Guest topsy1970 Posted October 16, 2003 Share Posted October 16, 2003 What do those winglets do on the wing? Why do Boeings look different than Airbus? Do they save fuel and if so, how? On the A319 in the back there are some noises. I know one is when those cargo doors close. But there is one that sounds simular as you taxi out. It sounds like a hacksaw going back and forth? What the h..l is it? Thanks Link to comment Share on other sites More sharing options...
Kip Powick Posted October 16, 2003 Share Posted October 16, 2003 Read this..... http://www.b737.org.uk/winglets.htm Link to comment Share on other sites More sharing options...
Kip Powick Posted October 16, 2003 Share Posted October 16, 2003 From Frontier Airlines Q and A..... The noise you are referring to, which is heard coming from the rear of the aircraft, is the result of the pressurization of the hydraulic system and the eventual equalization of the system on the aircraft. You'll hear this sound on most commercial aircraft, including the Airbus A319. The sound will be heard during the approach until all landing gear has been retracted and also upon landing gear extension. This is usually during taxi right before take off and again during taxi right after landing. This sound is very normal and you can be assured that when you hear it, the plane is functioning properly. Link to comment Share on other sites More sharing options...
Guest Crow Posted October 16, 2003 Share Posted October 16, 2003 Topsy, is it that intermittent whirring sound that happens just after they have started up, that you are wondering about? Sounds a bit like some gearing that is getting bogged down as it rotates about ten times? I've wondered about that too and was once told that it is a hydraulic pump or accumulator. Any other suggestions? Link to comment Share on other sites More sharing options...
Guest R64L977 Posted October 16, 2003 Share Posted October 16, 2003 That funny hacksaw like noise is the hydraulic power take-off unit (PTU) which couples the yellow and green hydraulic systems.It's a normal, although disconcerting sound. Link to comment Share on other sites More sharing options...
Mitch Cronin Posted October 16, 2003 Share Posted October 16, 2003 Bingo. ...and that hacksaw sound is quite specific to the airbus power transfer unit (PTU). I't becomes more of a steady grind when hydraulic demand increases, but when there is no demand it'll just saw away. Link to comment Share on other sites More sharing options...
Guest qb Posted October 17, 2003 Share Posted October 17, 2003 The winglets reduce induced drag by smoothing out the wingtip vortices which saves fuel, and the PTU noise, I believe, has been well explained below. qb Link to comment Share on other sites More sharing options...
Guest topsy1970 Posted October 17, 2003 Share Posted October 17, 2003 Thanks. But if they save fuel etc, why don't they just come of the production line like that? With regards to all those noises (FTU) why can't they design something not so loud? I know many,many people who are terrified of flying and those noises (which are normal)make them queasy to the point that they elect not to fly given the choice, (where they probably otherwise would). They have told me the plane sounded as if it were broken or getting near to it. The same goes for the lights flickering on and off during start and pushback etc. Why don't they design something so those lights just stay on? I know there must be a reasonable reason for it, but if they can make 1000's of lbs of metal get off the ground you would think they could design something that wouldn’t do the aforementioned things. These queasy passengers feed off each other and round the circle it goes. I know 95% of the flying public could probably care less (they are, after all small annoyances in the grand scheme of things), but for the remaining 5%, well, 5% is 5%... Cheers. Link to comment Share on other sites More sharing options...
Guest Ray Darr Posted October 17, 2003 Share Posted October 17, 2003 That "RrrRrrRrrrr....Rrrr...Rrrrrr"..."rrrRr" sound you hear during or just after pushback in the 'Bus? It's the hydraulic system creaking and groaning in protest. Just as the second engine is started, the hydraulic system power-transfer unit (PTU) goes though a self-test (if the drivers blink, you miss the ECAM on the screen...) then all that pent-up pressure leads to the groaning you hear as it settles back through the accumulators. Satisfied, topsy1970? (I recall the 146 quadrapuff had announcements to ensure the self-loaders wouldn't panic TOO much when the flaps groaned in-transit. All these birds make some odd sounds, agreed?!!) Link to comment Share on other sites More sharing options...
Guest Ray Darr Posted October 17, 2003 Share Posted October 17, 2003 That "RrrRrrRrrrr....Rrrr...Rrrrrr"..."rrrRr" sound you hear during or just after pushback in the 'Bus? It's the hydraulic system creaking and groaning in protest. Just as the second engine is started, the hydraulic system power-transfer unit (PTU) goes though a self-test (if the drivers blink, you miss the ECAM on the screen...) then all that pent-up pressure leads to the groaning you hear as it settles back through the accumulators. Satisfied, topsy1970? I recall the 146 quadrapuff had announcements to ensure the self-loaders wouldn't panic TOO much when the flaps groaned in-transit. Throw out the speed-boards in most birds and you get a few raised eyebrows from the back-baggage. (By the way: "That's for MY mistakes, not YOURS!" said Salty Sam to ATC....) MY personal 'Bus beef: Up goes the gear, and "DINGGGG" goes the same sound that the seat belt sign "OFF" "ding" makes. Seems the gang that made this machine back in the 1980's wired the "No Smoking" lights and "DING" to the gear retraction logic. Well, the smart people that decided to keep the No smoking lights on all the time have never removed that darn "DING" when the gear is raised. IT ALWAYS confuses at least a handful of pax. Look around on your next flight. I guarantee some new flyer is wondering why the heck that "DING" happens. ...rant over. (although I am still wondering why it still has to DING-DONGLE though!!!) All these birds make some odd sounds, agreed?!! ~ Ray Darr Link to comment Share on other sites More sharing options...
Guest Ray Darr Posted October 17, 2003 Share Posted October 17, 2003 That "RrrRrrRrrrr....Rrrr...Rrrrrr"..."rrrRr" sound you hear during or just after pushback in the 'Bus? It's the hydraulic system creaking and groaning in protest. Just as the second engine is started, the hydraulic system power-transfer unit (PTU) goes though a self-test (if the drivers blink, you miss the ECAM on the screen...) then all that pent-up pressure leads to the groaning you hear as it settles back through the accumulators. Satisfied, topsy1970? I recall the 146 quadrapuff had announcements to ensure the self-loaders wouldn't panic TOO much when the flaps groaned in-transit. Throw out the speed-boards in most birds and you get a few raised eyebrows from the back-baggage. (By the way: "That's for MY mistakes, not YOURS!" said Salty Sam to ATC....) MY personal 'Bus beef: Up goes the gear, and "DINGGGG" goes the same sound that the seat belt sign "OFF" "ding" makes. Seems the gang that made this machine back in the 1980's wired the "No Smoking" lights and "DING" to the gear retraction logic. Well, the smart people that decided to keep the No smoking lights on all the time have never removed that darn "DING" when the gear is raised. IT ALWAYS confuses at least a handful of pax. Look around on your next flight. I guarantee some new flyer is wondering why the heck that "DING" happens. Another one: Passing around 10,000 when the FA's are (usually) seated, there is enough "Pop!"-ping and crinkling to make me wonder "are they smashing the carts into their docking stations?" (NOT!) but rest assured, it is likely just the outer skin popping with the compression... ...rant over. (although I am still wondering why it still has to DING-DONGLE though!!!) All these birds make some odd sounds, agreed?!! ~ Ray Darr Link to comment Share on other sites More sharing options...
Guest givemeabreak Posted October 17, 2003 Share Posted October 17, 2003 or at 10,000 feet the boards come out, shake and rattle the airplane, because no one thinks past the monkey computer and pulls out the spoilers. Making noise, shaking, and wasting fuel! Link to comment Share on other sites More sharing options...
Financial Guy Posted October 17, 2003 Share Posted October 17, 2003 I always thought it sounded like a dog barking...... Link to comment Share on other sites More sharing options...
Guest The Clumsy Lover Posted October 17, 2003 Share Posted October 17, 2003 The best one that I heard was while sitting in the back on the way from YHZ to YYZ. A fellow from Newfoundland was sitting beside me and after the PTU starting turning... He turns to me and says.. "My Jesus Bye... they flooded it. Now we'll never get to Toronta!!" A good laugh was had by all around him. Cheers CL Link to comment Share on other sites More sharing options...
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