AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Afterburners v.s dump and burn. Goto page 1, 2, 3, 4  Next          AirTalk.org Forum Index -> Planes, gliders and flying in Australia View previous topic :: View next topic   Author Message BB Guest Posted: Sun Sep 14, 2003 5:36 am    Post subject: Afterburners v.s dump and burn. Okay, my knowledge of military jet engines isn't the best but I'm interested to find out the difference between afterburning and "dump and burn". My understanding of afterburners is that raw fuel is sprayed directly into the exhaust stream in the jet engine tailpipe and as a consequence a great increase in thrust is obtained. What of the practice of "dump and burning"? What actually is it (i.e. where and how is the fuel dumped) and what function does it achieve other than a spectacular light and sound show? Thanks in advance, BB. Back to top JB Guest Posted: Sun Sep 14, 2003 5:54 am    Post subject: Re: Afterburners v.s dump and burn. Dump and burn has no function other that looking good at airshows. JB Back to top veritas Guest Posted: Sun Sep 14, 2003 6:34 am    Post subject: Re: Afterburners v.s dump and burn. You seem to have the facts in the correct order :) BB wrote: Quote: Okay, my knowledge of military jet engines isn't the best but I'm interested to find out the difference between afterburning and "dump and burn". My understanding of afterburners is that raw fuel is sprayed directly into the exhaust stream in the jet engine tailpipe and as a consequence a great increase in thrust is obtained. What of the practice of "dump and burning"? What actually is it (i.e. where and how is the fuel dumped) and what function does it achieve other than a spectacular light and sound show? Thanks in advance, BB. Back to top Mick Guest Posted: Sun Sep 14, 2003 7:20 am    Post subject: Re: Afterburners v.s dump and burn. Its simply just jettison fuel through a nozzle located between the two exhausts. Then they light the afterburner which in turn ignights the fuel. It has no function in service.An F-111 pilot told me they actually discovered it by accident in the late 60s. "BB" <not (AT) all (DOT) com> wrote Quote: Okay, my knowledge of military jet engines isn't the best but I'm interested to find out the difference between afterburning and "dump and burn". My understanding of afterburners is that raw fuel is sprayed directly into the exhaust stream in the jet engine tailpipe and as a consequence a great increase in thrust is obtained. What of the practice of "dump and burning"? What actually is it (i.e. where and how is the fuel dumped) and what function does it achieve other than a spectacular light and sound show? Thanks in advance, BB. Back to top Qansett Guest Posted: Sun Sep 14, 2003 7:26 am    Post subject: Re: Afterburners v.s dump and burn. In other words he answered his own question. veritas wrote: Quote: You seem to have the facts in the correct order :) BB wrote: Okay, my knowledge of military jet engines isn't the best but I'm interested to find out the difference between afterburning and "dump and burn". My understanding of afterburners is that raw fuel is sprayed directly into the exhaust stream in the jet engine tailpipe and as a consequence a great increase in thrust is obtained. What of the practice of "dump and burning"? What actually is it (i.e. where and how is the fuel dumped) and what function does it achieve other than a spectacular light and sound show? Thanks in advance, BB. Back to top BB Guest Posted: Sun Sep 14, 2003 7:32 am    Post subject: Re: Afterburners v.s dump and burn. "veritas" <nospam (AT) hotmail (DOT) com> wrote Quote: You seem to have the facts in the correct order :) Fair enough, but how does the fuel get out there? Is there a dedicated "dump and burn" fuel system or is it a part of a normal jettison system if there is one (for example on an F-111).... Thanks again, BB. Back to top Tony Lathouras Guest Posted: Sun Sep 14, 2003 8:03 am    Post subject: Re: Afterburners v.s dump and burn. Just moving away from the original topic a little..... Air today in Hobart..... saw a little afterburner action, but unfortunately the weather turned bad, rained cats and dogs and before the pigs could do their stuff, the rest of the visual display was called off :( They had about a 3 hour window of opertunity to strut their stuff, a quiet time at Hobart between when Qantas 12.30pm leaves and the 3.30 arrives, no other domestic traffic during this time each day, but as they were leaving the dump and burn for the grand finale, we didnt get to see it at all. Typical tassie weather. The air show as a whole however was quite good, well for Hobart standards, and the crowd showed its support. Lots of static military displays as well as just about 1 of every aircraft the RAAF uses to have a feel, poke and play with. And suprisingly, not the usual ban on photo's being taken up close and personal within the aircraft/flightdeck/cockpit like has been the case in previous years with such shows. The roulettes were a highlight with flight audio being pumped thru the PA system. Back to top Aztec Guest Posted: Sun Sep 14, 2003 8:39 am    Post subject: Re: Afterburners v.s dump and burn. On Sun, 14 Sep 2003 18:03:14 +1000, "Tony Lathouras" <tony_lathouras (AT) hotmail (DOT) com> wrote: Quote: Just moving away from the original topic a little..... Air today in Hobart..... saw a little afterburner action, but unfortunately the weather turned bad, rained cats and dogs and before the pigs could do their stuff, the rest of the visual display was called off Yeah - twas annoying... I got sunburnt, cold and wet (and hailed on) all within a space of 2 hours... ya gotta love tassie weather... But for me the Hawk & Hornet show was the best part - aerobatics are fun to watch, but I like 'em fast and loud... And I got home to find a mate of mine was crewing the SeaKing... bugger, I could've caught up with him... Quote: They had about a 3 hour window of opertunity to strut their stuff, a quiet time at Hobart between when Qantas 12.30pm leaves and the 3.30 arrives, no other domestic traffic during this time each day, but as they were leaving the dump and burn for the grand finale, we didnt get to see it at all. Typical tassie weather. Yep - I think they should move the dates into summer (Jan/Feb) - better chance of good weather... Quote: The air show as a whole however was quite good, well for Hobart standards, and the crowd showed its support. Indeed - a good turn out for Hobart... pity about the delays leaving the car parks... Cheers, Richard Back to top Tony Lathouras Guest Posted: Sun Sep 14, 2003 8:49 am    Post subject: Re: Afterburners v.s dump and burn. "Aztec" <richard (AT) poontang (DOT) nospam.com.au> wrote Quote: On Sun, 14 Sep 2003 18:03:14 +1000, "Tony Lathouras" [email]tony_lathouras (AT) hotmail (DOT) com[/email]> wrote: Just moving away from the original topic a little..... Air today in Hobart..... saw a little afterburner action, but unfortunately the weather turned bad, rained cats and dogs and before the pigs could do their stuff, the rest of the visual display was called off :( Yeah - twas annoying... I got sunburnt, cold and wet (and hailed on) all within a space of 2 hours... ya gotta love tassie weather... You and me both!! Right now I am trying to re-warm but feel the the burning of a sunburnt forehead.... Quote: Indeed - a good turn out for Hobart... pity about the delays leaving the car parks... Yeah, a real bottle neck with just the one exit point, and with ordinary airport traffic as well as the usual traffic that is present on that highway as shack owners etc return to their suburbarn homes from primrose, carlton etc on sunday arvo made it a night mare to get out. I was there by a little after 8am and a handy spot near the Cab holding yard, but still didnt make it any easier getting the cars in front of me to move!! hehe Perhaps with the obvious interest Hobartians showed to this event, they may return a little sooner than later perhaps? Back to top JB Guest Posted: Sun Sep 14, 2003 8:51 am    Post subject: Re: Afterburners v.s dump and burn. You select fuel dump, and then light the burners. More or less what the Concorde did... Doesn't matter how the fuel gets there, but the burner flame extends a fair way back. JB "BB" <not (AT) all (DOT) com> wrote Quote: "veritas" <nospam (AT) hotmail (DOT) com> wrote in message news:CZT8b.100639$bo1.1593 (AT) news-server (DOT) bigpond.net.au... You seem to have the facts in the correct order :) Fair enough, but how does the fuel get out there? Is there a dedicated "dump and burn" fuel system or is it a part of a normal jettison system if there is one (for example on an F-111).... Thanks again, BB. Back to top Graeme Hogan Guest Posted: Sun Sep 14, 2003 9:21 am    Post subject: Re: Afterburners v.s dump and burn. "JB" <jb0767 (AT) hotmail (DOT) com> wrote Quote: Dump and burn has no function other that looking good at airshows. The Yanks used to do it in Vietnam. They called it 'Flaring'. Do it at night to light up. Back to top Graeme Hogan Guest Posted: Sun Sep 14, 2003 9:23 am    Post subject: Re: Afterburners v.s dump and burn. "JB" <jb0767 (AT) hotmail (DOT) com> wrote Quote: You select fuel dump, and then light the burners. More or less what the Concorde did... Doesn't matter how the fuel gets there, but the burner flame extends a fair way back. Most jet acft have the capability of dumping fuel in the event of an emergency. The f-111 dumps between the engines. Back to top Alan Guest Posted: Sun Sep 14, 2003 11:54 am    Post subject: Re: Afterburners v.s dump and burn. "Graeme Hogan" <ghogan01 (AT) optusnet (DOT) com.au> wrote Quote: Most jet acft have the capability of dumping fuel in the event of an emergency. Neither narrow-bodied aircraft developed for short and medium-haul distances (e.g. A320, B717, B737, B757, MD80) nor the medium-haul wide bodies (A300 and A310) are fitted with fuel dumping nozzles. The long haul wide-bodies only dump in a declared emergency situation to reach max landing weight. If it's not an emergency they will fly around at lower levels and burn the fuel to reach max landing weight. B747 Darwin to Cairns about a year flew across at FL210 and then held 50 nautical miles NE of Cairns at 10000 for 30 mins. Not certain of the reason for the extra fuel on board, so I won't include the conjecture. Alan Back to top JB Guest Posted: Sun Sep 14, 2003 12:55 pm    Post subject: Re: Afterburners v.s dump and burn. Like everything in the aviation world, fuel dump is an option. If you haven't bought the heavy take off weight, then you probably won't need the ability to dump fuel. Whether all A300/A310 can't dump as per this poster, I don't know. If they are at all like the 767, then I would expect that some have the ability whilst others don't. The ability to dump or not changes the tactics of handling many of the problems you may encounter. The logic of flying around for some hours, in a suspect aircraft, whilst you burn fuel to get down to a reasonable weight is perhaps itself suspect. It's a trade off of the risks. Which is worse; the overweight landing or the time wasting? JB "Alan" <sirronnala (AT) REMove (DOT) yahoo.com.au> wrote Quote: "Graeme Hogan" <ghogan01 (AT) optusnet (DOT) com.au> wrote in message news:3f643381$0$28118$afc38c87 (AT) news (DOT) optusnet.com.au... Most jet acft have the capability of dumping fuel in the event of an emergency. Neither narrow-bodied aircraft developed for short and medium-haul distances (e.g. A320, B717, B737, B757, MD80) nor the medium-haul wide bodies (A300 and A310) are fitted with fuel dumping nozzles. The long haul wide-bodies only dump in a declared emergency situation to reach max landing weight. If it's not an emergency they will fly around at lower levels and burn the fuel to reach max landing weight. B747 Darwin to Cairns about a year flew across at FL210 and then held 50 nautical miles NE of Cairns at 10000 for 30 mins. Not certain of the reason for the extra fuel on board, so I won't include the conjecture. Alan Back to top Bernie Samms Guest Posted: Sun Sep 14, 2003 1:00 pm    Post subject: Re: Afterburners v.s dump and burn. We missed it today due morning being terrific while static and storm coming in big time late in the show when the F11 was due. Still a great show anyway. I do think that dump and burn must be for getting rid of excess while not dropping fuel at low level over the countryside. Its ok dumping at 40,000ft in a B747 as its vapourised but an F111 might be a foot or two lower!! -- Bernie Samms Kingston Beach Tasmania Aero Club of Southern Tasmania www.acst.com.au Prologic Pty Ltd www.prologic.com.au Out Mail has been checked by Norton Anti Virus but no absolute guarantee is made that mail or attachment(s) are virus free. "JB" <jb0767 (AT) hotmail (DOT) com> wrote Quote: Dump and burn has no function other that looking good at airshows. 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