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Phaid

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Viewing 15 posts - 301 through 315 (of 337 total)
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  • Phaid
    Participant

    To regain the lost coverage compared to traditional mechanically scanned radars, two solutions exist: additional (‘cheek’) arrays or a swash plate installation in the nose.

    A third solution exists, as I said: to mount the array on gimbals, shown here in the Irbis-E radar on the Su-35

    http://sitelife.aviationweek.com/ver1.0/Content/images/store/6/5/c63620e7-b7c8-4610-b512-0a825f643bd9.Large.jpg

    With the gimbals, the array can be pointed through about a 220-degreee field of view, and it maintains its full performance at all angles since the antenna face can be directly pointed at the target. Although it doesn’t need to move as fast as gimbals on a MSA, since the gimbals are not used for “scanning” as such, they still have to move a lot of weight.

    This is different than a swashplate mounting, as is proposed for the Typhoon and Gripen:

    http://sitelife.aviationweek.com/ver1.0/Content/images/store/8/0/385ae619-9a93-437c-b0d9-b2871e7cab84.Large.jpg

    With the swashplate, the array is installed at a fixed angle and then can be rotated longitudinally. This is mechanically simpler and thus presumably more reliable than the gimbal system, but not quite as good in terms of angular performance. The proposed system on the Typhoon would have the antenna fixed at a 45 degree angle. This is touted as giving a 210 degree field of view, assuming the maximum electronically scanned FOV of 60 degrees, but in real life, performance across that 210 degrees will not be uniform.

    in reply to: Mechanical swash plate array versus digitaly steered array! #2380474
    Phaid
    Participant

    The main pro of ESAs from a performance standpoint is that they can scan the entire search volume nearly instantaneously, unlike an MSA which has a refresh based on its mechanical scan rate. This allows better interleaving of modes etc. They are also much more reliable since they have no moving parts and built-in redundancy.

    The cons are that ESA performance drops off as the angle increases. More than about 45 degrees off the perpendicular causes a dropoff in range and resolution, more than 60 degrees is pretty much not possible. They also generate a lot more heat than MSAs so require more cooling.

    A swashplate, or a gimbal system like the Irbis-E, can be used to rotate the emitter array, thus overcoming the angle limitations. But it does so at the cost of added weight and mechanical complexity, and does not truly solve the problem since the radar cannot scan its entire potential field of view at once. A swashplate is probably a more compact and reliable way of doing this, since these arrays are fairly heavy and you have to have a pretty beefy gimbal system. On the other hand the gimbal system probably moves faster and potentially gives a bigger field of view.

    The F-22’s solution to the angle problem was supposed to be lateral arrays mounted in the “cheeks”. This uses no moving parts and simply expands the field of view. Obviously though this is only possible if there is room for it in the airframe. To date the lateral arrays have not been funded, but the airframes have provisions for them.

    in reply to: F-35 News Thread III #2380481
    Phaid
    Participant

    The disconnect extends deep beneath the titanium and steel skin. Major subsystems for both aircraft are based on different computing architectures. So improving hardware or software on the F-35 yields no benefit for the F-22, and vice versa.

    That’s not true in all cases. E.g. the APG-77(V)1 which is a direct use of technology developed for the F-35 and retrofitted to the F-22.

    And anyway, let’s see an F-35 with a full, working, debugged avionics and sensor suite before we start waxing poetic about retrofitting that entire architecture into an F-22. Clearly, if we’re going to restart the F-22 production line in a post-2012 moment of lucidity, then we should do it right and develop an F-22C with an up to date architecture. That doesn’t necessarily mean the F-35’s one is the way to go.

    in reply to: Hot Dog Typhoon thread III #2381226
    Phaid
    Participant

    A good chance for Eurofighter Typhoon to prove itself and its own advertisements in the next 2+ weeks ~ RAF Typhoons versus IAF Su-30MKIs / Mirage 2000s / MIG-27 in Indra Dhanush 2010……

    http://www.upi.com/Business_News/Security-Industry/2010/10/13/War-games-pits-Eurofighter-against-Su-30/UPI-49151286991973/

    FTA: The RAF had deployed its Tornadoes the last time the exercise was held at Gwalior in 2007 but they were no match for the SU-30s as was evident from the black ‘kill marks’ on their tails when they landed.

    Man, those IAF guys must be awesome if they can paint kill marks in flight!

    in reply to: USMC cross-deck traing with RN in May 2010 #2382321
    Phaid
    Participant

    It was exercise Capella Strike, involving Harriers from VMA-223 and VMA-542 aboard Ark Royal. Here’s a USMC press release about it, and here’s a video produced by the USMC talking about the exercise.

    in reply to: Hawk 100/128 #2382326
    Phaid
    Participant

    The differences are in the cockpit instruments and avionics fit. The Hawk 128 has a modern glass cockpit with 3 large MFDs and only a couple of backup steam gauges, whereas the older Hawk 100s have a very 80s style cockpit with a mix of analog displays and MFDs. Externally they are nearly identical.

    in reply to: F-35 News Thread III #2384232
    Phaid
    Participant

    As is the heat sink on your computer’s CPU (and likely other chips prone to heat, such as the video card GPU).

    in reply to: A-10C to the USMC #2388953
    Phaid
    Participant

    I’m guessing more thought was put in the A-10’s survival against the SAM threat, too.

    Definitely, esp wrt MANPADS. The A-10’s engines are podded, separated, and partly masked by the tail and vertical stabilizers. The Harrier is about the most vulnerable airplane conceivable when it comes to IRMs.

    in reply to: A-10C to the USMC #2389148
    Phaid
    Participant

    In Desert Storm, USMC set up operations and flew from a soccer field. As a result, Harriers were the only fixed wing aircraft that did not need aerial tanker support. Had the ground war gone on longer, the plan was to have the Harriers accompany the troops, operating from roads or desert a few miles behind the battle line.

    Not really. The “soccer stadium” you refer to in GW1 was in fact a 4,000-foot asphalt runway at King Abdul Aziz Naval Base, 90 miles from Kuwait. The Marines housed their headquarters in a soccer stadium near the runway, which is how the base got that nickname. Sixty-six AV-8Bs were based there for eight months, along with a bunch of OV-10s. Over 2,000 Marines were based there in support of these aircraft.

    People like to tout the “flexibility” of the Harrier, but in fact the only reason Harriers ever operate from austere basing is because they have such poor range and payload. Yes, they have used damaged / abandoned runways in Afghanistan and Iraq as temporary refueling / rearming points, but the reason they do so is because they just don’t have the performance to operate effectively from farther away, so they try to make up for it with sortie rate.

    And while it may relieve some of the burden on the tankers, transporting the weapons and fuel to a remote location with ground vehicles is an even bigger logistics headache and puts troops in danger. The one time in OIF when Harriers used an improvised FARP on a road, the site was attacked by Iraqi rockets. After that, they gave up the whole FARP concept for Harriers and stuck to real airfields.

    At any rate, WRT the A-10, it is a far better CAS plane than the Harrier, but even if any were available it isn’t suitable as-is for the USMC for reasons stated above.

    Schwartzkopf may have said nice things about the Harrier, but then Horner also said its payload, range and suitability for close air support was far inferior to the A-10’s, and that the ability to stack conventional strike AC over the battlefield negated the need for quick response from forward-based Harriers in any case. The numbers don’t really work in the Harrier’s favor either; the same number of AV-8Bs as A-10s were lost to enemy action (5 each) but the A-10s flew 8100 sorties vs the Harriers’ 3300.

    in reply to: A-10C to the USMC #2389814
    Phaid
    Participant

    With the USAF ditching so many A-10 airframes to the desert isn’t it about time the USMC take a look at introducing them into their service on the cheap? Harrier was nice idea and all, but the A-10 would fit its needs well.

    Note that the Air Force is not retiring any A-10Cs. The AF/ANG/AFRES operate a total of 367 A-10s out of the original 715 built. Those are in the process of being converted to A-10C standard. While there are a couple hundred A-10s at AMARC, those are the oldest airframes, and they are being cannibalized to support SLEP efforts (e.g. the Hog Up wing reinforcement) on the in-service ones.

    Pulling the retired A-10s from AMARC and back into service would require structural SLEP as well as the A-10C upgrade to keep them relevant. Not exactly cheap, really.

    in reply to: AWACS question #2397211
    Phaid
    Participant

    Compared to the more modern PHALCON using AESA tech, its claimed that the R3 suffers because its rotating mechanical radome only updates target tracks every 20-40 seconds vs only 2-4 seconds for the AESA.

    The APY-1 and APY-2 on the E-3s rotates at 6 RPM when the radar is in use, so it scans every 10 seconds not 20-40. In 10 seconds a target moving about Mach 3 at sea level would go about 6 miles.

    As far as it goes, fixed phased-array radars are also limited in that their range and resolution drops when the beam angle exceeds about 45-60 degrees from the perpendicular. The Phalcon 707 in particular has a field of view of about 120 degrees with its side arrays, and uses smaller, lower-performance arrays in the nose and tail to cover the blind spots.

    Probably the best solution is one like the E-2D, which uses a rotating AESA. This provides the same uninterrupted 360 degree coverage as the E-3, but the rotation can be stopped to focus the radar on a particular sector if more range / resolution is needed.

    in reply to: What aircraft should the ANG buy? #2398480
    Phaid
    Participant

    The ANG needs more than an austere point-defense interceptor. ANG F-16 units spend a lot of time doing the same mud-moving missions in Iraq and Afghanistan that regular AF units do.They get tasked with ASA a lot when they are not deployed overseas, but that is far from their only mission.

    The option that makes the most sense is the one that lets them perform their full range of missions, and capitalizes on the experience ANG pilots already have as well as the existing logistics infrastructure. Which pretty much means more F-16s.

    in reply to: What aircraft should the ANG buy? #2400350
    Phaid
    Participant

    I’d have no qualms against using something already paid in full. This is much cheaper than new build replacements. Quite possibly the aviators that would get them would already be certified on them.

    The F110 engine uses a lot of fuel. It also weighs 1,500 pounds more than a F404. For comparison sakes:

    Not sure why that is important. The USAF doesn’t have any aircraft that use the F404. Buying foreign would be a political nightmare and require developing all kinds of new infrastructure for training, maintenance, logistics, all of which costs money we don’t have. Developing a new aircraft would have all the same problems, take far longer, and be even more expensive. Meanwhile, we already have F-16s and all the infrastructure, training pipelines, etc, we need to operate them is in place.

    Buying new F-16s is a better investment than refurbishing old F-16s — you get more airframe hours per dollar — and cheaper than any other alternative.

    in reply to: What aircraft should the ANG buy? #2400848
    Phaid
    Participant

    IMO we should buy new-build F-16s with AESA. The cheap option would be Block 50/52s with RACR or SABR, the higher end option would be Block 60/62 with Falcon Edge removed. Relatively cheap, fits easily into our existing logistics and training pipelines, etc. It’s clear we have to buy something, we have too many ASA commitments competing with too many other commitments for too few fighters.

    in reply to: Top Gun -The Movie Versus Reality #2401925
    Phaid
    Participant

    http://www.tvguide.com/News/Kelly-McGillis-Weds-1023272.aspx?rss=breakingnews

    Top Gun’s Kelly McGillis Marries Longtime Girlfriend in Civil Union

    Sep 19, 2010 10:34 AM ET

    Not very surprising considering in Top Gun she seems to be the only character who is uncomfortable around naked dudes.

Viewing 15 posts - 301 through 315 (of 337 total)