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-   -   Proportion of MTOW used as fuel on mil jets? (https://www.pprune.org/military-aviation/562963-proportion-mtow-used-fuel-mil-jets.html)

Trim Stab 14th Jun 2015 14:52

Proportion of MTOW used as fuel on mil jets?
 
Staring out of the window on a very long-haul flight yesterday, I got wondering what proportion of MTOW is fuel on most military jets. Typically civilian transport jets have about 30% of MTOW - so I wondered whether this would also be a ball-park figure for military fast jets?

High_Expect 14th Jun 2015 14:56

Proportion of MTOW used as fuel on mil jets?
 
Sounds about right. Tornado was anywhere from about 25-35% depending upon fit IIRC.

Fox3WheresMyBanana 14th Jun 2015 14:57

Tornado F3 - On max internal fuel, about 25%. With max external also, 36%; with AAR........

VinRouge 14th Jun 2015 15:14

C-17 is up at 42%, although that's increased from 31% originally.... Thirsty bird!

Willard Whyte 14th Jun 2015 16:09

E-3D around 43% (although some is unusable). I think Sentinel is around 45%.

I forget the exact fuel figures for a C-130K (64K? Over ten years since I flew 'em...) round about 40%. J must be a bit less though. A-400 around 36% (from Wikipedia).

All for max fuel/MTOW.

Pontius Navigator 14th Jun 2015 17:07

Vulcan on main tanks around 41% and with double drum tanks 46%.

Full internal plus 21k bombs would be 37%.

NutherA2 14th Jun 2015 17:12

IIRC the figures for the FG1 in Delta(?) fit would work out at about 40%, if I'm wrong I'm sure Courtney can put me right....

Onceapilot 14th Jun 2015 17:31

RAF TriStar tankers: over 50% / over 275,000lb.

OAP

Biggus 14th Jun 2015 17:40

WW,

The C-130K was 62.9k (some figures you never forget) vs MTOW 155k, or just over 40%.

It must be well over 10 years since you last flew them, as they went "metric" in about 1999. Quite what 62,900lbs is in kg I don't recall, it was obviously not a memorable figure!!

smujsmith 14th Jun 2015 18:17

Biggus,

28531 Kgs is the number you might seek in the modern world. Like you, 62,900 lbs is the number that comes to mind. I well remember another version of full tanks. On asking the required fuel load prior to an ASI/MPA flight, the navigator asked me to "fill it till it leaks". Happy days :eek:

Smudge :ok:

Biggus 14th Jun 2015 19:10

Smudge,

I used to operate the Herc tanker out of ASI for the airbridge, only it was to Stanley in my day, not MPA. Four extra fuel tanks plumbed in and mounted in the cargo bay of the tanker, I believe they were old long range Andover tanks, but am happy to be corrected. Total fuel load I think was 62,900 in normal tanks and 28,000 down the back....

As you say, happy days in concertina city, the exiles club, a bungalow in Georgetown, and, towards the end, travellers rest or whatever it was they called the purpose built accommodation....

ASRAAM 14th Jun 2015 22:21

Proportion of MTOW used as fuel on mil jets?
 
Victor K2 52 per cent at heaviest permissible.

Danny42C 14th Jun 2015 22:36

From a standpoint of complete ignorance, would not the ideal answer be: "As much as you can get off the ground with ?"

Says the Ancient Aviator: "Fuel in the bowser is expensive. Fuel in the air is priceless !"

Standing by for incoming......

D.

Mr C Hinecap 15th Jun 2015 00:40

There's no point in flying around with more weight than you need. It slows you down, puts extra strain on engines, airframe etc. You also take the landing weight into consideration as well - you can't land if you're too heavy.

So - there's an optimal fuel load rather than just filling it up.

battlecruiser 15th Jun 2015 02:07

Proportion of MTOW used as fuel on mil jets?
 
F18 (not Super) 20-30%.

Pontius Navigator 15th Jun 2015 11:30

Nuther, think you are correct. I always marvelled that Delta fuel at 21k was the same as a Domine MTW. Given an F4 at 54k . . .

NutLoose 15th Jun 2015 16:31

I would guess the F-35 will probably be less due to humping that great big lift fan about that is only actually used on the final part of it's sortie. I think a lot of pilots would probably prefer more fuel or ordnance than dead weight.

Trim Stab 15th Jun 2015 20:10

Interesting but not unexpected that the heavy multi-engines took high proportion of fuel in MTOW. Anybody got ball park figures for Lightning and Harrier?

Willard Whyte 15th Jun 2015 20:41

Biggus


The C-130K was 62.9k (some figures you never forget) vs MTOW 155k
Thanks, wasn't far off then. I was using 160K MTOW for a Mk3 in the fag packet calcs.

I well remember metrication (I was posted away in '04). Bloody farce. Stick-on metric calibrations until the digital conversion.

OK4Wire 17th Jun 2015 08:50

Can't find my "newer type" books, but a Hunter T8M was 10%-13%


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