Forum: F-35 Lightning II

Last edited by Corsair1963 on Jun 14, 2010 - 07:35 AM; edited 2 times in total

Really, considering the vast amounts of fuel that the F-35 carries. (i.e. 15,000 - 20,000 lbs) Is the range being purposely underestimated???

For example the F-15C has a internal fuel load of ~ 13,500 lbs and has to carry its weapons all externally! While, the F-35 carries everything internally and has 1,500 - 6,500 lbs more fuel. Let's also consider that the F-15C has two P & W F100's vs one P & W F135. Seems a stretch to believe the two older P & W Engines are more efficient than one brand new Turbo Fan from the same company! Question

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Last edited by spazsinbad on Jun 14, 2010 - 01:33 PM; edited 2 times in total

http://www.lockheedmartin.com/data/asse ... 35Broc.pdf (1.2Mb)
An official LM Brochure PDF dated May 2007 says this: (Is this what you require for comparison?)

my 'range' definition:
"the total distance which a ship, aircraft, or land vehicle is capable of covering without taking on fresh fuel."

F-35A CTOL:
Combat radius (internal fuel) >590 n.mi / 1,093 km
Range (internal fuel) . . ~1,200 n.mi / 2,222 km

F-35B STOVL:
Combat radius (internal fuel) >450 n.mi / 833 km
Range (internal fuel) . . . ~900 n.mi / 1,667 km

F-35C CV:
Combat radius (internal fuel) >600 n.mi / 1,111 km
Range (internal fuel) . . >1,200 n.mi / 2,222 km

I question the range of the F-35C CV because I believe it is heavier and has a different wing and nose (slightly different aerodynamic profile?) compared to the F-35A.

Last edited by spazsinbad on Jun 14, 2010 - 01:30 PM; edited 1 time in total

F16VIPER, I agree about F-35C CV but very slow temporary dialup speed restricts search time at moment. For sure any mention of F-35C mentions 'larger wing' "increased range". I'll post old graphics from briefings by LM soon. Here is a 2007 'Tailhook' briefing page by Tom Burbage "COMBAT RADIUS" comparison:

[EDIT] In several places the F-35C range is quoted as 1,400NM, here is one instance:

http://militaryhistory.about.com/od/mil ... /p/f35.htm

"Range: F-35A: 1,200 nmi, F-35B: 900 nmi, F-35C: 1400 nmi"
&
"F-35C: Designed for the US Navy, the F-35C is the carrier variant of the aircraft. Possessing larger folding wings and reinforced landing gear, the aircraft is capable of a longer range than the F-35A and F-35B."

spazsinbad wrote:

F16VIPER, I agree about F-35C CV but very slow temporary dialup speed restricts search time at moment. For sure any mention of F-35C mentions 'larger wing' "increased range". I'll post old graphics from briefings by LM soon. Here is a 2007 'Tailhook' briefing page by Tom Burbage "COMBAT RADIUS" comparison:

Yet, that comparison is with Harrier, Viper, and Super Hornet. All that have somewhat limited range to start with. Let's not forget in the case of the Hornet/Super Hornet. It has a reputation for having short legs to boot.

Corsair1963, I am guessing that the slide we see for 'Combat Radius' is mislabelled. If you substitute the first F/A-18C for F/A-18E/F you should get the correct comparison. I could amend the graphic I suppose. What a hassle. Very Happy

Corsair1963 wrote:

Really, considering the vast amounts of fuel that the F-35 carries. (i.e. 15,000 - 20,000 lbs) Is the range being purposely underestimated???

For example the F-15C has a internal fuel load of ~ 13,500 lbs and has to carry its weapons all externally! While, the F-35 carries everything internally and has 1,500 - 6,500 lbs more fuel. Let's also consider that the F-15C has two P & W F100's vs one P & W F135. Seems a stretch to believe the two older P & W Engines are more efficient than one brand new Turbo Fan from the same company! Question

Not really. Lots more fuel, but you have larger and more powerful engines and the planes are ~40-50 heavier than the ones they replace.

Last edited by spazsinbad on Jun 14, 2010 - 01:34 PM; edited 1 time in total

Corsair1963, what comparison would you like to provide then? COMBAT RADIUS is nebulous because there are more variables than you can 'poke a stick at'. Range or Ferry Range is clear cut. It is how far you can go on internal fuel without stopping (one would imagine that some reserve is left at end but then again that is another question so we can go with whatever the quoted ferry range is for any aircraft). Over to you.

This website may be a good place to start - but I think we can see that any numbers are rubbery at best and IMHO any range numbers would need to be 'official' (whatever that means).
____________________________
http://www.aerospaceweb.org/aircraft/fighter/
___________________
F-15C
internal fuel: 13,455 lb (6,105 kg)

ferry: 2,500 nm (4,630 km) without conformal fuel tanks

http://www.aerospaceweb.org/aircraft/fighter/f15/
_____________________

internal fuel:
(F-35C) 19,625 lb (8,900 kg)

(F-35C) 1,620 nm (3,000 km)

http://www.aerospaceweb.org/aircraft/fighter/f35/

spazsinbad wrote:

Corsair1963, what comparison would you like to provide then? COMBAT RADIUS is nebulous because there are more variables than you can 'poke a stick at'. Range or Ferry Range is clear cut. It is how far you can go on internal fuel without stopping (one would imagine that some reserve is left at end but then again that is another question so we can go with whatever the quoted ferry range is for any aircraft). Over to you.

This website may be a good place to start - but I think we can see that any numbers are rubbery at best and IMHO any range numbers would need to be 'official' (whatever that means).

F-15C
internal fuel: 13,455 lb (6,105 kg)

ferry: 2,500 nm (4,630 km) without conformal fuel tanks

http://www.aerospaceweb.org/aircraft/fighter/f15/
_____________________

internal fuel:
(F-35C) 19,625 lb (8,900 kg)

(F-35C) 1,620 nm (3,000 km)

http://www.aerospaceweb.org/aircraft/fighter/f35/

The think the point is that many 4th Generation Fighters have similar range with less fuel and more drag. As they say something is a foot......IMO

Last edited by spazsinbad on Jun 14, 2010 - 12:35 PM; edited 6 times in total

Corsair1963 are you referring to 'Combat Radius' or 'Ferry Range'? IMHO the thing that is afoot is that the 'legs' of the F-35 is unknown until it actually is ferried. For example that is yet to happen without refuelling or perhaps it has already. How did the two F-35As get to Edwards recently (unfuelled or refuelled in flight?). At this point all F-35 figures are theoretical until 'official' figures are released. And then what does that mean? You would be aware that 'official' often does not reflect reality that a pilot will see. So we have to go on 'official' or 'manufacturer's' figures for RANGE or whatever. Maybe one day we will see a NATOPS graph that will show how variable these 'range/radius' figures can be depending on many variables. You can download an A-4 Skyhawk graph for these situations here to see how complicated it can become: "A4EFGnatopsSkyhawk.pdf"

http://www.filefront.com/11615952/A4EFG ... yhawk.pdf/ 63Mb.

Left click on the URL above first to go to the page before downloading PDF.
____________

Same file with graphics at back slightly less clear at 43Mb: "EFG-NATOPS-OPT.pdf"

http://www.filefront.com/11686763/A4EFG-NATOPS-OPT.pdf/ 43Mb

Graphs less clear in this smaller file size version.
_________________

BEST QUALITY VERSION AT 135Mbs (for graphs): "A4Gnatops692ppBestQuality.pdf"

http://www.filefront.com/11720369/A4Gna ... ality.pdf/
___________________

There is a website with OLD aircraft official SAC (Standard Aircraft Characteristics) info:

http://www.alternatewars.com/SAC/

Regarding that slide, how can a combat loaded F-16C go nearly as far as the F-35A without external drop tanks or CFTs? Doesn't the F-16 have less than 7000 pounds of internal fuel without CFTs?

lampshade111, to me that graph is meaningless if initial conditions (loadout) for each aircraft is not made clear. [Forgot to add that we must remember these 'briefing slides' are only part of what is briefed (reminders) it is likely the briefer made clear the initial conditions but we don't know that here sadly.] Ferry Range is at least fairly standard with internal fuel only to consider. One can play games with these figures - possibly one reason why Sweetman bit the JSF dust eventually. Don't take that as gospel but his last post (pun intended) about this topic was a joke [IMHO]. Very Happy

Peruse the comments after original post to comprehend how some issues were mangled: {http://www.f-16.net/f-16_forum_viewtopic-t-14017.html}

ORIGINAL POST: http://www.aviationweek.com/aw/blogs/de ... d=blogDest
OR
http://alturl.com/4mbn

spazsinbad wrote:

Corsair1963 are you referring to 'Combat Radius' or 'Ferry Range'? IMHO the thing that is afoot is that the 'legs' of the F-35 is unknown until it actually is ferried. For example that is yet to happen without refuelling or perhaps it has already. How did the two F-35As get to Edwards recently (unfuelled or refuelled in flight?). At this point all F-35 figures are theoretical until 'official' figures are released. And then what does that mean? You would be aware that 'official' often does not reflect reality that a pilot will see. So we have to go on 'official' or 'manufacturer's' figures for RANGE or whatever. Maybe one day we will see a NATOPS graph that will show how variable these 'range/radius' figures can be depending on many variables. You can download an A-4 Skyhawk graph for these situations here to see how complicated it can become: "A4EFGnatopsSkyhawk.pdf"

http://www.filefront.com/11615952/A4EFG ... yhawk.pdf/ 63Mb.

Left click on the URL above first to go to the page before downloading PDF.
____________

Same file with graphics at back slightly less clear at 43Mb: "EFG-NATOPS-OPT.pdf"

http://www.filefront.com/11686763/A4EFG-NATOPS-OPT.pdf/ 43Mb

Graphs less clear in this smaller file size version.
___________________

There is a website with OLD aircraft official SAC (Standard Aircraft Characteristics) info:

http://www.alternatewars.com/SAC/

Well, both Ferry Range and Combat Radius. Again just wondering if the numbers put forth are anywhere close to reality??? As they seem very low considering the known factors.......... Wink

Corsair1963, 'combat radius' is meaningless unless 'the load' and other conditions are itemised for comparison between aircraft. I think you will be wondering for a long time about 'the reality' of anything to do with the F-35. This is no big deal for a new aircraft. It is not in service yet and lots of details would be classified. Why worry? Rolling Eyes

spazsinbad wrote:

Corsair1963, 'combat radius' is meaningless unless 'the load' and other conditions are itemised for comparison between aircraft. I think you will be wondering for a long time about 'the reality' of anything to do with the F-35. This is no big deal for a new aircraft. It is not in service yet and lots of details would be classified. Why worry? Rolling Eyes

I am not worried per se. Yet, many a F-35 Critics see "X" number and consider it fact. Confused

Clearly, I understand such variables as Altitude, Power Settings, Payload, Weather Conditions, etc. etc.

Just looking for a solid point of reference to make comparisons.

Forum: F-35 Lightning II

F-35 Range Greatly Underestimated???