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B2707SST
Posts: 1289
Joined: Wed Apr 23, 2003 5:25 am

RE: 345/346 HGW Versions

Wed Nov 02, 2005 7:21 am

Quoting A360 (Reply 47):
The 777F is a 777-200 sale, not a 772LR sale.

I don't understand where you're going with this. Both the 772LR pax and 777F are 772A derivatives. The 777F is a 772LR derivative. The freighter is based on the passenger version and would not have been developed without it. The same is true for the A300-600RF, the A380F, the 744ERF, and every other commercial freighter.

Boeing's internal accounting will measure the financial success of the 772LR program based on the revenue and net income brought in by airframes sold, counting both the passenger and freighter models. The only distinction will be whether the freighter version recoups the marginal costs of its own production and certification process, which will not take many frames to achieve. Since financial success is really the only criterion that matters, any other arguments about how 777F sales should be counted are hairsplitting.

--B2707SST
 
ikramerica
Posts: 15180
Joined: Mon May 23, 2005 9:33 am

RE: 345/346 HGW Versions

Wed Nov 02, 2005 7:25 am

Quoting A360 (Reply 47):
The 777F is a 777-200 sale, not a 772LR sale.

Yeah, the 772F has the engines, structural changes, wing changes, cockpit changes, and gear of the 772LR. That's the whole reason they can offer it with the abilities it has.
 
gigneil
Posts: 14133
Joined: Fri Nov 08, 2002 10:25 am

RE: 345/346 HGW Versions

Wed Nov 02, 2005 7:28 am

Quoting N1120A (Reply 20):
Given how baddly the A346 missed its targets

Mhm.

Quoting N1120A (Reply 23):
The A346 was supposed to have 8000nm range, which it didn't

No. It wasn't. It was never supposed to. Kthx.

N
 
A360
Topic Author
Posts: 426
Joined: Sun Jun 19, 2005 11:41 pm

RE: 345/346 HGW Versions

Wed Nov 02, 2005 7:38 am

Ikramerica, B2707SST... there's not much point discussing this any further... we are all aware of the facts on the subjects... I may disagree on some datails, but not really worth it continue to discuss it.  Wink

What matters is that even if the 772LF doesn't sell and the 777F sells, the program is still a sucess for boeing... we agree on that.

I just wanted to point that if the 772LR doesn't sell well, even if the 777F does, it's still a failure for the ULR market.
 
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zeke
Posts: 16356
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RE: 345/346 HGW Versions

Thu Nov 03, 2005 1:31 am

Quoting Widebodyphotog (Reply 40):
350-500 Seat Aircraft Data

350-500 Design Mission Data

How did you come up with the static and cruise thrust, fuel flow, and how did you derive the SFC ? The units in use seem a little unusual.

Did you mean to put TSFC ?

The fuel flows for the 744 and 346 don’t seem to be right either.

The range vs SFC (or TSFC is that’s what you mean) relationship does not look right either, range is a function of 3/TSFC.

Some comparisons I saw in flight international recently seem a little different to your figures.
 
widebodyphotog
Posts: 885
Joined: Wed Jun 30, 1999 9:23 am

RE: 345/346 HGW Versions

Thu Nov 03, 2005 3:51 am

Quoting Zeke (Reply 54):
How did you come up with the static and cruise thrust, fuel flow, and how did you derive the SFC ? The units in use seem a little unusual.

The cruise thrust values are maximum values and SFC in pounds/pound thrust are intantaneous values for that setting. These values are not specific to the mission analysis, rather they are representative of the specific engine at one specific value.

Quoting Zeke (Reply 54):
Did you mean to put TSFC ?

No I mean SFC...

Quoting Zeke (Reply 54):
The fuel flows for the 744 and 346 don’t seem to be right either.

Fuel flows are values from initial cruise weight at the design range and payload.

Quoting Zeke (Reply 54):
Some comparisons I saw in flight international recently seem a little different to your figures.

Please share the specifics and we can go from there.



-widebodyphotog
 
Hamlet69
Posts: 2542
Joined: Thu Mar 09, 2000 2:45 am

RE: 345/346 HGW Versions

Thu Nov 03, 2005 5:46 am

Quoting Prebennorholm (Reply 45):
With a little interpolation of the numbers we can for instance assume that on a 9,000nm sector a standard 345 can carry some 260 pax and the 345HGW can carry 313 pax

How do you figure that?

According to Airbus's own numbers, the -500HGW sacrifices payload for range. The standard -500 has a maximum range of 8,670nm and a max structural payload of 130,300lbs. The -500HGW has a max range of 9,000nm and a max payload of 126,100lbs.


Regards,

Hamlet69
 
zvezda
Posts: 8886
Joined: Sat Aug 28, 2004 8:48 pm

RE: 345/346 HGW Versions

Thu Nov 03, 2005 6:08 am

Quoting A360 (Reply 47):
The success of the 772LR will be based on the sales of the 772LR sales, not the 772LR plus the 777F sales.

I suppose that depends on how one defines success. I can guarantee that the bean-counters will define the success of the B777-200LR based on the development costs of the B777-200LR (beyond the B777-300ER) and of the B777F (beyond the B777-200LR) and the sales of both the B777-200LR and the B777F. Spotters may define success based on the number produced.
 
rootsair
Posts: 4014
Joined: Sun Feb 06, 2005 3:25 am

RE: 345/346 HGW Versions

Thu Nov 03, 2005 7:07 am

soory for my ignorance. What does HGW mean and what's the difference with and without HGW?


thanks

BM
 
A360
Topic Author
Posts: 426
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RE: 345/346 HGW Versions

Thu Nov 03, 2005 7:26 am

^Higher gross weight.
Read the rest of the thread please, so that you have your questions answered.  Wink
 
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zeke
Posts: 16356
Joined: Thu Dec 14, 2006 1:42 pm

RE: 345/346 HGW Versions

Thu Nov 03, 2005 12:56 pm

Quoting Widebodyphotog (Reply 55):
No I mean SFC...

Not sure what your trying to show then, power output comparisons are normally left for piston and turbo-prop engines aircraft as SFC remains fairly constant. TSFC is fairly constant for a jet for a given configuration and can be used for a comparison on the aerodynamic efficiency of the aircraft and power plant, the TSFC for the a jet engine is not the same as the TSFC for an airframe/engine(s) combination.

Quoting Widebodyphotog (Reply 55):
Fuel flows are values from initial cruise weight at the design range and payload.

The values for the 744 are too low, more like 12-15t/hr at the start of a flight, maybe coming back to 9t/hr when light.

The 340 values look high, I curve fitted some cruise values for you at FL370 over a 7500 nm trip for a A343 and A346.

For the 343 Fuel = -31.954(time)^2 + 5651.9(time) - 2019.5
For the 346 Fuel = -64.159(time)^2 + 7764.9(time) - 2891.6

(time in hours, does not include climb, descent or approach)

These curves agree with book values within +/- 150 kg, if you were to plot them you will see that its a long way off 9t/hr, suppose you would get that if your around FL280-FL300. At the start of a 7500nm trip I would expect to see 7.6-7.8 t/hr at FL310 or around 6.2-6.4 t/hr at FL370. Initial optimum altitude for the 346 is always above FL310 even at MTOW.

[Edited 2005-11-03 05:01:14]
 
Thorben
Posts: 2713
Joined: Fri Sep 09, 2005 10:29 pm

RE: 345/346 HGW Versions

Thu Nov 03, 2005 5:05 pm

Maybe we can agree to count the 777LRF sales when considering the overall success of the 772LR/773ER-program, but we don't count them in the A345 vs. 772LR battle, because Airbus doesn't offer a competitor.
 
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N328KF
Posts: 6025
Joined: Tue May 25, 2004 3:50 am

RE: 345/346 HGW Versions

Thu Nov 03, 2005 9:27 pm

Quoting Thorben (Reply 61):
Maybe we can agree to count the 777LRF sales when considering the overall success of the 772LR/773ER-program, but we don't count them in the A345 vs. 772LR battle, because Airbus doesn't offer a competitor.

I would like to congratulate you for making your very first insightful comment.
 
zvezda
Posts: 8886
Joined: Sat Aug 28, 2004 8:48 pm

RE: 345/346 HGW Versions

Thu Nov 03, 2005 9:57 pm

Quoting Thorben (Reply 61):
Maybe we can agree to count the 777LRF sales when considering the overall success of the 772LR/773ER-program, but we don't count them in the A345 vs. 772LR battle, because Airbus doesn't offer a competitor.

 bigthumbsup 

Quoting N328KF (Reply 62):
I would like to congratulate you for making your very first insightful comment.

Credit where credit is due. Thank you Thorben for a valuable contribution.
 
widebodyphotog
Posts: 885
Joined: Wed Jun 30, 1999 9:23 am

RE: 345/346 HGW Versions

Thu Nov 03, 2005 11:32 pm

Quoting Zeke (Reply 60):
Not sure what your trying to show then, power output comparisons are normally left for piston and turbo-prop engines aircraft as SFC remains fairly constant. TSFC is fairly constant for a jet for a given configuration and can be used for a comparison on the aerodynamic efficiency of the aircraft and power plant, the TSFC for the a jet engine is not the same as the TSFC for an airframe/engine(s) combination.

Yes, I understand that, I think we are talking about the same thing here. When I say SFC I mean Thrust Specific Fuel Consumption in pounds per pound thrust hour...

Quoting Zeke (Reply 60):
The values for the 744 are too low, more like 12-15t/hr at the start of a flight, maybe coming back to 9t/hr when light.



Quoting Zeke (Reply 60):
The 340 values look high, I curve fitted some cruise values for you at FL370 over a 7500 nm trip for a A343 and A346.

I see the point of contention here. I used block-hour fuel burn in the specification table. Apologies if I misrepresented what they were in some way. That value does not represent fuel burn at any segment of the flight, rather total fuel burn/operating time for the indicated flight distance.

For mission analysis I use my company flight planning software with sample aircraft definitions as per Boeing and Airbus. Here are images from the Nav Logs of the flight plans I made.


A340-600 Design Mission Nav Log

747-400ER Design Mission Nav Log



-widebodyphotog
 
A360
Topic Author
Posts: 426
Joined: Sun Jun 19, 2005 11:41 pm

RE: 345/346 HGW Versions

Fri Nov 04, 2005 1:45 am

Quoting Thorben (Reply 61):
Maybe we can agree to count the 777LRF sales when considering the overall success of the 772LR/773ER-program, but we don't count them in the A345 vs. 772LR battle, because Airbus doesn't offer a competitor.

 bigthumbsup 
 
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zeke
Posts: 16356
Joined: Thu Dec 14, 2006 1:42 pm

RE: 345/346 HGW Versions

Fri Nov 04, 2005 3:15 am

Quoting Widebodyphotog (Reply 64):
When I say SFC I mean Thrust Specific Fuel Consumption in pounds per pound thrust hour...

Okay, TSFC should be lb/hr/lb where the last lb refers to the pounds of thrust produced not LB/LBTH.

Some engine TSFC values here http://www.aircraftenginedesign.com/TableB3.html

How did you come up with the cruise thrust ratings for the engines ?

Quoting Widebodyphotog (Reply 64):
That value does not represent fuel burn at any segment of the flight, rather total fuel burn/operating time for the indicated flight distance.

Okay, I see you seem to be using block burn/flight time not fuel flows, not that useful for calculating the TSFC, where TSFC = FF/Thrust, as the assumption Thrust=Drag for the block fuel burn is not valid.

Quoting Widebodyphotog (Reply 64):
For mission analysis I use my company flight planning software with sample aircraft definitions as per Boeing and Airbus. Here are images from the Nav Logs of the flight plans I made.

Okay I see you have done it for 380 pax, that 100 more than I would normally see in a 346, and a lower cruise altitude, hence the higher block fuel flow. Looking at the your log, I got about 8.3 t/hr (299200/16.4166) for the 346, and 10.8 for the 744er. Not really sure why you would step climb to FL348 with the 744er ?

If I am reading it right, the 744er burns 36.7 t more fuel to carry just 2.1 t more payload than a 346 ?

Would be interested to see similar logs for the 745, 773er, 772LR, 345, 380.
 
Thorben
Posts: 2713
Joined: Fri Sep 09, 2005 10:29 pm

RE: 345/346 HGW Versions

Fri Nov 04, 2005 4:16 am

Zeke, widebody, sorry to interrupt your discussion (of which I don't understand too much), but wouldn't the easiest thing be to take the fuel volume (in l) and divide that by the range (in km) and the number of passengers. Then you take this number times 100 and you have the figure of fuel burn per pas per 100km, which is used sometimes to compare aircraft to cars. If you set all figures to the max range with only passengers you should have some good comparison of the aircraft's performances.
 
widebodyphotog
Posts: 885
Joined: Wed Jun 30, 1999 9:23 am

RE: 345/346 HGW Versions

Fri Nov 04, 2005 6:03 am

Quoting Zeke (Reply 66):
Okay, TSFC should be lb/hr/lb where the last lb refers to the pounds of thrust produced not LB/LBTH.

Granted, but I'm really not interested in going round and round about it. We are talking about the same thing...

Quoting Zeke (Reply 66):
How did you come up with the cruise thrust ratings for the engines ?

What's on the table is spec values from the manufactures for the engines that currently exist. For GEnX numbers are preliminary.

Quoting Zeke (Reply 66):
Okay I see you have done it for 380 pax, that 100 more than I would normally see in a 346, and a lower cruise altitude, hence the higher block fuel flow. Looking at the your log, I got about 8.3 t/hr (299200/16.4166) for the 346, and 10.8 for the 744er. Not really sure why you would step climb to FL348 with the 744er ?

What I am analyzing here are generic aircraft at the design payload/range points. Not specific aircraft, but the parameters that generate their quoted capabilities. If you notice OEW's are noteably lower than what your equipment actually is as well...

From your postings I assume you are crew on A340 and 747 types and I appreciate your perspective. FL348 came about because the system is live and there was a restriction on the fix I was using at the time. When I do these generics even though they are fictional there are a lot of rules that have to be obeyed and that one was left in. It does not make a huge difference in the big picture so I left it there. As for A340-600, the plan that the system laid out what seems to be an economical plan for the flight time distance and weight. In your experience what are usual times and altitudes you see after takeoff from max gross?

Quoting Zeke (Reply 66):
If I am reading it right, the 744er burns 36.7 t more fuel to carry just 2.1 t more payload than a 346 ?

At the distances I specified yes that would be the case. The numbers are noteably closer if the 744ER is backed down to 7,500nm though, and a 777-300ER would need roughly 40% less fuel than the 74. at that same range with design payload.

Quoting Zeke (Reply 66):
Would be interested to see similar logs for the 745, 773er, 772LR, 345, 380.

745 is highly speculative still, but I could do those as well for the others.



-widebodyphotog
 
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zeke
Posts: 16356
Joined: Thu Dec 14, 2006 1:42 pm

RE: 345/346 HGW Versions

Sat Nov 05, 2005 2:17 am

Quoting Widebodyphotog (Reply 68):
In your experience what are usual times and altitudes you see after takeoff from max gross?

Generally nothing below FL330/10200m depending on the cost index and ISA deviation, obviously RVSM airspace limits come into play also.

The CX ones are 368 000 kg (811 293 lb) MTOW versions, your plan was for 365t MTOW, maybe it was for a forward CG ? 365t would be the limit at 17% MAC.
 
aircanada014
Posts: 1224
Joined: Sun Oct 09, 2005 2:24 pm

RE: 345/346 HGW Versions

Sat Nov 05, 2005 2:49 pm

AC is getting some 777-200LR and 777-200LRF plus 777-300ER

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