Carbon715 Posted September 30, 2021 Share Posted September 30, 2021 Was testing some air starts and noticed even when I placed the EPU switch to off, it would still fire off once engine power was cut. Also the air light was on, which with the motor off, no bleed air is being supplied to the EPU to augment hydrazine power. Link to comment Share on other sites More sharing options...
Frederf Posted October 1, 2021 Share Posted October 1, 2021 Normal and correct. The EPU will fire is if the switch was placed in the ON position any time after takeoff. The triggering condition is main and standby generator offline even if switch is in OFF position. Air light is supposed to be on in this case. It is always on when the EPU is commanded on and pin is pulled, hydrazine augmentation or not. Link to comment Share on other sites More sharing options...
Carbon715 Posted October 2, 2021 Author Share Posted October 2, 2021 Just did some research at work, went through -49FI , -49GS including theory of operation, and asked 3 viper IPs the what if scenario and its all conclusive. If the EPU mode switch is in the off position, the EPU should not fire regardless of loss of engine , or hydraulic pump output <1000psi or both standby and main generators offline. In norm position, Epu should fire in the air if one of the mentioned issues happens and should fire if commanded on. I work blk 42s, not 50s but I see no reason the logic and system has changed between the blocks. Link to comment Share on other sites More sharing options...
lurch0080 Posted October 12, 2021 Share Posted October 12, 2021 sdirmitt, you are correct it shouldnt activate if positioned to off, regardless of if the conditions for activation are met, as well the air light should only come on if the engine is running as that if where the EPU gets its bleed air. ive worked block 40s/50s and the EPU works the same on every block Link to comment Share on other sites More sharing options...
ED Team BIGNEWY Posted October 12, 2021 ED Team Share Posted October 12, 2021 please include a track replay, and if you have any evidence please PM me. I am happy to take another look thanks Forum rules - DCS Crashing? Try this first - Cleanup and Repair - Discord BIGNEWY#8703 - Youtube - Patch Status Windows 11, NVIDIA MSI RTX 3090, Intel® i9-10900K 3.70GHz, 5.30GHz Turbo, Corsair Hydro Series H150i Pro, 64GB DDR @3200, ASUS ROG Strix Z490-F Gaming, HP Reverb G2 Link to comment Share on other sites More sharing options...
mvsgas Posted October 12, 2021 Share Posted October 12, 2021 (edited) https://forums.eagle.ru/topic/230436-cannot-reproduce-emergency-epu-doesnt-work/ Edited October 12, 2021 by mvsgas adding link To whom it may concern, I am an idiot, unfortunately for the world, I have a internet connection and a fondness for beer....apologies for that. Thank you for you patience. Many people don't want the truth, they want constant reassurance that whatever misconception/fallacies they believe in are true.. Link to comment Share on other sites More sharing options...
Bouli306 Posted October 14, 2021 Share Posted October 14, 2021 Frederf is correct. When the EPU switch is placed to off after takeoff the EPU WILL fire/start automatically. Also the AIR light will always be on when the EPU is commanded on, that is because the HYDRZN and Air light are socalled demand lights. ANd the EPU simply always demand AIR, and when needed the HYDRZN light will come on when it demands that to maintain turbine speed. Link to comment Share on other sites More sharing options...
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