircraft may start coming loose if you do 2.5G in the wrong direction. Also, 2.5G is enough to knock people out, depending on their health and body type, and possibly induce cardiac issues in those with existing heart problems. If you're flying a jet full of marathon runners you'll have put them all to sleep. e: beaten, mostly, need to refresh.
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Mar 21, 2014 01:32
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Powercube posted:Red R22, or if I have a friend along- it's a white or yellow R44. The blue R22 has janky seats. Are you guys out of one of the flight schools down at Boeing Field?
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Mar 21, 2014 01:41
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Duke Chin posted:Are you guys out of one of the flight schools down at Boeing Field? Classic Helicopters, they are awesome and professional!
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Mar 21, 2014 02:16
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Powercube posted:Classic Helicopters, they are awesome and professional! In 18 words or less why should I choose Classic over Helicopters Northwest or Atomic Helicopters for my flight training?  Okay only slightly kidding - I actually have been contemplating rotary-wing flight school again after almost enrolling at Precision Aviation down in Oregon. Just as I was about to I ended up getting a job and moving up here to Seattle. That was almost 8 years ago and I'm getting the bug again. What to do what to do. 
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Mar 21, 2014 02:30
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Kilonum posted:Believable, non-terrorism theory on Malaysian Airlines Flight 370 I really liked this. This guy came up with some arguments against: quote:Goodfellow’s account is emotionally compelling, and it is based on some of the most important facts that have been established so far. And it is simple—to a fault. Take other major findings of the investigation into account, and Goodfellow’s theory falls apart. For one thing, while it’s true that MH370 did turn toward Langkawi and wound up overflying it, whoever was at the controls continued to maneuver after that point as well, turning sharply right at VAMPI waypoint, then left again at GIVAL. Such vigorous navigating would have been impossible for unconscious men. http://www.slate.com/blogs/future_tense/2014/03/18/mh370_disappearance_chris_goodfellow_s_theory_about_a_fire_and_langkawi.html To me that is evidence of the plane flying a normal route on autopilot and it's an equally good argument against an emergency as foul play. If you want to stay hidden, why fly down the path to which the civil surveillance equipment is trained? On the other hand, if you are in an emergency and you know you want to go to that airport, it's just a few button presses on the FMS to get the plane started towards it while they possibly had to deal with other stuff on the inside. And I don't think fire in the actual cockpit is as likely as a fire in the avionics bay.
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Mar 21, 2014 11:29
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StandardVC10 posted:There's a Japanese domestic market 777-300 that has a new Pokemon scheme, I believe. Presumably that will be in service for some time to come. Can someone help explain the Japanese domestic aircraft thing to me? I mean, the longest distance between two major Japanese cities is only about a thousand miles, yet somehow they're flying 747-400s and 777-300s all over the place? How does that make any sort of sense from a cost perspective?
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Mar 21, 2014 11:33
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ctishman posted:Can someone help explain the Japanese domestic aircraft thing to me? I mean, the longest distance between two major Japanese cities is only about a thousand miles, yet somehow they're flying 747-400s and 777-300s all over the place? How does that make any sort of sense from a cost perspective? If it's anything like South Korea, it's because a shitload of people are travelling those routes.
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Mar 21, 2014 11:36
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Snowdens Secret posted:If it's anything like South Korea, it's because a shitload of people are travelling those routes. That, and having some gate/slot restrictions. If you can fill a 747-4, you can take advantage of incredibly low CASM. Provided you can fill it.
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Mar 21, 2014 13:34
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There are enough businessmen in Japan commuting to work and going to different business meetings that it is feasible to have this many large aircraft operating domestically. Most if not all of those jets are going to be set up for "cattle car" seating which isn't bad if the longest domestic flight is well under 2 hours. I think Domestic Japanese flights typically have the highest density seating coupled with the lowest luggage weights, so they also double as same-day couriers since a very high percentage of their passengers are "carry-on only". This is also why they are so interested in High-Speed rail, as not everyone can afford to do this every day/week. When I was living in Korea, the daily/weekly flight-commute wasn't really an option, but luckily they have 300km/h high-speed rail all over the country.
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Mar 21, 2014 13:36
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747-400D is an actual model. It's a -400 with the aforementioned all-coach seating arrangement, some extra upper-deck seating, and no winglets.
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Mar 21, 2014 15:22
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ctishman posted:Can someone help explain the Japanese domestic aircraft thing to me? I mean, the longest distance between two major Japanese cities is only about a thousand miles, yet somehow they're flying 747-400s and 777-300s all over the place? How does that make any sort of sense from a cost perspective? Melbourne and Sydney are only ~900km apart from eachother and each city only has 4.5 million people yet it is the fifth busiest air route in the world in terms of passengers, fourth busiest in terms of seating capacity and third busiest by aircraft movement. Sure it isn't 777's all the time, but the cities are close enough for people to get to the airport at 7am and make it to your companies office in the other city by 9am and return the same day. I presume it is the same in Japan, Korea, China and Brazil. http://en.wikipedia.org/wiki/World%27s_busiest_passenger_air_routes drunkill fucked around with this message at 15:26 on Mar 21, 2014 |
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Mar 21, 2014 15:23
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Look what I saw today: Is it still today? I also got to fly on one of ANA's 787s. People who say they're quiet aren't kidding... I was wondering what they actually sound like from inside when they start the engines (I've only heard it in the sim), and as I was having that thought, we started taxiing away! ctishman posted:Can someone help explain the Japanese domestic aircraft thing to me? I mean, the longest distance between two major Japanese cities is only about a thousand miles, yet somehow they're flying 747-400s and 777-300s all over the place? How does that make any sort of sense from a cost perspective? It's a very long skinny mountainous country. Even a bullet train from Tokyo all the way south takes all day. It's a 1h45 flight. Finger Prince fucked around with this message at 15:40 on Mar 21, 2014 |
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Mar 21, 2014 15:35
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YF19pilot posted:Yay! Something I can talk about! I'm an engineer and I'm here to help! This stuff is really cool to me as an utter layman. Do they do those kinds of stress tests on all the major components? Do they test the fuselage to failure like that? Also, how many airframes do they have to bust up like that in the process of testing?
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Mar 21, 2014 16:04
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I think the sheer size of the search area for MH370 just sunk in for me. I mean, in theory I appreciated that it was 'really big' but today I saw some maps in a BBC article and realized they're searching in patches of ocean the size of Australia. It's like trying to find one airplane in the whole of the country, except it's probably in little pieces underneath an unimaginable amount of water and also anything visible from the surface is moving. I'm sure everyone here is already acutely aware of all this, but I think a lot of people in the general public just assume the plane will be found because big things just don't go missing these days.
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Mar 21, 2014 17:01
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Generation Internet posted:I'm sure everyone here is already acutely aware of all this, but I think a lot of people in the general public just assume the plane will be found because big things just don't go missing these days. They need reminding of South African 295, which took over a year before it was found (in the indian ocean, after going missing over SE asia, after an electrical failure that knocked out all the comms and navigation... hey, wait...)
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Mar 21, 2014 17:06
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