No T6NL or JPOHT CWP captions after update?
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Hi,
I had noticed that after the update I no longer get any CWP captions for the over temp state when over 685 deg or 108% RPM? This used to be common before the update if you left full power on for too long.
Have I got an issue or was this just turned off after the update? -
@jake-m1900 I sort of have the same issue, after flying for about 15 minutes at full throttle the RPM was 101% and the TGT 680 oC, it didn't get any higher than that. So, in my case, the engine overheat does not occur, but I did manage to have that before. Not sure what is going on, but I do think that something has changed in this respect.
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Our real-world Hawk T1 pilot contacts confirmed that neither warning would occur under normal (i.e. non-failure) conditions so our logic was updated accordingly.
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@martyn Thank you for the info. I assumed a hot environment would cause this so turned up the ISA +30 and did some full-throttle flying to try and tease the warning but nothing. I'm pretty sure however I ran hotter than 685 and 108rpm but may be wrong.
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@martyn I guess that is a good thing :-) Now, I did try setting the temperature to 40 oC/104 oF. During engine run-up before takeoff the TGT very quickly rises to 680 oC and then abruptly stops rising. So it doesn't overheat but the behavior is surely different from normal temperatures, where the TGT creeps to its final value before it stabilizes. It looks like a hard limiter in the TGT was used, and that the engine model does compute a higher TGT than 680 oC. Not a big deal, btw.
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@corvus5624 This is from the Operations Manual...
Automatic limitation of fuel flow is effected by an LP shaft speed (NL) limiter and a TGT limiter which operate through the ECA to regulate a fuel trim valve. Limitation of RPM is provided by a hydro-mechanical governor integral with the HP fuel pump. At certain low altitude/high speed conditions, when air intake pressure exceeds a specific value, the engine is fuel-flow-limited by a flow control unit.
When either a TGT of 660°C or an NL of 104% is approached, the ECA energises the solenoid of the fuel trim valve. The amplifier then maintains the fuel trim valve in the position required to hold TGT or NL at the limiting value. Only one of the reference parameters can be in control at any one time.
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@retiredman93231 Thanks for pointing this out. So there actually is a limiter in place. This might also explain that sometimes there is no difference between full throttle and, say, 90% throttle.
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@martyn Hi, I still think this is broken as I flew yesterday to test this after an update with an RPM of 110+ and no indication... It's almost as if the engine temp stops just before reaching the limit but the RPM continues.
I will say I was flying like a D1ck... And in reality, the jet would not be operated as I flew it during that flight.
