S530 Range

[whiteladder]

 

If the missile dive for the target in terminal phase it may be the sign of a loft flight profile...isn't it ?

:

 

No it dived straight after launch, not in the terminal phase.

[Svend_Dellepude]

Question is how useful a loft profile would be against fighters/ highly maneuverable aircrafts anyway.

[jojo]

Because it increases missile's terminal speed, so its maneuverability.

 

Indeed for the same range the same missile without loft may not be able to intercept evading target while the same with loft will succeed because it's diving on target with higher speed.

 

So it's very important...

Edited December 12, 2015 by jojo

[Svend_Dellepude]

Doesn't that depend on the distance and trajectory it has to travel to impact?

[jojo]

Yes, we already said it in previous page: loft is for long range shot. You don't loft for close range shot.

 

But the missile is fed with firing data including target range. So the missile knows if it must loft or not.

[Svend_Dellepude]

Just trying to say that longrange SARH shots against fighters are a waste of ammo.

ARH makes sense because the bandit doesn't know what is coming his way, but an STT will get him defensive as soon as he gets the warning unless he is a complete moron or AI.

Might be useful against bombers as someone else suggested though.

 

Just my oppinion of course. :)

[whiteladder]

Doesn't that depend on the distance and trajectory it has to travel to impact?

 

Absolutely loft profile against a manouvering target with the Aim-7M would lead to a lower pk than an proportional shot. It would not not be used against a target that was at a significantly lower altitude than the launch aircraft any way and the first thing a manouvering aircraft at the same altitude will perform is a dive to a beam aspect. The chance of the missile hitting a gimbal limit or losing the tail reference signal is increased with a loft profile. If the reference signal is lost it will not guide against lower target.

[mjmorrow]

Question is how useful a loft profile would be against fighters/ highly maneuverable aircrafts anyway.

 

I think that is a beautiful aspect of the SARH BVR show. The medium range missiles were generally intended for taking out bombers flying straight and level. Fighters are not the easiest targets. If my Mirage 2000c's Super 530D missiles hit a maneuvering fighter one out of four times or one out of ten times, I will be satisfied with the performance of the Super 530D. My primary interest in firing the Super 530D is to get the other guy to dance, so I can close in and have a WVR fight, otherwise the Super 530D is just what I put on my wings when I don't have those crazy big fuel tanks there. :lol: I consider my 30 mm cannons and the Magic II missile my primary killing weapons. I assume that my superiors would not authorize me to fire a BVR missile except under highly controlled conditions, where it was certain that what I am firing on is an enemy fighter. Most times, I would be expected to close within visual range, clearly identify what the target is in point of fact, and then not authorized to fire unless given express permission to do so or in a situation where the other guy gave me a clear justification to fire, such as maneuvering in a way that indicated that he intended to engage me and fire on me, at which point I would be depending on the dogfighting prowess of the Mirage 2000c and employing the Magic II, and/ or my 30mm's.

 

:thumbup: MJ

Edited December 13, 2015 by mjmorrow

[il_corleone]

I think that is a beautiful aspect of the SARH BVR show. The medium range missiles were generally intended for taking out bombers flying straight and level. Fighters are not the easiest targets. If my Mirage 2000c's Super 530D missiles hit a maneuvering fighter one out of four times or one out of ten times, I will be satisfied with the performance of the Super 530D. My primary interest in firing the Super 530D is to get the other guy to dance, so I can close in and have a WVR fight, otherwise the Super 530D is just what I put on my wings when I don't have those crazy big fuel tanks there. :lol: I consider my 30 mm cannons and the Magic II missile my primary killing weapons. I assume that my superiors would not authorize me to fire a BVR missile except under highly controlled conditions, where it was certain that what I am firing on is an enemy fighter. Most times, I would be expected to close within visual range and not fire unless the other guy gave me a clear justification to fire, at which point I would be depending on the Magic II or my 30mm's.

 

:thumbup: MJ

 

Well, with the Mig 21 I made a lot of kills (Considering my death ratio :D ) using his R-3R, so with the 530D it will be easier to take down targets at "medium range" of 20km or less, I expect to have good kill ratio at that distance :) and if not, we can enter with the Magic and the cannon

[Zeus67]

There is one bit of information that I inadvertently dismissed regarding radar lock: target aspect.

 

The M-2000C's RDI is a pulse-doppler radar, in fact that is what RDI means in French: Radar Doppler à Impulsions. Allow me to quote wikipedia:

 

A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. This variation gives direct and highly accurate measurements of the radial component of a target's velocity relative to the radar.

 

BTW, the radars used by the police to fine speeding drivers are doppler radars.

 

Why is this important? Well, as I said, I dismissed something that I had read a long time ago about radar interception: A doppler radar cannot detect a target that is traveling perpendicular to its beam.

 

It seems our friendly AI pilots know this rule and as soon as they can, they will try to fly perpendicular to your flight path in order to become invisible to your radar. And I was helping them by flying directly to them! :). So after remembering this little bit of trivia, on my next engagement as soon as I detected that my target was trying to go perpendicular, I altered my flight path to keep them in a slant trajectory and thus denying them their "invisibility cloak".

 

I'll explain how you can do that in the radar thread tomorrow.

[SDsc0rch]

remember, its not perpendicular to your flight path over the ground - its is perpendicular to your radar beam

 

so no matter what your maneuver is, he can fly to the notch by putting you on his beam (3-9 line)

[Zeus67]

remember, its not perpendicular to your flight path over the ground - its is perpendicular to your radar beam

 

so no matter what your maneuver is, he can fly to the notch by putting you on his beam (3-9 line)

 

Of course, but since it is impossible to keep flying perpendicular to the radar beam, in this case the trick is to do it long enough for the radar to lose lock and thus for the missile to enter ballistic flight.

 

This is easier when your RWR tells you that the radar is in guidance mode and thus it is locked in your direction.

[PiedDroit]

A doppler radar cannot detect a target that is traveling perpendicular to its beam.

If I may, let me add something to avoid people think notching is a magical thing:

It can actually detect such a target, I mean, even if you fly zero doppler you still give a distance and azimuth - keyword here is "pulse", the radar is not continuously emitting, therefore it can get distance readings.

However the zero doppler will allow you to mix better with the environment clutter: ground, clouds and chaffs.

[mjmorrow]

There is one bit of information that I inadvertently dismissed regarding radar lock: target aspect.

 

The M-2000C's RDI is a pulse-doppler radar, in fact that is what RDI means in French: Radar Doppler à Impulsions. Allow me to quote wikipedia:

 

 

 

BTW, the radars used by the police to fine speeding drivers are doppler radars.

 

Why is this important? Well, as I said, I dismissed something that I had read a long time ago about radar interception: A doppler radar cannot detect a target that is traveling perpendicular to its beam.

 

It seems our friendly AI pilots know this rule and as soon as they can, they will try to fly perpendicular to your flight path in order to become invisible to your radar. And I was helping them by flying directly to them! :). So after remembering this little bit of trivia, on my next engagement as soon as I detected that my target was trying to go perpendicular, I altered my flight path to keep them in a slant trajectory and thus denying them their "invisibility cloak".

 

I'll explain how you can do that in the radar thread tomorrow.

 

Thank you very much for the tips. The way the radar works seems really neat. I like the limitations, a whole lot. That will really make using the radar and learning how to interpret the radar very exciting. The radar reminds me of how humans see things. We don't necessarily see what is there, right before our eyes, we see our mind's interpretation of what is there. The radar has analogous limitations and in its flawed conception mirrors, in a way, our own everyday experience of the limitations of visual perception. This makes the radar, something I am not very familiar with, somewhat relatable. :thumbup: MJ

Edited December 13, 2015 by mjmorrow

[mjmorrow]

Well, with the Mig 21 I made a lot of kills (Considering my death ratio :D ) using his R-3R, so with the 530D it will be easier to take down targets at "medium range" of 20km or less, I expect to have good kill ratio at that distance :) and if not, we can enter with the Magic and the cannon

 

That is really great that you know how to get the kills at that distance. I am not even too sure if I have ever had a kill in multiplayer with the Mig-21. I once had a A-10 lined up and someone dove in in front of me and finished the A-10 off. I barely know what is going on around me, when I use the Mig-21. I am there one minute, then, Poof! I am hanging in a parachutte.:megalol:

 

I don't have your skills, Corleone. Till I can consistently refuel the Mirage 2000c in the air, I know what is going on with the radar, how to use notching, and all of that, I am probably better off taking the wing tanks, in place of the Super 530D. I can let my more experienced 4TH Gen fellow sim pilots handle the medium range dance. I will try to learn how to work my way inside and behind my opposition, so I can get within shouting distance, for a Magic II shot.

 

:thumbup: MJ

Edited December 13, 2015 by mjmorrow

[Beamscanner]

At what velocity does the Doppler notch kick in for the RDI on the Mirage?

 

"Doppler notch" isn't truly a factor of angle/aspect, but rather of closing velocity. (i.e. the effective notch angle of a target widens as it slows down, and narrows as it speeds up)

[PiedDroit]

(i.e. the effective notch angle of a target widens as it slows down, and narrows as it speeds up)

I'm not sure to understand this, care to elaborate?

 

I think there is a mix up of terms here, if I understand correctly, "Doppler notch" threshold is simply used to eliminate slow moving objects from radar picture (i.e. any object within ground clutter with a doppler giving a speed < Xkts is rejected, effectively filtering ground vehicles).

Any object that has either high S/N ratio (i.e. not in clutter) and/or high doppler (i.e. moving fast enough) would be kept.

 

Notch angle would be something else that could "widen" or "narrowing" (?).

Edited December 13, 2015 by PiedDroit

[Zeus67]

As far as I remember, all Doppler radars suffer from the same weakness. If the contact manages to travel perpendicular to the radar beam, the radar will filter it out because Doppler radars detect objects by the changes in the returned beam's wave frequency due to the object's motion.

 

If the contact is perpendicular to the beam, there is no wave frequency change thus the contact becomes invisible to the radar.

 

I read this in a very old book (circa 1982) about the world's greatest interceptors (at the time of course :) ) and it had an entire chapter dedicated to radars and how they work.

[Azrayen]

As far as I remember, all Doppler radars suffer from the same weakness. If the contact manages to travel perpendicular to the radar beam, the radar will filter it out because Doppler radars detect objects by the changes in the returned beam's wave frequency due to the object's motion.

Uh, AFAIK the doppler filter (that throws out anything that travels perpendicular to the radar beam) is intended to remove ground echos.

Hence this filter is only active when the radar is looking down.

There is no way of "beaming" (that's the name for travelling perpendicular to the radar beam) a pulse-doppler radar when said radar is in look-up mode (no ground echo received = no need to filter = no doppler filter applied).

 

This is actually quite correctly modelized in the "old" FC3 fighters (since LO in fact).

The notion of radar horizon (Earth curvature) is implemented too for the radar to decide if it should work in look-up or look-down mode.

[JNelson]

There is still a frequency change when an aircraft is notching it is just the right frequency to correspond with a closure rate of the aircraft's speed. If there was no change in frequency it would mean that the object is travelling the same speed in the same direction as the aircraft.

[Azrayen]

Yes indeed.

And ground echos have the same closure speed as an aircraft beaming.

[VincentLaw]

There is still a frequency change when an aircraft is notching it is just the right frequency to correspond with a closure rate of the aircraft's speed. If there was no change in frequency it would mean that the object is travelling the same speed in the same direction as the aircraft.

Yes, but at certain relative velocities the Doppler shift is the same on the target as the ground clutter. That was the intended point.

[Bacab]

Hence this filter is only active when the radar is looking down.

That's not entirely true. In reality the radar antenna emits most of its energy in an area in front of it (in the case of a mechanical antenna). However you still have secondary emissions (called side lobes) around this main area of emission that can be reflected by the ground even if the antenna does not directly point to the ground. This produces echoes that need to be removed by doppler treatment, hence it may be present even if the antenna is not looking down. Obviously the influence of those side lobes vary with altitude and other parameters.

 

EDIT: I have to had that the radar may echo undesired things in the main lobe even if not looking down; in the case of a mountain for instance. Therefore I think the doppler filter presence does not rely on antenna elevation.

Edited December 13, 2015 by Bacab
Add precisions and personal guess

[Beamscanner]

I'm not sure to understand this, care to elaborate?

 

I think there is a mix up of terms here, if I understand correctly, "Doppler notch" threshold is simply used to eliminate slow moving objects from radar picture (i.e. any object within ground clutter with a doppler giving a speed < Xkts is rejected, effectively filtering ground vehicles).

Any object that has either high S/N ratio (i.e. not in clutter) and/or high doppler (i.e. moving fast enough) would be kept.

 

Notch angle would be something else that could "widen" or "narrowing" (?).

 

Depending on the targets closing velocity, the notch angles widen or narrow.

 

For example a high speed target may need to get within +- 4 degrees of perpendicular (86-94 degrees) from your radar beam to reduce the relative closing velocity enough to be filtered out with the low doppler ground clutter.

 

Now if that target is already flying at low speed, then your target will fall into your doppler notch much earlier into a beam maneuver. The target may only need to put you within +- 10 degrees of perpendicular because its closing velocity is already low.

 

The exact notch angles vary on your targets speed and your radars exact velocity notch. (i.e. anything below X knots get filtered out) The lower the velocity notch filter, the harder it is for your target to get filtered out (they need to be closer to 90 degrees perpendicular. But it also means more ground clutter traveling at high speed can make it into your radar processor, such as cars)

 

If your wondering if it helps in game to slow down in a beam maneuver so as to hide your return.. yes it does. So long as your cool with losing that energy.

 

I'm sure many of you have seen how easily you can lose track on a low speed ground attack aircraft. (tho terrain masking plays a big role in this as well)

Edited December 13, 2015 by Beamscanner

[PiedDroit]

Depending on the targets closing velocity, the notch angles widen or narrow.

 

For example a high speed target may need to get within +- 4 degrees of perpendicular (86-94 degrees) from your radar beam to reduce the relative closing velocity enough to be filtered out with the low doppler ground clutter.

 

Now if that target is already flying at low speed, then your target will fall into your doppler notch much earlier into a beam maneuver. The target may only need to put you within +- 10 degrees of perpendicular because its closing velocity is already low.

 

The exact notch angles vary on your targets speed and your radars exact velocity notch. (i.e. anything below X knots get filtered out)

 

If your wondering if it helps in game to slow down in a beam maneuver so as to hide your return.. yes it does. So long as your cool with losing all of your energy.

Thanks, I get what you mean now :thumbup: