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-   -   DC8 average Fuel flow Question? (https://www.pprune.org/tech-log/9468-dc8-average-fuel-flow-question.html)

G3 17th December 2000 01:47

DC8 average Fuel flow Question?
 
Hi Folks,

What would someone plan as an average fuel flow for a DC8-62/63 at max zero fuel weight on a 5 hr leg?

Thanks for the help,

G3

m&v 17th December 2000 07:33

DC8/63 average fuel burn in cruise was 11500
lbs/hr..Not bad for 200 pax at M82..
Improved considerably with CFM56 fitted after 1981.

before landing check list 17th December 2000 20:04

Hello G3,
On the 60 series aircraft (61,62,63) you can plan 10,000 LBS to climb, 10,000 LBS used at cruise evry 45 min and 3000 LBS for the decent. Idle will be 100/min/eng. Hope this helps you.

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The problem with the world is that everyone is a few drinks behind.

--Humphrey Bogart

G3 18th December 2000 04:32

Thanks M & V and BLCL, I know its alot, but I was actually expecting more per hour. Very much appreciated.

G3

before landing check list 18th December 2000 07:00

Hey G3, Let my clarify: Plan on USING 10,000 in the climb, 10,000/45 min at cruise and USING 3000 to decend. At idle on ground expect 100lbs/eng/min.
j

G3 19th December 2000 04:15

Thanks BFLCL,

I understand, I was just asking for burn, not
flight plan fuel.

G3

TowerDog 20th December 2000 01:37

I always thought the fuel flow for an older 8 was 18000 lbs per hour and 12000 lbs for the -70 series? (CFM-56)

Flew a -73 a long time ago and I think the max endurance before flame-out was around 18 hours, close to -340 country.




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Men, this is no drill...

m&v 20th December 2000 06:52

The original 8 (especially the Rolls Royce Conway engines were 'gas'hogs,but on a cold day the conway could put out 20000lbs thrust)
The model 61,long fuselage,small 50's series wing was a bit of a dog-didn't like to go too high. The 63 came with P/W JT3d-3/7
Good for 19000lbs thrust,and the redeveloped wing,an excellent aircraft,until the 70's came with the CFM56's.
The P/W JT3D proved to be so 'popular' that with the grounding of the 707-300 series(noise/fuel costs) the USAF acquired the engines off the grounded aircraft for refit to the KC135,to extend their range.

quid 20th December 2000 07:58

For the JT-8's, 10-12,000/hr is a good number, of course depending on weight and altitude, etc.

At idle, it's about 20 ppm/engine.

Still is a good, reliable aircraft. Carrying lots of freight lots of miles as we speak.

before landing check list 20th December 2000 22:05

20ppm? you don't mean pounds? For the 61-63 figure on 100ppm/eng/min. And the P/W JT3D and the -7's (ultra low bypass, lol)are on the 60 series
j

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For a plane to fly well, it must be beautiful.

— Marcel Dassault

[This message has been edited by before landing check list (edited 20 December 2000).]

quid 20th December 2000 22:29

blcl-

Idle is approx 1200 pph./eng. Divide that by 60 (minutes) and it yields 20 lbs. per minute.

If each engine burned 100 lbs. per minute, that would be 6000 pph, and if all 4 were running, it would be 24,000 pph. (On the ground at idle? No way.) That's about what they burn at takeoff thrust.

before landing check list 21st December 2000 07:10

Quid,
I stand corrected. I should have left it as 100ppm with all 4 running at ground idle. Don't know what I was thinking. The rest is correct though. Thanks,
j

------------------
For a plane to fly well, it must be beautiful.

— Marcel Dassault

alapt 23rd December 2000 17:57

Fuel burns for the DC-8-62 are as follows for a five hour flight is about 31,5 tons at FL 290, 30 tons at 310, 29 tons at 330.



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