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Old 11-30-2017, 10:19 PM   #11
gospadin
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So these changes are in the current openbeta? Awesome!
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Old 12-04-2017, 12:32 PM   #12
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Originally Posted by AdmiralQuality View Post
Hoping you keep in mind that engineers are conservative in their specs and these warnings describe a worst case scenario. For the most part the effect of excessive EGT would be reducing the engine's service life until the next overhaul, which isn't really a factor for us as we have a fresh Huey on every flight or so. (If there was a way to keep an airframe going from mission to mission that would be a cool thing to model though.)

I don't have any figures on this, but I'd suspect the engine degradation you could cause during a single flight wouldn't be that noticeable. In the real UH-1H flight manuals I've read it just tells you what maintenance form you need to fill out if you exceed the recommended limits. And again, those recommendations are very conservatively chosen. In times of war, which is what we're modelling, it would be an easy decision of whether to exceed them when you absolutely need to, or die.

Just hoping it doesn't become another exaggerated effect like I think the rotor departure currently is. Apparently only something like 5 Hueys ever did that in reality. Now that I've been flying it a few months I hardly ever cause it myself, but server lag freezes cause it to happen all the time.

Those degradation rates as described in the OP sound awfully high to me. It's like in Star Trek when they say the ship is in radiation and they have 5 minutes to get out of it or the crew will all die. (And they escape after 4:59 and everybody's just fine. ) It doesn't work that way, and I suspect heat damage to turbine blades doesn't either.

My $0.02. Thanks for listening.


We are within simulation limits and development time limits. And some situations we can model only to some point.

For EGT limits implementation we are seeking subject matter experts for particular engine, and currently making effort to reach some of them. Most likely feature will be tuned if we will receive elaborated/documented explanation on those severe modes processes for that particular engine

We would like to see more documents regarding this matter but it is hard to find them.

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Oh and P.S. Are we getting a clutch?
If by clutch you mean needle split within autorotation, I think we should address it in a separate thread. There is some nuance in clutch modeling which our devs can't find, extented documentation on that matter would help as well.

Thank you for your concerns!
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Old 12-04-2017, 12:51 PM   #13
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Thank you for your concerns!

Thank you for your responsiveness.
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Old 12-04-2017, 04:27 PM   #14
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Originally Posted by belsimtek View Post
We are within simulation limits and development time limits. And some situations we can model only to some point.

For EGT limits implementation we are seeking subject matter experts for particular engine, and currently making effort to reach some of them. Most likely feature will be tuned if we will receive elaborated/documented explanation on those severe modes processes for that particular engine

We would like to see more documents regarding this matter but it is hard to find them.



If by clutch you mean needle split within autorotation, I think we should address it in a separate thread. There is some nuance in clutch modeling which our devs can't find, extented documentation on that matter would help as well.

Thank you for your concerns!
Right, that's why I'm hoping you don't overdo it. Less isn't always more.

I did just try the Open Beta over the weekend and my (granted, overloaded) Huey engine appeared to seize very quickly, within the first few minutes of flight. (I don't recall the Fire light coming on but it all happened very quickly so maybe I missed it. Still, that seemed catastrophic rather than a performance degradation. Only happened once though -- I didn't get a lot of Huey time in as most online 1.5 servers seem to have had a performance issue regarding the Huey for the last few months -- lots of stuttering. Odd as the frame rate was smooth with other planes. I also had to switch back to the Release to play in the online servers I wanted to so didn't get much Huey time in yet.)

It didn't seem to want to auto-rotate, the rotor lost energy very quickly and I just fell out of the sky. (We're missing a clutch that should result in a split Rotor RPM needle, correct? Is the turbine and gearbox dragging the rotor speed down or is the effect of the clutch modeled and just not being represented by the needle?)

I'm really concerned about this. The Huey rapidly became my favorite aircraft and now I'm afraid it's going to be largely useless. If you're going to err, I hope it's on the generous side rather than imagining they fall out of the sky if the limitations in the manual are briefly exceeded. Engineers of they Huey's vintage had a saying, "Double it and make it safe", so I expect the manual to be very conservatively written.
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Old 12-04-2017, 05:21 PM   #15
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Right, that's why I'm hoping you don't overdo it. Less isn't always more.

I did just try the Open Beta over the weekend and my (granted, overloaded) Huey engine appeared to seize very quickly, within the first few minutes of flight. (I don't recall the Fire light coming on but it all happened very quickly so maybe I missed it. Still, that seemed catastrophic rather than a performance degradation. Only happened once though -- I didn't get a lot of Huey time in as most online 1.5 servers seem to have had a performance issue regarding the Huey for the last few months -- lots of stuttering. Odd as the frame rate was smooth with other planes. I also had to switch back to the Release to play in the online servers I wanted to so didn't get much Huey time in yet.)

It didn't seem to want to auto-rotate, the rotor lost energy very quickly and I just fell out of the sky. (We're missing a clutch that should result in a split Rotor RPM needle, correct? Is the turbine and gearbox dragging the rotor speed down or is the effect of the clutch modeled and just not being represented by the needle?)

I'm really concerned about this. The Huey rapidly became my favorite aircraft and now I'm afraid it's going to be largely useless. If you're going to err, I hope it's on the generous side rather than imagining they fall out of the sky if the limitations in the manual are briefly exceeded. Engineers of they Huey's vintage had a saying, "Double it and make it safe", so I expect the manual to be very conservatively written.
I was concerned too, but they made it pretty forgiving, and the Huey runs cooler than before. It's not like the Gazelle which kills the engine after 5 seconds of over-torque. I have only broken the engine on purpose just testing the limits, I turned the governor off and pulled full collective, I was able to ascend like 4-5000ft before an engine fire, it's pretty forgiving. The needles do split when the engine shuts off, they wont split if you simply roll off the throttle which will hopefully be fixed someday.
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Old 12-04-2017, 05:30 PM   #16
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Originally Posted by Deezle View Post
I was concerned too, but they made it pretty forgiving, and the Huey runs cooler than before. It's not like the Gazelle which kills the engine after 5 seconds of over-torque. I have only broken the engine on purpose just testing the limits, I turned the governor off and pulled full collective, I was able to ascend like 4-5000ft before an engine fire, it's pretty forgiving. The needles do split when the engine shuts off, they wont split if you simply roll off the throttle which will hopefully be fixed someday.
I did notice it was running a bit cooler, so that's good. (I've started watching it closely in 2.1 where I spend 90% of my flying time and there isn't much you can do while staying below 600!)

Not sure what the cause of my crash was, I'll try to spend some more time in the OB and do some serious testing. Could have been icing, I suppose, I forget what the weather conditions were exactly. (Though whatever it was, the rotor shouldn't slow down that fast. And if it did that should send the body of the chopper yawing along with it due to the torque reaction.)

Anyway, will see if I can reproduce it and if so, report back. Thanks all!
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Old 12-04-2017, 08:41 PM   #17
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Just did a couple of quick tests. Used the Instant Action Free Flight mission. Refueled to 100%. Went straight up keeping RPM at just above the lower limit. Torque was red-lined, EGT stable around 700 and never seemed to go over. Got to about 3000 ft after just a minute or so and the engine quits (seems to seize, in fact) catches on fire, and you can't auto-rotate, you're dead in the sky.

Sorry, but this damage is way over-modeled. What would amount to some minor scoring on the turbine blades in reality is resulting in catastrophic fires and instant loss of rotor speed (that somehow doesn't start the fuselage spinning with it) in the sim.

And even if relatively minor abuse like this did cause an almost instant engine fire, it wouldn't instantly stop your rotor from spinning. In fact, the second time I tried it the rotor departed. That's quite a fire! (Again I wonder if this is linked to the lack of a clutch/needle split.)

I wouldn't have bought this module if it performed like this in the game. This must be fixed before it goes into the release version!

Where in the real UH-1H flight manual does it say the engine will catch on fire (and seize!) if you run EGT at 680 for 90 seconds? And really, the variability is just between 90 to 95 seconds? Guaranteed catastrophic failure in 95 seconds? My Star Trek radiation analogy was more appropriate than I feared!

From the UH-1H manual, TM 55-1520-210-10:

Page Change 17 5-1: "5-3. Exceeding Operational Limits. Anytime an
operational limit is exceeded an appropriate entry shall
be made on DA Form 2408-13. Entry shall state what
limit or limits were exceeded, range, time beyond Limits,
and any additional data that would aid maintenance
personnel in the maintenance action that may be
required."

It doesn't say you're going to instantly fall out of the sky, it says you have to fill out a maintenance form.

Same page: "RED markings on the dial faces of these instruments
indicate the limit above or below which continued
operation is likely to cause damage or shorten life."

When they say "shorten life", they don't mean the pilots' and passengers'! All this is about is accelerated maintenance cycles and the lifetimes of parts, particularly the turbine blades, not instant catastrophic failure!

The maximum EGT according to the manual is 760 but we fall out of the air after just a few seconds at 680? Also (haven't tested this yet) are these limits cumulative? Hope not. If you reduce EGT before you reach a limit the engine shouldn't have any "memory" of having come close to it previously in the flight. (Just as it wouldn't about any previous flight -- unless damage had accumulated but these are the limits where you're supposed to be safe from damage.)

Just tried it one more time and yes, after 90 seconds (like Star Trek physics clockwork) at 700 C it fails catastrophically. (Why would a fire instantly stop the engine and rotor? And couldn't they have saved the money for the engine fire light as nobody is ever going to live to tell about seeing it come on? At least not if it came on while in the air.) And this time I tried it at 100 kias forward speed to see if that would help me auto-rotate. Nope, the rotor just comes to a screeching halt and then pops off, presumably due to the unloading.

Re: rotor departure...



I do hope they speak to some real Huey pilots about their experience exceeding limits and they talk them down from this drastic over-interpretation of the manual's warnings. As-is, this is just totally unacceptable.

Last edited by AdmiralQuality; 12-04-2017 at 09:07 PM.
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Old 12-04-2017, 08:58 PM   #18
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With the new EGT modelling, i can't really exceed a cruising speed of 80 knots, real world UH-1h is listed as 110knots cruising.

Am i doing something wrong or is the EGT modelling overdone?
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Old 12-04-2017, 09:24 PM   #19
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Oh and from that Honeywell report that the scary damage photos are taken from. The entire point of this report is that this damage is not normal. Also, most of that damage was caused by the original failure of a turbine disk cascading into further failures of the components behind it. This is not a good example of the kind of damage excessive EGT causes, which is typically just accelerated wear on the turbine blades.

http://ihst.rotor.com/portals/54/jhs...rts/117655.pdf


"1.3 Summary
The engine damage observed was the result of separation of a section of the second-stage
GP turbine disk.
The separation of the section of the second-stage GP turbine disk was due to peak strain
low-cycle fatigue. No material defects were identified which would contribute to the
separation of the section of the second-stage GP turbine disk.
The service history of the second-stage GP turbine disk could not be determined fiom
records provided by the operator.

All other engine damage observed is attributable to the unbalance and structural damage
induced by the separation of a section of the second-stage GP turbine disk.
No conditions were observed which would have caused or contributed to the separation
of a section of the second-stage GP turbine disk.
"

Also...

"There was no evidence of fire damage (Figure 3). The engine mounts were intact (Figure
3). "

Last edited by AdmiralQuality; 12-04-2017 at 09:29 PM.
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Old 12-04-2017, 09:55 PM   #20
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With the new EGT modelling, i can't really exceed a cruising speed of 80 knots, real world UH-1h is listed as 110knots cruising.

Am i doing something wrong or is the EGT modelling overdone?
What was the air temperature and the aircraft loadout ?

How does it compare to the limits in TM 55-1520-210-10

I̶'̶m̶ ̶n̶o̶t̶ ̶e̶x̶p̶e̶r̶i̶e̶n̶c̶i̶n̶g̶ ̶y̶o̶u̶r̶ ̶i̶s̶s̶u̶e̶ ̶i̶n̶ ̶n̶o̶r̶m̶a̶l̶ ̶f̶l̶i̶g̶h̶t̶.̶

Edit: Just checked, as I've been flying around the Tarawa in a slick Huey in 1.5.8 - yeah, I get pretty much the same as you but can't tell if it's right or wrong, until I check the figures in TM 55-1520-210-10

100% MTW = approx. 80 KIAS @ 20°C
90% MTW = approx. 95 KIAS @ 20°C
80% MTW = approx. 110 KIAS @ 20°C

A lot of default 'heavy' loadouts are pretty useless now, lol. Might be right though as I used to have to strip the Gazelle to the bare minimum to match the Huey's performance.

Last edited by Ramsay; 12-04-2017 at 11:19 PM. Reason: Checked a few MTW loadouts
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