Schorsch[ATTACH]172510[/ATTACH]
SchorschAnother consideration is maintenance access to the tail engine. If 2 engines are not enough for whatever reason – lack of big enough engines, lack of ETOPS, lack of underwing space – then 4 engines may be easier to handle than 3. Airbus chose to make A340 a quadjet, not trijet. Ditto about A380.
Advantages of trijets include fewer engines than a quad, and closer to centreline…
Why has the A340 4 engines?
The A340 has a design mission and was then consequently adapted to the available engine. The engine of choice was the CFM56, I guess because of its wide spread use.
The only other option would have been an extremely derated PW2000 for 4-engine config or the same engine at max thrust rating in a tri-jet.
Installed thrust of a WV024 A340-300 with 4 CFM56-5C4 is 4x34klbs = 136klbs.
PW2000: 3x 43.5klbs = 130.5klbs
PW2000: 4x 38.4klbs = 153.6klbs
Hence, as a tri-jet needs more installed thrust than a quad-jet, it would have limited the A340s MTOW and consequently performance.
The A330-300 has as WV052 installed ref thrust of ~142klbs, despite being 40t lighter.
SchorschNo engine gives so much thrust. You would need 3x GE90-115 to propel an A380.
But Airbus finds that the increasing bypass ratio of turbofans means that the fan size grows for a given thrust. They run out of underwing space for it. For example, the Cseries geared turbofan has 188 cm diametre fan, compared to A320 engines which are under 170 cm or so, and produces much less thrust.
For that reason, Airbus patented a trijet with H-tail, and the tail engine mounted in the middle. Only, they did not specify whether they intended a widebody or a narrowbody.
These patents have a significant show-off effect. Whatever.
For an aircraft significantly heavier than an A350-1000 a new core engine would be needed. For that purpose a trijet would be an option.
SchorschWill there ever be another large wide-bodied tri-jet a la L-1011 Tristar, DC-10 or MD-11?
Increasingly, large twin jets (e.g. 777-300ER) are being used for longer & longer sectors & I read that the A340s production days are numbered.
So will it ever again be economically viable to design & build a new Tri-jet which could be viewed as a 21st century MD-11 or Tristar?
I find it interesting the Soviets/Russians never built one.
Thoughts?
There is an option. The GEnx/T1000 have a thrust rating of up to 95k. For an aircraft replacing the B777-300ER (Yellowstone 3) 3 engines might be an option.
SchorschI’d guess there’s a lot more than sentiment involved.
Spares & training costs would be greatly reduced.
I shudder to think of all the paperwork…manuals, charts, procedures that would have to be changed with a different AC type.And it goes far byond pilots and maintenance workers, everything from gate parking markings to dispatch paperwork…new emergency cards, maybe even catering procedures, waste pumping…
Ah, that shouldn’t be that expensive, especially as the competing airframer would give you a discount on the package price. Anyways, the difference in performance of A320 and B737NG sometimes doesn’t justify a fleet change. But the decision B737/A320 was mainly done on pure price & slot considerations, means the cheaper offer with better availability of slot positions won the contract. Rarely an airline chose a B737 over an A320 for technical reason or vice versa, although the A320 is a different league when it comes to technology (with side effects).
SchorschPerhaps the old saying “Go with what you know” is true in those cases?
And what you can get. Although the A320 is claimed to be more efficient, it is not much better than a B737NG. Anyways, it shows that innovation in the aviation industry is sometimes painstakingly slow. The B737NG is to some extent a ******* child of 1990s, 1980s and 1960s tech.
Schorsch“But a punitive culture means people are too afraid to speak out.
“Two things, (flight safety and the punitive culture) in my view, that do not match in 2009 and in a major airline.
Quite true and recognized by insiders. As a pilot it becomes the better options to die in a crash.
As for the other claims, blaming the FLEX take-off technique is severe fraud. Any airline does it. Mistyping digits is no issue (and probably done often enough), but not double-checking take-off V1, VR and V2 is an error. That are the challenges long range operations offer and the obscene salaries paid should afford people who are able to master them.
SchorschQuite interesting to see that some airlines have twice replaced B737s with B737s, from 100/200 to Classic to NG.
SchorschI think in this case an unmanned system has its benefits, specifically much better endurance and quite a lot of weight like consoles can be put into the ship. The flight vehicle basically carries a radar and transfers data directly to earth-bound receivers.
When we now look at it, the specs seem rather simple:
– fly high
– remain on station long
– carry a payload of ~500-1000kg
– energy supply of several 100kW
Maybe even thinkable to use an lighter-than-air system. An aerostat with AESA radar dishes, sufficient power to fly 150kts TAS and the ability to climb to 15km.
SchorschI normally expect a well trained crew to have a feeling for the take-off distance and speeds, especially when the difference is 100t. A similar incident once happened to a B747 crew.
Such a mistake, though easy to conceive, shows a lack of familiarity or a lack of willingness to learn the ways of the aircraft. Over-reliance on computers and tools is the modern fallacy to the aviator.
SchorschI think the claim that LCCs are generally less safe does not have any evidence.
In terms of pilot’s quality, well, they make a couple of cycles a day and sometimes fly into funny airports, so I guess many Ryanair pilots have more proficiency than their much higher paid colleges at British Airways.
Compared to OY-registered aircraft the paradise of safety.
SchorschThe USMC divisions would have been handy for reinforcement of norway, iceland and denmark or northern germany/northwest poland.long range strategic bombing hitting rear guard areas(with large losses of course)
I am not sure if you have ever been to Norway, but a conflict using conventional armies is totally impossible there. You can effectively block it with very little troops. Additionally, Norway has lots of strategic backyard, from the Russian border to Narvik you have to go 500km, and still you haven’t actually conquered anything.
The Baltic Sea is off limits for any ship larger than a patrol boat. Especially, no sane commander would put troops in a big ship into a bathtube like the Baltic Sea.
Northern Germany: by chance I am actually living in Northern Germany, and I can assure you that we have quite a lot of deep-sea ports. No need for the USMC to get its feet wet.
And it has been obvious that there is a alot of hardware that NATO has that is superior to russian equipment(and some the other way round) the personnel factor also plays a role. well motivated ground troops and pilots, defending there homes and countries over terrain they have trained for generations over, in units with a lot more long-term members, versus a large consript army invading, would eventually lead to a NATO victory or a stalemate.
The individual technical might was probably better, but that wouldn’t necessarily determine the outcome. The Soviets build simple yet effective weapons, and they cared less for losses.
Western Germany has a conscript army, too, and would have (depending on the pre warning time) the largest number of troops.
SchorschThe US carriers and Marine amphibous forces were the big stick- the ability to deploy forces wherever needed was never matched, and that was what won the cold war
For a Cold War becoming hot, the carriers were close to useless. Sea dominance of the decisive North Atlantic routes could be achieved using land-based aircraft, frigates and submarines. Same in the Pacific. The Soviets were bound to their few ports and the egress routes were pretty easy to monitor.
The surface vessels were easy prey for NATO aircraft, and the chance of a single Kiew class getting into North Atlantic is slim (which I guess is the reason USN never really bothered about surface ships).
The carriers and the Marines always were a force for the other wars (Korea, Vietnam, Grenada, GW II+III, Lebanon). Versus a mechanized Soviet army a USMC division wouldn’t look good, especially as it would have serious difficulties to re-supply. There were no costal zones where a USMC landing would make sense.
Schorsch“Russians would have been on the Rhine before CONUS could even start to load the sealifter.”
please. do you really think that? Gulf War 1 showed the complete dominance of allied air power. applied to a few key choke points, the russian army would have been scrap. The US carriers and Marine amphibous forces were the big stick- the ability to deploy forces wherever needed was never matched, and that was what won the cold war
The question if the Russians would have made it to the Rhine is a question of how well NATO forces were alerted. With a three month “warning period” and at least one month for military mobilization the chances get increasingly slim for the Russians. Not that they loose, but they would never achieve the tactical and strategic surprise. When making an all out strike versus Western German airfields, they would have in majority hit empty fields and cash in big losses versus an activated air defence.
SchorschNever heard of it. Can you expand a little?
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