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Author Topic: Jet Crashing into Concrete Barrier Bobby Henderson "Ask me about Trajan." Posts: 10973 From: Lawton, OK, USA Registered: Apr 2001 posted 10-05-2004 10:40 PM                     Holy shit. That video was pretty cool. Even more cool than the video I shot this summer where one of my friends nearly blew himself up with fireworks.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 10-05-2004 10:51 PM                     I want to see the video of the tests aerospace companies do when they launch frozen chickens out of an air cannon into a spinning jet engine to test how it might withstand a real bird strike while in flight!  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 10-05-2004 11:34 PM                        I've got some of those tapes from the 70's. I actually can't remember much more recent footage either, too many animal rights issues.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-05-2004 11:38 PM                     quote: Randy Stanky I want to see the video of the tests aerospace companies do when they launch frozen chickens out of an air cannon into a spinning jet engine to test how it might withstand a real bird strike while in flight! Thats something that any Jet Engine has to withstand and I want to say that I've read somewhere that the number of frozen birds fired at a running test engine is 5 without the engine destructing (not that its goin to like it much though!). There are a number of manufacturers which now use composite fan blades on passenger jet engines, General Electrics GE-90 engine for the 777 is the best example. This engine has the largest turbofan of any jet engine made. The Nacelle covering at the front of the engine is larger in diameter than the fusalage of a 737. From the GE engine site: "During this intensive test, the engine ran for approximately 60 hours at triple red-line conditions (maximum fan speed, maximum core speed and maximum exhaust gas temperature) to evaluate the engine at its operational limits. The test is designed to demonstrate the engine’s capability beyond the most extreme operating conditions." Web Site is at: http://www.geae.com/engines/commercial/ge90/world_record_holder.html I don't think I'd want to be within 5 miles of that engine test stand with it running triple red line. Mark  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 10-05-2004 11:48 PM                        AFAIK, GE, Rolls Royce, Pratt & Wittney and others are all using 'synthetic birds' now. Cruelty to semi-frozen animals and all.  |  IP: Logged Greg Davis Film Handler Posts: 96 From: Vista, Ca, USA Registered: Sep 2004 posted 10-06-2004 12:23 AM                     "All we do crumbles to the ground though we refuse to see... dust in the wind... all we are is dust in the wind." And bored scientists... what did they think? It was going to run for mayor of Pitkin County, Colorado? And what was with the big crosshairs? Like you could miss a 20 foot concrete wall with a jet on a darn track. Your tax dollars at work, gentlemen.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 10-06-2004 12:27 AM                        Since it was the concrete was under test, and not the aircraft's ability to withstand destruction, the markings on the concrete would be quite important in post impact analysis. Markings on the aircraft were there likely to verify the projectile's trajectory and to help in calculating (the lack of) energy absorption of the concrete, using measurements from high speed and frame rate film.  |  IP: Logged Paul Mayer Oh get out of it Melvin, before it pulls you under! Posts: 3836 From: Albuquerque, NM Registered: Feb 2000 posted 10-06-2004 01:38 AM                        Not frozen chickens guys! Might as well throw a bowling ball in there while you're at it. The chickens (or gelatin blocks or whatever they're using these crazy PC days--jeez the damn birds are dead already! ) are quite thawed when they get fired out of the air cannon. I've seen slomo footage of one of the latest big engines "eating" a chicken, so they were still using birds as late as 10 years ago or so. Can't remember which engine (PW-4000? Trent 800 or 900? GE-90?). Yeah Mark, the GE-90 is quite the machine. They've had one up to around 105,000 lbs of thrust on the test stand! There is an old joke about firing frozen chickens for a windshield test. The technicians couldn't figure out why the laminated glass kept failing. Finally the designers of the test sent a note up saying, "Next time, use thawed chickens." Engine and windshield tests are done over a range of bird sizes and speeds like a 1-pound bird at 200 knots. Or was it a 200-pound bird at 1 knot? Another test that's fun to watch is a "blade off." They rig one blade on the front fan to be blown off by a pyro charge while the engine is turning at takeoff RPM. The engine case must contain the resulting unbalanced rotor. Watching the slomo you'd think the case was made of rubber. Most impressive! Those full-up engine stress tests are also done for ETOPS (Extended Twin OPerationS) certification, i.e. losing an engine on a twin-jet while over the ocean and having to run the remaining engine at max everything until landfall. The current max time certified is 208 minutes--a nice long time to think about how good your ditching, evacuating, and treading water skills are. I like the alternate meaning for ETOPS better (Engines Turn Or People Swim).  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 10-06-2004 07:53 AM                    What does that mean, max time certified is 208 minutes? Surely a twin can fly indefinitely on one engine if it's certified to cross oceans. Not much choice over the mid-Atlantic! Or is that how long one may opt to keep going, passing up airports with suitable runways in favor of landing at one of their own choosing?  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 10-06-2004 08:09 AM                        Nope, 208 minutes is the amount of time until you start placing bets on how long before the remaining engine blows itself up. Bypassing an airport on one engine would generally only happen if a pilot was more comfortable with landing at another nearby airport, or could avoid extra maneuvering (extra turns, rapid descent) if they were to bypass the closest and go to the next closest. In most cases 3.5 hours is long enough to make it to, or return to, the closest airport since the likelihood of engine failure decreases with time. In the event that it'll take longer to reach land you'll find that you won't be able to get a blanket since the flight attendants will be sowing them into parachutes. While they're getting off the plane you can hope that the aircraft has enough altitude to slowly descend at a lower cruise power, to avoid destruction of the remaining engine, and still make land fall. Of course it's not a huge concern since an engine is far more likely to fail in the first few minutes of flight than it is later in flight. A fuel system problem is probably far more likely than an engine failure later in flight, in which case it doesn't matter how long the remaining engine can last at triple red.  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 10-06-2004 09:00 AM                        Has there ever been a case of an airliner carrying fare-paying passengers having to ditch in the sea, purely as the result of mechanical engine failure? By this I mean all the engines failed internally - there wasn't any external cause such as fuel starvation, an explosive device detonating on board or the aircraft being struck by an object in flight. Coincidentally, my local public library was selling off this book for 50p the other week. The British public must have a pretty morbid fascination with accidents, as it had been so well read it was practically falling to bits! Among all the stories about planes being blown up, shot down, running out of fuel, disintegrating in midair collisions and so on, it made the point that at the time of writing (which admittedly was 14 years ago), no revenue earning EROPS flight had ever been downed by engine failure. The author argued that this was lulling airlines into a false sense of security where engine reliability was concerned, with the result that they were attempting to use aircraft for longer distance hauls than they were really designed to cope with. He cited the case of one charter airline which was even flying 737s from Vienna to Brazil with a refuelling stop on Ascension Island. Related to which, an outfit called Air Transat is now flying once a week from my local airport, Newcastle, non-stop across the pond to Toronto. It's astonishing that a small regional airport can now support direct intercontinental services, IMHO. Furthermore a return ticket costs little more than a full-price train fare from Newcastle to London! Presumably smaller twinjets are now reliable enough and have the range to operate intercontinental flights on a regular basis and more economically than bigger aircraft, which is certainly good news as far as I'm concerned. As long as the engines don't break down, of course...  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 10-06-2004 10:02 AM                        Ooooh, you haven't lived until you've flown Air Transat! I wonder if they still give out / sell little (knock off) Lego models of their aircraft. They come in handy when you want to demonstrate to the passengers who don't have window seats what parts of the aircraft (namely one of the engines) the maintenance crew is replacing.  |  IP: Logged Don Sneed Master Film Handler Posts: 451 From: Texas City, TX, USA Registered: Aug 2001 posted 10-06-2004 10:53 AM                        I'm dispointed, I wanted to see the final results, how large was the hole in the concrete, and view the plane after the dust has settle down...notice the plane did not come through the other side of the concrete...whoaaa weeee, after seeing this clip, if this would have been real,the people inside would never knew what they hit...  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 10-06-2004 11:51 AM                        They'd think they hit since the first officer would be screaming that!  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 10-06-2004 02:12 PM                        quote: They [Air Transat's Lego models] come in handy when you want to demonstrate to the passengers who don't have window seats what parts of the aircraft (namely one of the engines) the maintenance crew is replacing. At least they don't make the passengers fix the engines using bits of Lego... I'll have to find an excuse to visit Toronto sometime to see if they really are that bad!  |  IP: Logged

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