Discussion in 'General Chat' started by DIGGS, May 31, 2017.

1. I used this phrase in lecture today.

2. I don't get it...

4. The Navier-Stokes equations are both the most general possible description of flow, and very elegant - the equation itself very intuitively lays out that it's just Newton's law for a fluid, it parallels similar equations in solid mechanics betraying its history, and has a very simple vector form. The only issue is that it's hard to solve. But when we may a simplification to make it more mathematically tractable, we make it less intuitive, less general, less obvious and clear, and usually make the equation itself uglier and sometimes more complicated.

Maximum dumb.

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5. RAM rolling air frame

I like the caps plopping off. Someone will have to pick those up

6. look at the swedish rbs15
pretty cool. why arent the rockets pointed backwards?

harpoon is launched horizontally

7. The rolling-airframe missile essentially takes the spot of a Phalanx CIWS on a ship, and fills a very similar role: very close-in defense against incoming missiles and small, fast boats. In fact, the SeaRAM uses the same radar and control system as the Phalanx as a one-to-one, plug-and-play replacement (the base RAM system uses the ships integrated sensor suite). This is why it's on a maneuvering pod: its intended range goes right down to zero, so the missile might not have much time to manoeuvre on its own. Missiles intended for larger targets, or targets further out (eg: large anti-air missiles, anti-ship missiles, and land-attack cruise missiles) are more agnostic about launch direction, because they may have dozens of kilometers to adjust course (hence, on many modern ships, all of these such weapons are launched vertically).

The Harpoon and the Swedish missile you link to in your later post are both jet-powered cruise missiles, with a brief rocket boost to get them up to speed and to quickly clear the launch vehicle (solid rocks are much more reliable than turbines, so rocket motors not only quickly get the device up to speed, but they better guarantee that the missile will clear the launch vehicle to a safe distance in the event of a failure). But the exact launch profile will depend on the mission: if the cruise-phase is intended to be high (longest range, highest energy), or low (lowest range, but smallest detection envelope - hiding below the horizon), hence higher launch angles.

Both the Harpoon and the Swedish missile are very versatile, with land, sea, and air-based launch platforms. When launched by aircraft, the rocket boosters are omitted.

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8. The TF39 was introduced in 1964, and the CF6 in 1971... and GE is still building new CF6s! FedEx, for example, recently ordered 767s with CF6-80C2B7Fs. I frequently encounter CF6-80C2s older than myself; some of the newer ones may fly into the 2050's unless emissions- and noise regulations make that impossible. That's an impressive lifespan for any type of engine.

9. I saw a U2 today. It looks so clumsy at low speed

10. U2s are so stupid when they land

11. They still use U2's?

12. And what's more,

13. Any idea what these could be?

14. dronez

edit: covered in mirrors, for invisibility, and laser immunity

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15. #165
Last edited: May 30, 2019
Nope. Numerous questions, though. Both these incidents were reported by the Navy, and the new sensors they reference in the article are the Super Hornet's AESA radars and IRST pods. The US isn't the only country with AESA radars - why are they the only ones experiencing this? Neither is the Navy - why haven't we heard anything from the Air Force or Army? (Are others seeing them and is the Navy just more transparent about its observations?)

All this makes me suspect, although I have no hard evidence for the case, that it might be some type of countermeasure being tested. We can spoof radar signals - make a radar detect something that isn't there, even make it move around. Doing this in broadband - from radar to IR to visible - would be insane, especially on a AESA array, which has low-probability of intercept modes, making spoofing especially difficult. However, it is, at least, hypothetically within our understanding of physics (though a pretty big technological jump).

That's the only hypothesis I have at the moment. It would, at least, tell us why these things were detected .... in a testing range off of San Diego and then another off of Virginia.

edit: AESA arrays often operate at higher frequencies than older mechanically-scanned doppler radars. Up in the high microwave range, sometimes edging close to IR (though not the X-band radar in the F-18). I wonder, potentially, if they are countermeasures, if they were meant to be IR or optical countermeasures that the much higher frequency AESA arrays are suddenly able to pick up? They have a much, much longer range than human eyes or IRST, so they'd basically go unnoticed before then.

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