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    The currently funded $billion+ dollar programs will take the NG propulsion to TRL-6+ by early next decade. Further risk reduction could be performed if they incorporate more advanced prototype flight testing (that is an option built into the AETP). That is from what we know. On the AII-X's non propulsion side we do not know where a lot of the technology currently sits but I wouldn't be surprised if a heck of a lot of stuff was or will be matured by other programs leaving the PCA with an integration challenge as opposed to a technology development challenge (same thing with the B-21).

    It isn't like they aren't aware of the cutting edge sensor technologies or aren't invested in it themselves. The US is funding some of the most extensive research and acquisition of GaN systems at a very substantial scale and pace. Whether that is new family of sensors on the AEGIS combat system, upgrading other Ballistic missile defense applications, high power jammer systems or developing the Next Generation of long range ground based surveillance radars and large airborne sensors. The sensor modernization, and semiconductor material S&T and R&D pipeline is pretty robust. In many instances this is being done by the same organizations (services) or industry partners (companies) that are going to be tasked with developing the PCA or other advanced systems.

    http://defenseinnovationmarketplace....D-20160224.pdf
    Last edited by bring_it_on; 20th March 2017, 14:59.
    Old radar types never die; they just phased array

    Comment


      Originally posted by garryA View Post
      With both photonics and GaN , radar detection range will certainly improved alot. However, i don't see those technology as the death to stealth. In fact, they make stealth become even more important given that technologies like GaN can easily be implemented on jammers which synergy signifiantly better with a low RCS assets. Longer radar detection range also help stealth aircraft deal with threat from optical sensor much easier.
      Cost also. With a lot of different platforms now in need of radar fielding a high level of specific performance, photonics technologies will cut the cost of development and adaptation. You'll have a more robust architecture than can be arranged without the need to costly customized signal amplifiers for example.
      Last edited by TomcatViP; 20th March 2017, 21:43.

      Comment


        LM reject T-50 for OA-X but some hints suggest a rotary airframe

        Instead, the company is still weighing its options, with [Orlando Carvalho, executive vice-president of Lockheed’s aeronautics business] hinting that a solution may come not from the fixed-wing side of the company but rather from its rotary and mission systems business.
        Source:
        DefenseNews.com

        Comment


          Originally posted by garryA View Post
          AFAIK, according to USAF both F-35 and F-22 have better stealth than F-117.
          CNT RAM aside their shape should still deal with low band better since they have fewer sharp edges.
          Moreover, there are better edge treatment new stealth platform


          Regarding photonic radar, according to what said in these 2 articles
          http://www.nature.com/nature/journal...ture13078.html
          http://spectrum.ieee.org/tech-talk/a...e-radar-system
          in photonic system you can reduce internal noise of the system by 10 times ( 10 dB ) because analog hardware components such as mixers, amplifiers are replaced by two optical resonant mode-locked laser and a photodiode sensor, thus detection range will increase. While that no doubt very good , it is no where from a counter stealth system with face recognizition from 500 km aways like some journalists claimed. Personally, i see it as similar to the change from PESA to AESA ( rely on reduce internal noise for better detection range ).
          On the otherhand, GaN rely on better transmitting power for range improvement.
          With both photonics and GaN , radar detection range will certainly improved alot. However, i don't see those technology as the death to stealth. In fact, they make stealth become even more important given that technologies like GaN can easily be implemented on jammers which synergy signifiantly better with a low RCS assets. Longer radar detection range also help stealth aircraft deal with threat from optical sensor much easier.
          No one says there that they would have to be back to pre-stealth aircraft, just that actually the rate of advancement of radar technologies are actually superior than the ones of stealth and that sacrificing even more aircraft performances (because at the moment a multiband VLO plane would mean just a flying wing) trying to match them seems me just a recipe for troubles and a lot of money of time wasted.

          The photonic radar other great advantage is that it is software defined, meaning the band of emission can change at will spanning from low band to millimeters one in just one fitting, that would even be lighter than actuals.

          IMHO the point of maximum technological/tactical advantage of VLO technologies is even actually being trespassed and it would further deteriorate as time passes by.
          So, I sincerely hope that the programs that FBW are listings would take a whole different road to the first anticipation they send out but I still am quite worried they are starting from a wrong assumption i.e. trying to keep a level of advantage over competitors that the stealth once granted them 'cause an initial complete lack of efforts from their adversaries on that field.
          Now, there is not any new technologies that are not actively pursued by competitors also, so the relatively advantages would be just relative, as it usually was before the case in question.

          Comment


            (because at the moment a multiband VLO plane would mean just a flying wing)
            Flying wings are very aerodynamically efficient in cruise though and therefore a desirable planform for any design that requires range or endurance; Flying wing designs have been pursued since before the advent of jet engines let alone VLO requirements.

            It's not really much of a disadvantage for Strike, ISR/SEAD, strategic bombers or support aircraft to use a flying wing design with the advent of FBW.

            Also wouldn't a fighter sized low band radar be extremely limited due to it's small size?

            Comment


              Originally posted by Marcellogo View Post
              No one says there that they would have to be back to pre-stealth aircraft, just that actually the rate of advancement of radar technologies are actually superior than the ones of stealth and that sacrificing even more aircraft performances (because at the moment a multiband VLO plane would mean just a flying wing) trying to match them seems me just a recipe for troubles and a lot of money of time wasted.

              The photonic radar other great advantage is that it is software defined, meaning the band of emission can change at will spanning from low band to millimeters one in just one fitting, that would even be lighter than actuals.

              IMHO the point of maximum technological/tactical advantage of VLO technologies is even actually being trespassed and it would further deteriorate as time passes by.
              So, I sincerely hope that the programs that FBW are listings would take a whole different road to the first anticipation they send out but I still am quite worried they are starting from a wrong assumption i.e. trying to keep a level of advantage over competitors that the stealth once granted them 'cause an initial complete lack of efforts from their adversaries on that field.
              Now, there is not any new technologies that are not actively pursued by competitors also, so the relatively advantages would be just relative, as it usually was before the case in question.
              I think advancements in RADAR tech are going to hurt non-VLO fighters more than 5th-gen because the low frequency RADARs that are most effective against VLO are physically large (easier to fix and engage kinetically), while also operating in thin spectrum that is relatively easy to bury in noise.

              VHF is 30-300 Mhz compared to X-band at 8-12 Ghz. To raise the noise floor to the same level in both bands, you would need to pump out nearly 15 times the energy for X-band than you would for VHF. Also note that building antennas and transmitters capable of operating in the whole VHF band is massively more difficult than doing the same for X-band. A full VHF band antenna would have a fractional bandwidth of ~1.6 vs 0.4 for X-band, so it is unlikely for a VHF radar to be able to operate in the entire 30-300 Mhz spectrum. A closer comparison would be a VHF AESA that can use 200-300 Mhz vs an X-band radar that uses 8-12 Ghz. In that example, the VHF radar can be jammed with 1/40th the power output you would need for the X-band. If the tech exists for a VHF radar to operate in a wider slice of spectrum, then the tech also exists for a radar that can use the C, X, and Ku bands at the same time.

              I think current technology is already sufficient to build a SAM battery with a large X band AESA that would have no problem seeing legacy non-VLO jets at significant range even if they are supported by massive ECM. While VLO jets will undoubtedly need EW to defeat the IADS of the future, legacy jets may be absolutely unsurvivable with such support.

              Comment


                Originally posted by CastleBravo View Post
                I think advancements in RADAR tech are going to hurt non-VLO fighters more than 5th-gen because the low frequency RADARs that are most effective against VLO are physically large (easier to fix and engage kinetically), while also operating in thin spectrum that is relatively easy to bury in noise.

                VHF is 30-300 Mhz compared to X-band at 8-12 Ghz. To raise the noise floor to the same level in both bands, you would need to pump out nearly 15 times the energy for X-band than you would for VHF. Also note that building antennas and transmitters capable of operating in the whole VHF band is massively more difficult than doing the same for X-band. A full VHF band antenna would have a fractional bandwidth of ~1.6 vs 0.4 for X-band, so it is unlikely for a VHF radar to be able to operate in the entire 30-300 Mhz spectrum. A closer comparison would be a VHF AESA that can use 200-300 Mhz vs an X-band radar that uses 8-12 Ghz. In that example, the VHF radar can be jammed with 1/40th the power output you would need for the X-band. If the tech exists for a VHF radar to operate in a wider slice of spectrum, then the tech also exists for a radar that can use the C, X, and Ku bands at the same time.

                I think current technology is already sufficient to build a SAM battery with a large X band AESA that would have no problem seeing legacy non-VLO jets at significant range even if they are supported by massive ECM. While VLO jets will undoubtedly need EW to defeat the IADS of the future, legacy jets may be absolutely unsurvivable with such support.
                100% agreed there, in the sense that no one around plans to introduce or keep in service for more than a few years in wait for a replacement a plane that has not some serious RCS reduction features (i.e. something like SH, Rafale-D, Su-35S).
                What I was contesting is not the VLO in se but the sort of intention than I see underlined but in some cases also clearly expressed, in some US programs to try to replicate the, repeat again, absolute technological advantage the stealth once gave them.
                Now the genie is going back in the bottle i.e. also the others are introducing advanced VLO planes and there is not any more bottle around i.e. not any new technological advancements others can't cope in a reasonable length of time.
                So, if the PCA program would evolve in the realistical sense of explore ways to cope with advanced AD defence be absolutely my guest, if is an attempt to design some sort of wunderwaffe in the hope to replicate an one in a lifetime exceptionally favourable condition, I fear they would hit a very thick and hard wall.

                Comment


                  Originally posted by Marcellogo View Post
                  100% agreed there, in the sense that no one around plans to introduce or keep in service for more than a few years in wait for a replacement a plane that has not some serious RCS reduction features (i.e. something like SH, Rafale-D, Su-35S).
                  What I was contesting is not the VLO in se but the sort of intention than I see underlined but in some cases also clearly expressed, in some US programs to try to replicate the, repeat again, absolute technological advantage the stealth once gave them.
                  Now the genie is going back in the bottle i.e. also the others are introducing advanced VLO planes and there is not any more bottle around i.e. not any new technological advancements others can't cope in a reasonable length of time.
                  So, if the PCA program would evolve in the realistical sense of explore ways to cope with advanced AD defence be absolutely my guest, if is an attempt to design some sort of wunderwaffe in the hope to replicate an one in a lifetime exceptionally favourable condition, I fear they would hit a very thick and hard wall.
                  That is one way to look at it. Another is to consider that the advantage an IADS with double-digit SAMs has against fourth-generation aircraft may never be replicated again in the age of VLO aircraft since any further advances in RF tech will improve EW just as much as RADAR. Even if VLO tech has reached maturity, and there isn't much improvement left to be had, its introduction has IMO changed the balance of power between aircraft and air defense for the foreseeable future. The way I see it, it's other nations who made a bad bet on their IADS wunderwaffe, and will now need decades of massive investment to catch up. That said, we can't just sit on our butts and allow everyone else to match our capabilities if we want to maintain an advantage.

                  Comment


                    https://www.armed-services.senate.go...a_03-15-17.pdf

                    Future of all arms warfare- Gen. Deptula (Ret.)

                    ” This vision will
                    enable more rapid and effective decisions at the tactical, operational, and strategic levels of war
                    and will provide us an operating advantage that will be difficult for any adversary to overcome.
                    Key capability development areas in the Air Force to achieve this kind of operating paradigm
                    include:
                    a. Data-to-Decision: The objective is to fuse data from cloud-based sensor-effector
                    networks into decision quality information for use at the tactical as well as operational levels of
                    war. Machine-to-machine automation will be integral to allow for the rapid turning of data into
                    information and knowledge to inform decision-making. Big data analytics; incorporation of allsource
                    information; and sensor-to-sensor cueing must become the norm, not the exception in
                    creating a combat cloud.
                    b. ISR Collect and Persistent ISR: These are capabilities that focus on multi-domain
                    alternatives for placing the right sensor in the right place at the right time.
                    c. Penetrating Counter-air (PCA): PCA maximizes tradeoffs between range, payload,
                    survivability, lethality, affordability, and supportability to achieve penetrating counter-air effects
                    in anti-access, area denial environments. Establish PCA as a network nodal element to relay data
                    from penetrating sensors enabling the employment of standoff or stand-in weapons.
                    d. Agile Communications: This is increase in the resiliency and adaptability of integrated
                    networks. Focus on responsive, adaptable network architectures with functionality across all
                    platforms, weapons, apertures, and waveforms operating in a highly contested environment

                    Comment


                      Originally posted by Marcellogo View Post
                      No one says there that they would have to be back to pre-stealth aircraft, just that actually the rate of advancement of radar technologies are actually superior than the ones of stealth and that sacrificing even more aircraft performances (because at the moment a multiband VLO plane would mean just a flying wing) trying to match them seems me just a recipe for troubles and a lot of money of time wasted.IMHO the point of maximum technological/tactical advantage of VLO technologies is even actually being trespassed and it would further deteriorate as time passes by.
                      Iam not sure why would you think so. The whole point of stealth is so that you can detect, attack adversary before they can do the same to you.It doesn't matter if radar can detect stealth fighter from longer distance today than it did in the past. As long as , stealth technology allows VLO fighters to detect/target SAM before getting targeted themselves then obviously it done its job. There are technologies to improve radar detection range of ground radar, but most if not all of them can be put on stealth aircraft as well.Missiles range and jammers are also improve in capabilities. So in that aspects , there are improvement on both side.
                      Think of it as 2 snipers trying to find each others.Regardless of optics that you use, it is always better to have camouflage than not to have it. While kinematics certainly has its usefulness, i personally think it is of lesser important nowadays given the fact that aircrafts can't fly faster or higher than top of the line SAM. There may be some new trend when we finally have DEW though
                      Originally posted by Marcellogo View Post
                      The photonic radar other great advantage is that it is software defined, meaning the band of emission can change at will spanning from low band to millimeters one in just one fitting, that would even be lighter than actuals.
                      Not really, while photonics radar can give you a wide bandwidth with lower internal noise, others physic factors that limit capabilities of low frequency radar will be the same. In other words, if you try to make a photonic low frequency radar that fit on fighters, it will still has terrible resolution.
                      Last edited by garryA; 24th March 2017, 19:32.

                      Comment


                        General Atomics, Dynetics outline Gremlins approaches as phase two begins


                        Teams led by General Atomics and Dynetics beat competitors at Lockheed Martin and Composite Engineering to enter the second phase of the Defense Advanced Research Projects Agency's Gremlins project, and will continue competing over the next year to build a system capable of launching and recovering unmanned aerial vehicles with a C-130.

                        Gremlins would allow the Air Force to eventually field multiple disposable UAVs equipped with different payloads that could fly ahead of a host aircraft on strike, intelligence, surveillance, reconnaissance or other missions.

                        Company officials outlined their approaches going into phase two of the program in recent phone interviews following DARPA's March 15 announcement that the two teams would advance.

                        General Atomics sees Gremlins as a launchpad for a small UAS portfolio it will unveil over the next three years. The company plans to add recoverable, airborne UAS to its MQ-9 Reaper and stealthier Avenger as well as across the Air Force inventory and Navy platforms like the P-8 Poseidon and future MQ-25.

                        "GA's position for phase one and moving forward is to create a product within the Gremlins program that's transportable to as many host platforms as possible to include things like C-17s, C-130s, unmanned aircraft," Mike Atwood, director of General Atomics' advanced programs group, told ITAF March 22. "It's not necessarily to focus at the cargo bay or the wing or different aspects of the C-130, but to focus on a system that's transportable to different aircraft and different recovery stations in the future."


                        Tim Keeter, Dynetics' deputy program manager and chief engineer for Gremlins, said in a March 16 phone interview the UAVs could viably launch from and return to inside the aircraft, do the same from the wing, or launch from one and dock on the other.

                        "In one approach, you could launch it from a pylon and recover it on a pylon," he said. "You could launch it from inside an aircraft and recover it inside the aircraft. You have to look at automation and manpower and the time of recovery, and all those factors play into different approaches."

                        A Lockheed Martin spokeswoman confirmed March 20 the company's C-130 would be able to carry UAVs on its outer wing pylons, depending on their size, shape and weight. The Gremlins design has to account for how large, heavy and powerful UAVs are when carrying various payloads, to figure out the physics needed to fly on and off of a C-130.

                        The air flow around a large cargo aircraft adds another layer of complexity, Keeter said, particularly when flying in difficult weather conditions and at various altitudes. Those environmental factors could make it easier or harder to launch or recover a UAV from the wing compared to inside the aircraft. General Atomics officials did not offer details but said their solution allows for safe, robust recovery.

                        Air Force Special Operations Command missions are the target use for Gremlins' initial operational rollout, Atwood said. He said whether the small UAS launch from and return to the C-130 wing or cargo bay depends on how warfighters envision their use.

                        "Accomplishing this objective will eventually equip the military with the flexibility to complement current mission objectives by doing things like improving standoff of manned aircraft, multiplying efforts to geolocate targets, and extending strike capability of current combat platforms," Keeter said. "It will also provide a necessary architecture for future U.S. military objectives in the area of unmanned autonomous distributed capabilities."

                        DARPA wants the Gremlins concept to use swarms of low-cost, attritable UAVs that can be recycled about 20 times, with less than 24 hours between missions. The more UAVs that are part of the Gremlins system, the more affordable the program becomes, Keeter suggested. Atwood added General Atomics generally believes volleys consist of more than 16 UAVs in a swarm.

                        The UAVs are expected to fly 300 to 500 nautical miles away from the C-130 and loiter. Keeter imagines the radius will increase over time.


                        During the program's 10-month-long first phase, companies developed detailed concepts of operations, system-level requirements, performance and affordability studies, and plans for phases two and three with cost, schedule and performance estimates. In phase two, which will run over the next year, and phase three, which will last about 18 months, the teams will mature systems that can help UAVs overcome the challenges of airflow, speed, proximity to the C-130 and more to successfully launch and return the small aircraft.

                        "When you have an unmanned system and a manned system flying in close formation, there's a lot of safety concerns because you have to close the distance," Keeter said. "You want to make sure that at all times . . . the potential for that to strike the manned aircraft is very low. There's just a lot of technical complexities that go with that type of precision and those types of safety features -- mechanical, electrical, software, you name it."

                        Dynetics' Program Manager Mark Miller added during the March 16 interview the challenge lies in controlling multiple Gremlins while they wait to board the aircraft and designing the means to pull them in. Engineers need to make sure the aircraft align properly without bumping into each other and are recovered quickly enough to make the idea feasible.

                        While DARPA's directive focuses on the C-130, Dynetics did not elaborate on how designs may differ across the aircraft's variants. General Atomics' design would not change under different circumstances, Atwood said.

                        "The solution that GA's proposed and is executing on the phase two is not unique depending on the mission set, the type of configuration of the air vehicle or the host system platform," Atwood said. "You can perform the same recovery mechanisms whether it be EO/IR sensors, electronic warfare sensors, kinetic capability with the same investment."


                        That mindset applies to their unmanned aircraft plans as well: UAS could fly on the Reaper's seven hard points on the wing and body, or the Avenger's hard points and inside the internal weapons bay.

                        "If you're DARPA, you want a value proposition," Atwood said. "If GA is able to propose a system that is relevant, not only to our own unmanned platforms, but as well as P-8s and C-17s and B-1s, the larger community of aircraft that we have, you could see why it would be easy to select a company like General Atomics that's giving them a much more pervasive solution than something that's solely about a demonstration on the C-130."

                        Keeter added Dynetics' subsystem technology could also fly with manned-manned, manned-unmanned or unmanned-unmanned teams.

                        Dynetics prefers a completely autonomous system, though the Gremlins could be flown by someone on the C-130 or on the ground.

                        "There's just a number of different approaches that you could take in terms of when you hand off control of the vehicle and let it operate autonomously, versus when you have a man in the loop," Keeter said. "We're going to want to take the most reliable route with the technology that we can mature and implement between now and phase three."

                        Chris Pehrson, General Atomics' vice president of strategic development for the Defense Department, told ITAF March 22 their Gremlins technology will be similar to the company's automatic takeoff and landing capability, using high levels of autonomy.

                        Col. Brandon Baker, chief of the Air Force's remotely piloted aircraft capabilities division, told reporters last October the Air Force and DARPA signed a memorandum of understanding so the service's intelligence officers can explore the possibilities of command-and-control networks in relation to Gremlins. Pehrson said they regularly meet with Baker, Air Force ISR Capabilities Director Gen. John Rauch and Deputy Chief of Staff for ISR Lt. Gen. VeraLinn Jamieson to discuss key enabling network technologies and concepts of operations that could apply across the new class of small UAS.

                        Stakeholders are studying which datalinks would be most robust and resilient for a swarm, Pehrson added.

                        Gremlins could eventually serve as a testbed for payloads, datalinks, communication techniques and collaborative autonomy, Atwood said -- "kind of a flying garage shop to the AFRL community."

                        "The entire community's collaborating," Atwood said, noting the "early buy-in of the operations community and the futures community of wanting to be stakeholders on the ground floor and not waiting for a development program to happen and then figure out how to use it."

                        "I think it embodies where the defense industry's heading with more stakeholders early in the process, and to see a large organization like the Air Force want to partner with someone like DARPA, I think shows the health of the aerospace industry," he added.

                        The Dynetics officials said the MOU has not spurred any differences in their work.

                        DARPA awarded each company design contracts worth up to $21 million for phase two, according to Dynetics. One company will win a contract in early 2018 for phase three and conduct final flight tests in 2019. The Interior Department also awarded Dynetics and General Atomics "phase II, part B" test contracts on March 13 for nearly $500,000, and on March 8 for almost $1.5 million, respectively.

                        "Due to the rapid nature of the program and the fact that it is a demonstration (as opposed to a formal program of record), DARPA is acting as the airworthiness authority for all flight tests and funding those activities under the Part B contract," Dynetics spokeswoman Kristina Hendrix wrote in a March 23 email. "Differences in how the total amount is split between Parts A and B likely have to do with each contractor's airworthiness activities and rates."

                        DARPA did not respond to further questions by press time (March 23).
                        Old radar types never die; they just phased array

                        Comment


                          Confirmation on the Shield program objectives from ACC boss Gen. Mike Holmes at the Directed Energy Summit just now - 50kW podded directed energy system to be tested aboard a fighter in both the transonic and supersonic envelope. Testing to conclude within 4 years at which time they wil move to other phases. Phase III in the 2025-2030 time frame will move on to a three times larger system for larger aircraft.

                          Live Stream of the DE Summit 2017 :- https://www.boozallen.com/s/event/20...gy-summit.html
                          Last edited by bring_it_on; 29th March 2017, 21:59.
                          Old radar types never die; they just phased array

                          Comment


                            Originally posted by Marcellogo View Post
                            About the first part, I can only tell you also in all seriousness that I and the so called Sputnik have not any relationship of sort, for the rest I know you were joking as soon as you has not even taken the time of reading my post and so to not mistook what I said about F-117 (or B-2, or X-47) FLIGHT PERFORMANCES with its own level of stealth (that's is still better than the ones of F-22 and F-35, it seems).
                            I am inclined to believe that the better computing power to design stealth airframes has made it so that the jet design has to be less compromising to the shape/aerodynamics of the aircraft but is not necessarily better absolute stealth.

                            So if they were to make something as stealth as possible, at the expense of aerodynamics and performance, that the aircraft that they come up with, would look more like the F 1117 than the Raptor.

                            It would be super cool to see someone design the most stealth airframe possible, with all the coating tech applied too. I am a coatings skeptic. Which is why I think the F 1117 might actually be a more practical stealth jet. Because it relies less on coatings and more on the brute force of angles.

                            Comment


                              KGB, repeating this does not make it any more true the second time around. Your post shows an astounding lack of understanding on why the F-117 looks as it does, a misunderstanding of RAM, and a continued misunderstanding of LO principles. Please do basic research before continuing to post on this topic ( better yet, form a new thread for all of your stealth ideas and musings).

                              Comment


                                Originally posted by FBW View Post
                                KGB, repeating this does not make it any more true the second time around. Your post shows an astounding lack of understanding on why the F-117 looks as it does, a misunderstanding of RAM, and a continued misunderstanding of LO principles. Please do basic research before continuing to post on this topic ( better yet, form a new thread for all of your stealth ideas and musings).
                                KGB is right on this.. A curved shape will never be as predictable as a straight angled edge and will always have reflections to all possible directions which, then have to be handled by RAM.. there is no way around it..

                                Comment


                                  Originally posted by MSphere View Post
                                  KGB is right on this.. A curved shape will never be as predictable as a straight angled edge and will always have reflections to all possible directions which, then have to be handled by RAM.. there is no way around it..
                                  No- not when your considering a multifaceted aircraft vs something like a flying wing. No, he's not right. The only reason the F-117 was faceted was due to computing power of the time. There have been exactly two LO aircraft and prototypes that exhibit that type of shaping. We can count the number of UAV, Bombers, prototypes, fighters, that have both a lower RCS and more aerodynamic shape than the said F-117 as a matter of record.

                                  Not getting into this here. Simply put, no.

                                  Comment


                                    So, according to your own words, the alternative they have to reach the RCS reduction they have required is between something like the F-117 and a Flying Wing?

                                    Because you know, in my own country we have a phrase that say: if this in not a soup, it is warm water with something inside (se non zuppa, pan bagnato).

                                    Comment


                                      No, that was not my words (nor the meaning), that is your interpretation of them.

                                      Be happy to discuss this on a separate thread as to what I mean.

                                      Comment


                                        Originally posted by FBW View Post
                                        No- not when your considering a multifaceted aircraft vs something like a flying wing. No, he's not right. The only reason the F-117 was faceted was due to computing power of the time.
                                        Commonly spread BS.. Tacit Blue was developed in parallel and obviously there was enough computing power available to make it not faceted..

                                        Originally posted by FBW View Post
                                        There have been exactly two LO aircraft and prototypes that exhibit that type of shaping. We can count the number of UAV, Bombers, prototypes, fighters, that have both a lower RCS and more aerodynamic shape than the said F-117 as a matter of record.
                                        As usual, the pros do not outweigh the cons.. Obviously there is a way to make a more aerodynamic shape a reasonable compromise from the point of view of RCS.. so they do it..

                                        Originally posted by FBW View Post
                                        Not getting into this here. Simply put, no.
                                        That does not make your stance correct in any way, though..

                                        Comment


                                          Originally posted by KGB View Post
                                          I am inclined to believe that the better computing power to design stealth airframes has made it so that the jet design has to be less compromising to the shape/aerodynamics of the aircraft but is not necessarily better absolute stealth.

                                          So if they were to make something as stealth as possible, at the expense of aerodynamics and performance, that the aircraft that they come up with, would look more like the F 1117 than the Raptor.

                                          It would be super cool to see someone design the most stealth airframe possible, with all the coating tech applied too. I am a coatings skeptic. Which is why I think the F 1117 might actually be a more practical stealth jet. Because it relies less on coatings and more on the brute force of angles.
                                          Originally posted by MSphere View Post
                                          KGB is right on this.. A curved shape will never be as predictable as a straight angled edge and will always have reflections to all possible directions which, then have to be handled by RAM.. there is no way around it..
                                          No, F-117 is not the absolute shape for stealth, unless you only care about specular reflection. In reality radar reflection consist of various different kind of reflection. In optical region then specular reflection is more important than traveling wave return, surface scattering but as wavelength get longer relative to aircraft ( Mie or Rayleigh region ) then surface scattering become more and more important.



                                          A curve often has wider specular reflection cone than a full facet, but the benefit is that it can have less surface scattering. One can look at various modern VLO platforms and noiticed that eventhough many of them don't need agility at all , yet none of them uses full facet design like F-117. Notable examples are B-2 , X-47 their center bodies are actually quite curvy ( even from front aspect ) while there is not a single curve on F-117 design.



                                          On the other hand, a full circular/tube body or nose is very bad for stealth eventhough they have less scattering than a full facet design. The reason is that surface wave will travel the whole circle around in that case . Thus, reflection will be much higher. At the same time they still have wider specular reflection cone


                                          Last edited by garryA; 30th March 2017, 03:52.

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