Quote from: john smith 19 on 04/10/2018 06:53 am>The Cold War ended in 1989. Let it go.In case you haven't noticed, Cold War II started on March 4, 2012 with Putin's reboot.
>The Cold War ended in 1989. Let it go.
Quote from: docmordrid on 04/12/2018 03:14 pmQuote from: john smith 19 on 04/10/2018 06:53 am>The Cold War ended in 1989. Let it go.In case you haven't noticed, Cold War II started on March 4, 2012 with Putin's reboot.Which is OT for this thread. More relevant would be the fact that Russia (and its predecessor states) has had operational M5 (and M5+) capable long range missiles since the mid 90's at least. Despite this the US military has still not been able to build a strong enough case to fund an operational vehicle. USN has fielded previous long rang ramjet missiles (some with long operating lives) since the late 50's. Likewise some experimental US missiles with fixed inlets have hit M5+.
Prolonged M4 heating remains acceptable to titanium airframe (to withstand the total temperature in thermal equilibrium), prolonged M5 heating isn't.
Engines are less problematic, J58 in bypass ramjet mode is already a "turbofan", while modern turbofans are built with superalloys much better than J58.
It's tough to make a business case for M5-ish missiles when other, cheaper, missiles can go up to M12 with high accuracy. Not to mention Russia shredding the IRBM treaty with some of those birds.
Quote from: docmordrid on 04/12/2018 06:48 pmIt's tough to make a business case for M5-ish missiles when other, cheaper, missiles can go up to M12 with high accuracy. Not to mention Russia shredding the IRBM treaty with some of those birds.Then perhaps the US should bite the bullet and just accept if they want a fast missile they should stick it on top of a really big rocket, instead of betting on the SCramjet?
J58 without nacelle is a "leaky turbojet" which mimics turbofan by discharging air from comperssor.
Quite controversial, turbofans behave better than turbojets at M3.D-30F6 of Mig31 is modified from high bypass civil version D-30, bypass ratio is reduced but yet higher than typical military low bypass turbofans.At M2~M3, the core runs at idle speed, and the afterburner feds air mainly from large bypass duct. This solved overheating problem in R-15 turbojet of MIG25.
Imagine a civilian high bypass turbofan between shock cone inlet (which reduces air to subsonic) and gigantic afterburner, the whole system as an enormous turboramjet. At M3 the core fuel supply shuts down, with low compression ratio and low heating in free rotation, drag of fan blades are neglegible compared to high compression of inlet.Though at M1~2 the gigantic afterburner would be extremely fuel consuming.
Gliding RVs have been successfully tested by USAF in 1960s. But rocket boosted non nuclear fast missiles are too expensive to be operational up to now. Unless Russian shoots down all Tomahawks and SDBs in Syria tomorrow. Russia and China develop "operational fast missiles" since they would never fight with them.
The term "hypersonic vehicles" virtually means "technological backup", either SCramjet or gliding RV, either weapon or SST.Shuttles are hypersonic (even with wings), but nobody call them this way. It's interesting to see how BFR/BFS would fit in these names and applications.
Quote from: Katana on 04/13/2018 05:48 amJ58 without nacelle is a "leaky turbojet" which mimics turbofan by discharging air from comperssor.Strictly speaking no jet engine operates "naked." They are all inside a nacelle or a fuselage. Quote from: KatanaQuite controversial, turbofans behave better than turbojets at M3.D-30F6 of Mig31 is modified from high bypass civil version D-30, bypass ratio is reduced but yet higher than typical military low bypass turbofans.At M2~M3, the core runs at idle speed, and the afterburner feds air mainly from large bypass duct. This solved overheating problem in R-15 turbojet of MIG25.AIUI this was suggested in the US for their SST programme in the late 60's/early 70's under the name "fan burning." The issue remains, the higher the airflow speed you're looking to decellerate from the hotter that flow will be. Once you get to M5 that's still not enough and you're probably looking at some kind of liquid injection, or you go with the US response of a SCramjet.
Turbofans comparable to naked J58 could also be fitted with J58 styled nacelle.Air flow total temperature after deceleration is yet acceptable for titanium parts at M4, this differs form M5+.SST does not need to cross M5 and become hypersonic.
Shuttles and maneuverable ICBM RVs are technically strictly hypersonic. But people does not talk this way. Hypersonic vehicles (even rocket boosted gliders now) are boasted by their advocates as new technology, as if Shuttle and ICBM never existed.
X-51 based missile concepts have been abandoned. Fuel economy of X-51 is not very good, presumably NOTHING have satisfactory fuel economy at M5 for the size of a missile.
For aircraft, M4 turboramjet is practical enough when M6 is appreciable (e.g. SST). If M4 can't escape SAM interception, M6 is also dangerous.
To be hypersonic for this threadTo be civil for this forumTo be technically viableTo be economically appreciableWhich ongoing project could satisfy all these constraints?BFS only?
It’s a lot easier to travel at very high speeds if you go above the atmosphere and people have been doing it this way for more than half a century. I get that there’s a sort of engineering challenge that drives R&D into hypersonic flight in the atmosphere, but is there any serious purpose for it beyond what would follow from cheap orbital launch like BFR? It seems a bit like the teams trying to set new land speed records. It’s a cool challenge, it might produce some interesting spinoffs, there might be some niche military applications, but it’s not real important.There have been a series of Russian announcements about new weapons that seem kind of retro and silly. At best they’re produced out of a grossly exaggerated concern about the effectiveness of Star Wars anti missile systems. Claiming your missiles can hit targets “anywhere in the world” seems oblivious to the fact their missiles could do that in 1960. Saying they’re hypersonic is the same thing. They were hypersonic 50 years ago. Am I misunderstanding something?
The indefinite-delivery and indefinite quantity award worth up to $928 million suggests the USAF is ready to move past several decades of development and demonstrations of weapons that can cruise for long distances at speeds exceeding Mach 5.The award came out of a competitive acquisition process in which three offers where received, according to an award notice. The USAF did not name the other bidders, though when the competition was announced in July 2017 the service named Boeing, Lockheed Martin, Northrop Grumman and Raytheon Missile Systems as the only acceptable bidders due to timeframe constraints.The USAF is accelerating its efforts to develop hypersonic weapons and aircraft in light of advances and investments made in hypersonic technology by China and Russia.
Both are part of a program to develop advanced prototypes that can later be fielded on U.S. jets.“The Air Force is using prototyping to explore the art of the possible and to advance these technologies to a capability as quickly as possible,” Air Force spokeswoman Ann Stefanek said.Lockheed Martin executives have emphasized hypersonic aircraft and weaponry as an area of intense interest.“We are committed to the development of state-of-the-art hypersonic technologies, and we are excited to get to work on the Hypersonic Conventional Strike Weapon program,” Jon Snyder, Lockheed Martin’s vice president for Air Force Strategic Programs, said in an emailed statement.
Despite major strides in air-breathing hypersonic scramjet technology, developers of high-speed propulsion systems for future weapons, reconnaissance vehicles and space access still lack crucial knowledge about the fundamental flow physics and combustion chemistry at the engine’s heart. Although a better understanding of key aerothermodynamics inside scramjets has been gained through computational fluid dynamics modeling and other diagnostic methods, as well as trial and error in ...
The Air Force has established a nearly $1 billion program to prototype a long-range, air-launched, hypersonic strike weapon and Lockheed Martin has elbowed away two other competitors to win the project, the service has revealed.Lockheed, which beat a Raytheon-Boeing team and another competitor for the Hypersonic Conventional Strike Weapon prototyping effort, now assumes a dominant role in leading two parallel Air Force projects that aim to develop a long-range, conventional prompt strike capability.Spokesman for two other contractors the Air Force invited to compete in the HCSW program -- Northrop Grumman and Orbital ATK -- both declined to confirm whether their companies had submitted a bid or comment in any way on the contract award. Northrop is slated to acquire Orbital ATK this year. Debroah VanNierop, a Boeing spokeswoman, confirmed to Inside Defense the company was a subcontractor on a proposal led by Raytheon.On April 18, the Air Force announced Huntsville, AL-based Lockheed Martin Space to be the “successful offeror” of a contract potentially worth $928 million to design, develop, and perform engineering, systems integration, test, logistics, planning and aircraft integration support of all elements of a hypersonic, conventional, air-launched, stand-off weapon.The objective of the HCSW program, informally called “Hacksaw,” is to develop long-range hypersonic missile prototypes that can be integrated on the service's current bomber and fighter aircraft fleets and be supported in all operations, mission-planning and sustainment efforts, according to the Air Force.“This effort is one of two hypersonic weapon prototyping efforts being pursued by the Air Force to accelerate hypersonics research and development,” said Ann Stefanek, an Air Force spokeswoman. “The Air Force is using prototyping to explore the art-of-the-possible and to advance these technologies to a capability as quickly as possible.” The second Air Force prototyping project is the Air-Launched Rapid Response Weapon (ARRW), with support from the Defense Advanced Research Projects Agency, to also develop a long-range, prompt strike capability.Stefanek declined to offer further detail about the programs, specifically whether the core technology of the projects was based around an air-breathing, hypersonic system or a hypersonic boost-glide system.The full scope of the Hacksaw program -- which is slated to potentially fund work through engineering and manufacturing development -- was not previously known. The project was hatched in FY-18 as part of a “Lifecycle Prototyping” effort that sought $153 million to fund numerous technologies; it is not clear how much of that is allocated to Hacksaw. The Air Force's FY-19 budget request establishes a dedicated Hacksaw budget line, seeking $89.3 million. Future funding for the hypersonic conventional strike program was not previously disclosed.By comparison, the ARRW -- which also was broken out from the Lifecycle Prototyping project for the first time in the FY-19 budget -- is seeking $169 million, a potentially bigger program.The Air Force, according to the FY-19 budget request, plans to "leverage the synergistic efforts" of DARPA's existing contract with Lockheed Martin for a Tactical Boost Glide demonstration to further the ARRW program. It appears the Air Force's new ARRW project will overlap with the TBG program -- a joint DARPA-Air Force initiative to develop and demonstrate technologies to enable future air-launched, tactical-range hypersonic boost glide systems.The scale of the Hacksaw project is comparable to the Pentagon's marquee effort over the last decade to develop technologies for a long-range hypersonic strike weapon as part of the Conventional Prompt Strike program, run by the Office of the Secretary of Defense. The Defense Department has spent $1.2 billion over the last 10 years to develop a boost-glide weapon and earlier this year disclosed plans to put the Navy in charge of the project beginning in FY-20, with the goal of outfitting submarines with a hypersonic strike weapon.Last summer, the Air Force Life Cycle Management Center -- after asking industry to register interest in supporting Hacksaw requirements -- determined five companies were able to meet the service's needs: Boeing, Lockheed Martin, Northrop Grumman, Orbital ATK and Raytheon.In the end, the Air Force received a total of three offers from industry, according to the announcement.The Hacksaw program is being financed with funds from its advanced component development and prototyping accounts and is part of a larger Technology Transition Program to “demonstrate, prototype, and experiment with technologies and concepts to enable or accelerate their transition to acquisition programs and/or operational use,” according to the Air Force budget.“The Technology Transition Program addresses the gap between initial technology or concept development and demonstration, and successful acquisition and operational capability implementation,” according to the Air Force's FY-19 budget request.The Hypersonic Conventional Strike Weapon project integrates Air Force-enabled “system technologies into a prototype that will demonstrate the viability of this concept to be fielded as a long-range prompt strike capability,” according to the service's FY-19 budget request. “HCSW will design, develop, manufacture, and test, a number of prototype vehicles to inform decisions concerning HCSW acquisition and production,” the budget states.
The Pentagon wants its new AI center up and running in six months, but is taking a different track on directed energy and hypersonics, Deputy Defense Secretary Shanahan says.
While it’s clear the Pentagon leadership thinks they have a winner in the nascent JAIC, they’re doing things differently when it comes to hypersonics and directed energy weapons. In establishing new directed energy programs, “it may not be that there’s a center,” Shanahan said. “What we may do is parse things out until someone’s doing power supply, somebody’s doing beam control. It’s different aspects of the technology that we’ll probably parse out, either to a service or one of the research labs.”Griffin has repeatedly said that developing new hypersonic capabilities is his top priority, and Shanahan confirmed Tuesday that Griffin has already delivered an interim report on his plans for ten key technology areas for the Pentagon, with a final report due on his desk in July.
We can expect an important announcement in a few weeks that “a significant acceleration is doable” of the Air Force’s hypersonic efforts. Roper said he’d completed a review of all the service’s work on hypersonic, one of the Pentagon’s top priorities