Official statement: The F-35 CAN Supercruise.

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johnwill

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Unread post05 Nov 2012, 04:36

Obviously, there's no point in going supersonic with tanks and A/G bomb load, even if they were cleared to do so. So my statement referred to A/A loadings.
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linkomart

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Unread post05 Nov 2012, 10:26

SpudmanWP wrote:http://www.airforce-magazine.com/MagazineArchive/Pages/2012/November%202012/1112fighter.aspx

The F-35, while not technically a "supercruising" aircraft, can maintain Mach 1.2 for a dash of 150 miles without using fuel-gulping afterburners.

"Mach 1.2 is a good speed for you, according to the pilots," O’Bryan said.


This confirms two things.
1. LM does not consider just going over M to be supercruising.
2. It can :)



Well.. I'm not so sure that is what he is saying.
He says it is not technically a supercruising aircraft... But that it can fly at M 1.2 for about 150miles, without using fuel-gulping afterburner...

You can argue that he is saying that it flies with a low setting on the afterburner... that is not that fuel gulping as full AB.
Because, 150 nm sounds very short range if youre going in military power, considering the fuel fraction on the F-35.
caveat: I have not made any calculations, just used my humble experience.

my 5 cent.
linkomart
(/RAF at ARES)
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Conan

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Unread post05 Nov 2012, 14:01

linkomart wrote:Well.. I'm not so sure that is what he is saying.


What he is saying is black and white. It can do ... not using afterburner...

He says it is not technically a supercruising aircraft... But that it can fly at M 1.2 for about 150miles, without using fuel-gulping afterburner...


Correct. And the USAF and L-M definition of "supercruise" is?

Remarkably different to everybody else's... Because they only consider what the F-22A is capable of as "true" supercruise, because THAT is what the term was coined for.

When they say the F-35 isn't a supercruiser, they mean that it won't do M1.5+ on dry thrust. Not that it cannot exceed M1.0 on dry thrust, something even the F-16 has done.

You can argue that he is saying that it flies with a low setting on the afterburner... that is not that fuel gulping as full AB.
Because, 150 nm sounds very short range if youre going in military power, considering the fuel fraction on the F-35.
caveat: I have not made any calculations, just used my humble experience.

my 5 cent.
linkomart
(/RAF at ARES)


You can argue that. Of course you have to put words into his mouth to do so.

So can I put words into his mouth too? Okay, I read his statement as meaning the F-35 can make 0.5 past lightspeed...
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linkomart

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Unread post05 Nov 2012, 14:51

Conan wrote:You can argue that. Of course you have to put words into his mouth to do so.


Nae, I'm not really interested in putting words in to someone's mouth. What I want to do is to translate PR salesmans language in to easy to understand facts that me as a simple engineer can understand. Cause what's said by a salesman is not always exactly the truth, and if it have to be the truth, there is bound to be a caveat in a strange passus of the sentence that only a lawyer can understand and translate...

OK, a little rant, sorry about that.

It's just that, with the fuel volume of the F-35, the thrust of the engine and the supposed sfc (compared to for instance a F-100) the 150 mile range (not RoA) sounds too low for just going in military power.

150 mile (nautical) at M=1.2 is about 11 minutes.. give or take.
max thrust is (dry) 28000 lbf and with a SFC at about 0.89 that would be 28000 x 0.89 x 0.1875 = 4672 lbs, far from the 18480 lbs fuel stated to be in the F-35.
My numbers just don't add up, but thats presumably just me...
and, yes I know that his statement can be range from a cap or so, and that thate really isn't enough info to do any calculations, but still, I'm not convinced that it really can go that supersonic without AB


my 5 cent.
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sferrin

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Unread post05 Nov 2012, 15:02

linkomart wrote:but still, I'm not convinced that it really can go that supersonic without AB


my 5 cent.


So LM says it's cruised at Mach 1.2 armed without afterburner and you say they're lying because. . .?
"There I was. . ."
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SpudmanWP

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Unread post05 Nov 2012, 15:09

sferrin wrote:
linkomart wrote: you say they're lying because. . .?

He's LM...

I so called it ;)
"The early bird gets the worm but the second mouse gets the cheese."
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linkomart

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Unread post05 Nov 2012, 15:22

sferrin wrote:So LM says it's cruised at Mach 1.2 armed without afterburner and you say they're lying because. . .?


He (O'Bryan I presume) said "The F-35, while not technically a "supercruising" aircraft, can maintain Mach 1.2 for a dash of 150 miles without using fuel-gulping afterburners." and I'm just sceptical to if there is a caveat somewhere in that statement.

But sferrin you are right, he says that it cruises supersonic without using afterburner. Not saying straight and level, not saying at what weight, not saying at what ISA temmperature, not saying that the engine is ok afterwards. Not explaining how he got that range figure.
But one can assume that everything is standard and ok.

I'm just sceptical and don't believe everything I read on the internet....
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Conan

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Unread post05 Nov 2012, 15:33

linkomart wrote:
Conan wrote:You can argue that. Of course you have to put words into his mouth to do so.


Nae, I'm not really interested in putting words in to someone's mouth. What I want to do is to translate PR salesmans language in to easy to understand facts that me as a simple engineer can understand. Cause what's said by a salesman is not always exactly the truth, and if it have to be the truth, there is bound to be a caveat in a strange passus of the sentence that only a lawyer can understand and translate...

OK, a little rant, sorry about that.

It's just that, with the fuel volume of the F-35, the thrust of the engine and the supposed sfc (compared to for instance a F-100) the 150 mile range (not RoA) sounds too low for just going in military power.

150 mile (nautical) at M=1.2 is about 11 minutes.. give or take.
max thrust is (dry) 28000 lbf and with a SFC at about 0.89 that would be 28000 x 0.89 x 0.1875 = 4672 lbs, far from the 18480 lbs fuel stated to be in the F-35.
My numbers just don't add up, but thats presumably just me...
and, yes I know that his statement can be range from a cap or so, and that thate really isn't enough info to do any calculations, but still, I'm not convinced that it really can go that supersonic without AB


my 5 cent.


He said 150 miles (not nautical...) of dash. He didn't say ANYTHING about cruise, climb, joker or bingo fuel states or any such information you might need to accurately calculate things...

I would hope an engineer might wait for all the facts before starting his (said for convenience) calculating, but I guess we've seen other engineers be less picky about performing calculations for their "analysis" on the F-35 in a near complete absence of facts, so should we really be surprised it's happening again?

Mr O'Bryan is a Vice President of L-M. Not exactly sales level and he's an ex-USN F/A-18 Hornet driver to boot, so one might suggest he has an idea of what he's talking about, beyond merely the company line...
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sferrin

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Unread post05 Nov 2012, 16:16

linkomart wrote:
sferrin wrote:So LM says it's cruised at Mach 1.2 armed without afterburner and you say they're lying because. . .?


He (O'Bryan I presume) said "The F-35, while not technically a "supercruising" aircraft, can maintain Mach 1.2 for a dash of 150 miles without using fuel-gulping afterburners." and I'm just sceptical to if there is a caveat somewhere in that statement..


Not sure how it could say anything other than what it says. It's pretty clear.
"There I was. . ."
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wrightwing

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Unread post05 Nov 2012, 16:32

cola wrote: F16 also does dash supersonic in dry...that's not supercruising.


Not with 5,000lbs of weapons, targeting/jamming pods, and EFTs.
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Unread post05 Nov 2012, 16:43

falconedge wrote: :? what you mean ? , so in basic after the F-35 fly faster than mach 1.2 even if the pilot reduce thrust ,it still fly for 150 miles before decelerate to subsonic speed right ? :?


The afterburner is to break the sound barrier, not to maintain M1.2. Once thru the sound barrier, there's less drag to deal with, so dry thrust is sufficient to maintain speed.
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bigjku

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Unread post05 Nov 2012, 16:46

wrightwing wrote:
cola wrote: F16 also does dash supersonic in dry...that's not supercruising.


Not with 5,000lbs of weapons, targeting/jamming pods, and EFTs.


I think those last three things are what are really important. If you don't just count the weapons but the EW stuff the F-35 is carrying that is suddenly a lot of things you need hanging off your F-16 of F-15 or Eurofighter to make it do what the F-35 is doing.
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Unread post05 Nov 2012, 16:53

falconedge wrote:how far can the F-35 fly at top speed mach 1.6 ? , if it can only fly for 150 miles at mach 1.2 then the distance it can fly at mach 1.6 will even shorter right ?
btw even the F-22 which is designed to supercruise can only maintain mach 1.82 for 100 nm (185 km ) :shock: not very impress if go know that F-22's ferry range is over 3000 km :?


The F-22 supercruise range figures are generally given as a radius, not straight line distance. If the 150nm figure given is a radius, then the total distance at M1.2 might be as much as 300nm.
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m

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Unread post05 Nov 2012, 16:58

Remember I did read an article about the Swedish Saab Viggen. Flying at top speed, run out of fuel in less than five minutes.

Did some calculation. May I am wrong, but got this:

F22
mach 1.82 for 100 nm (185 km )

Mach 1.82 = 2229.5546 kilometers per hour / 1203.86317 nmi per hour

60 min = 3600 sec > 8,3% = 298.8 sec <> 4.98 min
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Unread post05 Nov 2012, 17:05

F35
Mach 1.2 for 150 miles (or 150 nmi?)

- 150 nautical miles = = 277.8 kilometers = 172 mi
- 150 miles = 241.401 km = 130.34644US nmi


Mach 1.2 = 1470.036 kilometers per hour / 793.75594 nmi per hour

150 nmi = 277.8 kilometers

60 min = 3600 sec > 10.2 % = 376.2 sec <> 6.12 min
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