PPRuNe Forums Could adding fuel ever decrease range?

 Tech Log The very best in practical technical discussion on the web

 14th Feb 2011, 23:06 #1 (permalink) Join Date: Dec 2007 Location: earth Posts: 10 Could adding fuel ever decrease range? As the question states, could adding fuel ever decrease the range of an aircraft, our class is having a pretty large debate on this topic and we'd like your input please. Thanks in advance
 14th Feb 2011, 23:11 #2 (permalink) Join Date: Dec 2002 Location: Where the Quaboag River flows, USA Age: 60 Posts: 2,264 Well, it costs about 3% per hour of the added fuel weight; that is, it is impossible to reduce range EXCEPT if you put in drop tanks. The A10 lost range when the third tank was used, the second tank might have 100 nm. Hardly worth it. GF
 14th Feb 2011, 23:23 #3 (permalink) Join Date: Sep 1998 Location: wherever Age: 44 Posts: 1,142 In the real world it could, indirectly, due to air traffic systems and weather. In still air with no restrictions, no, because no matter how much useable fuel you add you will always use fuel to get to the lower fuel quantity and unless you dumped it, you used it to produce thrust and therefore range.
 15th Feb 2011, 00:05 #4 (permalink) Join Date: Dec 2007 Location: earth Posts: 10 I guess what we've narrowed it down to is on a large jet it can cost 500kg to carry 1000kg of fuel, is it ever possible to get an aircraft to more than 1:1
 15th Feb 2011, 00:13 #5 (permalink) Join Date: Dec 2002 Location: Where the Quaboag River flows, USA Age: 60 Posts: 2,264 Your example implies 16 hours (500kg of 1000kg is 50% of the initial added fuel divided by 3% per hour equals 16.67 hours) which is about the longest flight time. On profile that might reduce range is when the added fuel causes a route change or causes the cruise level to be off the flight plan. GF
 15th Feb 2011, 00:18 #6 (permalink) Join Date: Sep 2010 Location: by the seaside Age: 63 Posts: 317 yes - because of being blocked in at a lower level on a NATS track and once from the eastern med going westbound when we couldn't make flight plan level and were left at FL290 for several hours. Also had it one time east bound where we were out of the narrow jet stream core and lost 60+knots of chuff wind. Always worked on 4% per hour for the extra fuel tanked - take 10 tons extra fuel and at destination after 10 hrs you have 6 tons left.
15th Feb 2011, 00:23   #7 (permalink)

Join Date: Jan 2008
Location: Herts, UK
Posts: 592
Quote:
 Could adding fuel ever decrease range?
The question to some extent is making assumptions and not fully phrased... e.g.assumes current (actual) aircraft designs

...rather than at the design stage, where of course, ultimately it's quite possible by preventing climbout or even take-off... overfuelling is theoretically possible, absolutely, taking extreme cases.

 15th Feb 2011, 00:36 #8 (permalink) Join Date: Sep 2010 Location: England Posts: 1,133 Adding fuel until you are over your MTOW will severely reduce your range.
15th Feb 2011, 01:22   #9 (permalink)

Join Date: Apr 2009
Location: San Clemente, CA
Posts: 1,574
Quote:
Obviously the only non-troll response.

 15th Feb 2011, 01:28 #10 (permalink) Join Date: Dec 2002 Location: Where the Quaboag River flows, USA Age: 60 Posts: 2,264 OTOH, aterpster, a plane will fly over gross, but it will NOT fly without fuel. GF

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

All times are GMT. The time now is 04:56.