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Posted: 7/23/2008 5:47:47 PM EST
[#1]
I'd guess HF antennas. |
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Posted: 7/23/2008 6:07:55 PM EST
[#2]
Same guess. But they're not on every 747. I guess you have to order it with HF radios and antennas to get them.
CJ |
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Posted: 7/23/2008 6:16:19 PM EST
[#3]
Static Dissipators ? |
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Posted: 7/23/2008 7:21:45 PM EST
[#4]
Thats an awesome story thanks for sharing! |
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Posted: 7/23/2008 7:52:33 PM EST
[#5]
That's where the chemtrails are injected into the upper atmosphere. Duh, everyone knows that. I gotta run to the store, I'm fresh out of tinfoil. |
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Posted: 7/23/2008 8:20:53 PM EST
[#6]
 I remember when my friend was convinced the contrails were chemtrails and he noticed stuff on his windshield and thought it was residue from the chemtrails... He thought I was nuts when I told him it was dead bugs 
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Posted: 7/23/2008 8:44:55 PM EST
[#7]
Nailed it. In most every other aircraft the HF antenna is located up in the vert stab. You gotta remember the size of an antenna is directly proportional to the size of the wavelength. The HF wavelength is so large that the entire airframe becomes an antenna. ETA: Hootbro, static dissipators are a lot smaller than those HF antennas. |
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Posted: 7/23/2008 9:12:23 PM EST
[#8]
I have a LOT of hours in 747s. Here are a few pictures:
The wings always look so clean and pretty in flight...  But when you land, all sorts of things hang out. (Points if you can guess the airport.)  This guy is a lot more powerful than you think... (More points if you can guess this airport.)  You know how some new cars have backup cameras? Well, that can be retrofitted to old 747s also. (Uuber points if you can guess this airport.)  When airframes get old, some of them continue to lead interesting lives. This is an old El Al plane at Ben Gurion that is used for anti-terrorism practice:  I have more pictures if anyone cares. -Gator |
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Posted: 7/23/2008 9:32:52 PM EST
[#9]
Thats an E4-B and those are ARF antennas on the wing tips, nice. Tell us about your ride.
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Posted: 7/23/2008 9:37:10 PM EST
[#10]
N475EV Capt Bill Jackson The jet was put back into service after repairs and a heavy check. I take it that you work for EV? |
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Posted: 7/23/2008 10:11:22 PM EST
[#11]
Ok well Civvy 747's are HF's. On the -400 I think they moved it up to the vert stab. |
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Posted: 7/23/2008 10:13:43 PM EST
[#12]
What's the reason for digitals in the #2 position and analogs in the other ones? |
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Posted: 7/23/2008 10:32:05 PM EST
[#13]
Sorry man, my head is up my ass. Those are HFs. It does have a 5 mile long antenna in the back and the sat ant in the dome on top, before elec steer sat antennas came about. That jet is is one of 4 and one of the most expensive 47s in the air. It can communicate on any freq you can think of. Seriously. I would love to here more about it from the poster, I got a small private tour once at Boeing Wichita. |
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Posted: 7/23/2008 10:49:26 PM EST
[#14]
 What's that doo-hicky on the tail aft of and under the rudder? 
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Posted: 7/23/2008 10:56:32 PM EST
[#15]
Thats the 5 mi long antenna |
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Posted: 7/23/2008 10:56:42 PM EST
[#16]
LF. Antenna on a reel. Talk to subs and stuff. ETA: beat by 10 seconds. |
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Posted: 7/23/2008 10:58:47 PM EST
[#17]
Quoted:
 when I was a little, little kid in Houston, my parents took me to see the then brand-new shuttle Endeavor while the carrier made a stop on its way to Cape Canaveral to deliver the shuttle to NASA from the factory. Tells ya how young I am, too. |
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Posted: 7/23/2008 11:11:01 PM EST
[#18]
Pity about the 717s. I got to sim-fly its predecessor, the MD-90, at the Boeing sim building in Long Beach, CA, back in early 2001. I thought it handled pretty well, then again I was just a kid at the time. And I used to live under the approach route to LGB, where Boeing built 717s and builds C-17s. And where Gulfstream builds their birds.... |
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Posted: 7/23/2008 11:17:22 PM EST
[#19]
Second photo looks like LAX |
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Posted: 7/23/2008 11:20:26 PM EST
[#20]
The problem with the 717, at least in Boeing's eyes, was that it would compete too much with their tried and true 737. Since the 717 was not an in house Boeing design, (the first one off the line still had MD-95 on the chart boards) Boeing really didn't want to build it. The reason that it was still built, was the fact that TWA, who was a longtime Boeing customer, had a rather large fleet of MD-83's that were getting a little long in the tooth, and were planning on replacing them with the MD-95. After the merger, Boeing originally balked at the idea, so TWA started to get bids from Airbus. Mind you this was a time that Airbus bids were going up, and Boeing bids were going down, so Boeing bended and produced the 717. There are actually some improvements over the DC-9 series. Boeing relocated the APU air intake to over the left engine to get rid of the APU air inlet contamination, among other improvments. |
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Posted: 7/24/2008 12:20:10 AM EST
[#21]
Good eye. That's because on that aircraft, #2 is not your Father's CF6.  There's additional instrumentation in the back of the plane, almost all of it regarding that #2 engine:  Say hello to GEnx. This'll be the engine that powers the 747-8 as well as optionally powering the 787.  -Gator |
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Posted: 7/24/2008 12:23:49 AM EST
[#22]
Yeah, I work for EMC in Marana, I'll ask around if I can break away from a gen fam class I'm in today |
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Posted: 7/24/2008 2:13:15 AM EST
[#23]
 x3!
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Posted: 7/24/2008 3:21:22 AM EST
[#24]
The testbed 747 used to test the GEnx engine is owned by GE. And it flew with just that one engine operating and the other three shut down at some point during the test program.
When you've got about 115,000 pounds of thrust available from just the one engine, you can do that!  CJ |
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Posted: 7/24/2008 4:53:41 AM EST
[#25]
Uhhhh... Yes and no. The plane is owned by GE and has flown more than once on one engine. It operates out of ARFCOM's favorite place place to hate, California, not too far from Edwards.  But these instruments show that the GEnx is putting out around 75,000 pounds of thrust. The engine you're thinking of that puts out over 100K pounds of thrust is the GE90, the engine used in the 777. The claim to fame for the GEnx is significantly lower fuel consumption than the CF6, with only a slight increase in power.  By the way, if you're wondering why we use old, heavy CRT displays in the monitor consoles, it's because simply, in that particular airplane, unlike almost every other plane flown, weight is of little concern. It's a testbed, and the 747 has so much extra payload capacity that for some tests extra ballast is added in the lower cargo compartments. Fun watching it try and tear itself loose from its pylon during high thrust tests, though...  -Gator |
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Posted: 7/24/2008 5:00:56 AM EST
[#26]
What makes the GEnx more efficient? |
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Posted: 7/24/2008 5:14:22 AM EST
[#27]
More efficient combustion chamber design, fewer overall moving parts, fewer, more efficient fan blades, stuff like that. Even though it's a clean sheet of paper the GEnx is an evolutionary design based off of stuff learned over the years on previous engines. I can't really answer more than that, I'm a computer guy, not a propulsion engineer.
The scallops on the rear engine cowling are meant to reduce noise, but standing next to it while it's running on the ground I can tell you it doesn't sound any quieter to me. :) -Gator |
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Posted: 7/24/2008 6:05:47 AM EST
[#28]
Of course you're right. I got mixed up on the GE90 (which also flew on a 747 test bed) and the GEnx. I should have caught that. I did know it but got my signals mixed.
The feature of the GEnx that is most intriguing to me is the scalloped rear edge of the fan housing. What's the story behind that? Somewhere, I read an article on one of GE's engine building teams. They're small teams of people who operate virtually autonomously, almost like they're their own small separate company. And I thought that I might enjoy doing that kind of work. Assembling complex and powerful machines (under very clean conditions, particularly) would be something I would enjoy a lot, I think. Incidentally, GE's aircraft engines website gives an overview of the GEnx and explains some of its technological advances that lead to its greater efficiency. CJ |
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Posted: 7/24/2008 8:02:51 AM EST
[#29]
IIRC, it's for noise abatement. Ah, beat to it by the post above yours:
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Posted: 7/24/2008 8:04:12 AM EST
[#30]
this is officially my favorite thread ever. i love the 747, it's a remarkable plane. got my oiwn little story to tell, even if it isn't as great as some others on here...
back when Dubya was campaigning for re-election in 04, I was working line delivery at whiteman afb, mo. seems the pres. had to land there to attent some kind of rally in Kansas City or something. Anyway, Air Force 1 was sitting on the tarmac. What was real cool was we had to make a delivery later that night, and when we went to cross the runway, we had to wait for AF1 to take off. First two escorts took off, followed by AF1...I swear its wingtip was only a hundred feet away, it was amazing to see such a big plane take off. I still wish we'd have flown a 747 to Guam instead of a 777 in 2005.... |
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Posted: 7/24/2008 8:16:24 AM EST
[#31]
The scallops are said to help reduce the sound of the "whine" when listeners on the ground hear a big turbofan jet take off. The idea was put in place as a noise reduction solution, but during aerodynamic testing they found that by shaping the scallops differently they could gain some aerodynamic efficiency as well. Look for this to become commonplace on turbofans in the future, though it's doubtful that existing engine cowlings will be redesigned. The Rolls Trent 1000 uses a sharper scallop. -Gator |
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Posted: 7/24/2008 9:12:18 AM EST
[#32]
I can't say about the GEnx, but on the Trent 1000, one thing that they're doing for an efficency boost is deleting the pneumatic supply system. I would guess since the 787 is being designed as pretty much a chapter 36 free aircraft that GE is pushing the same with the nx. |
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Posted: 7/24/2008 12:14:16 PM EST
[#33]
There should be a 747 sticky! Complete with FAQ!
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Posted: 7/24/2008 4:16:21 PM EST
[#34]
Quick question Gator, is GE still going to use the "CF6" family of indicators? (N1, EGT, N2, FF) or are they planning on moving to an EPR based indication of power? |
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Posted: 7/24/2008 4:19:56 PM EST
[#35]
Interesting point.
My father said the 747 was the easiest airplane to land of any aircraft he flew. Hold the pitch angle until the rear wheels on the aft trucks hit, and it just gently rolled you forward. Taxiing was difficult, though, because you couldn't see down. The shape of the fuselage made judging steering a challenge. The fuselage of the 747 acts as lifting body. The forward part of Pan Am 103 was blown off, and the that part was the fuselage forward of the wings (the well known weak spot of the 747.) The fuselage floated down like a falling leaf, and the F/O survived the impact, but was killed when he was ejected from the fuselage. The stringers on the oldest 747s were found to be cracked at the fuselage forward of the leading edge of the wing. An emergency inspection discovered that all the planes in the fleet had similar cracking. The nose of the aircraft was being held on by the skin. It was determined that the skin had more than enough strength to hold the nose on. |
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Posted: 7/24/2008 5:19:27 PM EST
[#36]
YES!!! this thread is FULL of win. |
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Posted: 7/24/2008 5:53:13 PM EST
[#37]
Kind of figured that. I was stabbing in the dark anyways. I have worked heavy aircraft and know the regular static dissipators are the size of a bic pen and have changed a few myself. Anyway, here is my 747 entry for the thread. Had this one drop in the local airport last year for refuel unscheduled due to diversion of weather. Sorry for the crappy pic as my optical zoom was maxed out and was outside the airport proper when taken. www.gunsnet.net/album/data//500/Amarillo-Space_Shuttle_2007_4_.JPG 
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