Ninguém respondeu??? Falta de educação.Luís Henrique escreveu:E essas fotos com o mesmo caminhão. Chegaram a qual conclusão? Qual o tamanho da criança???
Calculando, por trigonometria, aparenta ser, aproximadamente, 50% maior que o J-10.
Moderadores: Glauber Prestes, Conselho de Moderação
Ninguém respondeu??? Falta de educação.Luís Henrique escreveu:E essas fotos com o mesmo caminhão. Chegaram a qual conclusão? Qual o tamanho da criança???
O nome disso é...Marino escreveu:EUA admitem apreensão com avião chinês
Denise Chrispim Marin
Os EUA expressaram ontem séria preocupação com o investimento da China na produção do J-20, supercaça invisível aos radares, e de outros equipamentos militares sofisticados. O chefe das Forças Armadas americanas, almirante Mike Mullen, afirmou ter se surpreendido com as imagens do primeiro teste de voo do J-20, na terça-feira, realizado poucas horas antes do encontro entre o secretário de Defesa, Robert Gates, com o presidente da China, Hu Jintao, em Pequim.
"A questão sempre presente é: por quê? Sei que a China tem seus próprios desafios, como um país emergente com influência global, e têm todo o direito de desenvolver sua capacidade de defender seus interesses, assim como os EUA", declarou. "Mas muitas dessas capacidades parecem estar focadas nos EUA", completou Mullen.
O teste do J-20 reduziu as chances de o governo americano extrair de Pequim um compromisso de diálogo na área militar. Esse seria um dos pontos fortes da visita de Hu ao presidente americano, Barack Obama, na semana que vem, em Washington. Mullen ressaltou que esse seria o tema "mais importante" da pauta bilateral, assim como o diálogo na área econômica.
Ao reiterar a posição americana em favor de maior pressão da comunidade internacional sobre a Coreia do Norte, o almirante chamou a atenção para o papel da China na garantia da paz na região.
Pequim é contra a adoção de novas sanções contra Pyongyang e prefere a via diplomática. "As provocações (entre as duas Coreias) podem se tornar catastróficas e a China tem grande responsabilidade nisso", afirmou Mullen.
O cronograma do J-20 prevê que os primeiros aviões serão entregues em maio de 2017. A aeronave atinge cerca de 2.200 quilômetros por hora e tem capacidade de manter-se em velocidade supersônica por um longo período.
Ares
A Defense Technology Blog
J-20s Stealth Signature Poses Interesting Unknowns
Posted by David A. Fulghum at 1/13/2011 10:01 AM CST
David Fulghum and Bill Sweetman/Washington
Anti-stealth and stealth detection technologies will bring into question all stealth designs, including China’s new J-20. How much invulnerability will current low-observability techniques retain as air defense systems adopt even larger and more powerful active, electronically scanned array (AESA) radars?
Airborne detection of stealth aircraft may already be an operational capability. Raytheon’s family of X-band airborne AESA radar family (in particular those on upgraded F-15Cs stationed in Okinawa) can detect small, low-signature cruise missiles. Moreover, Northrop Grumman’s lower-frequency, L-band AESA radar on Australia’s Wedgetail airborne early warning and control aircraft is larger and potentially more capable of detecting stealth aircraft at longer ranges.
Better images emerging from China point clearly to the J-20’s use of stealth technology, but there are still major uncertainties and unanswered questions.
The overall shape resembles that of the F-35 and F-22, with a single “chine line” uniting the forebody, upper inlet lips and wing and canard edges, a curved surface above that line and flat, canted body surfaces below it. The wing and canard edges are aligned – the wing and canard leading edges are parallel and the trailing edge of the canard is aligned with the opposite wing trailing edge. The same basic philosophy has also been adopted in British, Swedish and Japanese studies for stealth fighters.
The aim in all cases is to endow a practical, agile fighter configuration with a “bow-tie” radar signature, with the smallest signature around the nose and the greatest (still much lower than that of a conventional aircraft with curved or vertical-slab sides) to the side. The fighter’s mission planning system, using a database of known radar locations, then derives a “blue line” track that weaves between radars and avoids exposing the side-on signature to those radars more than transiently.
The diverterless supersonic inlet avoids a signature problem caused by a conventional boundary layer diverter plate – the F-22 has a conventional inlet, which is likely to require extensive radar absorbent material (RAM) treatment.
The biggest uncertainty about the design concerns the engine exhausts, which as seen on the prototype are likely to cause a radar cross-section (RCS) peak from the rear aspect. One possibility is that a stealthier two-dimensional nozzle will be integrated later in the program: however, the nozzles on the current aircraft show some signs of RCS-reducing saw-tooth treatment, suggesting that the PLA has accepted a rear-aspect RCS penalty rather than the much greater weight and complexity of 2-D nozzles.
Other details of the design are unknowns. Stealth development has been dogged by detail design challenges. All the antennas on the aircraft have to be flush with the skin and covered with surfaces that retain stealth properties while being transparent in a specific frequency. Maintainability becomes a complex trade-off: some systems requiring frequent attention will be accessed via landing gear and weapon bays, and others by latched and actuated doors that can opened and closed without affecting RCS, but the latter are a heavy solution.
Perhaps the toughest challenge in stealth design is the need to manage RF surface currents over the skin. Early stealth designs used heavy, maintenance intensive RAM. The F-22 introduced a much lighter surface treatment, but it has proven unexpectedly difficult to maintain, causing corrosion issues. Lockheed Martin now claims that the F-35 will be robust and affordable to maintain in service, with a combination of a high-toughness sprayed-on topcoat and a conductive layer cured into composite skin panels.
The Chengdu J-20 design has struck many analysts and observers as familiar and somewhat different that the Lockheed-Martin F-22, F-35 or the Sukhoi T-50.
“The J-20 is reminiscent of the Russian MiG 1.42 both in terms of planform, and also with regard to the rear fuselage configuration,” says Douglas Barrie, senior fellow for military aerospace at London’s International Institute for Strategic Studies. “The most obvious difference is the greater forward fuselage shaping as the basis for low observable characteristics, along with the different engine intake configuration. The MiG program was cancelled by the Russian government around 1997.” However, the similarity to the MiG concept may suggest some collusion with the Russian aviation industry.
Moltoben escreveu:there are about 30 countries able to buil a raptorsky shape "looking like " 5G fighter and put engines into to test flights!
any country willing to design a new fighter in 2010 will not choose a badly copied 30 years old shape, but make a 6th gen fighter!