F-35A versus Saab Gripen NG

The F-35 compared with other modern jets.
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by loke » 26 Feb 2018, 09:43

gta4 wrote:
loke wrote:Not entirely... Gripen E empty weight is 8,000 kg. That compares quite well to an F-16 block 32 at 8,272 kg; however the block 32 had a P&W F100-PW-220 with 23,770 thrust.

Compare that to the F414 which is a "22,000 lbs class" engine.

F-16 block 32 weighs 3.4% more than Gripen E and has 8% more thrust.

Block 32 F-16 was probably not known for having great acceleration (just guessing, based on the above numbers), on the other hand, was it considered to be very poor from a kinematic POV?

http://www.f-16.net/f-16_versions_article6.html


Your figure is incorrect, according to LM test report.

Block 30 weights 17900 lbs (8121 kg)
Block 32 weight 17000 lbs (7713 kg)

Interesting, so the figures on F-16.net are wrong. Nevertheless the Gripen E and F-16 block 30 still have roughly the same weight.

What was the correct thrust of the Block 30?

I did not mean this as "d!ck measuring contest", I simply tried to find some fighter in the same weight class as Gripen E to check and see how different their thrusts were. Until we have more data about the Gripen E kinematic performance it should give us a rought idea of the kinematic performance of the Gripen E. No doubt it will not have great kinematic performance but how bad will it be? I was thinking that looking at historical data could give us an idea.

That was all.

So how sluggish was the block 30?

Something else: I as somewhat surprised that F-16 did not increase in weight from block 30 to block 50!?


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by basher54321 » 26 Feb 2018, 12:10

loke wrote:Interesting, so the figures on F-16.net are wrong. Nevertheless the Gripen E and F-16 block 30 still have roughly the same weight.

What was the correct thrust of the Block 30?

I did not mean this as "d!ck measuring contest", I simply tried to find some fighter in the same weight class as Gripen E to check and see how different their thrusts were. Until we have more data about the Gripen E kinematic performance it should give us a rought idea of the kinematic performance of the Gripen E. No doubt it will not have great kinematic performance but how bad will it be? I was thinking that looking at historical data could give us an idea.

That was all.

So how sluggish was the block 30?

Something else: I as somewhat surprised that F-16 did not increase in weight from block 30 to block 50!?






Loke - this information has already been posted so I will assume you are not quite understanding what is happening here - I will try to summarise.

The block 30 (28000 lb thrust class) despite being a bit heavier had significantly better performance over the Block 32 (25000 lb thrust class) due to the large thrust difference.

The Block 40/42/50/52 were all heavier than the Block 30/32 due to a revised structure - but they also gained more powerful engines (eventually).

Despite being inferior there is no evidence remaining Block 32s were reengined and still retain the lower thrust engines


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by loke » 26 Feb 2018, 12:38

basher54321 wrote:
Loke - this information has already been posted so I will assume you are not quite understanding what is happening here - I will try to summarise.

There are literally thousands of posts on this forum, many of them with conflicting numbers. The point of having a reference page such as the one I linked to, should be to make it possible to find those numbers without having to wade through those thousands of pages and try to guess which one is giving the correct information, and which one is misleading.

Anyway, good to know that the reference pages are wrong.


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by XanderCrews » 26 Feb 2018, 20:04

loke wrote:
sprstdlyscottsmn wrote:
XanderCrews wrote:
F414:
13,000 lbf (57.8 kN) military thrust
22,000 lbf (97.9 kN) with afterburner

Yeah, I know 22k is the oft quoted number but the SHornet NATOPS says 20k uninstalled.

GE Aviation says 22,000...


Hmm so trust the operators or the company that makes it....

Hmmm



Hmmm

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by F-16ADF » 26 Feb 2018, 20:24

22,000lbs or 20,000lbs thrust don't really know. But the point is that the E has gained much weight, now 8,000kg according to Saab Gripen E tech specs. So it probably will have (still) a good-great ITR, yet STR will (still) suffer.

This I think is from an IAI source. (Yes, I know the Lavi and Gripen are two different jets, yet both are close coupled canard delta; and rather small).

Lavi has great ITR like Gripen, STR (like Gripen) suffers.....
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by monkeypilot » 26 Feb 2018, 21:54

One can expect close coupled Gripen canard's flight rules to be more mature/sophiticated.


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by rheonomic » 27 Feb 2018, 03:17

monkeypilot wrote:One can expect close coupled Gripen canard's flight rules to be more mature/sophiticated.


I have no idea what you're trying to say here...
"You could do that, but it would be wrong."


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by gta4 » 27 Feb 2018, 13:14

loke wrote:
sprstdlyscottsmn wrote:
XanderCrews wrote:
F414:
13,000 lbf (57.8 kN) military thrust
22,000 lbf (97.9 kN) with afterburner

Yeah, I know 22k is the oft quoted number but the SHornet NATOPS says 20k uninstalled.

GE Aviation says 22,000...


It is normal. Engines' uninstalled sea level static thrust is always lower than the thrust on fact sheet.

For instance, AL-31F has a uninstalled sea level static thrust of 110KN, while the fact sheet says 122.5KN.

This is because the thrust is tested in this way: all engines have a "designed operating mach number" (say, Mach 0.7) and during test, a strong ventilation device is placed in front of the engine to simulate the incoming air flow at Mach 0.7. The thrust obtained in this condition is listed on the fact sheet.
(Surprise! The thrust on the fact sheet is not obtained at Mach number = 0 !)
So the uninstalled thrust at Mach number = 0 (A.K.A static) is always lower than that on the fact sheet (about 90%).

The installed thrust at Mach number = 0 (A.K.A static) is approximately 70% of that on the fact sheet, because all air intakes have a total pressure recovery of about 0.8 at Mach number = 0.


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by gta4 » 27 Feb 2018, 13:18

monkeypilot wrote:One can expect close coupled Gripen canard's flight rules to be more mature/sophiticated.

I think you mean "JAS39's advanced flight control law could make its canard to generate more lift and less drag to compensate for its low T/W ratio".

Sorry but to the best of my knowledge, no matter how well the flight control law is optimized, canard aircraft always have worse lift/drag ratio than RSS tail plane aircraft, especially at subsonic.

For instance, gliders emphasizes much on L/D ratio, and no glider uses carnard. They all use tail plane.


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by gta4 » 27 Feb 2018, 13:21

f-16adf wrote:22,000lbs or 20,000lbs thrust don't really know. But the point is that the E has gained much weight, now 8,000kg according to Saab Gripen E tech specs. So it probably will have (still) a good-great ITR, yet STR will (still) suffer.

This I think is from an IAI source. (Yes, I know the Lavi and Gripen are two different jets, yet both are close coupled canard delta; and rather small).

Lavi has great ITR like Gripen, STR (like Gripen) suffers.....


Lavi has good STR at transonic, however since it is in prototype stage (the lightest stage of a combat aircraft), one can expect it to gain more weight as it enters mass production. So it is unfair to compare it with other mass produced aircraft.


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by XanderCrews » 27 Feb 2018, 15:59

gta4 wrote:
f-16adf wrote:22,000lbs or 20,000lbs thrust don't really know. But the point is that the E has gained much weight, now 8,000kg according to Saab Gripen E tech specs. So it probably will have (still) a good-great ITR, yet STR will (still) suffer.

This I think is from an IAI source. (Yes, I know the Lavi and Gripen are two different jets, yet both are close coupled canard delta; and rather small).

Lavi has great ITR like Gripen, STR (like Gripen) suffers.....


Lavi has good STR at transonic, however since it is in prototype stage (the lightest stage of a combat aircraft), one can expect it to gain more weight as it enters mass production. So it is unfair to compare it with other mass produced aircraft.


Bad news for Gripen E then
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by monkeypilot » 27 Feb 2018, 19:26

gta4 wrote:
monkeypilot wrote:One can expect close coupled Gripen canard's flight rules to be more mature/sophiticated.

I think you mean "JAS39's advanced flight control law could make its canard to generate more lift and less drag to compensate for its low T/W ratio".

Sorry but to the best of my knowledge, no matter how well the flight control law is optimized, canard aircraft always have worse lift/drag ratio than RSS tail plane aircraft, especially at subsonic.

For instance, gliders emphasizes much on L/D ratio, and no glider uses carnard. They all use tail plane.


No i meant there is a long way between a Lavi flight control laws and Saabs probably (much more experience etc.)


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by XanderCrews » 27 Feb 2018, 20:06

monkeypilot wrote:No i meant there is a long way between a Lavi flight control laws and Saabs probably (much more experience etc.)


There's barely a 2 year difference in first flights between each, and Gripen had the crashes early on with flight software problems.
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by monkeypilot » 27 Feb 2018, 20:57

XanderCrews wrote:
monkeypilot wrote:No i meant there is a long way between a Lavi flight control laws and Saabs probably (much more experience etc.)


There's barely a 2 year difference in first flights between each, and Gripen had the crashes early on with flight software problems.


SAAB already had an experience with canards. And wone can suppose that the experience cumulated on C/D helped for E no?


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by swiss » 27 Feb 2018, 21:53

basher54321 wrote:The block 30 (28000 lb thrust class) despite being a bit heavier had significantly better performance over the Block 32 (25000 lb thrust class) due to the large thrust difference.

The Block 40/42/50/52 were all heavier than the Block 30/32 due to a revised structure - but they also gained more powerful engines (eventually).



Interesting. I always thought block 30 has 29000 lb thrust.


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