От oleg100
К All
Дата 29.04.2004 07:10:48
Рубрики Современность; ВВС;

JSF - проблемы с дизайном

по радио в новостях (Австралия) сказали что Австралийское участие под вопросом - не только все уже запаздывает на Н месяцев, но и дизайн не выходит - получается на 600 кг тяжелее чем следует..

Олег
От Exeter
К oleg100 (29.04.2004 07:10:48)
Дата 29.04.2004 18:44:51

Вот подробно про сие

Приветствую, джентльмены!

Две статейки близкого содержания из солидной буржуйской военной прессы.
Краткое изложение - проектный вес (как я понимаю, пустого) для F-35A и F-35C превышен на 635 кг, а для вертикально взлетающего F-35B - на 1090 кг. Для последнего вообще нависла угроза невыполнения ТТЗ по дальности. Фирмачи объясняют это тем, что предварительные весовые оценки делались по опыту проектирования двухдвигательного F-22, а реально конструкция F-35 довольно значительно отличается ввиду наличия одного большого тоннеля воздухозаборника двигателя и больших внутренних отсеков подвески оружия, что затрудняет компоновку. Все это ведет к затягиванию программы, и первый полет F-35A уже перенесен с запланированного ранее конца 2005 г на 2006 г. Также возможно F-35B будет задержан еще более и станет последней из трех модификаций по сроку принятия на вооружение.


JANE'S NAVY INTERNATIONAL - MAY, 2004

Bloated JSF on crash diet as flight tests pushed back

Nick Brown

The opening months of 2004 have brought a round of bad news for Lockheed Martin's F-35 Joint Strike Fighter (JSF), seeing delays force the planned first test flights back from 2005 to early/mid-2006 and the initiation of a major drive to shed weight from the aircraft.
February also saw the Pentagon note that around US$5 billion would have to be shuffled from the JSF procurement budget and into development to keep the programme on track. In addition, a critical design review scheduled for April 2004 has been pushed back to the second quarter of 2005. Michael Wynne, the US Department of Defence's head of procurement is currently evaluating a revised programme schedule proposed by the JSF joint programme office and Lockheed Martin.
Although there have been avionics stumbling blocks too, the main development 'speed-bump' causing all of these issues is down to the airframe's weight problem. According to programme officials, initial estimates of the aircraft's weight based on earlier programmes proved inaccurate as the design was refined.
Worst affected by the weight issue is the F-35B Short Take-Off Vertical Landing (STOVL) variant, which needs to shed a projected 1,090kg from the production version, but the F-35A conventional and F-35C carrier-based versions also have to shift a hefty 635kg. This is a major concern as it would affect range, endurance, speed, manoeuvrability and safe ordnance bring-back levels.
However, that is the worst-case scenario and relates directly to the power-to-weight ratio, which means that the required performance parameters could be met with some judicious weight-loss, reducing the drag co-efficient and uprating the thrust from the engine. Work is already underway in all these areas and Lockheed Martin has identified several areas that could be lightened, including removing redundant wiring, work on the landing gear and work to adjust the structural loads carried by the aircraft's skin.
The main drive is to reduce the all-up weight of the more complex STOVL version and then carry those over with common reductions on the other variants, followed by potentially lightening components unique to each.
Despite the slipping schedule, Tom Burbage, Lockheed Martin's executive vice president believes that it is crucial to get flight data early on and has announced the company's intention to push ahead with the programme and get an aircraft into the air as soon as possible. This potentially means flying aircraft before the full weight-reduction effort is completed as the initial test aircraft do not have to be constructed exactly as the final production aircraft.
That is, while the early aircraft could be trialing flight control systems and investigating the hover to conventional flight envelope, industry could be proving out the manufacturing process and filtering weight reduction and performance upgrades through to the test aircraft, according to Burbage.
This year has not all been bad news for the JSF. In mid-February, the programme received some good news to shore up the STOVL programme when the US Air Force (USAF) also stated its intention to buy a number of the F-35Bs to boost close air-support capabilities as the venerable A-10 Thunderbolts bow out of service. The USAF initially only planned to buy conventional versions, but operations in Afghanistan and Iraq have highlighted the potential of aircraft able to operate from rugged, ill-prepared strips close to the front.
This is particularly important as the F-35B is absolutely central to the future of US Marine Corps air power - and particularly to the UK Royal Navy (RN) as the RN's first FA-2 Sea Harrier squadron (800 Naval Air Squadron) was stood down on 31 March.



INTERNATIONAL DEFENSE REVIEW - APRIL, 2004

JSF gains weight and loses time

First flight of the Lockheed Martin F-35A Joint Strike Fighter has been delayed from late 2005 until early 2006, giving the industry team more time to resolve problems with the aircraft. So far, the most serious of these is that the aircraft is overweight.
The conventional take-off and landing (CTOL) and carrier-based (CV) versions of the JSF are each some 630kg overweight, and the short take-off/vertical landing F-35B variant is 1,000kg overweight. While the CTOL and CV versions still meet range requirements at the greater weight, the STOVL F-35B is marginal, barely meeting its 830km mission radius requirement with a standard internal load of two 450kg bombs and two AIM-120 missiles. Extra weight will also affect its bring-back load.
According to Lockheed Martin officials, one reason why the F-35 is heavier than was estimated when the system development and demonstration (SDD) phase started in late 2001 is that its internal configuration is unique, with a single large engine tunnel and large internal weapon bays occupying much of the body volume. Weight estimates were partly based on experience with the F-22, which has twin engines and a central structural keel. Routing wires and fluid lines through the complex volume of the fuselage has been a challenge, and system runs have been longer and heavier than expected. Weight-saving efforts are continuing, and the critical design review has been delayed from April 2004 to 2005 to give them more time.
Also under consideration is another schedule change, which would make the STOVL aircraft the third version of the JSF to be developed, rather than the second. This reflects the fact that the STOVL aircraft has the most serious weight problems of the three versions.
US Air Force (USAF) leaders, meanwhile, have suggested that the service might order STOVL JSFs to replace A-10s, operating from austere airfields that cannot support CTOL fighters. Details of the plan for example, how the USAF intends to support these forward-based aircraft have not been defined.





С уважением, Exeter
От Лейтенант
К oleg100 (29.04.2004 07:10:48)
Дата 29.04.2004 10:53:13

А какая ситуция с Рапторами?

Вроде как по планам уже в войска должны были пойти?
От А.Никольский
К Лейтенант (29.04.2004 10:53:13)
Дата 29.04.2004 12:32:23

уже и идут потихоньку

В то, что у нас называется опытная эксплуатация. Много дорогостоящих дефектов еще не устранено. Хотя из-за перерасхода в Ираке были недавно призывы какого-то сенатора закрыть программу вообще, и это, кстати, разумный подход.
С уважением, А.Никольский
От А.Никольский
К oleg100 (29.04.2004 07:10:48)
Дата 29.04.2004 10:19:15

кому дизайн не нравится, кого Локхид кинул

не только все уже запаздывает на Н месяцев, но и дизайн не выходит - получается на 600 кг тяжелее чем следует..
+++++
норвежцев так кинули с обещанным участием их промышленности в проекте.
С уважением, А.Никольский