Search found 2433 matches

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by LH707330
Thu Jun 10, 2021 5:24 am
Forum: Technical/Operations
Topic: DFW - You're number ???? for takeoff!
Replies: 37
Views: 4256

Re: DFW - You're number ???? for takeoff!

At LAX, when departing 24L, while taxiway E6 is the last taxiway onto the runway, ATC can assign departure from intersections E7 or E8. Similarly, when departing Runway 25R, aircraft are instructed not to proceed beyond Taxiway F until cleared to do so by the Tower. This gives the tower controller ...

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by LH707330
Thu Jun 10, 2021 5:06 am
Forum: Civil Aviation
Topic: Boeing offers 777X Freighter to QR. Eyeing Order for 30
Replies: 129
Views: 20306

Re: Boeing offers 777X Freighter to QR. Eyeing Order for 30

I agree with Revelation, the exact length is not that big of a deal. There's precedent in the 747-8, the freighter and pax versions were initially going to be different lengths for payload/range optimization for Emirates. In the end, LH wanted the payload more than the range, and was willing to coug...

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by LH707330
Sat Jun 05, 2021 12:06 am
Forum: Civil Aviation
Topic: Attempted Cockpit Breach on DL386
Replies: 37
Views: 10712

Re: Attempted Cockpit Breach on DL386

Insane. What is it about claustrophobia that makes people behave like monkeys? I had this happen on a flight a while back. First flight returned after an hour because something was broken, then they rebooked a bunch of us on the next one. One guy who had been in F and had a few went to the same bar...

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by LH707330
Sat Jun 05, 2021 12:03 am
Forum: Technical/Operations
Topic: Russian Aircraft and Very Tall Landing Gear
Replies: 41
Views: 4809

Re: Russian Aircraft and Very Tall Landing Gear

Thanks for that reference! I dug out my Norris and Wagner "A340 and A330" book, on page 68 there's a discussion of the gear: "Another change discussed at the meeting was a possible 1'4" extension to the nose gear leg to improve ground handling...Airbus planned to introduce the lo...

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by LH707330
Fri Jun 04, 2021 11:40 pm
Forum: Civil Aviation
Topic: Attempted Cockpit Breach on DL386
Replies: 37
Views: 10712

Re: Attempted Cockpit Breach on DL386

A single person attempting a cockpit breach is usually some drunk moron who thinks he wants to tell the pilot something. Not persuaded that this is anything more than an isolated nitwit. Like the guy years ago who took a dump on the food cart in first class after having too many free cocktails. Ins...

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by LH707330
Fri Jun 04, 2021 3:20 am
Forum: Technical/Operations
Topic: Russian Aircraft and Very Tall Landing Gear
Replies: 41
Views: 4809

Re: Russian Aircraft and Very Tall Landing Gear

AFAIK the wingbox isn't actually lower. The fairing is just much larger. If you look up an A330 wheel well you can see that the wing spar is way up in there. The reason the rear cargo door is higher on the A340 is that the fuselage is not horizontal when on the ground. The tail sits higher. Unfortu...

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by LH707330
Thu Jun 03, 2021 3:31 am
Forum: Technical/Operations
Topic: Retro-jet maintenance
Replies: 8
Views: 1562

Re: Retro-jet maintenance

A lot of the retrojets simply deviate from the historical design to make it easier to maintain, for exactly that reason. For example, Lufthansa's retro 747 has a pearl gray in place of the original natural metal, which is hardly noticeable unless you find it in the right lighting. At that point, the...

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by LH707330
Thu Jun 03, 2021 3:09 am
Forum: Technical/Operations
Topic: Russian Aircraft and Very Tall Landing Gear
Replies: 41
Views: 4809

Re: Russian Aircraft and Very Tall Landing Gear

Indeed. Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid off in spades, as it could be evolved/stretched all the way to the A340-600. That's a difference of almost 25 metres in length, from 50.97m to 75.36 m. The 330/340 had a completely different WB...

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by LH707330
Tue Jun 01, 2021 11:04 pm
Forum: Technical/Operations
Topic: Russian Aircraft and Very Tall Landing Gear
Replies: 41
Views: 4809

Re: Russian Aircraft and Very Tall Landing Gear

A huge negative: weight Weight is always a consideration But if you’re unable to stretch your design because the gear is too short you’ll have to add weight anyway in the modification process Indeed. Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid o...

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by LH707330
Thu Apr 29, 2021 12:55 am
Forum: Technical/Operations
Topic: boeing 747 400X, the 400 under a different name or something else?
Replies: 10
Views: 2924

Re: boeing 747 400X, the 400 under a different name or something else?

The 400X became the 400ER, which as the article mentions is barely externally different. The only physical change is the very slightly larger tires (51" vs 50" IIRC), which in 144 is negligible. Did'nt the -400ER have slightly taller winglets too? Not to my knowledge, no. It's possible th...

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by LH707330
Tue Apr 27, 2021 4:31 am
Forum: Technical/Operations
Topic: A321 vs B739 Fuel burn
Replies: 32
Views: 5542

Re: A321 vs B739 Fuel burn

The 321 is heavier and has slightly better aero, but has engines optimized for longer range, so its relative advantage from a fuel burn standpoint is at longer ranges. If you have the equivalent 737 and 32S, you're generally better off butting the A on the long stage length and the B on the short on...

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by LH707330
Tue Apr 27, 2021 4:25 am
Forum: Technical/Operations
Topic: boeing 747 400X, the 400 under a different name or something else?
Replies: 10
Views: 2924

Re: boeing 747 400X, the 400 under a different name or something else?

The 400X became the 400ER, which as the article mentions is barely externally different. The only physical change is the very slightly larger tires (51" vs 50" IIRC), which in 144 is negligible. The 610 seating is probably the all-economy layout. If you're planning to use a Revell 747-400 ...

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by LH707330
Mon Apr 05, 2021 3:46 am
Forum: Travel, Polls & Preferences
Topic: Why no Boeing 707 stretch?
Replies: 19
Views: 3784

Re: Why no Boeing 707 stretch?

The 707-300 series was a stretch over the original -100 series. There was also the shrink 720, so three different fuselage lengths. Boeing also studied further stretches - a -600 domestic version and a -800 intercontinental ranged version. I believe development was dropped in favour of the 747. The...

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by LH707330
Mon Apr 05, 2021 3:43 am
Forum: Civil Aviation
Topic: Reasons for DC-8 stopping production earlier than the 707?
Replies: 24
Views: 6209

Re: Reasons for DC-8 stopping production earlier than the 707?

It is interesting to note as well, as a side bar, that the DC-8 was incredibly stretchable, due to a relatively high landing gear system. I'm curious what went on with the 707-120 to 707-320. I see that the wing was lengthened due to a wing insert at the root of the wing. This shifted the engine lo...

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by LH707330
Mon Apr 05, 2021 3:35 am
Forum: Technical/Operations
Topic: Why did Boeing design the 707 to have a shorter landing gear than the DC-8?
Replies: 10
Views: 3967

Re: Why did Boeing design the 707 to have a shorter landing gear than the DC-8?

I think there were two main drivers: 1. The 707 shared much in common with the tanker and they wanted them to use existing GSE and be lighter, hence the lower gear. 2. Timing: in 1952 when they launched the 367-80, the engine thrust and traffic made a 5Y fuselage with 100-120 seats a big plane. The ...

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by LH707330
Tue Mar 30, 2021 1:25 am
Forum: Technical/Operations
Topic: Different manufacturers for jet engines #1 vs. #2
Replies: 25
Views: 4596

Re: Different manufacturers for jet engines #1 vs. #2

I think I recall from past discussions that engines from different vintages (e.g. line numbers 500 and 900) of the same make/model are allowed on a given airplane. Are airlines allowed to mix/match engines even further and do unusual combinations? Examples: [list] [*] PW4090 for engine #1; PW4098 f...

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by LH707330
Sun Mar 28, 2021 7:21 pm
Forum: Technical/Operations
Topic: When did English become the Considered Language of the Skies.
Replies: 10
Views: 2069

Re: When did English become the Considered Language of the Skies.

Just to point it out... nearly all radio traffic between ATC and aircraft is done in the local language of each country. Often they only talk English to foreign aircraft. Some countries try to maintain English as the preferred language on the main frequencies, but it's rare. If you fly through Sout...

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by LH707330
Sat Mar 27, 2021 9:08 pm
Forum: Civil Aviation
Topic: AY signs LOI for electric Heart ES-19
Replies: 23
Views: 3267

Re: AY signs LOI for electric Heart ES-19

Here is there website: https://heartaerospace.com/ They don’t seem to state the operating advantages necessarily of the aircraft. Scroll down a bit and you'll find this: "Cost-Effective 75% cost savings in fuel and 50% in maintenance Electrification changes the equation for regional air travel...

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by LH707330
Fri Mar 26, 2021 3:34 am
Forum: Technical/Operations
Topic: Daylight Savings Time - connections
Replies: 14
Views: 2460

Re: Daylight Savings Time - connections

I was having this discussion with friends recently, and had a related question for longhaul fleets: how do carriers that typically have a 24-hour average rotation manage with a 23-hour day? Do they go all-hands on deck and not schedule MX so that they can keep the schedule, remove schedule buffer 10...

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by LH707330
Fri Mar 26, 2021 3:21 am
Forum: Travel, Polls & Preferences
Topic: Why no Boeing 707 stretch?
Replies: 19
Views: 3784

Re: Why no Boeing 707 stretch?

There were seven total lengths of the 707 versions across four fuselage lengths. They are, in length order: 707-138 707-138B 720 720B 707-100/200 707-100B 707-300/300B/300C/400 Now for the long version (pun intended): Boeing originally planned the 707 with the same 144" wide (5Y) and 128' long ...

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by LH707330
Fri Mar 26, 2021 2:40 am
Forum: Technical/Operations
Topic: Modern Turbofan Engine Efficiency
Replies: 33
Views: 7740

Re: Modern Turbofan Engine Efficiency

The combined-cycle engines have two thermodynamic advantages: 1. As mentioned, the hot exhaust warms up water to power a steam turbine 2. Many CCGTs also use water in the compressor to reduce compressor temperatures, work required to compress the air mass, lower NOx, and allow higher fuel addition b...

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by LH707330
Sat Mar 06, 2021 5:08 pm
Forum: Technical/Operations
Topic: Modern Turbofan Engine Efficiency
Replies: 33
Views: 7740

Re: Modern Turbofan Engine Efficiency

From GE90 an introduction :- https://www.kimerius.com/app/download/5781574315/The%2BGE90%2B-%2BAn%2Bintroduction.pdf A GE90 has a mass flow at cruise of 576 kg/s, and generates 69.2 kN thrust, so from F = MA the air must be on average subject to a 120 m/s delta velocity or 433 km/h higher velocity ...

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by LH707330
Sat Mar 06, 2021 5:55 am
Forum: Technical/Operations
Topic: Modern Turbofan Engine Efficiency
Replies: 33
Views: 7740

Re: Modern Turbofan Engine Efficiency

In layman terms, where did the efficiency improvements come from in modern turbo fans? Let’s say JT9D vs RR Trent XWB. I guess I'll give this a try. :( JT9D -> Boeing 747-100 => 30% overall efficiency (~64% propulsive, ~48% motor thermodynamic) RR Trent XWB -> Airbus A350 => 40% overall efficiency ...

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by LH707330
Tue Feb 23, 2021 5:26 am
Forum: Technical/Operations
Topic: Cabin configurations, fuselage weight model
Replies: 67
Views: 5045

Re: Cabin configurations, fuselage weight model

Look in the other thread - a lot of data on 2-3-2 vs 3x3. A comparable capacity at about that 216 Y seats 32" seat pitch would have the 2-3-2 at about 9% less skin and 2% less internal volume and only a 10% greater circumference, and with a cabin 20% less in length than an A321/A322 - yet for ...

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by LH707330
Sat Feb 20, 2021 8:24 pm
Forum: Technical/Operations
Topic: Cabin configurations, fuselage weight model
Replies: 67
Views: 5045

Re: Cabin configurations, fuselage weight model

The silence on this thread has me thinking that a 2x3x2 with 13.2M ends is pretty close to 3x3 at 216 seats and could be better above. ...or that people are unwilling to continue engaging the 2-3-2 idea when most cited tech reasons that it could be better could also be applied to 3-3. Where's your ...

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by LH707330
Fri Feb 19, 2021 3:50 am
Forum: Technical/Operations
Topic: Cabin configurations, fuselage weight model
Replies: 67
Views: 5045

Re: Cabin configurations, fuselage weight model

The silence on this thread has me thinking that a 2x3x2 with 13.2M ends is pretty close to 3x3 at 216 seats and could be better above. ...or that people are unwilling to continue engaging the 2-3-2 idea when most cited tech reasons that it could be better could also be applied to 3-3. Where's your ...

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by LH707330
Fri Feb 19, 2021 3:43 am
Forum: Technical/Operations
Topic: Delta 757 Wing And Stabilizer Paint
Replies: 10
Views: 3253

Re: Delta 757 Wing And Stabilizer Paint

Now my next question is if this coroguard is applied to the top of the wing and is easily removed, or is it removed, and the wing surface painted over again. I assume they would be doing this during heavy maintenance. Not 100% sure I understand the question, but I'll take a whack anyway. I'm not su...

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by LH707330
Fri Feb 19, 2021 3:34 am
Forum: Technical/Operations
Topic: Can engines be too big?
Replies: 20
Views: 2695

Re: Can engines be too big?

... a longer-winged A330 could be more efficient around 210t, but as we saw, the airlines figured that it made more sense to have a more flexible design with more range. Or the T500 was simply not good enough. Did the A320 neo improve only 3% in specific fuel consumption? The A330-800 does suggest ...

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by LH707330
Thu Feb 18, 2021 4:41 am
Forum: Technical/Operations
Topic: Delta 757 Wing And Stabilizer Paint
Replies: 10
Views: 3253

Re: Delta 757 Wing And Stabilizer Paint

Copy. Thanks. Didn't know they were doing away with it on other fleets. Sure enough, looks like some of their 767s made the switch, as seen on N1603: Now my next question is if this coroguard is applied to the top of the wing and is easily removed, or is it removed, and the wing surface painted ove...

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by LH707330
Thu Feb 18, 2021 4:32 am
Forum: Technical/Operations
Topic: Can engines be too big?
Replies: 20
Views: 2695

Re: Can engines be too big?

What you're describing is basically the A330-100 idea: https://en.wikipedia.org/wiki/Airbus_A330#Undeveloped_variants Regarding the T500, they went up to 60k in thrust, which is similar to the highest-thrust CF6-80C2 engines on the 767, the heaviest of which is 204t at MTOW. Given takeoff drag is do...

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by LH707330
Wed Feb 17, 2021 4:12 am
Forum: Technical/Operations
Topic: Delta 757 Wing And Stabilizer Paint
Replies: 10
Views: 3253

Re: Delta 757 Wing And Stabilizer Paint

What you're referring to is called coroguard, it's an anti-corrosive coating that's made of metal flakes in a clear carrier and looks different under different light conditions. Mostly it's applied to the inspar areas where maintenance crews walk, so they want those areas to be more durable. See her...

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by LH707330
Mon Feb 15, 2021 10:44 pm
Forum: Technical/Operations
Topic: Cabin configurations, fuselage weight model
Replies: 67
Views: 5045

Re: Cabin configurations, fuselage weight model

Two possible things I can think of looking at this: 1. The seats/aisle problem shows that a tight 9Y 787 is the most efficient formula and there's not much point in going with a 7Y or 8Y for a new design under these assumptions. Assuming that Fred's checks don't reveal any serious issues with the mo...

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by LH707330
Sun Feb 14, 2021 9:30 pm
Forum: Technical/Operations
Topic: Cabin configurations, fuselage weight model
Replies: 67
Views: 5045

Re: Cabin configurations, fuselage weight model

[quote="morrisond" Yes - I believe that a 7W NMA may not be as weight efficient as a 6W - but it may not as big as a penalty as you think it may be. Remember the bare fuselage weight is somewhere around 5% of MTOW and there may be some inherent advantages of Carbon that make up some of the...

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by LH707330
Sun Feb 14, 2021 9:25 pm
Forum: Technical/Operations
Topic: Cabin configurations, fuselage weight model
Replies: 67
Views: 5045

Re: Cabin configurations, fuselage weight model

Fred, thanks for putting this together, great work! This really calls into question the design thinking behind the 767: why did they pick that diameter if they could have done a 757-300 with a bigger wing and saved weight and development cost? I suspect it may have been the case that the 767, like t...

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by LH707330
Wed Feb 03, 2021 4:57 am
Forum: Civil Aviation
Topic: Boeing CEO's Comments On Their Next Airplane
Replies: 2123
Views: 219913

Re: Boeing CEO's Comments On Their Next Airplane

Looks like Airways has that story too: Boeing Set to Produce Mid-size Aircraft | Airways Magazine. It's a bit sparse on details, claiming 270 pax at 11 hours range. That puts it at 767-300ER payload/range.

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by LH707330
Thu Jan 21, 2021 3:51 am
Forum: Technical/Operations
Topic: Quad and Tri Jets will come back in the skies "What is old is new again" Alternative fuels and good news!
Replies: 26
Views: 4096

Re: Quad and Tri Jets will come back in the skies "What is old is new again" Alternative fuels and good news!

Let's just assume that we figure out how to power planes with H2 or batteries or liquified natural unicorn farts (LCUF, it's all the range) or even fusion reactors. Why does that suddenly change the calculus around the number of fans you want (they're not "engines" unless they run by the ...

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by LH707330
Mon Jan 18, 2021 10:20 pm
Forum: Technical/Operations
Topic: What are some lesser known differences of 1st generation Boeing 777 and 2nd generation of Boeing 777?
Replies: 17
Views: 4338

Re: What are some lesser known differences of 1st generation Boeing 777 and 2nd generation of Boeing 777?

flutter wrote:
[list]
[*]The -300ER incorporates a taxi camera system which requires an extra knob in the cockpit.
.

Along with this came the racing stripes on the top edge of the wing that align with the main gear track. Airbus solved this by superimposing a stripe on the screen with the 345/346.

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by LH707330
Tue Jan 12, 2021 6:20 am
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

I just looked it up, turns out it was the 271T MTOW that they got. Per Norris and Wagner, "changes included strengthened landing gear and attachments, a beefed-up main wing box, and reinforcement of the pickup structure for the nose and main undercarriage legs." It's unclear whether furth...

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by LH707330
Tue Jan 12, 2021 5:48 am
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

In the sense I'm using it, similar performance means ability to perform roughly the same missions. From this perspective, MTOW is irrelevant; what actually matters in terms of how it performs as a commercial vehicle is useful load, in which the differences between the two were minimal. That said, I...

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by LH707330
Sun Jan 10, 2021 4:05 pm
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

The A340 had about 35 tonnes higher MTOW, and significantly longer range. Original difference was even bigger. MTOW of initial versions of A330 was 212tons, 340 was maxed at 276tons. That's over 60 tons difference, almost 65. Cheers, Adam 276 only came in 1996 when Singapore pushed for it so they c...

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by LH707330
Fri Jan 08, 2021 10:59 pm
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

The A339 now has the capability the A343 had, it is oversized for the original role the A333 had at 4000 nm, if they wanted to optimise for 4000 nm it would involve a smaller wing, and smaller engine however it would not be as effective at longer ranges, Anybody knows how much weight the new wing a...

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by LH707330
Fri Jan 08, 2021 10:49 pm
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

Based on the above payload/range chart, the 343 and the 359 have similar payload/range near MZFW, so giving the 340 better engines would put it out ahead of the 359. At a system level it would still be less efficient though, so I doubt it would sell very well. The A359 lifts around 10 tonnes more p...

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by LH707330
Fri Jan 08, 2021 10:43 pm
Forum: Technical/Operations
Topic: VFR with Airliners
Replies: 62
Views: 4970

Re: VFR with Airliners

Yes, the question for is is just - is it worth it. What I have heard and read so far (including the great book "how and why pilots die"), from a pure safety perspective, it is a huge gap forward. From a pure practical point of view it is totally unnecessary for me. I will only fly club ma...

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by LH707330
Thu Jan 07, 2021 6:14 am
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

Doesn't this argument also apply to the 339 with the wings being oversized for a lower fuel need? I'd imagine in the case of an A340neo, if you didn't need as much fuel, you'd leave the center tank empty and fill in more payload. Given the same structure as the 343, your range at MZFW would go out ...

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by LH707330
Wed Jan 06, 2021 7:47 pm
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

Somewhere else I read that a slat is different and some smaller tweaks but essentially it's the same wing that was also supposed to hold the Superfan, which is basically the PW1133g. Sorry I don't see, why there needes to be a new wing. Needs to be something else. Oh guys, that would be a superb lo...

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by LH707330
Sun Jan 03, 2021 9:19 pm
Forum: Technical/Operations
Topic: A330Neo versus old B777-300ERs
Replies: 55
Views: 9030

Re: A330Neo versus old B777-300ERs

So I need to go figure out why the 787-10 sells. The A350-900 has more efficient engines. That 2.5 tons of added weight is good weight (I posted links to the EASA certification documents up thread). As someone who has designed engines, this is the tradeoff I would make. The A350-900 has a better wi...

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by LH707330
Sat Jan 02, 2021 9:44 pm
Forum: Technical/Operations
Topic: 2 vs 4 engines
Replies: 128
Views: 12522

Re: 2 vs 4 engines

Thanks for posting this, the comparisons are good to see. One claim I'm having a hard time with, however, is that fuel burn per seat for the 343 vs a 744 is 14% better. From your experience on the 343, does that number for the burn on 4000 nm make sense? It was in the order of 4-5 tonnes per hour d...

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by LH707330
Sat Jan 02, 2021 8:01 pm
Forum: Technical/Operations
Topic: BA B744 RB211 engines
Replies: 11
Views: 2105

Re: BA B744 RB211 engines

Any idea how the T versions compare on fuel burn with the GE and PW engines? I heard the initial 524G was a bit worse, curious if they closed the gap. GE and PW are in still marginal in the lead, but the gap was nearly closed with the 2% SFC improvement of the -T version. See : https://www.rolls-ro...

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by LH707330
Fri Jan 01, 2021 2:38 am
Forum: Technical/Operations
Topic: Il-86 Performance
Replies: 54
Views: 9843

Re: Il-86 Performance

Probably how to optimize detailed design elements like positioning, outboard mounts to reduce flutter, etc. and some specifics. Boeing had early issues with the twist and counterweights on the 747, and Airbus later struggled on the 340 before adding the plastron. The Russians were probably aware of...

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by LH707330
Fri Jan 01, 2021 1:47 am
Forum: Technical/Operations
Topic: BA B744 RB211 engines
Replies: 11
Views: 2105

Re: BA B744 RB211 engines

It depends what type of RR engines are installed. AFAIK BA operated a mix of RR RB211-524/H-T engines (upgraded with a Trent core) and the "normal" RB-211-524H The last 9 aircraft were factory delivered with these new engines and several more RB-211-524H's were upgraded by installation of...

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