Effect of pitch angle on radar detection altitude
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Quick full rolls in sequence on one direction are neither recommended nor useful. Its actually forbidden in the real F-16 flight manual. Risk of roll departure is too important, especially if you are in CAT1 with a CAT3 loadout.
Tell me one situation where you need to do 2 or 3 full rolls in a row.
In fairness this speaks more to the fact that you shouldnt be in CAT I if you have a CAT III loadout…
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In fairness this speaks more to the fact that you shouldnt be in CAT I if you have a CAT III loadout…
It’s a good idea to switch to CATI before releasing bomb load on a pop-up or loft profile. Then you don’t have to take your hand off the HOTAS to flip the CATI/III switch after releasing the bombs. You might need CATI limits to dodge the AD.
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In fairness this speaks more to the fact that you shouldnt be in CAT I if you have a CAT III loadout…
Very true. But it can happen anyway, either by error or before a bomb release, as caper said.
Anyway, if you do quick rolls in succession, no matter your loadout, your AOA will gradually increase, up to a point where roll departure becomes likely when your roll rate is important.
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It’s a good idea to switch to CATI before releasing bomb load on a pop-up or loft profile. Then you don’t have to take your hand off the HOTAS to flip the CATI/III switch after releasing the bombs. You might need CATI limits to dodge the AD.
After dropping bombs, I still have a pair of wing tanks. In real life, I believe that set-up can be CATI when they’re empty for x%, but not sure how BMS handles this, so I keep it in CATIII.
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Wings tanks is CAT 1 in real.
But Sniper is CAT3 so…. -
Wings tanks is CAT 1 in real.
But Sniper is CAT3 so….Any chance that the TGP will end up as a removeable store like ECM pods are in a future release?
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Gimbal limit is important in pitch. As the antenna has a +60/-60 field, you really need to get your nose up or down to lose coverage. Gimbal in yaw is not really relevant, the radar does not scan in a specified fixed bearing but always compared to the AC nose.
The antenna moves pretty fast anyway : a bar scan takes 2s to scan 120°. So I think it can keep up with whatever pitch rate you have.
Roll rate is something else though. As you need to keep the bar horizontals, and the F-16 roll rate is quite big, you can lose the ability to do a proper scan. Maybe have troubles maintaining track too.
But you are not really supposed to do quick rolls in succession anyway, its neither useful nor safe for departures prevention.Yeah but if you scan lets say 0 30 kgft , which is max opening of your antenna down up , if you pitch 30 deg up , the down mechamixal limit is not the same so the result could something like 8 - 30….
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Yeah but if you scan lets say 0 30 kgft , which is max opening of your antenna down up , if you pitch 30 deg up , the down mechamixal limit is not the same so the result could something like 8 - 30….
Good point. I guess the antenna can move 60° in all direction, resulting in a “cone”, and not a “pyramid” of possible directions, is that it ?
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Good point. I guess the antenna can move 60° in all direction, resulting in a “cone”, and not a “pyramid” of possible directions, is that it ?
So assuming the antenna scan the most opened any pitch change should result in a variation of max or min because of mechanical limits
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Well, it was pasted as-is…
As was mine. Straight out of the CDCs for an avionics technician working on the airframe.
So according to your assumption,
No assumption here. This is out of technical data that maintainers are given to learn to fix the aircraft.
if the bird looses INS, = no radar proper operation due to drifts… Or better, if INS = off, and GPS = jammed or EGI lost alignment, then again no radar proper tracking…
LOL well I think that if a pilot loses that much of his aircraft whether or not his FCR is stabilized is the LEAST of his concerns. Just saying.
The antenna movement vs aircraft reactions is controlled from its dedicated Inertial Measurement Unit. The FCR through MMC and INS provide target data placement in the 3D space and FCR MFD.
What is your source? I’ve listed mine.
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As was mine. Straight out of the CDCs for an avionics technician working on the airframe.
What is your source? I’ve listed mine.
Directly from that little v9 thing that is inside the radome.
I have no idea what the cds state, but everything required by the topic question are clearly answered there.
LOL well I think that if a pilot loses that much of his aircraft whether or not his FCR is stabilized is the LEAST of his concerns. Just saying.
Well, I don’t think that this is an clear answer to the “scenario” nor is the “that much”, more a maneuver 2 me.
Just saying…
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The radar antenna has a maximum gimbal area. What happens if you are flying higher and use in level flight in a -30 deg elevation then you do a barrel roll to evade a SAM?
The antenna has +/- 60 degrees about both axis so I highly doubt a barrel roll is going to cause it to go to gimbals. Now having the antenna set to the horizon and going beyond 60 degrees into the vertical will.
It can happen that to keep the necessary scan zone the radar will go outside the gimbal limit… This does not modeled in game. What about the realitiy? Regardless of turn rate the radar is capable to change always and so quickly the scan pattern?
The FCR computer sends update commands for antenna positioning 200 times per second. I think it can hang as long as it is within gimbal limits and doesn’t exceed roll stabilization.
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Directly from that little v9 thing that is inside the radome.
Are you honestly trying to state the functions of the FCR system based on what the radome says?
I have no idea what the cds state, but everything required by the topic question are clearly answered there.
I do as I pulled mine out and read it to come up with this answer.
Well, I don’t think that this is an clear answer to the “scenario” nor is the “that much”, more a maneuver 2 me.
Just saying…
It should be pretty obvious that if you have lost INS and GPS so you only have good weather (IF you even have that) and TACAN to get home your primary concern is getting your bird back home on the ground. The FCR system losing it’s stabilization feature thanks to that is a problem but it is not your PRIMARY problem.
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Long time ago I wanted to ask I just always forgot until I saw in EF2000 (DID, 1995). In Falcon why is not modeled the effect of pitch angle on the elevation values of radar detection? Of course I guess that until a certain angle the system can compensate the effect but for ex if you are in a 60 deg climb or dive is hard to keep the same position if eleavation was the min… or max.
I am not sure if i understand correct. Is this (pic) your question?
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It should be pretty obvious that if you have lost INS and GPS so you only have good weather (IF you even have that) and TACAN to get home your primary concern is getting your bird back home on the ground. The FCR system losing it’s stabilization feature thanks to that is a problem but it is not your PRIMARY problem.
There is a big difference in the question in a situation given “what should the pilot do” and “what behavior will the system exhibit.” If he asks is FCR behavior if X fails it has nothing to do with practical advice. He wants to know how the mechanical system behaves.
I’m curious if radar train limits are 120/120 then it’s a square solid angle. If you go +60 pitch zero bank then the bottom of the search solid angle is parallel to horizon 120 degrees wide. This is easily understood.
But if bank is involved then radar can theoretically see more than 60 degrees off the nose if it’s a combination of lateral and vertical. I wonder if at +80 pitch, 45 bank if the radar will scan the horizon limited in azimuth. Pythagoras says the corner of the search volume should be ~84 deg off the nose.
Is the FCR smart enough to attempt to scan the desired horizontal slice of air if only the corner of the scan volume can reach it? I assume the scan pattern is horizon-seeking (traverse of the antenna is a mix of tilt and pitch if there is non-zero bank). In the case of bank the scanable space becomes rhombus shaped instead of a rectangle.
One more question if you exceed the limits of traverse will the radar scan and detect in the closest scanable slice? Or will it not attempt to acquire contacts outside the expected volume?
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@A.S:
I am not sure if i understand correct. Is this (pic) your question?
Yeah A.S. that is roughly what he is getting at. The question is what happens when you go beyond the physical gimbals of the FCR and it cannot scan the same space you selected. Good question as my CDCs don’t even cover the scenario.
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Well i know the answer (horizontally and vertically), in other words i know where my radar-gimble and -gate is at all times, but ain´t that very simple to test ingame for those who want to find out for themself? I mean just put up a high-aspect engagement online with a mate and at good distance and give it a shot.
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There is a big difference in the question in a situation given “what should the pilot do” and “what behavior will the system exhibit.” If he asks is FCR behavior if X fails it has nothing to do with practical advice. He wants to know how the mechanical system behaves.
Which I had explained and he had verified while explaining this hypothetical situation. He didn’t ask if that is what it would do, he made the statement based on my “assumption” then proceeded to incorrectly state how the system works again.
However just in case it wasn’t clearly received I will re-state how it works. The FCR system gets pitch and roll from the INS system. The PSP in the FCR is what commands the antenna to move about and that is how it is pitch and roll stabilized. The antenna doesn’t have it’s own INS and it doesn’t correct it’s position by itself. That is all commanded via the PSP.
So his hypothetical is correct in that if you lose your INS/GPS then you also lose FCR stabilization as it won’t have INS data to work from.
I’m curious if radar train limits are 120/120 then it’s a square solid angle. If you go +60 pitch zero bank then the bottom of the search solid angle is parallel to horizon 120 degrees wide. This is easily understood.
The antenna can go +/- 60 degrees in both axis so yes 120/120 is correct. So if you went 60 degrees nose high no bank the lowest the scan could go would be at the horizon due to gimbal limits. 70 degrees high no bank, 10 degrees above the horizon, so on and so forth.
But if bank is involved then radar can theoretically see more than 60 degrees off the nose if it’s a combination of lateral and vertical. I wonder if at +80 pitch, 45 bank if the radar will scan the horizon limited in azimuth. Pythagoras says the corner of the search volume should be ~84 deg off the nose.
I’m not a math wizard so I couldn’t tell you that.
Is the FCR smart enough to attempt to scan the desired horizontal slice of air if only the corner of the scan volume can reach it? I assume the scan pattern is horizon-seeking (traverse of the antenna is a mix of tilt and pitch if there is non-zero bank). In the case of bank the scanable space becomes rhombus shaped instead of a rectangle.
One more question if you exceed the limits of traverse will the radar scan and detect in the closest scanable slice? Or will it not attempt to acquire contacts outside the expected volume?
The CDCs don’t even mention what happens in simple circumstances of say 70 degrees pitch no bank. Perhaps a -34 or a -1 explains what it does but I would have to dig farther for answers to that.
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… When you say INS/GPS … Lets by clear, while FRC (radar) can get a/c’s attitude from the INS, it can’t get it from the GPS.
GPS provide only a position, true course, ground speed, altitude relative to the earth mathematic geoid … But ever never can provide a/c’s attitude. -