View Full Version : B737 NG De-rated Climb
Boneman
21st Jun 2010, 14:15
Does a de-rated climb increase fuel burn during the climb?
(Please discuss in excruciating detail :bored:)
Pugilistic Animus
21st Jun 2010, 14:31
more time at non-optimum level ,also more time in high drag configuration and more time in the climb---derates are nice for engine reliability:)
if this thread gets worse I'm outta here:\
de facto
21st Jun 2010, 14:32
Stoneman:eek:
Use derate will increase your fuel burn as it will take longer to reach your cruising/opt level.
To save fuel,no derate(not as good for engines though) and use NDP2(3-4% fule save compare to other ndp1).
Sorry i wont get into details, especially without the magic word:E
Pugilistic Animus
21st Jun 2010, 14:36
especially without the magic word
---------Vm:oh:
:}
Boneman
21st Jun 2010, 14:59
Sorry i wont get into details, especially without the magic word
But I said please.:{
de facto
21st Jun 2010, 15:09
you did indeed.:8
Still,easiest is to believe us,burning more fuel by using less thrust,hence a longer time to reach higher level.
Derate is better in many ways...there are many threads concerning this...only bad thing is the fuel burn which is increased.
drive73
21st Jun 2010, 15:15
It wouldn't burn much more fuel as climb power switches at 15k feet. The savings to the engine would be way more valuable than the small fuel savings through 15k. Please correct me if I am wrong.
Oh, since you've been so polite :)
Take it 'ab absurdo' - reduce power to just above cruise and look at the fuel burn when you are still at 10000ft 200 miles after take-off. As above, the quicker you get up there the less you burn. Generally climbing above 35000ft 'ish when the air is about as cold as it gets will not make so much difference
bumpyflight
21st Jun 2010, 16:44
I dont really know on a 737, but I got some info that might helpmax take off weight = 144,500–187,700 lb (65,500–85,100 kg)take off field length = 8,000–8,300 ft (2,400–2,500 m)above is for 737 800 aircraft
Boneman
21st Jun 2010, 16:46
OK, now I'm going to throw in a cost index; 5 vs. 50. Any takers?
:ugh:
Please?
Thank you. It depends on which climb speed 5 or 50 give. Whichever is nearer to the best r of climb speed will win.
I also suspect we are being trolled (no, boneman, not you:))
VH-ABC
28th Jun 2010, 07:35
BOAC,
Whatever you put in as the TOC wind will also change your climb speed will it not?
citizensun
7th Jul 2010, 17:40
:)i am flying 737NG ,and i have couple questions. as the manual says, the take-off thrust has a 5 minutes limit, could anyone tell me where is this limit come from, the reason for this and why it`s still a limit in de-rate and assume-temp take-off when the engines are not in full power. thanks~