So, FBW, can you explain why those links are relevant? Checkmate? This is more like Mornington Crescent than chess.

Halloweene – Exactly the case re Rover.

Also, let us not forget that the physical aperture of a radar is important too, because all the TR modules in the world won’t catch the trons that go whistling past the antenna, and the repositioner means that aperture doesn’t drop off in the same way off-boresight.

The first link from SAAB in above post explains SAAB’s rationale for starting work on what would become the NG, one describes the polish selection of the f-16 over the Gripen. I’m sure your familiar with both the Polish report and the Swiss eval, neither are manufacturer data, and both show that that Gripen C was considered inferior to competition. The claims that somehow the NG will be a quantum leap above the C are specious at best. Most likely competitive with the f-16 block 60 , not the f-35.
Edit- the icas link was wrong one for Gripen doc from saab, my first post on page is correct one, perhaps that will clear up what the links were supposed to show.

You mean to say you dont believe the raven radar sit on a re-positioner/swashplate ?

Dont’t be so contrarian. You know that chart attempts to show f-35 vs Gripen NG capabilities. Let’s not be blind to the double standards that are applied, it’s shows a narrow minded bias, that makes debate pointless.

So pilot will have to turn their head 180° to see whats behind on their HMS???

This is one of those things I find completely hard to swallow. I’m not going to sit and yell that the AN/ASQ-239 is so much more advanced than Spectra. They are very classified and it’s a waste of time. But how many Rafales are equipped with topsight right now. Looking down is far worse for situational awareness than being able to look around and get: classification of target, range, a prioritized shoot list while being able to keep a visual on the fight

What is new and unique was mentioned earlier in the discussion about DAS, targets are passed off from one sensor to another seamlessly on F-35 (theoretically). They are classified, given a symbol for pilots ID and tracked throughout battlespace. Pilot is aware of where friendlies and bogeys are in a potentially chaotic situation where a moments hesitation can kill you or at least limit your response time. And Amega, it’s not that other designer have not thought of it, other aircraft can slave their IRST to radar and vice-versa, it’s then tracking them and presenting the information to the pilot in a 360* view that is unique. How long it will stay that way remains to be seen, but come on, give some credit to the revolutionary nature of it. For the first time, a pilot will not have to multi-task between hud, radar display, and HMS (if equipped) to form a tactical picture of the fight.

Sorry for a late answer;

Its basically due to the fact air gets thinner at the altitude. In order to stay in level -let alone make a turn- an aircraft a) higher lift coefficient -OR- b) needs to go faster.

a) Higher lift coeefficient, always require higher AOA. As to WHY wing loading affects high altitude performance;

Lift = 1/2 * density * Wing Area * Lift Coefficient * airspeed ^2 and Lift = aircraft weight * amount of G aircraft pulls;

Wing loading = Aircraft Weight / Wing area; or we can say: aircraft weight = wing loading * wing area;

For a level flight condition; if we are to put this into lift formula it becomes;

Wing loading * aircraft G load = 1/2 * air density * Lift coefficent * airspeed^2

In other words; Wing loading is directly proportional to Lift coefficient aircraft requires to pull a G load. Lower wing loading means less Cl, or in other words less AOA is required. This generally leads to less drag coeffient so aircraft flies -or turns- more efficiently.

At sea level aircraft fly proportionally too fast to make this relevant, as Cl increase is linear, but Cd increase is more exponential: I couldn’t find 64A204 but lets take 64A215 airfoil, its similar to the F-16’s airfoil, but thicker and does not have LE flaps:

[ATTACH=CONFIG]225576[/ATTACH]

(Though this graph made by to CFD modelling there are inaccuracies; there should be minimal CD increase between 0-5 deg AOA following the parabolic behaviour of the graph)

Lets take this airfoil as the F-16’s airfoil;

For an F-16 blk50 (27,87m2 wing area) flying with 50% fuel + 4 missiles (12690 kg) at sea level (air density = 1,2)

Level flight at M0,5 reqiures 0,23 CL. this (coindicentally) happens at 0 AOA, and with minimal drag coefficient. As drag is also multipled with wing area, having smaller wings is beneficial and will create less drag. This will help in level flight accelerations.
Turning at 9G at M0,85 requires: 0,72 CL. This happens at 5 deg AOA; still at very low Cd. Low Cd multipled with low wing Area results in low drag, which explains the impressive sustained turn performance of the F-16. If F-16 had bigger wings, it would only increase its drag, and lower its sustained turn performance.

However when same aircraft reaches 30k feet (air density = 0,35)

Level flight at M0,5 requires 0,98 Cl at 10 deg angle of attack; this corresponds to 0,02 Cd; Now the Wing Area becomes important: IF F-16 aircraft had 33% larger wings; it would have required ~0,75 cl and had 0,01 Cd: This 33% increase in wing area and 50% decrease in Cd would actually resulted in 33% LESS draggy aircraft (despite being physically larger), directly improving acceleration.

Turning at 4Gs at 30k feet would require 1,27 Cl at 15 deg AOA resulting in 0,06 Cd (note that this is not entirely accurate for the Real Life F-16 has LE flaps which would decrease the Cd). If F-16 had twice the wing area; it would have had only 0,01 Cd; and be 300% less draggy;

Wing Loading also tells about how much available lift aircraft can produce; At M0,85 Clmax= 1,5; F-16 can pull 5Gs at best, resulting in 10,3 deg/s instantenious turn rate at 30k feet. Greater the wing area, greater the instantenious turn rates.

This all comes to optimization and engineering choices: Current small wings of F-16, are optimal at Sea level, but inferior at 30k feet. Slightly enlarging wings would improve both maneuvering and acceleration performance at high altitude, at the cost of low altitude performance. Enlarging wings too much would horribly worsen the low altitude turn, acceleration and climb performance; worsen high altitude acceleration, but improve high altitude turn performance. And I am talking purely about aerodynamics; an increase in deadweight would also decreased payload and further increased the drag etc etc.

With ever increasing payloads; smaller winged and lighter aircraft have more drastic increases in wing loading;

When we fuel an F-16 and Su-27 at 50% fuel load; they will have 383 and 338 kg/m2 wing loading respectively. However if we are to add 3 tons of fuel/payload; they will become; 490 and 387 kg/m2 respecively. Remembering the formula above; this means, F-16 will require 28% greater lift coefficient to achieve same turn rate; Su-27 will only require 14%; Considering Cd increases exponentially, that means there will be huge performance drop for F-16 while both accelerating and turning; but -aerodynamically speaking- Su-27 wont be affected at all while accelerating; and only a slight performance drop while turning. That is if we are speaking about high altitude.

In simpler terms smaller the aircraft gets, greater the Cl requirement will become with equal payload. Wings stay same; so there will be greater AOA requirement; and lower L/D as in this graph.
[ATTACH=CONFIG]225577[/ATTACH]

As to add to the discussion; let me try to explain how wing loading, T/W, and other factors can be used to *roughly* estimate and compere maneuverability: look at F-15; F-15 uses NACA 64A203 airfoil, very similar to the F-16’s 64A204.

At 50% fuel clean, F-16 has wing loading of 383 kg/m2, whereas F-15 has 285 kg/m2. Wing’s Low AOA behaviour is the same, but F-16 has Clmax of ~1.6 at M0,5 maneuvering conditions F-15 has 1,1; due to lack of LE flaps it stalls earlier.

Remembering this formula: Wing loading * aircraft G load = 1/2 * air density * Lift coefficent * airspeed^2

45% less Clmax + 26% less wing loading means F-15 will have less available G and less instantenious turn rate by 8% at sea level. Obviously this is no coincidence that FM data shows at M0,5 F-16 can pull 24,2 deg/s and F-15 22 deg/s, 9% difference.

As wing behaviour is similar due to similar airfoils; 26% less wing loading = 26% less necessary Cl at 9G; We can assume (albeit a little inaccurrately) that means 26% decrease in Cd. F-15 has 202% greater wing area (read = drag) of F-16, it has 63% greater static thrust. All relations are linear; so multiplying all relations will tell us; F-15 will have 91% Sustained turn performance of F-16; Real numbers are 20,5 vs 21,5 respectively; 5% drop in performance.

As Su-27 uses different airfoil such estimate about STR is not possible because we simply dont know how Cd changes; We can however estimate Instantenious turn rate:

Compared to F-16; it has 15% better Clmax; and 11% less wing loading. Knowing this; means we can estimate 24,2*1.11*1.15 = 30,8 deg/s ITR at M0,5. But that would result in greater than 9Gs; Truth is Su-27 achieves its highest ITR at M0,48 (30,2 deg/s); That is still an accurate estimate.

Here is the STR graphs of 4th gen fighters compared to F-4E at 30k feet when clean 50% fuelled:

[ATTACH=CONFIG]225578[/ATTACH]

Numbers on graph a bit off for F-15 A/C, clean 35,000 lbs will turn at 8.5* per second at 30,000 feet, f-16 blocks vary greatly- block 50/52 being heaviest in U.S. service. Earlier blocks were similar to F-15 at 8.5* per second according to flight manual and wiki-leaks info released on F-16A. The F-16CJ flight manual shows similar values to your chart .82 mach, 22,000 lbs results in 7.5* per second, right on . (of course this depends on definition of “clean”, F-15 drops to around 8* per second at 36,000 pounds w/plyons)