F-35 internal fuel, range

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outlaw162

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Unread post08 May 2020, 16:07

Did youse yanks have a preference for which wing for drop tank?


F-101 drivers would have needed a bigger wing to go with their tailored trousers. :mrgreen:

Not a lot of wing area to hang a fuel tank. The short time I was associated with the VooDoo at Niagara, I also don't think I ever saw one with 2 tanks (interference drag?). Couple of X-country flights I rode along on while waiting for a local checkout were flown clean, roughly 650 nm legs at 0.88 IIRC (hour+15ish?+reserve), which seemed pretty impressive to me for that era. Beautiful machine.

Niagara VooDoo with one tank and below belly of VooDoo with 2 tanks:
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Unread post08 May 2020, 20:43

:roll: :twisted: :devil: They must have had tight trousers to make room for dem BALListics! :doh: :mrgreen: :shock:
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energo

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Unread post09 May 2020, 01:19

spazsinbad wrote::roll: :twisted: :devil: They must have had tight trousers to make room for dem BALListics! :doh: :mrgreen: :shock:


Or JUGGs. :mrgreen:
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spazsinbad

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Unread post09 May 2020, 01:26

:applause: Correct. Depends upon your individual perspective. :doh: Thanks for the mammaries.... 8)
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Unread post09 May 2020, 05:20

energo wrote:
eagle3000 wrote:Btw.,Israel to Bushehr is around 820 nm, to Tehran around 800 nm. Both more than 670 nm, but less than 40% more than 670 nm :wink:


The 670nm is a combat radius under specific conditions. This figure can be shortened or extended depending on the misson at hand. The below 2016 LM chart states a 760nm combat range in an air-to-air config. Norwegian F-35 pilot Morten Hanche is on record stating that the F-35A enjoys 30-70 percent more range than the F-16AM depending on the circumstances.

Then there is the "routing factor": The distance to target vs. the distance actually flown to reach the target. A non-stealthy fighter will tend to fly around the SAM or radar bubbles - increasing the distance flown - whereas a stealthy aircraft can fly a more direct route through the SAMs. According to this chart, an F-15E enjoys a -30 percent routing factor whereas an F-22 (or F-35, probably) only has a -6 percent factor. Meaning: The stealthy aircraft has a lot more effective range for the same amount of fuel (and tanker support).

Image

Image

Nicely done.
Another way is to say, both have about 18k lb internal fuel. One weighs 43.3k. The other weighs 29.3k.
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Unread post09 May 2020, 15:49

It's good to (finally) have a fighter with real legs. I mean in both the F-22 and 35's cases, especially the latter.

The F-14D carried 16,200lbs of gas, F-15C 13,500, F-16 7,000 and SH I think is 13,550 or so. It always bugged me the Flanker carries a lot more, over 20,000lbs. I realize there's more to an aircraft's range though, than just internal fuel load. Number of engines, alititude, airspeed, lift vs. drag etc all play a part.

But now, we have two beasts that carry 18,000lbs or so - flying "clean". It's about time we got an aircraft out there not so dependent on tankers. It's good SH Block III is getting additional gas with CFT's, I'm a fan of those. Unless they're on an F-15EX.. can't punch them like you can EFT's.

Anyway, it looks like the F-35 will be our longest legged fighter for awhile. At least until PCA gets here. Fantastic piece of engineering. Saw one at an airshow sitting next to an F-15C. Would have never guessed it carried so much more fuel, especially given the size discrepancy!
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Unread post09 May 2020, 17:45

BDF wrote:
mixelflick wrote:I find the F-22's range remarkable, especially when considering its configurated for the air to ground mission. Carrying 2 1,000lb JDAM's plus 4 AAM's.. Makes you wonder what it's true range with just 8 AAM's is.

It may not be comparable to the F-35, but it's an incredible achievement IMO, especially considering they shaved 5,000lbs of fuel from the prototype. Throw in the fact its second to none at well, almost everything - and it's truly exceptional IMO.

If I were one of those engineers, I'd be really proud. Hell just as an American, I'm proud of what they accomplished..


Its not going to be much, about a 420lbs difference assuming that they use AVEL's to carry the GBU-32s. If they use a different heavier launcher it'll be a bit more but in the grand scheme of things a 500lb difference is only about 0.7% of the gross T/O weight without bags. Probably will have only a very minor affect on range.


A BRU-46/A is used. Mounted on a plate which is in turn bolted to the structure, at least that's what it looks like to me. Overall, such a setup should be quite a bit lighter than two LAU-142/A AVELs, which are reportedly 113 lbs each. One BRU-46/A weighs 46 lbs.
Meaning any difference in weight and thus range is negligible.
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eagle3000

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Unread post09 May 2020, 17:58

Gums wrote:A Raptor with only internal load and no supercruise segment should have a really super radius, but I haven't seen exact numbers.


590 nm is the official subsonic radius. As shown in the Combat Radius Comparison chart posted above.
450 nm with a 100 nm supersonic dash.

What I find remarkable is how the F-22 has a 590 nm radius, when the F-35A has a 760 nm radius. With an as near as makes no difference identical fuel load.
The F-22 is about 48% heavier - so you would image it should have about 68% of the F-35A's radius. In fact it has 78% of the radius. Which means the F-22 uses its fuel about 15% more efficient than the F-35A. And that is despite being burdened with fuel hungry leaky turbojets.
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Unread post09 May 2020, 18:05

eagle3000 wrote:
What I find remarkable is how the F-22 has a 590 nm radius, when the F-35A has a 760 nm radius. With an as near as makes no difference identical fuel load.
The F-22 is about 48% heavier - so you would image it should have about 68% of the F-35A's radius. In fact it has 78% of the radius. Which means the F-22 uses its fuel about 15% more efficient than the F-35A. And that is despite being burdened with fuel hungry leaky turbojets.

Twin engines and bigger wing let it fly higher, a higher fineness ratio and better wave drag characteristics let it fly faster (even if just 20-50kts in cruise it all adds up). These let it use less fuel than the weight implies and lets it go a tad farther per unit fuel than its weight would imply.
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eagle3000

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Unread post09 May 2020, 18:06

optimist wrote:
energo wrote:
eagle3000 wrote:Btw.,Israel to Bushehr is around 820 nm, to Tehran around 800 nm. Both more than 670 nm, but less than 40% more than 670 nm :wink:


The 670nm is a combat radius under specific conditions. This figure can be shortened or extended depending on the misson at hand. The below 2016 LM chart states a 760nm combat range in an air-to-air config. Norwegian F-35 pilot Morten Hanche is on record stating that the F-35A enjoys 30-70 percent more range than the F-16AM depending on the circumstances.

Then there is the "routing factor": The distance to target vs. the distance actually flown to reach the target. A non-stealthy fighter will tend to fly around the SAM or radar bubbles - increasing the distance flown - whereas a stealthy aircraft can fly a more direct route through the SAMs. According to this chart, an F-15E enjoys a -30 percent routing factor whereas an F-22 (or F-35, probably) only has a -6 percent factor. Meaning: The stealthy aircraft has a lot more effective range for the same amount of fuel (and tanker support).


Nicely done.
Another way is to say, both have about 18k lb internal fuel. One weighs 43.3k. The other weighs 29.3k.


It doesn't adress the issue at hand though.
Which is range increase due to more fuel carried.

No matter what your radius r is, if you add 40% to that, r is going to be 1.4*r afterwards. You can insert 600, 670 or 760nm for r, 40% more is 40% more.

Btw., note how the F-22's radius goes from 590 nm to 850 nm with 2 600 gal bags. That's 44% more, albeit with tanks dropped. So I'm assuming LM assumed the same for the F-35s 40% increase.
Last edited by eagle3000 on 09 May 2020, 18:13, edited 2 times in total.
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Unread post09 May 2020, 18:11

sprstdlyscottsmn wrote:
eagle3000 wrote:
What I find remarkable is how the F-22 has a 590 nm radius, when the F-35A has a 760 nm radius. With an as near as makes no difference identical fuel load.
The F-22 is about 48% heavier - so you would image it should have about 68% of the F-35A's radius. In fact it has 78% of the radius. Which means the F-22 uses its fuel about 15% more efficient than the F-35A. And that is despite being burdened with fuel hungry leaky turbojets.

Twin engines and bigger wing let it fly higher, a higher fineness ratio and better wave drag characteristics let it fly faster (even if just 20-50kts in cruise it all adds up). These let it use less fuel than the weight implies and lets it go a tad farther per unit fuel than its weight would imply.


Thanks for saying that. It's what I figured, I just didn't want to say what might be considered heresy by the F-35 crowd. :mrgreen:
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