16 février 2022 | International, Aérospatial
14 août 2019 | International, Aérospatial
Precooler Technology Could Bring Advantages To Fighter Engines
By Tony Osborne
Technology developed by Britain's Reaction Engines for its SABRE (Synergistic Air-Breathing Rocket Engine) hypersonic powerplant is to be fitted on the Eurojet EJ200 engine from a Eurofighter Typhoon to understand if the technology can help transform the powerplant's operating envelope.
The £10 million ($12 million) project announced by the Royal Air Force (RAF) Rapid Capability Office (RCO) in July will see BAE Systems, Reaction Engines and Rolls-Royce engineers work to better comprehend Reaction's precooler technology and how it could be integrated for use on a jet engine—perhaps even the powerplant for Britain's future combat aircraft, the Tempest.
Two-year project will scope integration to better understand precooler potential benefits
Heat exchanger is an enabler for Reaction Engines' SABRE technology
The trials represent the first acknowledged application of the precooler technology
At high speed, jet engines struggle with a thermal challenge as air entering the intake becomes too hot, reducing thrust and limiting the ability to reach speeds beyond Mach 3. Reaction's precooler, essentially a highly efficient heat exchanger, already has proven its ability to quench megawatts of heat energy from the incoming air. Trials in the U.S. have shown the precooler technology to cool intake airflow from more than 800F (426C) to around 212F in just 1/20th of a second, helping to maximize performance.
Applied to a fighter engine, the precooler could allow it to work more efficiently at high speeds but also enable manufacturers to be less reliant on exotic, expensive and heat-resistant materials such as titanium. This could lead to lower costs in terms of purchase and maintenance, which are both key focuses of Britain's Future Combat Air System Technology Initiative (FCAS TI). The goal of the FCAS TI is to research and develop new technologies that can be spiraled into Britain's Eurofighter Typhoons and Lockheed Martin F-35s, but also potentially featured in a combat aircraft to replace the Typhoon in the 2030s.
“This is Phase 1 of something more,” Air Vice Marshal, Simon “Rocky” Rochelle, chief of staff for capability and the brainchild behind the RAF's RCO, said at the Royal International Air Tattoo, where the contract was signed. “There is something here that needs to be explored, investigated, tested and tried.”
Over the next two years, engineers will study how the precooler can be integrated onto the EJ200. Once this is established, the engine and precooler will be ground-tested together.
“This isn't about a new market for EJ200. We are using existing assets to try and address that heat challenge,” Conrad Banks, Rolls-Royce's chief engineer for future defense programs, tells Aviation Week.
“If you can cool the intake air down, suddenly you can expand the flight envelope of your gas turbine and it introduces some exciting supersonic and hypersonic applications.”
There is no suggestion the UK is looking for a hypersonic fighter, especially with the high costs associated with the airframe alone. Nonetheless, the technology could enable higher supercruise performance—sustained supersonic flight without the use of afterburner, or more simply better fuel economy.
“What we will do on the testbed is assess the drop in temperature and then see how that affects the core of the engine, that then validates our model. . . . This is not about massively changing the engine,” Banks explains.
How the precooler could be fitted to the engine is also part of the scope of the study. One option could be a donut-like configuration around the intake, Banks suggests. The work also will consider how the introduction of a precooler affects the rest of the airframe and whether such an installation is affordable. The precooler fitted to the EJ200 will be “designed and scaled to the engine to match its performance,” says Banks.
As Banks describes it, the technology will not change the low-observability aspects of the platform such as the engine's infrared signature, pointing out that will depend on what is done on the back end of the engine. However, officials note such a heat exchanger also could be mounted to the rear of the engine.
For Reaction Engines, the trials build on its lightweight heat exchanger (HTX) experiments, which were conducted in Colorado and used a J79 engine from an F-4 Phantom to feed the precooler. The technology is key to the company's SABRE concept, which is targeted at air-breathing hypersonic and space access vehicles. In this role, the engine is designed to efficiently extract oxygen from the atmosphere for rocket combustion. In the fully integrated SABRE, the chilled air will be passed from the HTX to a turbo-compressor and into the rocket thrust chamber, where it will be burned with sub-cooled liquid hydrogen fuel.
Reaction Engines has raised over £100 million in the last three years from public and private sources. In addition, the UK government in 2013 announced a £60 million commitment to assist with the demonstrator engines. Strategic investments also have been made at BAE Systems in 2015 and more recently in 2018 by Rolls-Royce and by Boeing's capital venture arm, HorizonX.
https://aviationweek.com/defense/precooler-technology-could-bring-advantages-fighter-engines
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10 septembre 2018 | International, C4ISR
Cyber Command’s acquisition authority still in its infancy
By: Mark Pomerleau U.S. Cyber Command is still in the beginning stages of building out an acquisition capability. Eight years after its launch and about two years after being granted limited acquisition authority from Congress, the command is still working to demonstrate that its wares and abilities make good use of funds and that it is capable of managing contracts, its acquisition executive said. “I will say we are in our infancy from an acquisition perspective. We are putting the foundation of the personnel and the skills,” Stephen Schanberger said Sept. 6 at the Billington Cybersecurity Summit. “We're in the beginning stages right now.” In the fiscal 2016 defense authorization bill, Congress gave Cyber Command limited acquisition authority capped at $75 million with a sunsetting in 2021. Congressional aides have equated this authority to that of Special Operations Command, noting that they wanted to employ a crawl, walk, run mentality to make sure Cyber Command can execute it. Schanberger said the command is asking for more on both fronts, with a ceiling of $250 million and a sunset of 2025 — the timeline being the most important element as it makes it easier to work with vendors who know contracts might not be in doubt three years from now. For Congress's part, Schanberger said they want the command to show it can use the authority in the way it's supposed to and start to stand up the backbone of a contracting organization. This includes being able to put together solicitation packages, plan contracting strategy for years ahead and be able to effectively implement and put out proposals and award them without making a mess, he said. Schanberger said the command currently has one contracting officer and one specialist and a couple of contractors aside from himself in the contracting shop, though he expects those numbers to double in the next three months. Cyber Command issued its first contract under this limited authority in October 2017. Schanberger said the command awarded only one contract in fiscal 2017, due in part to the fact they lacked a contract writing system, which is now in place. In fiscal 2018, the command is on track to award roughly $40 million in contracts and in fiscal 2019 is on a path to get close to its cap, Schanberger said. Congress has also asked what the delineation lines are between the acquisition efforts of Cyber Command and those of the services, Schanberger said. “Right now what we really look at are what are the gaps between us and our service partners and how do we help fill those gaps,” he said. “Typically, there are a couple of programs where we did the prototyping efforts and we transitioned that to the services. That's where we see our most value ... things that can benefit all our service cyber components.” Some within Congress have expressed that Cyber Command has approached acquisition cautiously and are concerned the services aren't budgeting and providing the tools and capabilities that the cyber mission force needs. Schanberger said he thinks that command has demonstrated that it can issue contracts effectively, efficiently and quickly. However, he noted, he still does not think the command has the wherewithal internally to run something as big as the Unified Platform, one of DoD's most critical cyber programs, from a resource perspective. https://www.fifthdomain.com/dod/cybercom/2018/09/07/cyber-commands-acquisition-authority-still-in-its-infancy
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20 août 2019 | International, Autre défense
A robot as slow as a snail ... on purpose
By: Kelsey D. Atherton Snails and slugs are so commonplace that we overlook the weirdness of how they move, gliding on a thin film across all sorts of terrain and obstacles. Popular imagination focuses on how slow this movement is, the snail defined by its pace, but it is at least as remarkable that the same mechanism lets a snail climb walls and move along ceilings. The movement is novel enough that there is now a snail-inspired robot, sliding across surfaces on an adhesive membrane, powered by a laser. The snail robot, produced by a joint research team at the University of Warsaw Poland, together with colleagues from Xi'an Jiaotong-Liverpool University in Suzhou, China, created a centimeter-long robot powered by light. The research, published July in Macromolecular Rapid Communications, sheds new insight on how animals move in the wild, and on how small machines could be built to take advantage of that same motion. Why might military planners or designers be interested in snail-like movement? The ability to scale surfaces and cling to them alone is worth study and possibly future adaptation. There's also the simple efficiency of a creature that maneuvers on a single, durable foot. “Gastropods' adhesive locomotion has some unique properties: Using a thin layer of mucus, snails and slugs can navigate challenging environments, including glass, polytetrafluoroethylene (PTFE, Teflon), metal surfaces, sand, and (famously) razor blades, with only few super-hydrophobic coatings able to prevent them from crawling up a vertical surface,” write the authors. “The low complexity of a single continuous foot promises advantages in design and fabrication as well as resistance to adverse external conditions and wear, while constant contact with the surface provides a high margin of failure resistance (e.g., slip or detachment).” Snails can literally move along the edge of the spear unscathed. Surely, there's something in a robot that can do the same. The small snail robot looks like nothing so much as a discarded stick of gum, and is much smaller. At just a centimeter in length, this is not a platform capable of demonstrating much more than movement. The machine is made of Liquid Crystalline Elastomers, which can change shape when scanned by light. Combined with an artificial mucus later formed of glycerin, the robot is able to move, climb over surfaces, and even up a vertical wall, on a glass ceiling, and over obstacles, while it is powered by a laser. It does all of this at 1/50th the speed a snail would. This leaves the implications of such technology in a more distant future. Imagine a sensor that could crawl into position on the side of a building, and then stay there as combat roars around it. Or perhaps the application is as a robot adhesive, crawling charges into place at the remote direction of imperceptible light. Directing a robot into an unexpected position, and having it stay there with adhesive, could be a useful tool for future operations, and one that would be built upon research like this. The robot may be comically slow now. The pace of the technologies around it is not. https://www.c4isrnet.com/unmanned/robotics/2019/08/19/do-snail-robots-foreshadow-the-sticky-grenades-of-the-future/