Gripen NG supercruzin for a bruzin

[Vivendi]

Not meaning to put words into AD's mouth but what he posted was the following...



He did not specifically mention here that a requirement of useful supercruising was that it be done while carrying A2G munitions. What he did mention was that a large external load had to be able to be carried while supercruising for the capability to be useful, and therefore worth claiming as a feature of the Gripen.

AD said:

I then went on to say that until Gripen has demonstrated an ability to supercruise with a large external load, then I will be impressed.

The reason for this is simple. It's a multi-role fighter. If it can't "supercruise" when it's carrying A2A and A2G munitions, external sensor pods (ie: Litening) PLUS the fuel load it will likely carry in combat situations (2-3 external tanks) then it's ability to supercruise, is in reality, irrelevent.

AD focused on the fact that as a multirole fighter it should be able to carry both a2a and a2g munitions, an external sensor pod PLUS 2-3 external tanks, and that only in a multirole configuration (that is both a2a and a2g) supercruise is interesting.

My point was that in a lighter a2a role, the Gripen supercruise sounds feasible; I also think it could be of interest, e.g., in a2a situation with the future SU-35 which also claims some limited supercruise capabilities.


Having said that, I agree that supercruise as such is probably not very significant in any case -- other features, such as sensors, EWS, networking, man-machine interface, and VLO are more important. However, when AD makes statements I disagree with (or don't understand), I feel a strong urge to comment... even if the feature being discussed is probably not very significant in the grand scheme of things.

V

 

[Vivendi]

On top of this, I can't find anywhere in newspapers or other media, reports of Gripen's flying supersonically over residential areas, either.

Now, that doesn't mean it didn't happen, doesn't even mean it wasn't reported (my Google fu, might be playing up) but I KNOW that supersonic aircraft flying over residential areas, causes significant damage and destruction.

This is the sort of thing I am talking about. It's the result of flying supersonically over residential areas:

http://www.ledger-enquirer.com/news/story/662943.html



But that's exactly what your source said:



And yet, no-one apparently complained and no damage was caused.

Amazing.

Or complete crap...

http://www.patentstorm.us/patents/7416155/claims.html

What is claimed is:

1. A supersonic aircraft comprising: a fuselage extending forward and aft; wings coupled to lateral sides of the fuselage; and canards coupled to lateral sides of thefuselage forward of the wings, the individual canards being configured to generate shocks that wrap around the fuselage and intersect with wing leading edges on opposing sides of the fuselage.

2. The aircraft according to claim 1 further comprising: the individual canards being configured to cause a shock cancellation effect whereby leading edge suction and/or expansion is canceled by the canard-generated shock wrapped around thefuselage.

3. The aircraft according to claim 1 further comprising: the canards coupled at a position on the fuselage forward of the wings and at an elevation that attains a target equivalent area distribution for low sonic boom whereby active areadistribution reduces sonic boom amplitude at ground level.

4. The aircraft according to claim 1 further comprising: the canards configured with sufficiently high dihedral that enhances aircraft lifting length to attain a target equivalent area for low sonic boom and that enables asymmetric differentialcontrol on canards on opposing aircraft sides for lateral directional mode control.

5. The aircraft according to claim 1 further comprising: an inverted V-tail coupled to the fuselage aft of the canards and forming a channel; and the canards configured with positioning and structure whereby wing tip vortices from the canardspass through the inverted V-tail channel, avoiding impingement on leading edges of the wings and the inverted V-tail.

6. The aircraft according to claim 5 further comprising: the canards configured with positioning forward of the wings and the inverted V-tail arranged in combination whereby the aircraft center-of-gravity and center-of-pressure align tomaintain trim and have an equivalent area due to lift distribution to attain a minimum sonic boom signature.

7. The aircraft according to claim 1 further comprising: the canards comprising an all-moving surface whereby an entire canard moves and/or rotates in relation to the fuselage.

8. A supersonic aircraft comprising: a fuselage extending forward and aft; wings coupled to lateral sides of the fuselage; canards coupled to lateral sides of the fuselage forward of the wings and having controllable aerodynamic surfaces; and a controller coupled to the canards and adapted to control the canard controllable aerodynamic surfaces, the canards being configured and controlled to generate shocks that wrap around the fuselage and intersect with wing leading edges on opposingsides of the fuselage.

9. The aircraft according to claim 8 further comprising: the canards being configured and controlled to cause a shock cancellation effect whereby leading edge suction and/or expansion is canceled by the canard-generated shock wrapped around thefuselage.

10. The aircraft according to claim 8 further comprising: an inverted V-tail coupled to the fuselage aft of the canards and forming a channel; and the canards configured with positioning and structure and controlled by the controller wherebywing tip vortices from the canards pass through the inverted V-tail channel, avoiding impingement on leading edges of the wings and the inverted V-tail.

11. The aircraft according to claim 10 further comprising: the canards configured with positioning forward of the wings and the inverted V-tail arranged in combination whereby the aircraft center-of-gravity and center-of-pressure align tomaintain trim and have an equivalent area due to lift distribution to attain a minimum sonic boom signature.

12. The aircraft according to claim 8 further comprising: the canards configured with sufficiently high dihedral that enhances aircraft lifting length to attain a target equivalent area for low sonic boom; and the controller adapted toasymmetrically and differentially control canards on opposing aircraft sides for lateral directional mode control.

13. The aircraft according to claim 8 further comprising: the individual canards being configured to cause a shock cancellation effect whereby leading edge suction and/or expansion is canceled by the canard-generated shock wrapped around thefuselage.

14. The aircraft according to claim 8 further comprising: the canards comprising an all-moving surface; and the controller moves and/or rotates an entire canard in relation to the fuselage.

15. A method for implementing canards on an aircraft comprising: performing a multiple-variable analysis of flow fields produced by an aircraft including a fuselage with canards and wings coupled to lateral sides of the fuselage; andconfiguring the canards to generate shocks that wrap around the fuselage and intersect with wing leading edges on opposing sides of the fuselage based on the multiple-variable analysis.

16. The method according to claim 15 further comprising: performing the multiple-variable analysis whereby the number of variables is equal to the number of objectives, including analysis of variables comprising horizontal canard position inrelation to the wings, vertical canard position on the fuselage, canard incidence and twist, canard dihedral, canard span and aspect ratio, and canard reference area.

17. The method according to claim 15 further comprising: selecting a range of canard surface area that attains a predetermined trim and stability condition; selecting canard vertical position on the fuselage that attains a selected lift and aselected aircraft equivalent area stretch; and selecting canard longitudinal position relative to the wing leading edge that opposes wing side expansion.

18. The method according to claim 17 further comprising: selecting canard dihedral whereby a vortex from the canard trailing edge passes interior to a tail channel of the aircraft and avoids striking leading edges of the wings and tail.

19. The method according to claim 15 further comprising: selecting canard longitudinal and vertical positioning whereby a shock or expansion from the canard trailing edge cancels the expansion or shock generated at a leading edge of the wing onan opposite side of the fuselage from the canard.

20. The method according to claim 15 further comprising: performing a shock cancellation analysis by applying computational fluid dynamics to trace a shock and analyzing inverse Mach cone characteristics for a linear flowfield from a leadingedge of the wing.

Other References
http://www.faqs.org/docs/air/avgrpn.html, the gripen aircraft.

Do you wish to actually have a discussion, or is your mind already closed on the issue?

Well put...


V

 

[caprise]

Thanks Vivendi! Hadn't seen that before.

C.

 

[yoron]

What I believe to be the reason for the RS military not to discuss those things (like specific super cruising abilities) is exactly what viperfan writes here. No matter what rank anyone might have on this forum, real or not

"viperfan wrote:

The Swedish Air force has for decades gone to great lengths to officially undersell the capability of their jets especially about range and altitude. Keeping much of the general capability a secret (such as the datalinks they used already back on Draken) considering the warzaw pact next door. Even the JAS 39A and B models has a widely unknown war setting on the fuel tanks to "topfill" them by another 14%.

Bill... Gripen NG @ 7000 kg empty vs the F-16C empty @ 8936 kg. Internal fuel on the NG would be a pint more than the F-16C. But still, the NG is almost 2000 kg lighter with a more low drag airframe. Thrust to Weight is equal.

Can't speak for the JSF but the Gripen should at least be quite a lot more fuel effective than the F-16C. Not taking engine modes and altitude etc into account."

 

[Marc 1]

Bill... Gripen NG @ 7000 kg empty vs the F-16C empty @ 8936 kg. Internal fuel on the NG would be a pint more than the F-16C. But still, the NG is almost 2000 kg lighter with a more low drag airframe. Thrust to Weight is equal.

Can't speak for the JSF but the Gripen should at least be quite a lot more fuel effective than the F-16C. Not taking engine modes and altitude etc into account."

So the NG has a lower drag airframe? I confess I cannot see it - do you have any stats to back that claim up?

Also, what do you mean by fuel effective? Are you talking about the rate for fuel consumption?

 

[SlyDog]

I think some points must be clarified.

The fuel efficiency for F414 are stated to be somewhat better than for RM12.

Gripen NG demonstrator have approx. 1 inch wider air intake than Gripen C

Weight difference between RM12 and F414* (don't know what version of F414) is something like....15 kg maybe. Not a big issue really.

As I have understand, the engine upgrade was already envisioned during the early stages in the development of Gripen. That might explain how the "Gripen NG-demonstrator" could be build that fast and relatively cheap.

 

[Aussie Digger]

http://www.patentstorm.us/patents/7416155/claims.html

And? Are you suggesting the Gripen doesn't create a sonic boom when it flies supersonically?

Well put...


V

As to my earlier comment, I don't believe for one second the Gripen does have a useful supercruise capability, in any operational configuration.

The engine and airframe simply isn't designed for it ("a surprise" like that to the designers, would reflect rather poorly on their competence) and whilst it might be able to "demonstrate" a capability in a narrow supersonic test area with a clean ore near clean airframe, it ain't going to be clean in combat and therefore this claim is relatively meaningless, unless your job is to sell Gripens.

 

[Aussie Digger]

Also AD: About The air intakes, they were modified. Not so hard to do thanks to the design philosophy of Gripen. The intake module was simply replaced with a bigger one. Something that was planned from the beginning.

Regards C.

Edit: Spelling

I wasn't suggesting the inlet design couldn't handle the airflow required for the engine...

I was suggesting the inlet design and ducts would have to be modified to deal with the supersonic air flowing into the engines.

Turbofans need to have subsonic air flowing in to them...

 

[Vivendi]

And? Are you suggesting the Gripen doesn't create a sonic boom when it flies supersonically?

No of course not; I am suggesting that the boom may be less adverse and less likely to cause damage; in combination with the dispersed population of Sweden, it makes the story you found rather unbelievable, more credible.

V

 

[Vivendi]

I wasn't suggesting the inlet design couldn't handle the airflow required for the engine...

I was suggesting the inlet design and ducts would have to be modified to deal with the supersonic air flowing into the engines.

Turbofans need to have subsonic air flowing in to them...

Are you suggesting the current Gripen cannot fly supersonically?

V

 

[freethinker]

In the Indian promo vid for Gripen NG the test pilot talks about how easy the Gripen is to handle while supercruising so its obviously a feature they are happy with. (Or i guess they wouldnt boast about it)

 

[caprise]

Turbofans need to have subsonic air flowing in to them...

Isn't the deceleration of air to a low-speed at the compressor face needed regardless the use of afterburner or not(supersonically)?

C.

 

[Aussie Digger]

In the Indian promo vid for Gripen NG the test pilot talks about how easy the Gripen is to handle while supercruising so its obviously a feature they are happy with. (Or i guess they wouldnt boast about it)

They also want to sell India 126 Gripens, far more than ALL the Gripens exported to date. What does the Gripen have going for it, apart from alleged low cost, that the other entrants in MRCA don't?

Range and payload? Negative.

Independence in usage? Negative. Sweden is worse than the USA with it's end-user requirements and you need US permission anyway, or your Gripen won't have an engine.

Avionics and sensor system advantage? Negative.

They have to come up with something, don't they?

Until a contract is signed, any military capability is described publicly as all singing all dancing with no possible flaws whatsoever.

Once a capability is actually locked in for acquisition, the claims tend to become rather more realistic...

 

[Aussie Digger]

Are you suggesting the current Gripen cannot fly supersonically?

V

Not at all. I'm merely suggesting that the Gripen is not designed for extensive and sustained supersonic flight.

It is an aircraft that, like all 4th gen's, happens to be optimised for sub-sonic cruise profiles, with supersonic dash capability, and perhaps a limited ability to "supercruise" a short distance at a relatively low mach number, with very light or no stores only and most likely only with the assistance of reheat to pass through the transonic range.

Unlike those, who barely or don't even understand what some of these terms mean, I don't think the Gripen's performance alone, offers it a decisive advantage over other 4th Gen fighters and most definitely not over the current 5th Generation aircraft.

What I'm interested in, in fighter aircraft or any other military platform is USEABLE operational capability.

Flying Cobra maneuvres at airshows and performing a 60nm (more or less) supercruise run, with virtually no stores, proves absolutely nothing about combat capability.

Seriously thinking it does, shows a complete lack of understanding of modern combat, especially air combat.

Cheers.

 

[Aussie Digger]

No of course not; I am suggesting that the boom may be less adverse and less likely to cause damage; in combination with the dispersed population of Sweden, it makes the story you found rather unbelievable, more credible.

V

The problem that I had with it, is the good Colonel explains quite distinctly how they were regularly flying supersonically over residential areas.

Another issue with this claim, is that Gripen, like every other modern jet, displays it's mach airspeed in the HUD, and possibly in HMS, if in fact, Sweden's Gripens are so equipped (I'm not sure of that, offhand).

We are therefore required to believe that;

1. Not only is the Gripen aerodynamic performance so amazing that pilots are surprisingly finding themselves flying supersonic, (apparently passing through the transonic range goes completely unnoticed in the Gripen too... ) over residential areas on the ground AND the Gripen is of such an amazing and advanced design that it has such a low sonic boom, that no-one living in these residential areas has ever complained, nor has this issue apparently ever been brought to any media attention, outside a Gripen marketing article...

but, if all this is not unbelievable enough;

2. The Swedish airforce pilots flying these Gripens are regularly not paying attention to information provided to them in their Head up displays!

I wonder what the "enthusiastic nationals" will say about this? :lul

Call me a sceptic, but the more one REALLY looks into these claims, the shoddier they are becoming...

 

[freethinker]

They also want to sell India 126 Gripens, far more than ALL the Gripens exported to date. What does the Gripen have going for it, apart from alleged low cost, that the other entrants in MRCA don't?

Range and payload? Negative.

Independence in usage? Negative. Sweden is worse than the USA with it's end-user requirements and you need US permission anyway, or your Gripen won't have an engine.

Avionics and sensor system advantage? Negative.

They have to come up with something, don't they?

Until a contract is signed, any military capability is described publicly as all singing all dancing with no possible flaws whatsoever.

Once a capability is actually locked in for acquisition, the claims tend to become rather more realistic...

Well the final specs of all next gen planes is anybodys guess at this point.
However i dont agree about the export restrictions. I guess the US could keep us from selliing the plane to Iran for example but its highly unlikely they would interfere with possible sales to "allied" countries. And in any case sweden is free to transfer whatever technology they want whereas the US is not. Oh and there are no obtuse strings attatched.

Personally im really looking forward to see some real proven specs from both manufacturers. And i dont doubt the JSF will be a great fighter.

 

[yoron]

Am I correct in assuming that you see your own estimate of Gripen as more correct then that Saab's pdf from 2001 and others contributions (India f ex.) showing that it do have 'supercruising" abilities AD? Doesn't A2A count here? As for the rest of its capabilities we all know that they are classified. But its linkingsystem that is others aircrafts first generation we have used since Draken my friend. And our new ASEA radar have the ability to 'see' stealthed aircrafts due to the 'electromagnetic holes' they will create in the air flying under stealth. It will be aircrafts in 'passive mode', getting their positions, lock and shoot. You can't jam our linking system, at least as far Saab and our 'radar division' is concerned, they gave refined that system for fifteen years now. And its not really a 'generation anything' when it comes to its electronics, we were the first ever doing any linking.

Our new Gripen will see a F35 JSF coming at least as fast as it will be able to see a Gripen, and that is in good time before any need to shoot. Take a look here about what the JSF stealth might be http://www.scribd.com/doc/2460745/The-Radar-Game-Understanding-Stealth-and-Aircraft-Survivability We choose away any increased 'stealth', due to that it generally cost a aircraft its flight performance, creates a small weapon load, combined with a higher fuel consumption. And if it comes to a dogfight? Which plane would you prefer..

 

[F-15 Eagle]

I want to know if the F-35 will be able to maneuver like the F-15 or F-16. Yeah its a 9G fighter but thats only one small part, what about AoA and will the F-35 be able to do the areal combat maneuvers that the F-15 and F-16 can do? I hope so...

 

[Vivendi]

The problem that I had with it, is the good Colonel explains quite distinctly how they were regularly flying supersonically over residential areas.

Another issue with this claim, is that Gripen, like every other modern jet, displays it's mach airspeed in the HUD, and possibly in HMS, if in fact, Sweden's Gripens are so equipped (I'm not sure of that, offhand).

We are therefore required to believe that;

1. Not only is the Gripen aerodynamic performance so amazing that pilots are surprisingly finding themselves flying supersonic, (apparently passing through the transonic range goes completely unnoticed in the Gripen too... ) over residential areas on the ground AND the Gripen is of such an amazing and advanced design that it has such a low sonic boom, that no-one living in these residential areas has ever complained, nor has this issue apparently ever been brought to any media attention, outside a Gripen marketing article...

but, if all this is not unbelievable enough;

2. The Swedish airforce pilots flying these Gripens are regularly not paying attention to information provided to them in their Head up displays!

I wonder what the "enthusiastic nationals" will say about this? :lul

Call me a sceptic, but the more one REALLY looks into these claims, the shoddier they are becoming...

I looked at the source document: it says:

“There was one interesting problem,” Colonel Eldh concludes with a smile. “Gripen is supersonic at all altitudes and can cruise supersonically with an external load including fuel tank, four AMRAAM and two sidewinder missiles without the need to engage the afterburner“In the early days of operations, we found some pilots inadvertently flying supersonic over populated areas. The problem was one of habit, as these pilots had their throttle settings as high as on the older-generation fighters that Gripen replaced. “It is fair to say there were a few startled people on the ground, as their day-to-day work, or perhaps sleep, was disturbed by unexpected sonic booms! It was, of course, a simple task to solve the problem – the throttles were re-set and everyone was happy.”


It says this happened "in the early days", and that this happened because the pilots were used to flying older a/c that did not have the "problem" of going supersonic.

Finally, it says that the "problem" was fixed by adjusting throttle settings. Thus, after adjusting the throttle settings of the Gripen "in the early days", presumably the problem was strongly reduced (but probably not completely eliminated).

Where does it say it happened "regularly" as you claim?

I agree with you that going supersonic without using the A/B with one drop-tank, 4 AMRAAMs and 2 sidewinders is rather surprising -- perhaps that's why, "in the early days" this happened -- the pilots themselves probably did not believe that they would go supersonic with such a load...

V

 

[AndiPandi]

...
The early start to it's data-link technology is often lauded and rightly so, but it's hardly relevant now. Data-link technology has caught up and even Gripen's international sales are delivered with Link 16/MIDS rather than Sweden's proprietary link system.

TIDLS and Link-16 are two completely different systems! TIDLS can be used to fuse raw radar data and makes it possible for two or more Gripen to track an enemy in situations where one Gripen cant. AFAIK Link 16 does not have that capability. The only reason for having Link 16 in Gripen is NATO compatibility.

Yes, this will be a necessity against LO/VLO targets. With the new AESA antenna, this capability will be further improved

Eurofighter just recently demonstrated this capability.
http://eurofighter.com/news/20090104_AMRAAMFiring.asp

No, that is not the same. In this example there was only one radar active. The question was about using several radars together "as one".

Chuck on 2x 2000lbs weapons, 2x AMRAAM, 2x IRIS-T, a targetting pod of your choice, 2-3x external fuel tanks and then demonstrate a supercruise speed of M1.2 for a considerable part of the entire flight .

3 drop tanks and 2x2000 lbs weapons is impossible at any speed.

No air to ground weapons in that load and only one centreline fuel tank and limited wing mounted stores. (AMRAAMs are only 335lbs each and sidewinders 180lbs each).

Hardly "fulll air 2 air / air 2 ground configuration".

Well, on the Gripen A/B/C/D it IS the full AA configuration.
I agree that supercruise capability only is relevant with some weapons, but does it have to be max payload to be impressive? The Mach 1.7 supercruise speed on the F-22 is hardly achieved with maximum payload (external store).

On top of which, anecdotal reports around the place, claim that Gripen is only able to "supercruise" provided it uses it's afterburner to pass through the transonic region, achieve supersonic speed and then switch the afterburner off and maintain it's supersonic speed, on dry thrust only at that point.

I think you have misunderstood the term "transonic region". You dont have to pass through the entire transonic regime to fly faster than Mach 1.

I might add uncharitably, waited until the F-22 went into service, before announcing such a capability...

The statement that Gripen can supercruise came in 2001, the F-22 became operational in December 2005.

...
Is the Gripen C/D (as we are talking about 2001) capable of transiting through the transonic region, between sub-sonic and supersonic flight on dry thrust (otherwise known as mil power) only?

Again, the transonic region is not "between" subsonic and supersonic speed. I think you earlier defined supercruise speed as Mach 1, the transonic region is between Mach 0.9 and 1.2 (normally) which mean that accordning to your own definition of supercruise, the aircraft does not have to pass through the transonic region.

Now, that doesn't mean it didn't happen, doesn't even mean it wasn't reported (my Google fu, might be playing up) but I KNOW that supersonic aircraft flying over residential areas, causes significant damage and destruction.

At sea-level yes, at 30000 feet no!
(I googled "ljudbang jas" and found a couple of sonic boom complaints from 2007 and 2008)

The problem that I had with it, is the good Colonel explains quite distinctly how they were regularly flying supersonically over residential areas.

Thats not what he said!
The colonel said: "In the early days of operations, we found some pilots inadvertently flying supersonic over populated areas. The problem was one of habit, as these pilots had their throttle settings as high as on the older-generation fighters that Gripen replaced. It is fair to say there were a few startled people on the ground, as their day-to-day work, or perhaps sleep, was disturbed by unexpected sonic booms! It was, of course, a simple task to solve the problem – the throttles were re-set and everyone was happy.”

Thats not really the nation wide sonic-boom disaster of yours...

Another issue with this claim, is that Gripen, like every other modern jet, displays it's mach airspeed in the HUD, and possibly in HMS, if in fact, Sweden's Gripens are so equipped (I'm not sure of that, offhand).

We are therefore required to believe that;

1. Not only is the Gripen aerodynamic performance so amazing that pilots are surprisingly finding themselves flying supersonic, (apparently passing through the transonic range goes completely unnoticed in the Gripen too... ) over residential areas on the ground AND the Gripen is of such an amazing and advanced design that it has such a low sonic boom...

...

You dont have to pass through the transonic range to get a sonic boom and I dont find it hard to believe that a former Viggen pilot reaches Mach 1.0 in a Gripen instead of 0.9+ by setting the throttle to the same position he always has done. And what do we know about when the transonic regime starts for the Gripen? The transition to supersonic flight could be more smooth than for example the Viggen?



I think the question is if the F-414 is designed to fly for any longer periods of time at Mach 1.1-1.2. Hopefully SAAB will reveal more about the supercruise capabilities as the flight testing continues.