The original TU144 was an extremely crude attempt by the Soviets at commercial supersonic aviation |
Having seen some of their other efforts, this one doesn't wonder. Ever fly on an IL96 or see a IL62? Their fighters aren't crude, they are positively agricultural! Out tractors are more elegant in their engineering.
GF |
The TU144D used in the 1990's as a joint NASA/Russian experiment was a different beast altogether however, with far better engines and systems, but as far as I am aware the only western pilots to fly it were American chaps |
M2dude I have another question concerning "debow" You very clearly answered my original question on another thread. I just wondered how the engine was kept at a sub idle 30% N2? Was it done by careful metering of the fuel? and if not how was it done? I ask because the throttles would be closed during start up.
The whole engine installation with the ramps, spill doors, reheats and noozles must have been a nightmare to "fine tune" through all the different phases of flight. Thanks for the explanation of how the pitch was "trimmed" Due to Concorde having elevrons instead of ailerons; was the aileron trim dealt with in a similar way? I guess the rudder trim could be applied normally. Thanks again Nick |
Originally Posted by galaxy flyer
Having seen some of their other efforts, this one doesn't wonder. Ever fly on an IL96 or see a IL62? Their fighters aren't crude, they are positively agricultural!
That said, this thread is about an aircraft which was the result of - unarguably - some of the best engineering in aviation history, and I'd much rather talk about that! :) |
Nick Thomas
...I just wondered how the engine was kept at a sub idle 30% N2?... Just below each engine's individual start switch, there was a second switch, which would select the type of start required, either NORMAL or DEBOW. When between ten minutes and five hours had elapsed since an engine was last run, a debow start was required. With a debow start selected, the engine was started normally, but the debow system automatically stabilised the engine at a sub-idle RPM, around 30% N2, whilst the interior engine temperatures became more uniform and the HP spool shaft re-aligned/straightened itself. As to exactly how it did this, you're going to need a reply from an engineer not a pilot. As far as we were concerned, it was the PFM box in the engine start system! After running for one minute stabilised in debow (or when the debow light came on) the F/E would return the debow switch to normal and check that the N2 returned to idle and the debow light went out. The F/E would monitor the N2 very carefully over these few seconds, as the engine came out of debow, to check that the engine cleared rotating stall. If it didn't, two things would happen. Firstly the F/E got fairly busy, trying to clear the engine out of rotating stall without causing it to surge, and secondly, as with any Concorde engine malfunction drill, I quietly give thanks that I was a pilot and not a F/E. If a debow start was required, but somehow got missed, the engine could give a reasonable impression of an out-of-balance tumble drier, or so I'm told. ;) Best Regards Bellerophon |
DW
No argument from me on former Soviet fighters being capable, but please read Red Eagles, if you want a Western view on their planes. Lots of poor engineering and execution, not that impressive. GF |
M2Dude,
Sorry, I certainly don't consider it a wasted two hours - I should be more careful in my phrasing in future... I never got to fly on Concorde, but I did get to sit in the left hand seat in Manchester for a few minutes on one of their tours - it's one of my prouder pictures on my desk. Apologies for not getting the tone I wanted across - and no offence taken! No more post from me in this forum - I'll leave it to the experts... Lurking_SLF |
Originally Posted by M2dude
The TU144D used in the 1990's as a joint NASA/Russian experiment was a different beast altogether however, with far better engines and systems, but as far as I am aware the only western pilots to fly it were American chaps.
Originally Posted by atakacs
(Post 5902749)
I wasn't aware of the significant upgrades - devised to the tune of $300mn - that were applied to this airframe.
The Tu144D was the last production model of the Tu144. With improved engines and other refinements, it was capable of supercruise (Mach 2 without afterburners). Only five were built, and they came too late ; the aircraft went out of service, and were put into storage. Tu-144D s/n 77114 was brought out of mothballs (with less than 83 hours "on the clock") for the joint NASA/Russian program in the '90s and modified, with completely new more powerful engines (same as those of the 'Blackjack' Tu-160 bomber) and a fit of sensors and test equipment, to become the Tu-144LL (flying laboratory). A total of 27 flights were made. The entire "High Speed Civil Transport" study indeed cost over $300M, but the actual work on the Tu-144LL reputedly cost less than $20M, although it's not known exactly what that bill represents. CJ |
DozyWannabe
Well, it was essentially a development airframe pressed into premature service for the sake of beating a western project into the air. One wonders whether the story would have been different if the designers had been allowed to take their time and develop it properly. In reality the Soviets really lacked both propulsion technology as well as the systems expertise required to build an aircraft with even a remote hope of Mach 2 cruise, let alone safe and comfortable enough for fare paying passengers. The original aircraft had all for engines in one giant nacelle, and the landing gear retracted into the engine inlet duct itself, great for an undistorted flow path to the engines :}. The variable inlets were manually operated by the flight engineer as well, no automatics here. In the mid 1970's the Russians even approached PLESSEY to build a digital engine control unit for the TU144. A similar PLESSEY unit had been VERY successfully flight trialled on production series aircraft 202 (G-BBDG) and only lack of funds prevented it being used on the production aircraft. As this unit could obviously be used for Soviet military applications, there was objection from the UK government, and more than just a little trans-Atlantic pressure applied, and so this venture never happened. Those "agricultural" fighters can mix it up with the best the west has to offer (until - or if - the F22 comes online) in terms of manoeuvering ability, if not in terms of weapons. ANYWAY, back on topic :mad: Lurking SLF No problem at all Darragh, please keep visiting us and post here also anytime. :) Nick Thomas M2dude I have another question concerning "debow" You very clearly answered my original question on another thread. I just wondered how the engine was kept at a sub idle 30% N2? Was it done by careful metering of the fuel? and if not how was it done? I ask because the throttles would be closed during start up. Now for the PFM bit, equally eloquently alluded to by Bellerophon: DEBOW itself was maintained by a special sub-idle datum in the electronic Engine Control Unit, and once the engine was accelerated towards normal idle (61-65% N2, depending on the temperature of the day) even if the switch described by Bellerophon was accidently re-selected, an electronic inhibit gate in the ECU prevented this sub-idle datum from being used again that engine cycle. Thanks for the explanation of how the pitch was "trimmed" Due to Concorde having elevrons instead of ailerons; was the aileron trim dealt with in a similar way? I guess the rudder trim could be applied normally. Dude :O |
The BR710 on the GLEX and G 550 also need to "rotor bow" on start within the same time limits. I fly the GLEX and the FADEC does it automatically, but I understand the G550 installation requires the pilots to recognize the requirement and motor for 30 seconds. Sub-idle vibration is quite discernible during an unbow start. Interesting that RR engines require this as I have flown GE and P&W, never heard of it.
GF |
Originally Posted by DozyWannabe
Well, it was essentially a development airframe pressed into premature service for the sake of beating a western project into the air.
Originally Posted by M2dude
(Post 5904352)
Good point I suppose, but you could say that the six Concorde prototypes, Pre-Production and Production Series Test aircraft were also development aircraft
Wherever you look... the cockpit, the visor, the engines, the tail, the avionics, other systems... the prototypes were a first "iteration", designed and built to prove the concept. The real development was done on what were the real "development aircraft", the pre-production and first two production aircraft (even if 01 / G-AXDN was a bit of a hybrid, retaining the short tail and the early engine nozzles). I hope sometime the story; of how different were 001 and 002 from those that followed, will go on record before it fades into the mists of time. CJ |
If you look at the air war over Vietnam, when an F4 met a MIG 19 or MIG 21 in an even air-to-air combat, the MIG was going down. (OK this could be partially down to superior US pilot traing etc Certainly in F-4 v a Mig 19/21 (especially the later varient 21's) with a determined pilot I wouldn't be as bold as to assume "the "MIG" was going down" - ask anyone who's done any training with the Aggressor Squadrons :E |
Originally Posted by wiggy
(Post 5904962)
Umm, at the risk of thread drift ....
That sort of discussion belongs in the Military Aircrew forum. One could say that the Tu-144, and also the Boeing 2707 and Lockheed L2000 were part of the background against which Concorde was born. But "F-4 v a Mig 19/21" is not really part of that context...... so please? CJ |
CJ
Back to thread, which came first, the American designs or the Concorde? Somehow I thought the American entries were a reaction to the Concorde. In any case, both US planes would have been huge. There has been talk of a supersonic biz jet for decades, but no real progress and I doubt there will be until it can fly over land supersonic. GF |
Originally Posted by galaxy flyer
(Post 5905106)
CJ
Back to thread, which came first, the American designs or the Concorde? Somehow I thought the American entries were a reaction to the Concorde. Interestingly, all the supersonic transport designs of the era (Concorde,Tu-144, B2707, L2000) can trace their ancestry back to NASA (NACA?) public-domain studies of the late fifties, that demonstrated the advantages of a slender delta for a supersonic transport aircraft. CJ |
Hi everyone
Please correct me if am wrong but was there not a slender delta wing prototype built by Fairley in the middle fifties. As I understand it, the plane was built to study a delta wing performance at low speeds. Therefore it had a fixed undercarriage. Regards Nick |
But "F-4 v a Mig 19/21" is not really part of that context...... so please? As a general point many in the West have almost always believed in the superiority of Western designers and engineers and whilst Concorde may be one shining example of what the West did right we should not forget that on the evidence of Sputnik, Vostok, Luna 9, Lunakhod and even the MIG21 Russian ( or German :E) engineers can achieve worldbeating results with minimal resources. But, to summarise, yes, it would seem the TU-144 was a dog :sad:, does that get us back on thread? |
Nick Thomas
Please correct me if am wrong but was there not a slender delta wing prototype built by Fairley in the middle fifties. As I understand it, the plane was built to study a delta wing performance at low speeds. Therefore it had a fixed undercarriage. Dude :O |
Thanks M2dude. You are right and my memory is getting worse due to old age!
Regards Nick |
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