A serious L-39C AI bug - ED Forums
 


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Old 08-04-2018, 04:21 PM   #1
Dr_Arrow
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Default A serious L-39C AI bug

I have already posted that L-39C AIs are too slow: https://forums.eagle.ru/showthread.php?t=209586

This is some serious AI flight model bug which prevents use of L-39c in any realistic manner in missions as wingman or other tasks (recon, aerobatics, training, etc.). If you set AI L-39C to fly for example at 5000 meters at 600 G/S, its speed will continuously drop up to 323 km/h IAS, which translates to 417 G/S at standard ISA atmosphere. The AI has its throttle at 99% and is flying at 5.7 degrees of AoA and cannot attain any higher speed than 323 km/h. See the attached picture:
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Why is it a bug?? Because the L-39c in clean config should not have any problem to maintain cruise at 5000m at 464 km/h IAS = 600 km/h GS at standard ISA and if you change the aircraft to L-39ZA, which is heavier and has the same engine and nearly the same airframe it has no problem to maintain the set ground speed, it uses 90% RPM and flies at 2.9 AoA:
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This regards only AI flight model, which is correct for the ZA but not working for the L-39C, which seriously limits the use of this aircraft in AI scenarios.
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Old 08-15-2018, 03:22 PM   #2
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Still not fixed (or noticed) in the latest update - DCS 2.5.2.20601 Update 9 OB. I am also attaching a track showing flight of AI L-39C set to maintain 600 G/S at 5000m but barely managing 416 G/S with its throttle set to 99%, there must by something of in its AI flight model. AI L39-ZA is working fine, human L-39s are both working fine.
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File Type: trk L-39c_cruise_bug.trk (24.5 KB, 8 views)
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Old 08-16-2018, 02:24 PM   #3
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At 8000 meters AI is not capable of flying at all and will stall and fall out of the sky. Does this really bother no-one? At 8000 the aircraft is falling out of the sky, it seems like engine power is not well defined or L-39C AI is using some bad flight model. AI L-39C is unusable this way in campaigns or anywhere above 2000 meters.

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Old 08-18-2018, 03:21 PM   #4
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I have noticed similar behavior in the recent past with other AI aircraft for example the M-2000.

Last edited by Rowan; 08-18-2018 at 03:23 PM.
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Old 08-23-2018, 01:47 AM   #5
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AI seems to suffer from this with many, many AI aircraft, it's not unique to the L-39.

Sometimes they work, sometimes not. Setting up an AI S-3B Tanker is a prime example. Occasionally they will fly their orbit pattern at the desired speed, other times they'll only fly at 250Kts...
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Old 08-24-2018, 06:46 AM   #6
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Let me guess, you spawn your AI in the air ?

Yeah, spawning AI in the air seems to bug their speed and altitude.

Try spawning them on an airfield and take-off, they should maintain their given parameters
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Old 08-24-2018, 07:52 AM   #7
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Quote:
Originally Posted by Shadow KT View Post
Let me guess, you spawn your AI in the air ?

Yeah, spawning AI in the air seems to bug their speed and altitude.

Try spawning them on an airfield and take-off, they should maintain their given parameters
Unfortunately not, it is the same problem - AI is running at 99% throttle all the time and has even big problems to climb to 5000 meters. Seems like engine power at altitude is insufficient. L-39ZA works well.
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