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Aircraft Vs Thread 5


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Well, I am just surprised how quiet it was in the A380's cabin compared to the A320s , B777s and 747s I have been in. Just felt wierd since I am used to engine noise while in the planes. Wondering if it is because of better insulation since the bird is so phat or its because of the engine design.

Got a question on moveable LERXs messing up the stealth. How different is that to the moving airlerons and rudders on say a F-22? Besides it being out in front.

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Because "head-on" is considered the most important aspect for stealth. If you're not stealthy from the front, you're not stealthy. Rear-aspect is next, then sides.

As for airliner noise--cabin noise isn't regulated, exterior noise is. Some of the planes that are quietest inside, are noisiest outside. And vice-versa.

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There's also the fact that the sheer size of the A380 means you were probably a lot further away from the engines then you are used to, that can make a big difference. One of the quietest flights I was ever on was when I was able to snag a last minute upgrade to business class on a 717. I ended up in the very front row, the only way I could have been further from the engines would be to sit in the cockpit. It was near dead silent.

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There's also the fact that the sheer size of the A380 means you were probably a lot further away from the engines then you are used to, that can make a big difference. One of the quietest flights I was ever on was when I was able to snag a last minute upgrade to business class on a 717. I ended up in the very front row, the only way I could have been further from the engines would be to sit in the cockpit. It was near dead silent.

I considered that but for the A380 flight, I was in an Economy seat right next to the wing. For the other B777 flights I normally take, I was in Business. I suppose, even in Economy, the A380 is so big that I am further away from the jets even compared to a cockpit in a B777.

I would also suppose the fuselage/cabin walls on the big bird are thicker too...

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Bigger engines tend to be quieter, simply due to increased bypass ratio. Cold air is quiet air. Slow air is quiet air. Bypass air is cold and slow compared to what goes through the turbine. The more bypass air, the colder and slower the overall exhaust.

Note that afterburners are very loud, becuase they speed up the air and increase its heat beyond what's already coming out. Know what's REALLY loud? Air heated to an extremely high temp, being displaced very rapidly---AKA thunder, caused by lightning.

The noise of moving air is HEAVILY influenced by its heat and velocity. (as both impart energy, and more energy makes more noise)

As for thicker walls/fuselage---not really. All airliners are extremely similar in that regard. The Convair jets are an exception, they had notable thicker skins, and were quieter inside as a result. (good thing too, as they were loud even by early jet standards). It also made them very hard to scrap, the first couple were scrapped at a loss, as the machines simply couldn't chew through them, despite many a 707 and DC-8 being scrapped easily by the same machines.

Insulation is added weight, so there's really only enough to help keep the fuselage the right temp (heating and air conditioning costs fuel, so it's worth a bit of weight to save a lot of environmental system use). Noise insulation is more an after-effect, rather than reason for it.

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That's a new one. 757 refuelling in mid-air. Seems it may be one-of-a-kind, assigned to SOCOM.

David I'm surprised you of all people don't know about the C-32. Although the all white paint scheme on that particular aircraft does in fact scream black ops.

::Edit:: Upon further research this appears to be a C-32B which the State department uses to fly people in and out of foreign disaster areas.

Edited by Nied
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Truly awesome the degree of detail you can see, especially the engines. if only it showed more of the cockpit interior! Thanks for posting that link David! B))

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I'll show it to my northrup guys at work who worked on the ATF-23 program and see what they have to say about it. As for the bike chain launcher, er, I'm not so sure about that, electrical, pyros, etc... would be a pain to hook up in that configuration, not to mention the kick out lugs.

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Oh, looky what just became available again:

::Snip giant F-23 pics::

Do you know how rare weapons bay pics are?

And that right there is one of the big reasons the F-23 lost to the F-22: What happens when the bottom AMRAAM in the stack fails to fire? Answer: You lost half your missiles kid, but hey your plane is real pretty! Don't even get me started on those "geometrically possible" loadouts, apparently we're supposed to believe bombs will just drop through the AMRAAMs as though they turned on a no-clipping cheat (though I guess that answers what happens if you get a hung missile, the pilot just punches idspispopd into the weapons MFD).

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Comparing drawings to photos, I almost think the bicycle chain isn't the final design. It goes against the "trapeze" description always provided of what PAV-1 actually had, and PAV-2 (which these pics almost all are AFAIK) seems to have a triangle/trapeze configuration too. I can't imagine the bicycle-chain-drive would be suspended from the trapeze---seems pointless and complex.

(though the actual arrangement of vertically-stacked missiles of the chain drive does match the Italeri model kit, which did get a surprising number of small things right, like cockpit/seat/gear)

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And that right there is one of the big reasons the F-23 lost to the F-22: What happens when the bottom AMRAAM in the stack fails to fire? Answer: You lost half your missiles kid, but hey your plane is real pretty! Don't even get me started on those "geometrically possible" loadouts, apparently we're supposed to believe bombs will just drop through the AMRAAMs as though they turned on a no-clipping cheat (though I guess that answers what happens if you get a hung missile, the pilot just punches idspispopd into the weapons MFD).

But it looks SO PRETTY!!!!

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Oh, looky what just became available again:

http://s784.photobucket.com/albums/yy128/c.../Weapons%20Bay/

f23weaponconfigurations.jpg

05YF-23weaponsbaylookingfwd.jpg Do you know how rare weapons bay pics are?

Looks like you've stumbled across stuff that's been on, or linked from, the Secret Projects forum for quite a few months now. :)

The weapons layout illustration I think was created by someone who is a member of of Secret Projects forum and is based on the weapons locations intended for the production F-23. YF-23 #1 had a single trapeze hanging inside its weapons bay and was capable of being mounted with a rail for launching one missile. The Air Force didn't require them to have a live missile fire and Northrop ended up passing on doing so. YF-23 #2 did not have the trapeze and had some test equipment in the bay instead.

The rarest YF-23/F-23 pictures are those showing its cockpit display layout.

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As for some REAL F-23 porn, these have been posted at Secret Projects for the last year or so. Unfortunately it doesn't illustrate the number of AIM-9's or 120's or how exactly they would have been mounted, but it looks like the AMRAAM bay is probably deeper then the F-22's main weapons bay and probably would have been capable of carrying larger weapons. Note the hidden lines for a possible IR sensor. :)

post-342-1266429855_thumb.gif

post-342-1266429869_thumb.jpg

post-342-1266429877_thumb.jpg

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lol, non-metric units: fail.

Actually I have run those pictures past one of the northrup guys here I work with, who worked on the ATF-23 test program, and he confirms that they are legit "concept" drawings, for what a production F-23 would have looked like. They were produced as part of the submission package to the air force during the ATF competition in order to illustrate the difference between the prototype and production unit, and to show how long it would take to get to a production standard configuration. He likes to joke that Lockheed lied out their rectums on their drawings, based on how long it took them to get to production.

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Well I wasn't exactly commenting on the legitimacy - just poking fun at the inferior system of units & measurements. :p

It seems like there is no difference in any Systems Engineering project, whereas you're building a plane, ship, or software (which is my area). Everyone has the most beautiful powerpoint slides promising to their clients the world + 2 beautiful strippers, but the delivery always leaves a little bit to be desired. At the end of the day, even in cases of under-delivery, the client never sues or is upset, because everyone is "in on it." It would look really bad for the client manager who hired the consultants/contractors/mfg's ... and it would reflect badly on the manager of that manager - consequently the buck never stops.

Every project is a success. yaaaay! With the MBA culture, everyone is a winner!

Edited by Ghost Train
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