Gripen NG supercruzin for a bruzin

[Haavarla]

Well I dont think it was useless since a couple of people in here have questioned the GE-F414s ability to fly Mach 1.2 for longer periods of time, now we know that there are no such limitations and that the fuel load is the limiting factor.

I will reply him and let you know the answer!

I dont get the obsession about the supercruise on the NG Gripen...

It's classification role are a short tactical fighter, yes?

Hens, it can't carry any substancial fuel amount to sustain a supercruise over a period of time.

It has limitations.

The Medium/heavy fighter/interceptor like F-14(obselete), F-15, F-22A, Mig-31, Su-27series do gain more from supercruise.

But even those plane have its limitations..Flying time vs fuel consumtion on supercruise!

In most case going full A/B for shorter periods gives an fighter the same effects and bennefits.



Thanks

 

[Todjaeger]

I dont get the obsession about the supercruise on the NG Gripen...

It's classification role are a short tactical fighter, yes?

Hens, it can't carry any substancial fuel amount to sustain a supercruise over a period of time.

It has limitations.

The Medium/heavy fighter/interceptor like F-14(obselete), F-15, F-22A, Mig-31, Su-27series do gain more from supercruise.

But even those plane have its limitations..Flying time vs fuel consumtion on supercruise!

In most case going full A/B for shorter periods gives an fighter the same effects and bennefits.



Thanks

I agree. To my understanding, the major difference (in terms of effects) between supercruising and using afterburners is that while supercruising is a slower supersonic mode of travel, it is more fuel efficient than using 'wet-thrush' like afterburners. Either method is less fuel efficient than normal subsonic flight and therefore has a significant impact upon an aircraft's range and/or loiter time.

As has been mentioned, the capability is useful, but including it is not a major coup in terms of fighter design. If it was, the feature would be specifically designed for in more/additional combat-capable fighter designs and ordnance load-outs. The feature as I see it provides a useful longer-ranged rapid intercept/escape capability, but aside from times when a fighter needs to rapidly close with a target at long range, or when escaping an intercepting aircraft, the ability will likely not be needed.

-Cheers

 

[Aussie Digger]

If the Gripen C/D can fly supersonic with 6 AA-missiles and a droptank without engaging the afterburner we can be sure that the NG can supercruise with 6 AA-missiles without a droptank. Removing the drop tank and adding 20% thrust will more than enough compensate for the extra drag induced by the wider fuselage.

As for the range its easy to calculate since the NGs internal fuel load and the specific fuel consumption are not secret. 3300 kg internal fuel, 80 kg / (KN * h) * 60 kN => something like 40 minutes if I'm not wrong.

Flying supersonically increases fuel burn significantly whether you are using reheat or not.

Dry thrust "supercruise" doesn't burn fuel as quickly as reheat, but still results in significantly increased fuel burn over the subsonic cruise profiles the Gripen was intended to fly, predominantly. It was a "surprise" remember?

If it supercruises for any length of time, it's range will be reduced dramatically, just like the F-22.

 

[AndiPandi]

I dont get the obsession about the supercruise on the NG Gripen...

It's classification role are a short tactical fighter, yes?

Hens, it can't carry any substancial fuel amount to sustain a supercruise over a period of time.

It has limitations.

The Medium/heavy fighter/interceptor like F-14(obselete), F-15, F-22A, Mig-31, Su-27series do gain more from supercruise.

But even those plane have its limitations..Flying time vs fuel consumtion on supercruise!

In most case going full A/B for shorter periods gives an fighter the same effects and bennefits.

Thanks

This thread is about Gripen NG supercruising, I dont see any more obsession here than in any other thread discussing a specific topic?

Why would a heavier fighter benefit more from SC than the Gripen NG? Note that the NG does not have the short legs the A/B/C/D had.

I dont think the NGs supercruise capability is a war-winner, but its tells a lot about the Gripens low drag and good acceleration the transonic region, and that is never bad!

And finally, I am not stupid, I dont need 3-4 different people telling me that full mil power burns more fuel than half mil power...

 

[Haavarla]

And finally, I am not stupid, I dont need 3-4 different people telling me that full mil power burns more fuel than half mil power...

That was never my intentions..


The larger medium/heavy interceptors do have more internal fuel storage.
Hens not that dependent on droptanks.

Some planes like Su-27, Mig-31, F-22A dont need tham at all.
That way, less drag. Droptanks do generate drag.

In that respect those planes would have a greater bennefit from Supercruise as i see it.


Thanks

 

[AndiPandi]

That was never my intentions..


The larger medium/heavy interceptors do have more internal fuel storage.
Hens not that dependent on droptanks.

Some planes like Su-27, Mig-31, F-22A dont need tham at all.
That way, less drag. Droptanks do generate drag.

In that respect those planes would have a greater bennefit from Supercruise as i see it.


Thanks

OK, maybe I overreacted...

Anyway, the Su-27s internal fuel load of 9,400 kg is impressive, but it does have two big engines as well. And filling it up to max makes the Su-27 just as clumsy as a Gripen with 2 drop tanks.

If we make the same calculation for the Su-27 (all numbers from wikipedia) we get:

Specific fuel consumption: 0,67 lb/(lbf·h)
Dry thrust: 33508 lb
fuel consumption on dry thrust: 0,67 *33508 = 22450 lbf / h
max internal fuel: 20,700 lbf
minutes on dry thrust: 20,700 / 22450 * 60 =>
55 minutes on mil power and internal fuel (if I got the numbers right).

Can the Su-27 fly supersonic with the AL-31F engine on mil power and 9 tons of fuel? I have no idea.

 

[Haavarla]

AndiPandi;172585]

Anyway, the Su-27s internal fuel load of 9,400 kg is impressive, but it does have two big engines as well. And filling it up to max makes the Su-27 just as clumsy as a Gripen with 2 drop tanks.

Agreed, but in a transite it will bennefit from no droptanks.

If we make the same calculation for the Su-27 (all numbers from wikipedia) we get:

Specific fuel consumption: 0,67 lb/(lbf·h)
Dry thrust: 33508 lb
fuel consumption on dry thrust: 0,67 *33508 = 22450 lbf / h
max internal fuel: 20,700 lbf
minutes on dry thrust: 20,700 / 22450 * 60 =>
55 minutes on mil power and internal fuel (if I got the numbers right).

Can the Su-27 fly supersonic with the AL-31F engine on mil power and 9 tons of fuel? I have no idea.

On full mil power?
A legasy Su-27 will probably be borderline supercruise at xxx feet and with minimum weapons config, and not a chance with standard A2A weapons config.

I'm not sure what impact a full tank vs standard 5.600kg(or was it 6.500kg?) fuel have on supercruise or top speed for that matter if flying strait and level..?

I'm sure it has a negative impact on overall performance, but much less than having the same amount of fuel.. but carring droptanks.



The new Su-35 is different beast, with more power,
less drag and max 11.500kg internal fuel.

I believe it will supercruise with a moderate A2A weapons mission config.

Anyway, back to Gripen..
So it can go full millitary power for about 40min?



Thanks

 

[energo]

OK, maybe I overreacted...

Anyway, the Su-27s internal fuel load of 9,400 kg is impressive, but it does have two big engines as well. And filling it up to max makes the Su-27 just as clumsy as a Gripen with 2 drop tanks.

If we make the same calculation for the Su-27 (all numbers from wikipedia) we get:

Specific fuel consumption: 0,67 lb/(lbf·h)
Dry thrust: 33508 lb
fuel consumption on dry thrust: 0,67 *33508 = 22450 lbf / h
max internal fuel: 20,700 lbf
minutes on dry thrust: 20,700 / 22450 * 60 =>
55 minutes on mil power and internal fuel (if I got the numbers right).

It's likely more than that. Thrust and TSFC are usually specificed at sea level/static conditions and will change considerably with altitude, speed and throttle setting as the fuel/air mix changes. But without knowing the performance conditions and flight profile of the particular airplane an assesment of endurance or range is going to be rudimentary. An F-16 might, for instance, have a fuelflow of 15000 lb/h bogged down on the flightline, but only half that at Mach 0.9/35000 feet. Still, flight is a dynamic event. As fuel is burned and weight decreases, speed and altitude increases changing thrust and conditions again.


B. Bolsøy
Oslo

 

[yoron]

Anyway, back to Gripen..
So it can go full millitary power for about 40min?

Thanks

Here is a good page from the Netherlands comparing the 'legs' between the JSF, and Gripen Demo/NG. I've been in to Swedish military forums and they too seem to find the figures there as being relatively correctly described. It is a guess, but according to them a rather good one.

http://www.aviationweek.com/aw/blog...79a7Post:c37bf741-e055-48ca-8c82-e7234d227276

 

[AndiPandi]

It's likely more than that. Thrust and TSFC are usually specificed at sea level/static conditions and will change considerably with altitude, speed and throttle setting as the fuel/air mix changes. But without knowing the performance conditions and flight profile of the particular airplane an assesment of endurance or range is going to be rudimentary. An F-16 might, for instance, have a fuelflow of 15000 lb/h bogged down on the flightline, but only half that at Mach 0.9/35000 feet. Still, flight is a dynamic event. As fuel is burned and weight decreases, speed and altitude increases changing thrust and conditions again.


B. Bolsøy
Oslo

True, and all that will be the case for the Gripen NG calculation as well.
This was just a rough comparison of the range.

 

[IPA35]

Will the NG carry any weapon system that the normal Gripen cannot carry?

 

[Haavarla]

Here is a good page from the Netherlands comparing the 'legs' between the JSF, and Gripen Demo/NG. I've been in to Swedish military forums and they too seem to find the figures there as being relatively correctly described. It is a guess, but according to them a rather good one.

http://www.aviationweek.com/aw/blog...79a7Post:c37bf741-e055-48ca-8c82-e7234d227276

Good info yoron.

Umm..
I never heard any of this..:

"Meanwhile, Norwegian newspapers are reporting that Eurofighter is re-entering the fray in Norway, with the encouragement of the Norwegian MoD. The European consortium bailed from Norway in a huff late in 2007, but is apparently detecting a changed climate now. The report says that state secretary for defense Barth Eide asked Eurofighter to reconsider and that the consortium could out an offer together in time for the formal evaluation this fall."


Can anybody confirm this?


Thanks

 

[Grand Danois]

Good info yoron.

Umm..
I never heard any of this..:

"Meanwhile, Norwegian newspapers are reporting that Eurofighter is re-entering the fray in Norway, with the encouragement of the Norwegian MoD. The European consortium bailed from Norway in a huff late in 2007, but is apparently detecting a changed climate now. The report says that state secretary for defense Barth Eide asked Eurofighter to reconsider and that the consortium could out an offer together in time for the formal evaluation this fall."


Can anybody confirm this?


Thanks

No. It was a fluke or lost in translation thing. IIRC Bill Sweetman later corrected this.

 

[energo]

Good info yoron.

Umm..
I never heard any of this..:

"Meanwhile, Norwegian newspapers are reporting that Eurofighter is re-entering the fray in Norway, with the encouragement of the Norwegian MoD. The European consortium bailed from Norway in a huff late in 2007, but is apparently detecting a changed climate now. The report says that state secretary for defense Barth Eide asked Eurofighter to reconsider and that the consortium could out an offer together in time for the formal evaluation this fall."

Can anybody confirm this?

Thanks

It was a rumour at the time, but was quickly demented by the project management and the state secretary. Bill Sweetman retracted the story the following day.

B. Bolsøy
Oslo

 

[energo]

No. It was a fluke or lost in translation thing. IIRC Bill Sweetman later corrected this.

The story appears to have been put forward by a little known norwegian news portal with a history of highly inaccurate reporting on the fighter bid.

B. Bolsøy
Oslo