Gripen - Red Flag

[Ozzy Blizzard]

aussie digger i doubt F-35 will be superior EF in air 2 air yes..

why? because no one have said it will be, and where ever i go, doesnt matter if i´s, LM or usaf webpage, all say the same, F-35 is a strike fighter with secondary air 2 air capabilities, and i don´t think EU, are so far behind USA that even their own Bomb plane are superior Europas best air 2 air fighter..

but like you, i can only assume.. and like you, i can be wrong!!

Geesh... Think for yourself on this one eh? F35's A2A capabilities may be 'secondary' but that deosent mean they will be inferior to a 4.5 gen platform that was a long way from a world beater in the first place. Think about the effect of VLO, AESA and first class offenceive EA (electronic attack) capability, vs a legacy airframe with les sophoitocated avionics and external payload. Theres a difference betwen what you want to beleive and whats reasonable. What exactly are you baseing this fantasy on? Thats its a "bomber", its no such thing, they called it Joint Strike Fighter for a reason. Gripen holds NO realistic advantages of any weight over the F-35 so how on earth is it going to be a better air superiority fighter? Remeber F-16's A2A capability was secondary aswell, you think an upgraded MiG 21 would stand a chance??? No friggin way...


@ Oryx....

AD did clearly state that said numbers were no were near accurate and were only achieved by some "back of the napkin" stuff which could only give a reough indication at best. Your only repeating what he said himself. Therefore whats your point?

As for the rule rant, perhaps you should look at the purpose of said rules. i.e. 1 lines seem to be ok as long as they contribute something, rather then them being that magic number one. If someone askes a direct question that only requires a one line answer then thats seems to be acceptable, just not the whole 'yeah i like that one too' post. Anyway who was "compleatly disrespectfull" towards an author? As for off topic, well we are still talking about gripen which i would argue is close enough. In fact some exapmles of breaches of rules 15 & 22 would be nice if you wanna make a stink about it?

Anyway i'm not a mod so i dont know but this is pretty much the way i found things opperate.

 

[Dr Freud]

For once, i saw something to remark on AD:!

I never said the F-35 "will" supercruise, but I believe it should be capable of doing so. However I do doubt the overall utility of it in the overwhelming majority of missions anyway

Here, i totally disagree with you.
Wether you A:want to intercept an aircraft, supercruise lets you hunt down the attacking aircraft and he can do one of two things: 1: cruise around and get shot down or 2: try to afterburn until empty fuel and eject.
or B: in attack, outrun the interceptor in your supercruise, mirroring mission A.
And it is just as important in a2a, you just can't hunt down a supercruiser.
And another thing: supercruise also helps you outrun missiles without depleting your fuel.

 

[Ozzy Blizzard]

For once, i saw something to remark on AD:!


Here, i totally disagree with you.
Wether you A:want to intercept an aircraft, supercruise lets you hunt down the attacking aircraft and he can do one of two things: 1: cruise around and get shot down or 2: try to afterburn until empty fuel and eject.
or B: in attack, outrun the interceptor in your supercruise, mirroring mission A.
And it is just as important in a2a, you just can't hunt down a supercruiser.
And another thing: supercruise also helps you outrun missiles without depleting your fuel.

Supercruise does not replace afterburning supersonic dash in the 'supercruisers', with the sole execption of the F22. Cruising at M1.2 instead of M0.9 does not change much tactically. You will still be sitting on you burner trying to better your position plenty. Thers no way you'll sit at M1.2 at mil power while the other guy is on his burner at M1.8 and achieveing a better position becasue it'll save you some fuel. So realistically in an engagement haveing a couple of hundred MPH higher cruise speed wont change much becasue you are going to be on your burner as much as the other guy. The only thing it really effects is transit times.

F-22A is a different story though, because the F119 provides Mach 1.5+ cruise speed, which is as good as most fighters supersonic dash. That means you can sustain those speeds for much longer. That definatly changes things from a tactical perspective. But for EF-2000 and JAS-39, it doesnt change much.

 

[Aussie Digger]

Four significant digits, just from that information? OK, you did say "around", but not "around Mach 2.1 or Mach 2.2", it is "around Mach 2.148". As someone working regularly with flight dynamics, performance prediction, applied aerodynamics and the flight testing of military aircraft, this one really hit a nerve. You can't even measure it that accurately, let alone predict it that accurately with the most advanced analysis software available. And you got that just from 2D drawings and available thrust (which, btw, is rounded to the closest 1000lbs and only valid for standard sea-level conditions, most likely also uninstalled thrust)? Even if you could cite a source for this number, I would not believe it as whoever came up with it originally doesn't understand how maximum speed is determined, evaluated or by which factors it is influenced.

Seems I've offended yet another Gripen fan. My, what a touchy lot...

Did I not clarify that there was just a "tad" more to it than what I posted? Ozzy seems to think I did...

All I mentioned was what speed the mach angle indicates. At no time did I claim this was the "be all and end all" of aerodynamics. As you yourself have pointed out the "maximum speed" of an aircraft is an incredibly difficult thing to predict yet entirely uniformed persons around here insist on referring to the F-35 as slow, heavy, "bomb truck" or some other ridiculous claim, they cannot support and do not even try.

I am aware that drag is much more important in attempting to determine the performance of an aircraft, however determining it is far more difficult, otherwise wind tunnels wouldn't be so popular...

My post was obviously therefore not intended to address the aerodynamics of the aircraft in a comprehensive manner. A simplistic analysis intended to help prove a point against entirely illogical comments.

Perhaps given your obvious understanding of such things, you'd care to share your opinion of these issues rather than simply criticise others?

Btw, Zeven, here is the US DoD's F-35 Joint Project office's website:

http://www.jsf.mil/index.htm

Have a look through at some point and show me where exactly it outlines that air to air capability is only a "secondary requirement".

 

[Dr Freud]

I can agree with you to some extent <50% ozzy, except the "save some fuel", i would say "save an ocean of fuel"

 

[Aussie Digger]

For once, i saw something to remark on AD:!


Here, i totally disagree with you.
Wether you A:want to intercept an aircraft, supercruise lets you hunt down the attacking aircraft and he can do one of two things: 1: cruise around and get shot down or 2: try to afterburn until empty fuel and eject.
or B: in attack, outrun the interceptor in your supercruise, mirroring mission A.
And it is just as important in a2a, you just can't hunt down a supercruiser.
And another thing: supercruise also helps you outrun missiles without depleting your fuel.

Firstly,

Supercruise offers a significant fuel burn penalty. Even the F-22 can only manage a 390nm range because of it and it's a massive fighter with massive internal fuel load. Using more thrust burns more fuel. Fighters cruise subsonically because extensive aerodynamic research shows that to be the most fuel efficient speed to fly at.

To me this shows that range is more important than speed...

The only aircraft in the world truly designed for sustained "supercruising" operations therefore has limited overall range when it makes use of this capability.

Imagine precisely what that does to other smaller aircraft with lower internal fuel fractions and no external tanks (because the more drag the more difficult "supercruise" becomes)?

Even aircraft such as Typhoon and Gripen which are allegedly "supercruise capable" have done so with minimal external stores (generally AAM's and a single tank at most, when during typical profiles they carry 3).

Big deal. So has the F-15, F-16 and F/A-18.

And every time you read about it, do you ever get the slightest mention of how long they can keep it up for? How far they can travel whilst supercruising? What effects the stress of this has on the maintenance required for the engines and airframe? The effects on the fragile weapons systems carried by all these aircraft, of being exposed to supersonic speeds so much longer?

Why there is little or no mention of supercruising being a design requirement or indeed barely ever mentioned before the F-22 demonstrated it's own capability to do so? Or why, if it's such an important capability, that EVERY fighter since the English Electric Lightning in the 1950's isn't supercruising (since it could)?

F-22 has been announced, possesses a 390nm range through supercruising. Have SAAB or Eurofighter Consortium published anything like that for their "supercruisers" cause I haven't found it...

Btw, if you think even F-22 pilots don't go to afterburner "during the merge", I'm afraid you need to re-read what they actually say about their own aircraft...

 

[Dr Freud]

I admit right away i didnt know F22 supercruise was a paltry 390 useless nm.
In fact i thought they didnt use that much more in supercruise then another plane in cruise.
Can anyone tell me the normal cruise speed of F22, and compare it with F35, EF, and Gripen ?
Until the introduction of lasers as the primary weapon, the fighter pilots axiom "speed is life" will remain

 

[Oryx]

AD did clearly state that said numbers were no were near accurate and were only achieved by some "back of the napkin" stuff which could only give a reough indication at best. Your only repeating what he said himself. Therefore whats your point?

My point was that you cannot write down four significant digits if you got them from back-of-the-napkin calculations, or from any other calculations for that matter. The very fact that you do it demonstrates a lack of understanding of what you did, at best, or an intentional attempt to mislead, at worst. I pointed it out here, because to the uninitiated reader all those significant digits may wrongly give him the impression that the author had some additional level of knowledge.

Unless he has access to much more information than he admitted to in this thread, he cannot possibly make a call more accurate than that the top speed of the aircraft in question is somewhere between Mach 1.5 and 2.5. As an example, an inlet that was not specifically designed for very high supersonic performance can quickly limit your maximum speed regardless of how good your static thrust to weight ratio looks. The same goes for other limits that people not directly involved with the project may not know, such as flutter limits, aerodynamic heating in certain areas, control system limitations, etc. There is no way you can look at a drawing, an engine spec, and come up with any accurate estimate of maximum speed. Some of the other performance parameters, yes; maximum speed, no.

About the inconsistency in applying the rules - its been bothering me a while as I've seen it in many threads on this site. As I said, I've never been a very active contributor here so no-one will miss me if I stop visiting here altogether, but I thought I may as well point it out in case other contributors that they do care about felt the same as me. If you see it as a "rant" without justification, I respect your opinion but disagree. I intentionally did not quote an example for each of my points, although I am sure most here will be able to find them, as I just wanted make them aware of the issue rather than get involved in a new discussion over whether each seperate "accusation" was true or not.

Thanks, Grand Danois, got it.

 

[Ozzy Blizzard]

My point was that you cannot write down four significant digits if you got them from back-of-the-napkin calculations, or from any other calculations for that matter. The very fact that you do it demonstrates a lack of understanding of what you did, at best, or an intentional attempt to mislead, at worst. I pointed it out here, because to the uninitiated reader all those significant digits may wrongly give him the impression that the author had some additional level of knowledge.

Unless he has access to much more information than he admitted to in this thread, he cannot possibly make a call more accurate than that the top speed of the aircraft in question is somewhere between Mach 1.5 and 2.5. As an example, an inlet that was not specifically designed for very high supersonic performance can quickly limit your maximum speed regardless of how good your static thrust to weight ratio looks. The same goes for other limits that people not directly involved with the project may not know, such as flutter limits, aerodynamic heating in certain areas, control system limitations, etc. There is no way you can look at a drawing, an engine spec, and come up with any accurate estimate of maximum speed. Some of the other performance parameters, yes; maximum speed, no.

Ofcource 2d basic shock wave calculations are not going to show you anything with real accuracy. IIRC that is exactly what he said. But it will give you a number (an inaccurate number) which happend to be M2.148. Now your absoloutly correct there are various other factors that limit top speed, intake design being a large one, however I think the intention was just to illustrate that the F-35 may not be limited to M1.6 after all.

About the inconsistency in applying the rules - its been bothering me a while as I've seen it in many threads on this site. As I said, I've never been a very active contributor here so no-one will miss me if I stop visiting here altogether, but I thought I may as well point it out in case other contributors that they do care about felt the same as me. If you see it as a "rant" without justification, I respect your opinion but disagree. I intentionally did not quote an example for each of my points, although I am sure most here will be able to find them, as I just wanted make them aware of the issue rather than get involved in a new discussion over whether each seperate "accusation" was true or not.

Thanks, Grand Danois, got it.

Well I would miss you.

There's not enough rational, knowledgeable, experienced posters around here. Allthough I disagree with you doesn't mean i would be happy if you stoped posting! Imagine how boaring this place would be if everyone agreed? As for the inconsitencies, well I think a little flexability is a good thing. If this had been called "Off Topic" becasue we were not talking about red flage, alot of interesting conversation would have been stifled. As for one liners, well I explained my position on that. If someone is being disrespectfull then I agree with you but i cant think of when or who it was.

 

[Ozzy Blizzard]

I can agree with you to some extent <50% ozzy, except the "save some fuel", i would say "save an ocean of fuel"

Then you missed my point. You wont save any fuel becasue you not going to sit on M1.2 while the other guy gains an advantage by useing his burner to achieve a better position. Then you would have saved some fuel, but you'd be dead.

Non F-22A supercruise of the likes of the Eurocanards is NOT a substitute for afterburning dash, but only sub-sonic cruise. Therefore in real terms its not going to save you any fuel, just some time.

 

[Dr Freud]

I should admit right away i don't know anything at all about tactical manouvers in a2a, like positioning, i'm not a fighter pilot. (i guess that, with some justification, you could call me an old disillusioned depraved shrink.) I do insist, however, that having higher/lower speed in cruise and military settings relative to the other plane makes one HELLUVA difference in catching/speeding away from the other plane. After aproximatly 120.000 simulations, it has been proven that:
If my cruise speed is less then his, i have to go to military, (wich cost A LOT more,) if he go military, -i have to go afterburn (wich cost A LOT more again then military,) and i'm very likely to lose, due to fuel shortage. This problem is even more important for a fighter then an attack aircraft, because an attack aircraft just need to keep it even to be safe, while the fighter needs to do better to get a shot at a fleeing target.(here you must also take into account how much longer your missile have to travel) It can also be assumed the fleeing target is getting closer to his base with every nm, while the fighter gettin farther away from his base with every minute of persue/guzzling, wich really messes up the whole thing. Needless to say, afterburn is useful only for a very short time.
Fighter pilots axiom no1: "speed is life"

 

[Aussie Digger]

My point was that you cannot write down four significant digits if you got them from back-of-the-napkin calculations, or from any other calculations for that matter. The very fact that you do it demonstrates a lack of understanding of what you did, at best, or an intentional attempt to mislead, at worst. I pointed it out here, because to the uninitiated reader all those significant digits may wrongly give him the impression that the author had some additional level of knowledge.

I can make an additional point or 2 with respect to the aerodynamic performance of the F-35 (or at least it's potential), but I fail to see the point of doing so, unless persons such as yourself who apparently DO possess such relevent knowledge, feel inclined to do so similarly...

Would "3" or "2" digits have made such a difference for such a simplistic discussion? I haven't seen a single poster include ANY equation to date on this board (including yourself) and yet here we are starting to discuss aeronautics!

I admit I am no aeronautical engineer, but I've done a bit of "learning" in relation to these matters, as they interest me...

Unless he has access to much more information than he admitted to in this thread, he cannot possibly make a call more accurate than that the top speed of the aircraft in question is somewhere between Mach 1.5 and 2.5. As an example, an inlet that was not specifically designed for very high supersonic performance can quickly limit your maximum speed regardless of how good your static thrust to weight ratio looks. The same goes for other limits that people not directly involved with the project may not know, such as flutter limits, aerodynamic heating in certain areas, control system limitations, etc. There is no way you can look at a drawing, an engine spec, and come up with any accurate estimate of maximum speed. Some of the other performance parameters, yes; maximum speed, no.

Perhaps you'd care to comment on the divertless intakes on the F-35, with the effect that they will have on the aircraft's (potential) speed then?

It's awfully easy to criticise afterall...

About the inconsistency in applying the rules - its been bothering me a while as I've seen it in many threads on this site. As I said, I've never been a very active contributor here so no-one will miss me if I stop visiting here altogether, but I thought I may as well point it out in case other contributors that they do care about felt the same as me. If you see it as a "rant" without justification, I respect your opinion but disagree. I intentionally did not quote an example for each of my points, although I am sure most here will be able to find them, as I just wanted make them aware of the issue rather than get involved in a new discussion over whether each seperate "accusation" was true or not.

Thanks, Grand Danois, got it.

As a Mod, I can tell you that IF we applied the rules consistently, rather than attempting to be fair, the majority of posts would be edited, if not deleted...

Still I take your criticism on board. If I feel inclined in future to take umbrage at a particular claim, I'll do my homework a bit more thoroughly first, okay?

 

[Grand Danois]

OK, I'll introduce a little amateurish calculation!

It was asked earlier what the range of the F-35 was to the Gripen NG with a similar mission and loadout, ie 600 nm and 90 min cap with 4 aam. However the ranges given are for dissimilar missions!

From the JSF presentation to Norway:

Optimal Cruise
Maritime Patrol Mission
Sensors Employed:
! EW
! Radar
! EOTS
Weapons Load:
!AIM-120 (2)
!GBU-12 (2)
!Internal Gun
!Countermeasures
The resulting radius is 740 nm
(or total distance of 1480 nm)
The range of altitudes during the
cruise is 33,200 ft to 40,400 ft


I have no books on aeronautical engineering on my bookshelf, so I'll use an equation for range by jet propulsion from wikipedia; it seems the conditions fits for a first order approximation for the cruise part:

When cruising at a fixed height, a fixed angle of attack and a constant specific fuel consumption, the range becomes http://en.wikipedia.org/wiki/Range_(aircraft).

Range 2k lbs munitions (R_2k) = 1480 nm

Question: What is range for F-35A with 4 AAMS or R_aam?

OK dump the 2 x 2k ordnance, replace with 2 x AIM-120 at 335 lbs apiece. This would shave ~3300 lbs off take-off weight. 29k empty plus 18.5k fuel plus 1.5k ordnance = 49k lbs take-off.

Assuming all else being equal, reduce and solve the equation, it boils down to:

R_aam = (((sqrt(W_aam1)-sqrt(W_aam))/(((sqrt(W_2k1)-sqrt(W_2k2))) x 1480 nm

W_2k1 = 52.5k lbs
W_2k2 = 34.0k lbs

W_aam1 = 49.0k lbs
W_aam2 = 30.5k lbs

R_aam = (((sqrt(49000)-sqrt(30500))/((sqrt(52500)-sqrt(34000)) x 1480 nm = 1546 nm

So the F-35 has a range in excess of 1200 nm of 346 nm. If the advantage of not having to get to altitude with 2 x 2k lbs munitions is taken ito account, it seems that the F-35 has a similar range performance with 4 aams to the Gripen NG with 4 aams and at least 1 external tank. Approx 90 min @ 600 nm. Perhaps even slightly less - but we don't know the excess range of the original 1480 nm number for the F-35 either, so the 1546 nm is probably a minimum.

Edit: Alright, forgot to take reserve fuel when landing into account, but don't care enough to do it over again. If anyone wish to take a shot at adding detail or correct, you're welcome.

Edit 2: Just remembered that the GBU-12 is not a 2 k lbs piece of ordnance! It has to be done all over again. :

 

[Dr Freud]

Thank you GD for this effort to bring some light over this vital matter
I'm havin a hard time here though believing that tiny Gripen can even begin competing in range.
Until proven wrong, i will have to assume Gripen NG must mean a longer version.(wich i honestly dont believe is forthcoming)

 

[Dr Freud]

DR. Freud.

the NG frame is build from an existing A/B frame, it´s no major changes we´re talking about here. so no, it is the SAME airframe as the A/B version

Damn....i did it again! i thought it was concering Gripen N. one of these days i'm goin to cut down on beer. and thats a promise!

 

[Dr Freud]

I Have quietly read this thread for a while now, with some amusement I have to say.

Well.... some are amused about declining standard of applying rules, some are "very disappointed with this"...

 

[zeven]

Dr, Freud,

the Demo flight will occur, 23rd of March, this year.

 

[Dr Freud]

Still i dont get it, how can that small aircraft have that combat range
anyone feel free to explain how that can be...
It just defy logic. IMHO

 

[zeven]

Dr,Freud,

good aero dynamics, light, increased internal fueltank, small egnine.

thousends of reasons..

 

[Dr Freud]

I hope SAAB had the decency to give the engineers a really good tip!