Cat III Limits AOA
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I see in that one you ALSO linked to a previous thread XD
How deep does the rabbit hole go??
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The CAT III system is a g-command system with only an AOA feedback. It won’t take your loadout configurations or Gross Weight into account. You are able to pull 9G at low AOA. But as soon as the AOA reaches 15.5°-15.8°, max G command is reduced to 1G in order to prevent any AOA excursions. (According to T.O.1F-16CM-1-2, each type of configurations has its own G limits. And pilots are responsible for keeping the jet below the limits. FLCS will not do that for you.)
The concept is, by limiting the AOA, the available Gs will be reduced. (pure physics). Let’s take an HAF F-16C Block52+ flying at 0.4Mach with a Gross Weight of 34000lbs for instance. Under CAT I configuration, you can pull to a max 4.8G. But with CAT III, the load factor reduced to 3.8G. This is because the aircraft requires higher AOA to produce enough lift in order to reach a higher load factor (under a certain Gross Weight/Airspeed conditions)…
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You can see then, that limiting the available alpha does limit the available G. As the alpha gets to 16°, the FLCS limits the available G command to prevent the alpha increasing further…So I put 34089 pounds of bombs on the jet and CAT III was automatically set. And took off. Using the chart Peregrine provided, at 10,000 feet what kind of feedback from the jet instruments, or the jet itself, should I look for at mach .4, mach .63, and higher mach as I attempt to pull Gs?
Edit: Just saw Toad’s post, but may I get a response here anyway?
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If you make a limiter pull with a GW of 34K lbs, in CAT III at 10K ft and M0.4, in a block 52 jet, you will get 3.66G. If you first switch to CAT I, you will get 4.8G instead. If you accelerate to M1.0 first you will get 9.0G instead.
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the purpose of CAT limiter has never been to control G’s or protect stations from overG
point beeing you can pull 9G easily in cat3
the purpose of the CAT limiter is to restrain AOA / G couple and roll rate to limit the roll depatures in case of loads.
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You can see then, that limiting the available alpha does limit the available G. As the alpha gets to 16°, the FLCS limits the available G command to prevent the alpha increasing further.There was a chart in the original post. How do you read that chart?
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Yeah, we goofed it up actually.
Enter the bottom of the chart with mach number, and follow it vertically until you intercept the altitude reference line. Follow that across to the baseline on the left panel. Enter the panel at the bottom with gross weight and follow that vertically upward. Then from the original entry at the baseline, draw a line parallel to the curve to the second line drawn from GW, then go horizontally left to read available G. I think.
Its all in the dash, but I dont have it to hand at the moment, so thats guessing really.
The goof was that the chart has a sample entry in green and red, showing two speeds (M0.4 and M0.66), but it doesnt use the correct baseline and I think overestimates allowable G due to that. Would have to check the dash to be sure.
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Yeah, we goofed it up actually.
I don’t think you goofed that chart up. It shows the correct baseline at 34,000 pounds for CAT I and CAT III, and the Gs for 10,000 Altitude and mach .4 and .6. Anyway, here are the instructions from T.O. GR1F-16CJ-1-1
Actually, the chart I was asking about was the chart you included in your post yesterday at 01:30, the 4th post in this thread. How do you read that one?
Edit:
I read Flight Model (FM) Developer’s Notes Part 4, “Revealing the Dark Side of the F-16-FLCS”, pages 16-17 but I’m still not sure how to interpret those dashed lines. -
Oh. Well, that one is a lot easier - or simpler perhaps is the better word.
Conditions to the left of the appropriate line are valid. Conditions to the right of the appropriate line are outside the FLCS limits.
At 15 degrees alpha, you can get 9G if you are going fast enough, regardless of CAT switch position. At 25 degrees alpha, you can only get 1G flight - and then only in CAT I. Switch to CAT III at that moment and it would command nose down to lower the AoA to somewhere around 15.5 degrees alpha.
As for the other chart, I didnt goof it up in my last post, but the one prior, and the colors highlighting an example, are goofed at the part where the two lines meet. It does mean that the numbers I quoted are incorrectly high.
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…Conditions to the left of the appropriate line are valid. Conditions to the right of the appropriate line are outside the FLCS limits.
At 15 degrees alpha, you can get 9G if you are going fast enough, regardless of CAT switch position. At 25 degrees alpha, you can only get 1G flight - and then only in CAT I. Switch to CAT III at that moment and it would command nose down to lower the AoA to somewhere around 15.5 degrees alpha.
Thanks for this explanation of the dashed lines in the chart in post #4 of this thread.
As for the other chart, I didnt goof it up in my last post, but the one prior, and the colors highlighting an example, are goofed at the part where the two lines meet. It does mean that the numbers I quoted are incorrectly high.
You got my head spinning on this. When you say “my last post, but the one prior” which post are you talking about? The chart in post #2 in this thread looks OK. If possible, could you show the chart that you say is incorrect and then show a corrected version of that chart?
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The chart is correct - the green and red lines overlayed on that chart show an invalid solution.
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Sry my fault. Corrected:
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Here’s the corrected….
okay, Im too slow.
Here’s my version XD
