homepage Forums Air Combat & Civil Aviation Wings: Over Flanders Fields Wings: Over Flanders Fields - Mods Possible Engine Mod

Hi BB, my last but one post was something of a stream-of-consciousness effort - I was just appending to it as I went along, over a number of days, so the end of it rather contradicted the beginning, as I found out more!

<FailureRule SystemID="engine_one" average_hrs="10" damageAmount_pct="1" frequency_secs="60" dump="y"/>

I am not sure that the damageAmount_pct="1" represents a 1% loss of power - I think it may be a single 'hit' to the engine (which can sustain 100 hits before it fails completely). From inspecting the log entries I think an engine can sustain up to 30-40 'hits' before there are any damage effects (such as loss of power, or the clunk-clunk damaged engine sound). Look at these log entries for an aircraft that sustained such damage:

At the start

2022/10/02 16:43:07 759.000000 failureStart alb_dva_sq2 0x04011019 engine_one 10.000000
2022/10/02 16:43:07 759.000000 0x04011019 RunFailure AddDamageToSystem_frac 0x00000004 engine_one 0.010000
2022/10/02 16:43:07 759.000000 0x04011019 overallDamage 0 / 10 dontTouchFlag 0 deadFlag 0 deletePendingFlag 0

The second and third line repeats every minute, until

Approx. 30 minutes later, there is a new line added with 1/65

2022/10/02 17:12:07 2499.000000 0x04011019 RunFailure AddDamageToSystem_frac 0x00000004 engine_one 0.010000
2022/10/02 17:12:07 2499.000000 0x04011019 overallDamage 0 / 10 dontTouchFlag 0 deadFlag 0 deletePendingFlag 0
2022/10/02 17:12:07 2499.000000 0x04011019 0x00000004 engine_one 1 / 65

This third line is then present every minute thereafter, but the 1/65 goes up to 2/65 a few minutes later

2022/10/02 17:15:07 2679.000000 0x04011019 0x00000004 engine_one 2 / 65

and then 4/65, after another two minutes

2022/10/02 17:17:07 2799.000000 0x04011019 0x00000004 engine_one 4 / 65

at which point, 2 seconds later, a Leave Formation/Go Home is triggered, approximately 35 minutes after the engine started taking 'hits' (i.e 35 hits, or 6% loss of engine power?)

2022/10/02 17:17:09 2800.687500 AIF::LeaveFormation Jasta 41-C ID(6002) 0x04011019 alb_dva_sq2 1
2022/10/02 17:17:09 2800.687500 TacsPush(TACS_TRANSIT_F) Jasta 41-C 0x04011019 alb_dva_sq2 APPEND
2022/10/02 17:17:09 2800.687500 AI_Formation::InitGoHome(GO_HOME_RUN) Jasta 41-C 0x04011019 alb_dva_sq2 td->code==TACS_TRANSIT_F
2022/10/02 17:17:09 2800.687500 TacsChange(TACS_GO_HOME) Jasta 41-C 0x04011019 alb_dva_sq2 REPLACE
2022/10/02 17:17:09 2800.687500 TacticsGoHome::InitGoHome GO_HOME_RUN Jasta 41-C 0x04011019
2022/10/02 17:17:09 2800.687500 0x04011019 goFriendly run newWayptIx 7 currWayptIx 4 route.size 8
2022/10/02 17:17:09 2800.687500 AIF::InitTransit Jasta 41-C 0x04011019 alb_dva_sq2 7 Landing

The aircraft continued to accumulate 'hits' until it landed with 20/65 which, I would guess, represents a 31% loss of power? I have also seen the "overallDamage 0 / 10" go up to 1/10 or 2/10 when there has been a lot of damage (representing damage to the aircraft structure from excessive vibration?).

So I think it is the 1/65...2/65 that is the start of the power loss, which also triggers the Go Home. The threshold where this starts to happen is not fixed. So far I have seen it occurring around 30-40 'hits', but the variation might be wider. The accumulation of 'effects' figure is not linear in the above example: it remained at 1/65 for three minutes before increasing to 2/65 and then 4/65 two minutes later (but I think it accelerates as time goes by). This makes more sense to me, the engine loosing exponentially more power as damage accelerates rather than a linear gradual decrease in power from 100%-0%. I think only damage types that have this 'accumulator' (frequency_secs=) get worse in this way over time.

Here is one for gradual coolant loss:

2022/10/02 16:56:51 1583.000000 failureStart se5a_sq1 0x04011034 coolant_reservoir 190.000000
2022/10/02 16:56:51 1583.000000 0x04011034 RunFailure AddDamageToSystem_frac 0x00000002 coolant_reservoir 0.040000
2022/10/02 16:56:51 1583.000000 0x04011034 overallDamage 0 / 10 dontTouchFlag 0 deadFlag 0 deletePendingFlag 0
2022/10/02 16:56:51 1583.000000 0x04011034 0x00000002 coolant_reservoir 1 / 38

The damage accumulates every minute: 2/38...3/38...at which point it gets the Go Home instruction and lands after 10 minutes with a total of 36 'hits' and 9/38 damage (27% loss of coolant? The drop in this case appears to be linear, a constant leak)

The one-off damage events are, I think, just that. I don't have a log entry for one now, but I have noted several including one for your 12% failure line), and they always look like:

2022/10/02 16:43:07 759.000000 failureStart alb_dva_sq2 0x04011019 engine_one 10.000000
2022/10/02 16:43:07 759.000000 0x04011019 RunFailure AddDamageToSystem_frac 0x00000004 engine_one 0.120000
2022/10/02 16:43:07 759.000000 0x04011019 overallDamage 0 / 10 dontTouchFlag 0 deadFlag 0 deletePendingFlag 0

with no further repetition.

A 'hit' of 30+ (e.g. 31) looks like that, but with the extra damage line, so something like

2022/10/02 16:43:07 759.000000 failureStart alb_dva_sq2 0x04011019 engine_one 10.000000
2022/10/02 16:43:07 759.000000 0x04011019 RunFailure AddDamageToSystem_frac 0x00000004 engine_one 0.310000
2022/10/02 16:43:07 759.000000 0x04011019 overallDamage 0 / 10 dontTouchFlag 0 deadFlag 0 deletePendingFlag 0
2022/10/02 16:43:07 759.000000 0x04011019 0x00000004 engine_one 1 / 65

but with no further repetition.

I hope that makes more sense!

So far as the two-engine aircraft goes, I think their engines can fail independently so long as there are two failure lines (one for engine_one and one for engine_two). If there is only a line for engine_one, then engine_two will not fail. But I get the impression that they may not be entirely independent - after one engine fails, I have noticed that the other one also starts to fail either immediately or at a slightly later time. But that may just be coincidence, based on only a very few observations. I will have to test more to confirm if this is the case.

"Damage that accumulates over time, e.g. <FailureRule SystemID="engine_one" average_hrs="150" damageAmount_pct="5" frequency_secs="112" dump="y"/> WILL result in engine destruction and/or fire when the hit points for the engine are eventually exhausted"

That may be so, or the engine might just conk out. We would have to test that. Or engine fires might be another 'threshold' event associated with a particular damage type, such as oil loss. I have not yet seen any engine fires in the logs as a result of engine failure. Does the engine reach 65/65 before it receives 100 hits? Or does one or the other cause an engine fire? I don't know, but I guess we can test for that...

"I think something like <FailureRule SystemID="engine_one" average_hrs="20" damageAmount_pct="2" frequency_secs="120" dump="y"/> represents the best compromise for this approach"

Yes, that would make the warning messages less intrusive - or even damageAmount_pct="5" frequency_secs="300" which would give the same result but even less intrusively.

B.