SAAB Gripen and Gripen NG thread #4

Profile picture for user obligatory

Member for

11 years 1 month

Posts: 6,983

significant weight is reduced when built from ground up vs re-welding, even if the same material were to be used,
which they arent, air intake this time around is composites.
E also has slightly more wing area.

Profile picture for user FBW

Member for

7 years 11 months

Posts: 3,106

significant weight is reduced when built from ground up vs re-welding, even if the same material were to be used,
which they arent, air intake this time around is composites.
E also has slightly more wing area.

Ah, so without Gripen 39-10 in the air, and even with SAAB stating that the estimated weight is now roughly 2,000lbs heavier than initially stated, you think that the production versions will be lighter? BTW, having slightly more wing area may help keep some of the initial Gripen agility, but it most certainly will not help acceleration.

Member for

7 years 4 months

Posts: 3,156

significant weight is reduced when built from ground up vs re-welding, even if the same material were to be used,
which they arent, air intake this time around is composites.
E also has slightly more wing area.

http://saab.com/globalassets/commercial/air/gripen-fighter-system/gripen-for-brazil/pdf-gripen-ng/gripen-ng-brochure.pdf

Gripen NG

Empty weight, 8,000kg. Thrust, 98KN. Internal fuel, 3,400kg.

F-35A

Empty weight, 13,200kg. Thrust, 191KN. Internal fuel, 8,390kg.

Member for

11 years 4 months

Posts: 516

The Finns can buy as many aircraft as they want & they are not limited to air to air. The limits referred were established by the Treaty of Paris in 1947. Finland declared in 1990 that the treaty restrictions were no longer valid. None of the other signatories responded, thus indicating that they accepted the nullification, so the relevant clauses no longer apply.

The lack of response does not mean consent, in my humble opinion specialty when it comes about diplomacy manners, indeed the silence can be itself as complete denial, once the other side has been signaling it will not put this issue on the table.

I do not know if the F/A 18 C/D Finland has been received weapons for ground or anti ship missions, also I do not know if Russia would consider this treaty as valid today.

However I guess if this treaty has not been officially broken by all parties, at least it would be appropriate to analyze the implications of this, before stating that there will be no obstacles for the Gripen NG or other fighter that could be equipped for ground and anti ship missions in Finland.

In this case this treaty still valid, the greater implication would be that fighters from 4.5 ° generation will not at the beginning of conflict an anti radiation missiles against SAM with long range capabilities , both in land and on ships.

In the case of fighters from 5° generation these could suffered less with this threat since it would not be detected and hit by SAM that has been fired at long range.

If the treaty has been valid for one side, in fact there are serious implications when the Finland will choice its fighters to replace the F/A 18 C/D, because of the weapons that could be available for its missions.

Member for

11 years 4 months

Posts: 516

significant weight is reduced when built from ground up vs re-welding, even if the same material were to be used,
which they arent, air intake this time around is composites.
E also has slightly more wing area.

The Gripen Demo was such great idea, as it has been allows to trial several systems and subsystems from Gripen NG, however Gripen Demo is only the Gripen Demo.

The Gripen Demo has been using the Gripen C / D structure, since this were modified for this purpose, but it is still Gripen C / D structure.

About putting a more powerful and weight engine as well as fuel , along more useful load, the Gripen C/D structure as well as the Gripen Demo will be under a higher stress than the original Gripen C / D.

In this case it should have been possible for that this higher stress would be within the safety margin, but will put up of the values ​​from Gripen C / D.

So the biggest difference between the Gripen Demo and the Gripen NG should be the last one will have its structure has been reinforced to support a useful life of 8000 hours or 30 years, while the Gripen Demo could be limited for something like 2000 hours.

However this reinforced structure from Gripen NG could increase the weight relative to the Gripen Demo, indeed this is a strong possibility , but another simple possibility would be that such new material could offers lighter weight but with the same load, or even new process to assemble this structure.

Each project has been keep its reliability, but in general even small increases of the stress in the same structure always cause a reduction in useful life.Anyway if the stress will getting closer the safety limit, the useful life will be reduced in such rate several times high than the value of the increased stress.

There is no linear relationship between stress and useful life , but exponential. Because of this each project has been required its own solution for this problem.

So it would be interesting to wait for the actual data of the new Gripen NG.

Member for

10 years 8 months

Posts: 208


So it would be interesting to wait for the actual data of the new Gripen NG.

Agreed, will be very interesting to see final weight!! I hope and expect that weight will be significantly below 8000kg, however for now these are hopes only.

What I know of so far in regards to weight,
A) Increase
+Larger airframe ? kg
+Heavier Engine (66 kg)
+More Avionics (IRST 30kg extra, new cooling system, new radar 59kg extra, PAWS-2 ~20kg, satcom ?kg)
+ More RAMs ??? If present at all ??kg
=Total known increases 175kg

B) Weight reductions
-Much better manufacturing techniques and 15 years of new material developments

A-B =???

Profile picture for user eagle

Member for

19 years 11 months

Posts: 2,266

I do not know if the F/A 18 C/D Finland has been received weapons for ground or anti ship missions, also I do not know if Russia would consider this treaty as valid today.

The have received A/G weapons. I don't know however if they've redesignated their F-18s as F/A-18s ;)
--> Large pic.
More pictures in this gallery.

Member for

7 years 4 months

Posts: 3,156

Agreed, will be very interesting to see final weight!! I hope and expect that weight will be significantly below 8000kg, however for now these are hopes only.

What I know of so far in regards to weight,
A) Increase
+Larger airframe ? kg
+Heavier Engine (66 kg)
+More Avionics (IRST 30kg extra, new cooling system, new radar 59kg extra, PAWS-2 ~20kg, satcom ?kg)
+ More RAMs ??? If present at all ??kg
=Total known increases 175kg

B) Weight reductions
-Much better manufacturing techniques and 15 years of new material developments

A-B =???

One can always hope, but Saab is already saying 8,000kg and planes do not generally get lighter as they proceed through development.

Profile picture for user swerve

Member for

14 years 6 months

Posts: 13,433

The lack of response does not mean consent, in my humble opinion specialty when it comes about diplomacy manners, indeed the silence can be itself as complete denial, once the other side has been signaling it will not put this issue on the table.

You are right to express humility when stating your opinion, since it is wrong. International law is clear. When Finland stated that it was unilaterally cancelling the clauses of the Treaty of Paris relating to the arms limits imposed on Finland, the other parties (IIRC all of which were informed privately, in detail, via the usual diplomatic channels) had a date to respond by. Failure to respond by that date meant assent. None responded.

All they had to do to block Finland's change to the treaty was to send back a note before that date saying "We do not agree". Not one of them did so. Finland's declaration only took force when that waiting period was over & there had been no replies.

In the 25 years since Finland changed the treaty, none of the other parties has even hinted that it considers those clauses to still be in force. They have all acted as if the treaty change was valid. By doing so, they have demonstrated that their original silence really did mean assent, as international law states.

BTW, Finland is buying JASSM for its F-18s.

Profile picture for user MSphere

Member for

9 years 9 months

Posts: 8,850

Great Question! For one, the Gripen Demo and the so-called Gripen NG are not the same. The production Gripen E/F (already is) will be heavier than envisioned and there may very well be more changes as the pre-production models move through development. The more powerful F414 is offset by that added weight and if there is a performance weakness apparent in the Gripen, that it does not have the T/W ratio of it's bigger European brothers to begin with. It is still on the lightweight side of the fighter spectrum with all of the benefits and drawbacks inherent in designing a small multirole fighter.
I am not arguing about that.. It's possible and even probable that some weight shall be added and that the performance could be shifted accordingly. But how is that different from any other prototype on this planet? Frankly, I am not even sure if increasing the T/W was a goal of the NG, rather than greater range, more ordnance and more growth potential (read increased power to support AESA).. There is a retrofit program for the PS-05/A Mk4 radar for Gripen C/Ds but none so far for the Vixen AESA, maybe the C/D is not able to adhere to increased cooling requirements.. (?)

http://saab.com/globalassets/publications-pdfs/aeronautics/gripen/ps_05_a_fighter_radar_brochure.pdf

Member for

9 years

Posts: 300

From what is known so far

Gripen C/D
- Newbuild airframe with sub systems and components salvaged from Gripen A.

Gripen E/F
- Can be a conversion of current C/D airframes with new components and sub systems. Sweden decided later to have all new airframes to preserve current C/D numbers for later sale or lease.

Member for

7 years 11 months

Posts: 175

From what is known so far

Gripen C/D
- Newbuild airframe with sub systems and components salvaged from Gripen A.

Gripen E/F
- Can be a conversion of current C/D airframes with new components and sub systems. Sweden decided later to have all new airframes to preserve current C/D numbers for later sale or lease.

No. The Gripen E airframe would have been new build in any case (it's longer, larger, thicker). Sweden was thinking of reusing some minor parts of the old C/D, like canopy, ejection seat, etc.

Member for

4 years 10 months

Posts: 121

The Gripen Demo NG is an NG.. We can spend hours arguing about whether it's a true "prototype" or just a heavily reworked Gripen B under a private initiative financed by the industry but the fact is that it is an NG. It has a new airframe with additional fuel capacity, two rows of fuselage pylons, new landing gear, F414-GE engine, new satcom equipment, electro-optical RWR and MAWS by Avitronics, as well as the Vixen 1000E AESA radar. Whatever changes have been proposed for the final config prototype from your link, they will hardly be discernible..

Actually the radar is not a vixen 1000 its an evolution of it called raven =) http://www.gripenblogs.com/Lists/Posts/Post.aspx?ID=9

Member for

4 years 10 months

Posts: 121

http://saab.com/globalassets/commercial/air/gripen-fighter-system/gripen-for-brazil/pdf-gripen-ng/gripen-ng-brochure.pdf

Gripen NG

Empty weight, 8,000kg. Thrust, 98KN. Internal fuel, 3,400kg.

F-35A

Empty weight, 13,200kg. Thrust, 191KN. Internal fuel, 8,390kg.

Yeah they'll be flying alot when empty .....F-35 is 22ton with fuel only. Gripen is 12ton with full fuel.

Ill give you the max loaded version of it MTOW comparison.
Weight dry wet
31800 125 191

92,7% 115,5% 94,9%

16500 58 98

You see here (surprisingly) that @ max weight the f-35 only has a 2,4% stronger engine then gripen NG (compared to weight) yet still having -35% less lift area to use, AND having much bigger air resistance

Member for

4 years

Posts: 4

The more powerful F414 is offset by that added weight and if there is a performance weakness apparent in the Gripen, that it does not have the T/W ratio of it's bigger European brothers to begin with. It is still on the lightweight side of the fighter spectrum with all of the benefits and drawbacks inherent in designing a small multirole fighter.

Yes, and one of the main benefits of the Gripen is being able to afford more flight hours for training and being able to field more planes with better availability for the same amount of financial and human resources. So T/W is hardly relevant apart from a systemic evaluation of the results of choice of craft type in the total war scenarios.

And BTW, even with added weight (remains to be seen) it still does supercruise, which can make it reach targets faster with more fuel to hover where it needs to be.

Member for

7 years 4 months

Posts: 3,156

Yeah they'll be flying alot when empty .....F-35 is 22ton with fuel only. Gripen is 12ton with full fuel.

Ill give you the max loaded version of it MTOW comparison.
Weight dry wet
31800 125 191

92,7% 115,5% 94,9%

16500 58 98

You see here (surprisingly) that @ max weight the f-35 only has a 2,4% stronger engine then gripen NG (compared to weight) yet still having -35% less lift area to use, AND having much bigger air resistance

What possible utility is a max weight comparison? Nobody is worried about flight performance if they are flying an aircraft anywhere near its maximum take off weight.

Besides, the F-35 has a vastly greater load carrying capacity than a Gripen NG. This is an advantage not a weakness.

Member for

7 years 4 months

Posts: 3,156

Yes, and one of the main benefits of the Gripen is being able to afford more flight hours for training and being able to field more planes with better availability for the same amount of financial and human resources. So T/W is hardly relevant apart from a systemic evaluation of the results of choice of craft type in the total war scenarios.

And BTW, even with added weight (remains to be seen) it still does supercruise, which can make it reach targets faster with more fuel to hover where it needs to be.

Thrust to weight isn't relevant for a fighter anymore?

Also, the claimed supercruise for the Gripen NG is extremely limited.

The engine, a General Electric F414G turbofan, is a modular, fuel-efficient low-bypass ratio, afterburning turbofan with the latest technology. With a thrust rating of more than 22,000lb (98kN), the F414G produces 20% more thrust than Gripen’s current Volvo Aero RM12 power plant, and will enable super-cruise performance of Mach 1.1 with air-to-air weapons.

Supercruise at M1.1 isn't tactically useful... it isn't really even supercruise as that is squarely in the trans-sonic region.

A Gripen might be able to maintain a hair above M1 in level flight without turning while at its ideal SC altitude after accelerating with afterburners... but in the real world that just isn't useful. Certainly it isn't a case where the Gripen NG will be getting anywhere appreciably faster while saving fuel.

http://saab.com/air/gripen-fighter-system/gripen/gripen/Proud-to-be-brazilian/the-fighter/

Profile picture for user FBW

Member for

7 years 11 months

Posts: 3,106

Yes, and one of the main benefits of the Gripen is being able to afford more flight hours for training and being able to field more planes with better availability for the same amount of financial and human resources. So T/W is hardly relevant apart from a systemic evaluation of the results of choice of craft type in the total war scenarios.

And BTW, even with added weight (remains to be seen) it still does supercruise, which can make it reach targets faster with more fuel to hover where it needs to be.

"Supercruise"..... yes, the most abused new claim in fighter marketing. The Gripen Demo was able to fly above the speed of sound without afterburners. The final (production representative) E/F development airframe 39-10 has yet to fly, then Saab can assess how long, with what loads, the Gripen E/F can "super cruise". P.S. what is the IAS difference between an aircraft cruising at mach .9 and mach 1.1 at 30,000 feet?

Edit- I don't mean the last part to be a "test", you don't have to answer. Just look it up and you'll see what I'm driving at.

Member for

4 years 10 months

Posts: 121

@ Hopsalot "What possible utility is a max weight comparison?" Well, more utility then an empty comparison which you always like to give out. A good calculation would be 50% fuel and 3 air to air, where Gripen lands on 10,6ton and F-35 at 17900 with 3 aim-120. At this weight f-35s engine is luckily 25% stronger but still has 35% less wing area for lift and turn and still has at least 2-3 times the air-resistance (weapons included) so it most likely need it, to compensate lift/drag with the engine and very much so in anything above speed of sound and while lift of and landings.

"Supercruise at M1.1 isn't tactically useful" well that is...not right at all. Low super-cruise is much more usable then high speed super-cruise since the fuel requirements at high super-cruise is terrible, a few minutes of super cruise is what you get at super-cruises @ high supersonic (f-22) 10 minutes at 1,8 then fuel is gone. Super-cruise has been done by Gripen demo at mach 1,25 and at that speed it would be able to travel for quite some time (35-55min on internal depending on load). Maybe to travel back for reload without turning on the afterburner (ir protection) or going for a faster assault. Super-cruise at mach 1.1 is in fact useful in many ways and one of them is to fire missiles above the sound barrier saving up to 50% range.

Supersonic travel is expensive. It's expensive because the parasitic drag increases exponentially. Building and aircraft any bigger then Gripen will require one more engine to super-cruise. And having one more engine increase air resistance with bigger air intakes bigger fuel tanks and bigger body which all increase air resistance. It all increases fuel draw which result in a non useful high super-cruise. That said ! Except for a faster travel, super-cruise in low region speeds still has the above mentioned advantages.

Last but not least, i would like to you guys to wait a few more months and you will have Gripen E flying.