Engine Longevity Problem

[Mars Exulte]

On these failed takeoffs/landings, are you facing into the wind or with it? Manual mentions reingesting hot exhaust gases can cause power loss/reduction. Just an idea I had.

 

I've experienced some intermittent issues, though much less of late, as I've become more aware of limitations and quirks. This is just something I happened to think of, I don't know if it's actually modeled.

[Eldur]

The test mission I use has no wind. But yesterday I noticed that the continuous JPT limit ist 645 and I thought it was 650. Most probably I flew more than 15 minutes with a JPT just in between which already activates the death clock which just seems to add up regardless the break in between. Even if it's as intended, it's definately not realistic. 640 max is just fine even for hours. Multiple take offs with water and CMBT adding up can seize the engine already after some time.

 

The worst part about it: We can't repair as long as there's no actual combat damage. IIRC (didn't actually try this for ages, but I remember it) other planes get a repair when requested for just the canopy blown off, the Harrier doesn't.

[Shrike88]

+1 Razbam please address this, even if not allow for simulated Overhaul on repair to reset the clock. Tested last night Takeoff / Cruise no vertical landing, no combat. Never exceeded 645 JPT. Second sortie Engine Failure, Failure to relight 15 min into second flight never exceeding limitations, never in combat, Empty aircraft.

 

Apparenty Bug please address for those of us that do not enjoy restarting from a cold aircraft every 60 min.

[Muybonito523]

Yep problem I have is that I get jpt limited to 710 at some point when using maximum thrust profile, that's fine should do that, but then when I go to land, say I'm stuck at 102 rpm or little less because of jpt, I flip the water switch and it's like 50 50 chance that the water engages or not. Last night was getting JPT limited so I couldn't do more than 98 rpm, didn't think I blew the limits, so when I came in for slow landing, flipped my water on and nothing happened, water would not engage, even placed water in h2o mode and then tried land mode, no response. Is there a point where the harrier refuses to allow you to use water?

[ricktoberfest]

Yep problem I have is that I get jpt limited to 710 at some point when using maximum thrust profile, that's fine should do that, but then when I go to land, say I'm stuck at 102 rpm or little less because of jpt, I flip the water switch and it's like 50 50 chance that the water engages or not. Last night was getting JPT limited so I couldn't do more than 98 rpm, didn't think I blew the limits, so when I came in for slow landing, flipped my water on and nothing happened, water would not engage, even placed water in h2o mode and then tried land mode, no response. Is there a point where the harrier refuses to allow you to use water?

 

 

Did you run out of water?

 

 

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[LazyBoot]

Yep problem I have is that I get jpt limited to 710 at some point when using maximum thrust profile, that's fine should do that, but then when I go to land, say I'm stuck at 102 rpm or little less because of jpt

 

But how long are you flying in max thrust mode? Because max thrust can only be sustained for 15minutes.

Attached picture taken from the pocket guide supplied with the module.

[Muybonito523]

As I said, don't think I maxed out the limits, certainly didn't go 109 anywhere near 15 minutes, and 111 anywhere near 10 min. And yes, if I run out of water I would be getting warnings and such that I am out, it stayed at 500.

[Muybonito523]

Ahh, but there is a difference between combat at 111 and normal lift at 111, that might've been the problem why my engine was degrading, I didn't use combat when using 111, I was in a slow turn. However, would this disable the water from engaging still?

[ricktoberfest]

Ahh, but there is a difference between combat at 111 and normal lift at 111, that might've been the problem why my engine was degrading, I didn't use combat when using 111, I was in a slow turn. However, would this disable the water from engaging still?

 

 

 

You can’t go by rpm, you have to go by EGT as far as when it’s over the limit.

 

 

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[Repth]

See the attached from the NATOPS for the Harrier regarding Water injection and how it operates. :)

NFM Cover.pdf

[Muybonito523]

Maximum thrust profile forces JPT to stay at 710 if you are using decs. If I read that manual correctly says that water won't start unless I can reach 105 rpm or more, so if JPT limited to less than 105 % no water then. Interesting....

[Muybonito523]

Tests I ran today,

 

1. Low altitude, around 700 to 710 JPT 109% RPM, 15 minutes, received left of UFC 15s warning for JPT over limit warning, DECS adjusting for JPT to 710, RPM was brought down to 97% rpm.

 

2. Repeated 1 same result

 

3. High altitude, where JPT stayed at 640 at 109% RPM, same result, 15 minutes on the dot, JPT increased all the sudden, 15s warning on left UFC warning light, then JPT reduced to 710, RPM at 97%.

[Ramsay]

109% RPM has a 15 minute time limit, you are exceeding the engine RPM limit.

 

[Falcon41]

So did this get concluded as a non-bug work in progress model then?

[Ramsay]

So did this get concluded as a non-bug work in progress model then?

 

IIRC the damage model was made more permissive (or power loss reduced) shortly after this thread was created (February).

 

The damage model (loss of power/o/heating) can still be punishing if you abuse the engine, don't note your VL weight limit (20,500 lb) or don't back off the throttle if the power margin hexagon is showing.

 

Damage is not usually an issue for VL's at normal temp's at SL but is more challenging in Nevada (due to altitude and temp), however TBH, I mostly use 60° FNSL (fixed nozzle slow landing) in Nevada.

 

Even with reduced power (due to damage), it's possible to land safely by diverting to an airfield and using FNSL.

 

IRL it'd probably reduce engine life to a point were it would require changing but as every DCS flight is in a new airframe - Razbam have a difficult job to balance between reality and gameplay i.e. making engine damage meaningful within DCS.

 

IMHO Razbam did well.