30 mars 2020 | International, Aérospatial
Steve Trimble
The design of the Northrop Grumman B-21's trailing edge has led to speculation about a high-altitude role for the secretive stealth bomber, and new U.S. Air Force statements appear to confirm that analysis.
As the U.S. Air Force enters a legally required environmental impact review process for basing the new bomber, service officials disclosed a few new details about the design on large poster boards displayed at public meetings since February. The posters are now available on B21EIS.com, a clearinghouse web site set up by the Air Force to share data during the year-long process to complete the final environmental impact statement.
“The B-21 is not expected to use low altitude training routes,” the Air Force poster says.
The B-2 was originally conceived as a high-altitude bomber, but a last-minute requirements change during the development phase forced Northrop Grumman to redesign the bomber for a low-altitude mission. As a result, the trailing edge was transformed from a simple W-shape to the sawtooth design seen today. The B-2, like the preceding B-52 and B-1B fleets, need low-altitude training routes.
The renderings of the B-21 released by the Air Force so far reveal a trailing edge that resembles the original, high-altitude design for the B-2. The Air Force has never confirmed operational details about the future stealth bomber.
Another comment on the Air Force's poster provides the first official description of the B-21's acoustic signature, as well as the performance of the engines.
“The B-21 engine noise is expected to be quieter than the B-1B and about the same or quieter than the B-2,” the poster says.
Previously, the only detail released by the Air Force about the B-21's engines is that Pratt & Whitney is named as one of seven of Northrop's suppliers. The poster data appears to confirm expectations that the B-21 would use a non-afterburning engine, like the similarly subsonic, flying wing-shaped, B-2. The supersonic B-1B is powered by afterburning engines.
The Air Force has selected Ellsworth Air Force Base in South Dakora as the site for the first B-21 operational squadron, followed by Dyess AFB in Texas and Whiteman AFB, Missouri. The environmental impact review is evaluating Ellsworth and Dyess for the main operating beddown 1 location.
22 février 2021 | International, Aérospatial
Unit prices aren't likely to decrease much, if at all, in the next three lots of F-35 production—now being negotiated, says Lockheed Martin.
26 mai 2021 | International, Aérospatial
Fitted with the new Eagle Passive Active Warning Survivability System, or EPAWWS, the twin-engine, two-seat F-15EX in theory could project a protective bubble of radar-muddling noise around itself and nearby warplanes.
4 janvier 2019 | International, C4ISR
DARPA seeks to develop schema-based AI capability to enhance reasoning about complex world events and generate actionable insights Rapid comprehension of world events is critical to informing national security efforts. These noteworthy changes in the natural world or human society can create significant impact on their own, or may form part of a causal chain that produces broader impact. Many events are not simple occurrences but complex phenomena composed of a web of numerous subsidiary elements – from actors to timelines. The growing volume of unstructured, multimedia information available, however, hampers uncovering and understanding these events and their underlying elements. “The process of uncovering relevant connections across mountains of information and the static elements that they underlie requires temporal information and event patterns, which can be difficult to capture at scale with currently available tools and systems,” said Dr. Boyan Onyshkevych, a program manager in DARPA's Information Innovation Office (I2O). The use of schemas to help draw correlations across information isn't a new concept. First defined by cognitive scientist Jean Piaget in 1923, schemas are units of knowledge that humans reference to make sense of events by organizing them into commonly occurring narrative structures. For example, a trip to the grocery store typically involves a purchase transaction schema, which is defined by a set of actions (payment), roles (buyer, seller), and temporal constraints (items are scanned and then payment is exchanged). To help uncover complex events found in multimedia information and bring them to the attention of system users, DARPA created the Knowledge-directed Artificial Intelligence Reasoning Over Schemas (KAIROS) program. KAIROS seeks to create a schema-based AI capability to enable contextual and temporal reasoning about complex real-world events in order to generate actionable understanding of these events and predict how they will unfold. The program aims to develop a semi-automated system capable of identifying and drawing correlations between seemingly unrelated events or data, helping to inform or create broad narratives about the world around us. KAIROS' research objectives will be approached in two stages. The first stage will focus on creating schemas from large volumes of data by detecting, classifying and clustering sub-events based on linguistic inference and common sense reasoning. Researchers taking on this challenge will apply generalization, composition and specialization processes to help generate schemas that describe both simple and complex events, sequence multiple schemas together to understand key contextual elements like roles and timelines, and apply domain-specific knowledge to tailor the analysis for a particular need. The second stage of the program will focus on applying the library of schemas created during stage one to multimedia, multi-lingual information to uncover and extract complex events. This stage will require identifying events and entities, as well as relationships among them to help construct and extend a knowledge base. DARPA will hold a Proposers Day on January 9, 2019 from 10:00am to 2:30pm (EST) at the Holiday Inn at Ballston, 4610 N. Fairfax Drive, Arlington, Virginia 22203 to provide more information about KAIROS and answer questions from potential proposers. For details of the event, including registration requirements, visit https://www.schafertmd.com/darpa/i2o/KAIROS/pd/. A Broad Agency Announcement that fully describes the program structure and objectives can be found here, https://www.fbo.gov/index?s=opportunity&mode=form&id=0fc6d1a237556c5d59847e7165af3aef&tab=core&_cview=1. Image Caption: This image outlines the two stages of the KAIROS program. The first stage will focus on creating a library of schemas from large volumes of data by detecting, classifying and clustering sub-events based on linguistic inference and common sense reasoning. The second stage will apply those schemas to new information to uncover and extract complex events, as well as relationships among them, to help construct and extend a knowledge base. https://www.darpa.mil/news-events/2019-01-04