OT: Aircraft Fuel in Pounds Instead of Gallons?

During Mail Call they had a bit on in flight refueling. Any reason for
measuring the fuel transferred by pounds instead of gallons?
Something to do with the aircrafts payload capacity?
thx - Craig
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Jet fuel is usally measured in pounds, Avgas by gallons Matt Gunsch, A&P,IA,Private Pilot Riding member of the Arizona Precision Motorcycle Drill Team GWRRA,NRA,GOA
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Because weight is measured in pounds, not gallons. Eliminates the step of converting gallons to pounds. 6 lbs. per gallon of AvGas, roughly 7 lbs. per gallon of Jet Fuel.
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Frank May
what does the fuel weigh, whatever the main jet juice is? (i realise there's a bunch.) water is what, about 8.6 lbs per gal?
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That depends on whether you are using US Gallons or Imperial Gallons. As US Gallon is 0.82 of an Imperial Gallon. That reason alone would be enough to measure aviation fuel in pounds as they are the same whether you are in the USA or UK
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Roger Demming
Yep, not only payload but even more importantly, CG. Since if you measure by gallons (and most trucks and pumps do), you need to convert to pounds anyway to do weight and balance. An aft CG can spoil your whole day. Of course, with tanks in wings this is usually not too much of a problem, but pilots are still taught to do weight and balance with care.
Another factor. The energy content of a fuel is proportional to weight. Volume can vary a bit due to temperature. Not a big effect, but still another reason to do computations (such as range) in weight rather than volume.
Craig wrote:
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Don Stauffer
If only my bf read newsgroups! You folks seem right up his alley. Not only is he a modeller, but he's also a HUGE fan of this show.
About us: I enjoy plastic models, especially cars. I started out making models for the bf because my fingers were smaller, but ended up enjoying the making process more than him.
He is all about the wooden boat. I mean, what does a yacht builder by trade do in his spare time? Build little boats. So far he has built two Dumas kit Chris-Crafts. One is a double-cockpit barrelback and the other a triple. He's now on to building a 1954 Arno XI Ferrari hydroplane from the Amati kit. As soon as it comes in, he plans on getting the aftermarket transkit including 12 cyl. engine.
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Craig asked:
Yes and the range planning chars in the manuals are plotted based on wieght. If you keep everything in one measuement system, it eliminates one math step and possible error. In B-57s the low level consumption at 300 knots was"about" 600lb/min, a convenient number to work with mentally. The guages read in lbs, the weight and balance was in lbs, the flight plan was in pounds, the pilot's rear end was in lbs (beer capacity in cans, but that is another tale). You get to remember and work with friendly numbers.
Oxmoron1 MFE.
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Don Stauffer wrote in news:3F140D16.860088D2 @usfamily.net:
I believe that an airliner (Canadian?) crashed due to incorrect conversion calculations when it was begin refulled. IIRC ther was a bureaucratic bungle about using metric measurements on the ground tankers -- the ground crew were not trained correctly and uploaded the incorrect amount of fuel to the aircraft.
From memory the story was examined in "The Naked Pilot"
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Andrew Fraser
Probably this one in Gimli Manitoba.
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While cruising at FL410, both of the aircraft's engines flamed out due to fuel exhaustion. Captain Robert Pearson, an experienced glider pilot, flew the aircraft for thirteen minutes with no engine power and limited hydraulic pressure to a safe landing on a closed runway at Gimli, Manitoba. The aircraft's nosewheel collapsed on landing. A local group was holding drag races on the closed runway at the time, and assisted in the evacuation and treatment of the passengers and crew. .
Best regards, Spehro Pefhany
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Spehro Pefhany
shouldn't everyone in the world weigh fuel in kilograms rather than pounds? Everyone in the world knows what a kilogram is
Tim Brimelow
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tim brimelow
True enough, but unless you plan to fly somewhere where gravity is different from Earth, the distinction is meaningless.
That's the real problem--but pose it backwards--do European aircraft (say, for example, the Airbus) have their gauges calibrated in pounds or in kilos?
Mark Schynert
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Mark Schynert
Um not quite....several have mentioned the effects of temperature and pressure, that would probably make enough difference on the pounds/kilos thing when calculating maximum range.
Probably pounds due to A)pounds was used first and became a worldwide standard before kilos became popular, B)like ATC which is in English as a worldwide standard, fuel measurement probably is too.
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