Nice Article on the F-22

Anything goes, as long as it is about the Lockheed Martin F-22 Raptor
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zero-one

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Unread post25 Jan 2017, 16:45

garrya wrote:It does give us pretty much all we need to know: information about altitude, speed. Weapon load wasn't specified but quite obvious that it would be internal AA load.It wasn't just there to show that F-22 can match F-15 performance. It stated quite clear that sustain G value is the demonstrated value


But fuel and weapons load have so much to do with how the turn rate will turn out. and to me it's not "obvious" that it would be an internal load. Thats an assumption with no backing.

garrya wrote:I know it have higher IR signature than a helicopter or an UAV because of common sense.

Well common sense tells you that a brick wall is a better barrier against a 50 cal round than an Aquarium full of water, but apparently its not, the Aquarium is better if we are to believe ballistics test. If anything, the F-22 is the plane that defies common sense.

garrya wrote:There are a lot of nonsense in newspaper and magazine that never get officially disputed. They barely bother to correct the bad press ( i mean how often do you read on the new that F-35 is a useless trillions USD fighters ?, Moreover, Fightersweep doesn't just claim that F-15 had aim-9X and HMS , they also claimed that a single F-22 , gone against 8 F-15 , and 2 of them at dogfight range. Extraordinary claim require extraordinary evidence


Well according to a lot of people here, the F-22 has been pitted against F-15s/16s/18s with 9X in WVR and won. So this claim isn't really an extraordinary claim at all.

The claims about LF radars making Stealth useless has been countered so many times, as was the F-35 can't turn argument, RTs propaganda pieces were dismantled countless times as well. In fact I have a lot of links for counters against negative publicity. But this one has no counter. FighterSweep isn't like RT, they don't publish over the top claims just to get publicity, I think they deserve more credit than RT when it comes to articles about fighters

garrya wrote: Generally speaking, lower speed mean lower G with equal or even superior turn rate,however, lower speed mean less lift, and lift is a valuable thing at 20K feet

Not necessarily. G is a byproduct of turnrate and speed, So even if I'm slow, if I turn at a certain rate, I will still generate the desired G rate.

garrya wrote:I dont know much about early AIM-9 but iam quite certain that Aim-9x can do significantly better.Given that even your modern phone's camera can recognize human face in second.
zero-one wrote:In fact in 9X test footage, you'll notice the pilots taking a long hard look at the target before fox 2? why? well to me, its a clue as to how long it takes for the missile to recognize the target.

Missiles doesn't need to recognize target themselves , the pilots literally point them at target and give order ( that shape is your target ).We are not talking about LOAL and ATA here


First off, needing to recognize a target first is not new, the Aim-9 has growl that the pilots can hear through a headset, now when they are behind a target, they listen to the growl's intensity. Even if the target is in full AB, if that growl isn't loud, that means that the missile can't recognize the target.

Now, new missiles have improved more sensitive seekers that can see better, but the requirement to recognize the target first remains. You don't just look and shoot, you need to make sure that the missile is seeing what you're looking at.

Take a look at that escort shot again in the Aim-9X test footage, the F/A-18 pilot took a long hard look at that target which was flying beside him before firing. He didn't just turn his head and shoot, he needed to take some time to stare at the target which was white hot F-4 by the way before he had "good tone" and then shoot.

We can't simply take 2 different technologies and make conclusions based on their relation, the Aim-9x that was probably used in this exercise that took place in 2007 was likely using technology from the early 2000s. Its like saying, because my new Hybrid car can do 20km a gallon, the Abrams can probably do the 40 or 50. I know thats exaggerated, but its similar.


garrya wrote:Or it didn't and the part we read was an exaggeration by writer

We have nothing to support that accusation.

garrya wrote:Using that logic then we should also take all RT proparganda pieces as truth since they don't bother to correct themselves

RT has been debunked by Fightersweep so many times, we have no problems when we agree with them, but why do we have problems with this one
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Unread post26 Jan 2017, 00:15

zero-one wrote:But fuel and weapons load have so much to do with how the turn rate will turn out. and to me it's not "obvious" that it would be an internal load. Thats an assumption with no backing

F-22 is a stealth aircraft, it would be expected for its KPP are of its normal operating condition ( or at least close to that). Sure you can argue that F-22 KPP is in a situation where it carries 4 external fuel tanks. But most people would disagree with that, because it doesn't seem very plausible froma fair logical standpoint


zero-one wrote:Well common sense tells you that a brick wall is a better barrier against a 50 cal round than an Aquarium full of water, but apparently its not, the Aquarium is better if we are to believe ballistics test.

It depend on the thickness of the brick wall and the kind of aquarium you are talking about. If they are of equal thickness, iam pretty sure a brick stop bullet better than an aquarium. Most, brick wall aren't that thick though, however, most aquarium are made from glass so they are useless after the first shot.The same can't be said about a brick wall.
Brick seem to do pretty well against piston and automatic rifle level caliber
www.youtube.com/watch?v=Jy5DjzGpXvU
www.youtube.com/watch?v=GyKx6b2NOoU

zero-one wrote:If anything, the F-22 is the plane that defies common sense

I am not so sure about. Is F-22 a good aircraft, obviously.But that doesn't mean it just gonna defy laws of physics. Moreover, i already see the IR photo of F-22 and there is no indication that it would be cooler than a helicopter or a small UAV


zero-one wrote:Well according to a lot of people here, the F-22 has been pitted against F-15s/16s/18s with 9X in WVR and won. So this claim isn't really an extraordinary claim at all

That depending on the specific situation it defeats those aircraft , could just be a sneak up.Moreover, most people don't have access to exercise detail

zero-one wrote:The claims about LF radars making Stealth useless has been countered so many times, as was the F-35 can't turn argument

I mean like official counter claim from the same press '

zero-one wrote:RTs propaganda pieces were dismantled countless times as well. In fact I have a lot of links for counters against negative publicity. But this one has no counter

Maybe because it a good publicity

zero-one wrote: FighterSweep isn't like RT, they don't publish over the top claims just to get publicity, I think they deserve more credit than RT when it comes to articles about fighters

Obviously, RT and the like are very infamous for their proparganda , but what iam trying to say is that all information on magazine should be taken with a grant of salt

zero-one wrote:Not necessarily. G is a byproduct of turnrate and speed, So even if I'm slow, if I turn at a certain rate, I will still generate the desired G rate.

I dont think you understand what iam trying to say.
To achieve a certain amount of G , you need a certain amount of lift , and this lift came from speed
At the same time, turn rate is a function of speed and G
With a fixed G value, the slower you fly , the faster your turn rate and the lower your turn radius would be. However, slower speed also mean less lift, which is very necessary at high altitude.



zero-one wrote:First off, needing to recognize a target first is not new, the Aim-9 has growl that the pilots can hear through a headset, now when they are behind a target, they listen to the growl's intensity. Even if the target is in full AB, if that growl isn't loud, that means that the missile can't recognize the target.

Now, new missiles have improved more sensitive seekers that can see better, but the requirement to recognize the target first remains. You don't just look and shoot, you need to make sure that the missile is seeing what you're looking at.

For early IR missiles, pilot have to listen to the tone. But for modern IIR missiles, the one linked with HMS , the missile's sensor will be pointed at the exact same direction as the HMS


zero-one wrote:We have nothing to support that accusation

The fact that it wasn't in the original article or others popular press is a big red flag for me
The fact that it doesn't seem to fit with KPP value is another big red flag
Moreover, it just sound illogical for me overall.But ofcourse , you are free to have your own point of view on the matter

zero-one wrote:RT has been debunked by Fightersweep so many times, we have no problems when we agree with them, but why do we have problems with this one

Because it doesn't sound plausible
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Unread post26 Jan 2017, 11:16

garrya wrote:F-22 is a stealth aircraft, it would be expected for its KPP are of its normal operating condition ( or at least close to that). Sure you can argue that F-22 KPP is in a situation where it carries 4 external fuel tanks. But most people would disagree with that, because it doesn't seem very plausible froma fair logical standpoint


But for an unclassified data sheet, its possible that non-optimal configurations were used. this is exactly the same defense we had when the F-35's sustained G was reportedly reduced in 2012 from 5.3Gs to 4.6Gs. we said that without weights, speed and altitude taken into consideration we can't draw a conclusion. But the F-35 crowd said that this was "most likely taken within optimal conditions". We rebutted by saying, "thats quite an assumption"


garrya wrote:I am not so sure about. Is F-22 a good aircraft, obviously.But that doesn't mean it just gonna defy laws of physics. Moreover, i already see the IR photo of F-22 and there is no indication that it would be cooler than a helicopter or a small UAV

The F-35 has an active IR suppression system where the fuel is circulated around the plane to cool the skin. The F-22 may have a similar system as well. What if it was not activated on that shot. The F-22 is considered IR stealth. Now it would be hard to believe that they spent billions on it just to make it a little cooler than a regular F-4.


garrya wrote:That depending on the specific situation it defeats those aircraft , could just be a sneak up.Moreover, most people don't have access to exercise detail


as you know, WVR exercises are set up to cover all aspects of WVR, Neutral merge, perch setup, defensive BFM, offensive BFM. and as far as we know the F-22 dominates. So I'm not convinced that all those WVR wins were by "sneaking up back stabbing tactics".

garrya wrote:I mean like official counter claim from the same press '
it doesn't have to be official, most of our counter claims against the anti-F35 crowd were from unofficial but more credible claims like from the pilots themselves, published through sites like fightersweep.





garrya wrote:I dont think you understand what iam trying to say.
To achieve a certain amount of G , you need a certain amount of lift , and this lift came from speed
At the same time, turn rate is a function of speed and G
With a fixed G value, the slower you fly , the faster your turn rate and the lower your turn radius would be. However, slower speed also mean less lift, which is very necessary at high altitude.

Exactly, but which fighter would you bet to be capable of producing the most lift. the F-22 has 840 sq feet of wing, the largest of any fighter, plus chines plus a lifting body design plus tail lift. So if anything, the Raptor can produce an insane amount of lift even at slow speeds as demonstrated by it's short take off run in a demo.



garrya wrote:For early IR missiles, pilot have to listen to the tone. But for modern IIR missiles, the one linked with HMS , the missile's sensor will be pointed at the exact same direction as the HMS


Even if the seeker is pointed at the target, it will take time before the seeker actually sees the target. Even modern missiles still have tones, you need to have good tone before firing, Thats why you have LOAL. thats when you fire even without tone and then data link the targeting data after. Not all LOAL shots are HOBS, your can take a LOBS-LOAL shot.
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Unread post26 Jan 2017, 17:45

F-22 has larger wing area than PAK FA?

I'll have to go look that up, but if so it'd surprise me. Still, that 1000ft until airborne takeoff roll always amazed me!
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Unread post26 Jan 2017, 18:37

Sustained 28 deg/s Nz turn at 20,000ft? Let me go into why this is a great big "No".

First is the lift required to get there in the first place. For a Raptor whose motors are .2sec away from fuel starvation and has no weapons this turn rate would require a CLmax between 2.07 and 4.65 for 9G and 4G respectively. 2.07 is not an unreasonable CLmax value for the Raptor, but turning at Empty Weight is. For the standard AA loadout and 60% internal fuel the CL max values go up to 2.74 and 6.17 for those respective Gs. These values are absurd. The idea that the Raptor can hit 28deg/s in an Nz turn at all about defies physics.

Second, to SUSTAIN said turns you would need un-holy amounts of thrust. On vapors the raptor would need to be putting out in excess of 106,174 lb of thrust, as that is the minimum possible INDUCED DRAG ALONE. I also can guarantee you will not see an "e" of 1 with a Cl over 2, .5 would more reasonable than 1, so even my absurdly optimistic numbers are absurd. To do that turn at the Loaded Weight? 186,565 lbs of minimum possible Induced Drag. Yes the Raptors engines are powerful but if they were that powerful the .8M to 1.5M acceleration would be 10 seconds not 57 seconds.

So, either that Col was blowing smoke or he was not talking about an Nz turn and was instead referencing a rudder turn where the rate is sustained but the flight path is essentially ballistic.
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Unread post27 Jan 2017, 00:56

zero-one wrote:But for an unclassified data sheet, its possible that non-optimal configurations were used. this is exactly the same defense we had when the F-35's sustained G was reportedly reduced in 2012 from 5.3Gs to 4.6Gs. we said that without weights, speed and altitude taken into consideration we can't draw a conclusion. But the F-35 crowd said that this was "most likely taken within optimal conditions". We rebutted by saying, "thats quite an assumption"

When the value first came out , it didn't have speed or altitude which is why it is certainly useless to deduce anything. However when the exact speed and altitude of F-35 when it achieve the sustain turn is released , people get pretty decent estimate of its sustain G performance
Same for F-22 case

zero-one wrote:The F-35 has an active IR suppression system where the fuel is circulated around the plane to cool the skin. The F-22 may have a similar system as well. What if it was not activated on that shot. The F-22 is considered IR stealth. Now it would be hard to believe that they spent billions on it just to make it a little cooler than a regular F-4

May be F-22 airframe is much cooler than an F-4, may be even a helicopter. But the exhaust flame though.
zero-one wrote:as you know, WVR exercises are set up to cover all aspects of WVR, Neutral merge, perch setup, defensive BFM, offensive BFM. and as far as we know the F-22 dominates. So I'm not convinced that all those WVR wins were by "sneaking up back stabbing tactics".

Plane are not supposed to use HOBS missiles in those setups AFAIK

zero-one wrote: it doesn't have to be official, most of our counter claims against the anti-F35 crowd were from unofficial but more credible claims like from the pilots themselves, published through sites like fightersweep

A claim doesn't need to be official if it has a physic based. For example : you dont need to be an F-35 pilots to know that aircraft turn rate reduce proportionally with air density, you dont need to be a S-400 commander to know that radar beam width is reversely proportional to wavelength..etc. and you dont need to be an official to put out those claim because they can be explained by simple physics that can be double check by anyone.
On the other hand, to claim that F-22 fought a certain number of enemies, equipped with certain kind of weapons, that is a kind of claim that would need some sort of authority.



zero-one wrote:
Exactly, but which fighter would you bet to be capable of producing the most lift. the F-22 has 840 sq feet of wing, the largest of any fighter, plus chines plus a lifting body design plus tail lift. So if anything, the Raptor can produce an insane amount of lift even at slow speeds as demonstrated by it's short take off run in a demo.

Spurt does a better job of explaining this, so see above



zero-one wrote:Even if the seeker is pointed at the target, it will take time before the seeker actually sees the target. Even modern missiles still have tones, you need to have good tone before firing, Thats why you have LOAL. thats when you fire even without tone and then data link the targeting data after. Not all LOAL shots are HOBS, your can take a LOBS-LOAL shot.

LOBL is when the missiles locked on the target before launch
LOAL is when the missiles is launched before its seeker can even see the target ( either due to distance or aspect )
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Unread post30 Jan 2017, 22:34

garrya wrote:When the value first came out , it didn't have speed or altitude which is why it is certainly useless to deduce anything. However when the exact speed and altitude of F-35 when it achieve the sustain turn is released , people get pretty decent estimate of its sustain G performance
Same for F-22 case

What were the conditions for the F-35's sustained turn KPP reduction? Were they ever release, please feel free to post the link here.

garrya wrote:May be F-22 airframe is much cooler than an F-4, may be even a helicopter. But the exhaust flame though.


Then there you go, the IR seekers have much harder time seeing the F-22 than the F-4. In the Aim-9X test footage, the pilots needed to stare down at the target QF-4s before launching. Imagine how much longer they would need to stare against a much colder F-22.




garrya wrote:Plane are not supposed to use HOBS missiles in those setups AFAIK


Care to back that up please. It doesn't make sense to me for comanders to intentionally tell pilots to handicap their planes for certain scenarios all the time. Yes I know that this is done, like when pilots are told to go guns only. But if you're saying that all WVR neutral merges/perch setups, deffensive and offensive BFM setups are purposely conducted without HOBS and HMD, then it doesn't make sense.




garrya wrote:
Spurt does a better job of explaining this, so see above


Okay, since its Spurts who said it, I give. Heres the flip side though, Im not saying I don't believe Spurts, because I do. But now its his word against an F-22 pilot's. And from watching Israeli pilot interviews, the first western pilots to fly the Mig-21. They also said that they fought with Arab pilots that made many incredible acrobatic feats that were supposedly "impossible" for a Mig-21. Sometimes planes just don't know the rules.


garrya wrote:LOBL is when the missiles locked on the target before launch
LOAL is when the missiles is launched before its seeker can even see the target ( either due to distance or aspect )


And HOBS means High off boarsite, LOBS means Low off boresite. I think you misunderstood my statement, thats why you felt the need to define it, thank you
But I didn't say LOBL-LOAL, I said LOBS-LOAL(Low off boresite - Lock on after launch)

So what I was saying is. Not all LOAL (Lock on after launch) shots are HOBS (high off boresite). Technically you can have a LOAL (lock on after launch) LOBL (low off boresite) shot.

Basically when you have the plane in front of you but the seeker can't see it yet (because All seekers take time to register their target depending on the heat if its an IR seeker or the RCS if its a Radar guided seeker) but you shoot anyway, and simply data link the data after.
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Unread post31 Jan 2017, 09:27

sprstdlyscottsmn wrote:Sustained 28 deg/s Nz turn at 20,000ft? Let me go into why this is a great big "No".

First is the lift required to get there in the first place. For a Raptor whose motors are .2sec away from fuel starvation and has no weapons this turn rate would require a CLmax between 2.07 and 4.65 for 9G and 4G respectively. 2.07 is not an unreasonable CLmax value for the Raptor, but turning at Empty Weight is. For the standard AA loadout and 60% internal fuel the CL max values go up to 2.74 and 6.17 for those respective Gs. These values are absurd. The idea that the Raptor can hit 28deg/s in an Nz turn at all about defies physics.

Second, to SUSTAIN said turns you would need un-holy amounts of thrust. On vapors the raptor would need to be putting out in excess of 106,174 lb of thrust, as that is the minimum possible INDUCED DRAG ALONE. I also can guarantee you will not see an "e" of 1 with a Cl over 2, .5 would more reasonable than 1, so even my absurdly optimistic numbers are absurd. To do that turn at the Loaded Weight? 186,565 lbs of minimum possible Induced Drag. Yes the Raptors engines are powerful but if they were that powerful the .8M to 1.5M acceleration would be 10 seconds not 57 seconds..

Spurt, how do you estimate drag or Cd from Cl value?,and what are induced drag?
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Unread post31 Jan 2017, 13:45

Induced Drag is the drag created as a result of the lifting force. The aerodynamic force we generally think of as lift does not act perpendicular to the flight path or the wing surface. It pulls up and back. The up part is what we call lift, the back part is induced drag. It is estimated as Cl^2/(pi * e * AR) where AR is the aspect ratio and e is the Oswald's Efficiency Factor. The e can vary depending on airflow and angle of attack and it is often averaged as 0.8. I used the unrealistic value of 1 just to prove how absurd the amount of drag being generated was. As an example, some wind tunnel test results I have for an F/A-18 indicate that e can drop down around 0.5 at CL max for a fighter. Hope that helps, I need to get back to my coffee.
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Unread post01 Feb 2017, 01:32

sprstdlyscottsmn wrote: The up part is what we call lift, the back part is induced drag. It is estimated as Cl^2/(pi * e * AR) where AR is the aspect ratio and e is the Oswald's Efficiency Factor. The e can vary depending on airflow and angle of attack and it is often averaged as 0.8.

Do i then use Cl^2/(pi * e * AR) and multiply it with the lift required ( aircraft weight*G value) to calculate induced drag?
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Unread post01 Feb 2017, 03:47

eloise wrote:
sprstdlyscottsmn wrote: The up part is what we call lift, the back part is induced drag. It is estimated as Cl^2/(pi * e * AR) where AR is the aspect ratio and e is the Oswald's Efficiency Factor. The e can vary depending on airflow and angle of attack and it is often averaged as 0.8.

Do i then use Cl^2/(pi * e * AR) and multiply it with the lift required ( aircraft weight*G value) to calculate induced drag?

No, you multiply the Cl^2/(pi * e * AR) by (0.5 * air density * V^2 * Wing Area) , or qS. To get the CL value you take the lift and decide by qS.
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