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Phaid

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  • in reply to: USN UCLASS FLYOFF #2276314
    Phaid
    Participant

    Video of landing released:

    in reply to: USN UCLASS FLYOFF #2276398
    Phaid
    Participant

    X-47B Completes First-Ever Carrier-Based Arrested Landing

    USS GEORGE H. W. BUSH, at sea (NNS) — The X-47B Unmanned Combat Air System (UCAS) demonstrator completed its first-ever carrier-based arrested landing on board USS George H.W. Bush (CVN 77) off the coast of Virginia July 10.

    “By evolving and integrating new technology like the X-47B and the unmanned aircraft to follow, carriers will remain relevant throughout their 50-year lifespan,” said Secretary of the Navy Ray Mabus.

    Today’s demonstration was the first time a tailless, unmanned autonomous aircraft landed on a modern aircraft carrier.

    This test marks an historic event for naval aviation that Navy leaders believe will impact the way the Navy integrates manned and unmanned aircraft on the carrier flight deck in the future.

    In May 2013, the X-47B successfully completed underway carrier deck operations aboard USS George H. W. Bush to include a first-ever catapult launch and nine touch-and-gos.

    “We have certainly come a long way in the 102 years since Eugene Ely made the first arrested landing aboard an aircraft carrier. Naval aviators have always been at the forefront of operational and tactical innovation, and today was no exception,” said Mabus. “People make unmanned aviation possible and it is people who will provide the fresh thinking and new ideas so crucial to successes like the X-47B program and the unmanned aircraft of the future.”

    The Navy will continue to update this story as more information from today’s demonstration is made available.

    in reply to: USN UCLASS FLYOFF #2276515
    Phaid
    Participant

    Stavatti.com is a completely science-fiction site. If you’re going to compare CPFH for aircraft, keep it to believable examples.

    in reply to: guidance of BVR missiles? #2276692
    Phaid
    Participant

    Modern active terminal homing missiles like AMRAAM, MICA, Meteor, and R-77 use a datalink for mid-course updates, not semi-active homing. The only operational active terminal homing missile that used semi-active midcourse guidance was the AIM-54 Phoenix, though it used a somewhat advanced form of SARH, which did not require constant updates like most contemporary SARH missiles, so it could be time-shared and allowed the aircraft to guide multiple missiles.

    Interestingly, the late-model AIM-7P Sparrow is a bit of a hybrid: it uses SARH for terminal homing, but a datalink for midcourse updates. This allows nearly “silent” BVR shots with the Sparrow since illumination is not required until the terminal phase.

    in reply to: Question about radar size #2276700
    Phaid
    Participant

    As to why longer wavelengths / lower frequencies are better for search radars: the lower the frequency, the less subject the signal is to atmospheric attenuation, so they are more appropriate for very long range applications. However, longer wavelengths have less angular accuracy and angular resolution than shorter wavelengths. So shorter wavelength / smaller antenna / shorter range radars are preferred for guidance systems.

    in reply to: Question about radar size #2276702
    Phaid
    Participant

    Most surface AA systems use two different radars: a large search radar, possibly shared among multiple guns/launchers, and a smaller fire control radar dedicated to each gun/launcher. The search radar initially detects the targets, then cues the fire control radar to engage it once it is in range. The most effective search radars use longer wavelengths, which require larger antennas, and large amounts of radiated power. Fire control radars, on the other hand, work best with short wavelengths and only need a range that matches the weapon they are guiding. In general, fighter aircraft radars are much more similar to fire control radars than to search radars in all of those respects.

    in reply to: Your Favorite Hornet/Super Hornet pics. #2254786
    Phaid
    Participant

    Except they’ve been using a helmet mounted cueing system and off-boresight missiles way before the US did.

    Not really. The USN was flying F-4Js equipped with helmet-mounted sights (VTAS helmet, AIM-9G SEAM mode slaving IR sensor to radar) in 1969.

    in reply to: Your Favorite Hornet/Super Hornet pics. #2259959
    Phaid
    Participant

    The “Tomcatters” existed long before there was such a thing as an F-14 Tomcat.

    in reply to: Anti-BVR tactics #2266861
    Phaid
    Participant

    Those tactics rely on the “Doppler notch” which is a weakness of pulse-Doppler radars. Pulse-Doppler radars operate by detecting the frequency shift in the reflected signal as range to a target changes. These radars have a minimum velocity (“velocity gate”) below which they will not display a target, so as to filter out clutter. Anything moving at less than this gate velocity is said to be “in the Doppler notch”. The tactic of “Beaming” or “notching” is the tactic of changing your heading to be perpendicular to the target’s heading, which temporarily reduces closure rate enough that the target loses lock.

    Someone earlier said this is a weakness of Continuous Wave illumination. This is not true, it applies to any radar that relies on the Doppler effect.

    With modern digital radar processing this is no longer a viable tactic.

    in reply to: F15 Eagles at Lakenheath 09/05 #2274882
    Phaid
    Participant

    Those are not live AIM-9s. Note the blue stripe, which denotes an inert warhead. Also, the missile does not have rollerons at the corners of the fins, indicating that it is a CATM (captive air training missile).

    in reply to: Harrier/AV8 engine intake blow-in doors #2275011
    Phaid
    Participant

    The doors are not there exactly to increase thrust, they are there to increase airflow to the engine at low (or zero) airspeeds. They are a compromise to allow the engine to operate with full power at low airspeeds, without requiring massive intakes that would add too much drag at high airspeeds. The doors are not opened mechanically; the negative air pressure that occurs when the engine is trying to pull in more air than airspeed can provide forces them open.

    As far as quantifying the difference in performance, they were installed or modified between generations of the Kestrel / Harrier to account for increased airflow requirements as engines grew more powerful. So in effect, the difference they made between the P.1127 Kestrel and GR1/AV-8A is the difference between the 15,000 lbf of the Pegasus 5 in the Kestrel, and the 19,000 lbf of the Pegasus 6 in the GR1.

    in reply to: Su-27 vs F-15 #2277325
    Phaid
    Participant

    I have the same edition as you and you are correct.
    it says LINE, ok so i missed it. And they where inside the No-Fly Zone then. But if they where not heading back out of the No-Fly Zone, where were they then heading? Further inside the No-Fly Zone?

    According to the radio calls the UH-60s were en route from Zakho to Irbil, so heading east-southeast.

    But as for the record, i did not catagory state they was flying outside the No-Fly Zone eighter, it was a mere slipp on my quoting, so no big deal anyway.

    :rolleyes:

    in reply to: Su-27 vs F-15 #2277332
    Phaid
    Participant

    And finally, since Haavarla requires more official proof, here is the AAIB report on the loss of the two UH-60s. It goes into as much detail as you would like, but on Page 9 of the PDF, attachment 1 shows a map of the No-Fly zone and the location of the crash sites well within that zone.

    Now you can stop misquoting authors and making up facts.

    in reply to: Su-27 vs F-15 #2277339
    Phaid
    Participant

    Oh please. Now I know what the problem is. Either you are deliberately misquoting the book, or you are looking at an old version of it.

    I just looked in my own paper copy of F-15 Eagle Engaged. Your quote is incorrect, at least compared to my edition (2007). On page 211, it states (emphasis mine):
    [INDENT]
    The F-15 pilots failed in a fundamental fighter pilot responsibility — to be able to correctly visually identify an enemy aircraft from one in their own nation’s military — and miscommunicated the ID. Despite the fact that the squadron commander was the wingman (as was often the case in these normally dull and boring missions, the flight lead responsibilities were alternated to give the younger pilots more flight leadership experience), he set the tone in the squadron, he failed to communicate his true (if later testimony is accepted) appreciation for the situation and, if he himself was truly unsure of whether the targets were friendly or Iraqi, he failed to call off the flight lead until the issue could be resolved with certainty. At 130 knots the Black Hawks were still 40 miles from the No-Fly Zone line and were not headed there anyway. There was plenty of time to be sure, but no time was taken.[/INDENT]

    Notice the difference — 40 miles from the No-Fly Zone line. What he is saying there is that the UH-60s were inside the NFZ, and were not heading out of the NFZ, so there was plenty of time to verify their ID before they could “escape” out of the NFZ.

    in reply to: Su-27 vs F-15 #2277372
    Phaid
    Participant

    At 130 knots the Black Hawks were still 40 miles FROM the No-Fly zone and were not headed there anyway.

    That doesn’t make sense.

    1) the official locations for the two shootdowns were 36°46′N 44°05′E and 36°55′N 43°30′E. Both sites are well north of the 36th parallel, the southern border of the Operation Provide Comfort no-fly zone. Likewise, every single official document pertaining to this shootdown acknowledges that this event took place inside the northern no-fly zone.

    2) the author you quote says himself, “Two minutes later TIGER 01 reported a radar contact on a low-flying, slow-moving aircraft 40 miles southeast of his own position and approximately 52 miles north of the No-Fly Zone line.” That was at 07:22Z. The shootdown occurred at approximately 07:28Z, six minutes later. How did these UH-60s flying at 130kts get from 52 miles north of the NFZ border, to 40 miles south of it, in 6 minutes? This is obviously a mistake.

Viewing 15 posts - 46 through 60 (of 337 total)