Pakistan F-16 Discussions 2

[Donatello]

View attachment 41785
guys what is that ??
@Munir @Manticore @araz@dexter

That's called elegance.

 

[Windjammer]

View attachment 41785
guys what is that ??
@Munir @Manticore @araz@dexter

They are called airbrakes, all jet aircraft have them on different locations.
The likes of F-15, Typhoon or SU-30 have a massive airbrake on the spine.

 

[Munir]

Windjammer has explained it perfect. Brakes are wheelbrakes... These flaps to use airflow to stop kinetic energy are AIRbrakes. And indeed different position which has lots of impact on flight characterisitics, system, usage etc... The Gripen can use flaps as airbrakes during landing (not inflight!) because they are placed well behind nose gear (so the pressure goes to the middle of the plane and not flipping the aircraft or destroying nose gear. If you look at the EF2000 then you see that it will flip... Putting the brakes in front means lots of turbulent airflow so you need to strengthening rudder a lot more... And there is lots of impact when you look at the size. One big like Flanker, F15 or EF2000? 4 like Mirage (above and under wing), 4 like JF17 (above and under belly) or three (f6?).... There is a huge variety and lots of impact. Only if you think of rcs then there are lots of variables when it comes to airbrakes. Not just simple a stiff panel that flips out!

Looking at JF17 style... Being effective and cheap was the motto. So 4 small (less pressure needed to extend or retract) placed around the main body (less impact if used during flight) and at the end (less effect of turbulence caused by airbrakes).. Besides that very low impact on rcs and one can control very neatly the braking power then with one big door (A la flanker).But the F16 style is a little better. Yet more complex. It blends the brakes perfect into the body. But terrible impact on rearward RCS.


Besides airbrakes and wheelbrakes one has another form...The Tornado has thrust reversing system. It makes the aircraft dirty ( ). and there is no option of chute...

 

[Manticore]

air break over ventral fin

 

[airmarshal]

That is true, you simply need the HTS pod and the AGM-88 (or any other compatible missile). I mentioned this once before but I would really love to see HARMs in the PAF arsenal.. it is a game changer and definitely a very successful, tested weapon.

It is unfortunate that they can prove to be quite costly and the US doesn't give them up easily. I wonder if the MAR-1's are compatible with our F-16s, or whether the US would allow it....

Turkey has HARM capable F-16Cs. All block 50 and onward F-16s can carry them provided they have HTS pod. I think not all CCIP F-16s can carry them.

CCIP F-16s preceded the block 50 version when older F-16s were brought to Common Configuration with F-16 block 50 and 52 standards.

Correct me if I m wrong, I think the F-16 MLU can carry HARMs.

 

[Donatello]

Turkey has HARM capable F-16Cs. All block 50 and onward F-16s can carry them provided they have HTS pod. I think not all CCIP F-16s can carry them.

CCIP F-16s preceded the block 50 version when older F-16s were brought to Common Configuration with F-16 block 50 and 52 standards.

Correct me if I m wrong, I think the F-16 MLU can carry HARMs.

Yes they can, plus you use the HTS pod anyway for initial guidance.

Turkey cannot be seen as an example, because they are member of NATO, and as such can buy what ever they want.

 

[airmarshal]

Yes they can, plus you use the HTS pod anyway for initial guidance.

Turkey cannot be seen as an example, because they are member of NATO, and as such can buy what ever they want.

If thats the case, Turkey being a NATO member, I dont see Pakistan getting HARMs. I dont think US has exported them to any non-NATO country.

 

[gambit]

The speedbrake, or airbrake, is a member of the flight control devices, or structures, family. The thing about the speedbrake is that it can be removed, but it cannot be installed.

What I mean is that if an existing design have a speedbrake and we decide not to use it anymore, we can disable or even literally remove speedbrake from each aircraft. But we cannot arbitrarily install the speedbrake on any existing design just because we think that design is needed. The speedbrake is, or rather should be, designed from paper, as in when the aircraft is in concept.

The speedbrake's job is to produce drag, but not at the expense of aerodynamic disruption to other flight control members that may be downstream from its position or overall affect aircraft's controllability and stability, meaning once deployed, the pilot must still be able to execute maneuvers, albeit within the flight conditions that necessitate the deployment of the speedbrake in the first place, such as landing.

The worst thing a speedbrake can do is to produce pitch attitude change upon deployment. Does not matter if it is pitch up or down. If, even under simulation, a deployed speedbrake is found to induce any pitch attitude changes, especially if it eventually evolves into aircraft oscillation, then the speedbrake's intended location is a poor choice. Not just location but its design parameters, such as area size, speed and angle of deployment, are now suspect. So when landing require the speedbrake and it induces pitch attitude changes on deployment, there is going to be a disaster. Most likely a non-recoverable one.

This is why we can remove the speedbrake but not install it.

 

[Donatello]

If thats the case, Turkey being a NATO member, I dont see Pakistan getting HARMs. I dont think US has exported them to any non-NATO country.

Sold them to their illegitimate child: Israel.

 

[airmarshal]

The speedbrake, or airbrake, is a member of the flight control devices, or structures, family. The thing about the speedbrake is that it can be removed, but it cannot be installed.

What I mean is that if an existing design have a speedbrake and we decide not to use it anymore, we can disable or even literally remove speedbrake from each aircraft. But we cannot arbitrarily install the speedbrake on any existing design just because we think that design is needed. The speedbrake is, or rather should be, designed from paper, as in when the aircraft is in concept.

The speedbrake's job is to produce drag, but not at the expense of aerodynamic disruption to other flight control members that may be downstream from its position or overall affect aircraft's controllability and stability, meaning once deployed, the pilot must still be able to execute maneuvers, albeit within the flight conditions that necessitate the deployment of the speedbrake in the first place, such as landing.

The worst thing a speedbrake can do is to produce pitch attitude change upon deployment. Does not matter if it is pitch up or down. If, even under simulation, a deployed speedbrake is found to induce any pitch attitude changes, especially if it eventually evolves into aircraft oscillation, then the speedbrake's intended location is a poor choice. Not just location but its design parameters, such as area size, speed and angle of deployment, are now suspect. So when landing require the speedbrake and it induces pitch attitude changes on deployment, there is going to be a disaster. Most likely a non-recoverable one.

This is why we can remove the speedbrake but not install it.

Never ever thought speed brake could involve so much technology and parameters.

 

[gambit]

Never ever thought speed brake could involve so much technology and parameters.

Yes, they do...Here is an example...

http://naca.central.cranfield.ac.uk/reports/arc/rm/2614.pdf

Reports and Memoranda No. 2614* June, 1942

For dive bombers, the drag should reduce the terminal velocity sufficiently to enable the aeroplane to be pulled out of the dive at a reasonably low height. It is clearly impossible to specify this requirement exactly, but it is probable that a terminal velocity of about between 300 and 350 m.p.h. in a 50-deg. dive should be aimed at. The terminal velocity of the Ju.88, for example, is about 350 m.p.h. (50-deg. dive, weight 26,200 lb). Fig. 2a shows very roughly the size of the flaps needed to fulfil these conditions on a typical modern aeroplane.

For torpedo aircraft, the air brakes must enable the aeroplane to lose speed as rapidly as possible in level flight after a dive from, say, 6,000 ft. It has been suggested that the speed possible in level flight after a dive from, say, 6,000 ft. It has been suggested that the speed should drop to 150 knots within about 9 secs after flattening out.

Finally, it is essential that any form of wing or tail buffeting, or any vibration of ailerons or other control surfaces, must be avoided.

Note the date of the report.

These WW II aircrafts used speedbrakes for purposes other than for landing. A dive bomber had a different attack profile than a torpedo bomber but both needed speedbrakes to foremost stabilize those flight profiles. This is because the torpedo is, in a manner of speaking, more 'delicate' than a bomb. The torpedo must be delivered in a certain manner to increase its odds of survival of impact into the water, the initial drop cannot have the torpedo below a certain depth, the pilot needed a stable aircraft to aim the torpedo, etc. The last sentence indicate what was true then is true today, that speedbrake deployment should not affect other flight control surfaces under flight profiles that uses the speedbrakes.

 

[SQ8]

Yes, they do...Here is an example...

http://naca.central.cranfield.ac.uk/reports/arc/rm/2614.pdf

Note the date of the report.

These WW II aircrafts used speedbrakes for purposes other than for landing. A dive bomber had a different attack profile than a torpedo bomber but both needed speedbrakes to foremost stabilize those flight profiles. This is because the torpedo is, in a manner of speaking, more 'delicate' than a bomb. The torpedo must be delivered in a certain manner to increase its odds of survival of impact into the water, the initial drop cannot have the torpedo below a certain depth, the pilot needed a stable aircraft to aim the torpedo, etc. The last sentence indicate what was true then is true today, that speedbrake deployment should not affect other flight control surfaces under flight profiles that uses the speedbrakes.

A nice mention of how LO aircraft have different methods of airbraking would not go amiss. Both the Raptor and the lightening I believe use their rudders in full deflection to achieve airflow disruption.

 

[gambit]

A nice mention of how LO aircraft have different methods of airbraking would not go amiss. Both the Raptor and the lightening I believe use their rudders in full deflection to achieve airflow disruption.

Any fighter with twin vertical stabs can do the same. Basically, the stabs deflects in equal degree but opposite directions.

The vertical stabilator is not the rudder. It contains the rudder, or some engineers would call it 'rudder panel' or 'rudder structure'. For the example above, the F-22's rudders are splayed -- outboard -- in equal degree. You can see the signs of deflections at the bottom of the rudders.

This is a software based speedbrake design where the flight control surfaces themselves acts in concert to produce the effects of a standalone speedbrake structure, like that huge thing behind the cockpit on the F-15. Software based speedbrake design must not use full deflection because we want to allow the particular flight control surface some freedom to execute maneuvers.

 

[airmarshal]

Yes, they do...Here is an example...

http://naca.central.cranfield.ac.uk/reports/arc/rm/2614.pdf

Note the date of the report.

These WW II aircrafts used speedbrakes for purposes other than for landing. A dive bomber had a different attack profile than a torpedo bomber but both needed speedbrakes to foremost stabilize those flight profiles. This is because the torpedo is, in a manner of speaking, more 'delicate' than a bomb. The torpedo must be delivered in a certain manner to increase its odds of survival of impact into the water, the initial drop cannot have the torpedo below a certain depth, the pilot needed a stable aircraft to aim the torpedo, etc. The last sentence indicate what was true then is true today, that speedbrake deployment should not affect other flight control surfaces under flight profiles that uses the speedbrakes.

Superb explanation @gambit. Mention of dive bomber always reminds me of Luftwaffe Ju-87 Stuka. A truly inspiring plane and a predecessor to A-10 as tank buster. But this is a topic for some other thread

 

[fatman17]

Turkey has HARM capable F-16Cs. All block 50 and onward F-16s can carry them provided they have HTS pod. I think not all CCIP F-16s can carry them.

CCIP F-16s preceded the block 50 version when older F-16s were brought to Common Configuration with F-16 block 50 and 52 standards.

Correct me if I m wrong, I think the F-16 MLU can carry HARMs.

Block 40 and above can.