Jamovich Posted March 25, 2015 Share Posted March 25, 2015 Hi guys My engine sometimes flames out on the f86 when flying too long inverted and simply restarts when I point the nose down (similarly on the mig 15 bis) On the mig 21 bis the engine flames out if I stay in a steep climb and pull out of it too quickly. However in this case I actually have to use a switch to restart it. My question is that on the f 86 control panel on the right there is a provision to restart the engine in a similar way but I have NEVER had to use it. Does this mean that engine stalls are "simplified" on the f86/mig 15? Link to comment Share on other sites More sharing options...
SUBS17 Posted March 25, 2015 Share Posted March 25, 2015 I think you starved the engine of fuel flying too long inverted. [sIGPIC] [/sIGPIC] Link to comment Share on other sites More sharing options...
Jamovich Posted March 25, 2015 Author Share Posted March 25, 2015 Ok so it is possible to actually stall the compressor requiring you to perform a "hot start"? Link to comment Share on other sites More sharing options...
mvsgas Posted March 25, 2015 Share Posted March 25, 2015 (edited) Ok so it is possible to actually stall the compressor requiring you to perform a "hot start"? Not sure if you can stall ( or stagnate) the compressor on the F-86 engine in DCS. A hot start is when the FTIT/EGT gets above the limits. Not a good thing. A hot start is normally accompanied or cause by a hung start not corrected quickly enough. I have not seen one in DCS. Not sure if it is modeled. Edited March 25, 2015 by mvsgas 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...
Jamovich Posted March 25, 2015 Author Share Posted March 25, 2015 Actually according to Change Log 1.2.10 Update 1 compressor stall is modelled in the F-86 (http://forums.eagle.ru/showthread.php?p=2178959). I just have never had one occur. Link to comment Share on other sites More sharing options...
mvsgas Posted March 25, 2015 Share Posted March 25, 2015 (edited) Ok, but what did you mean by "hot start"? Also, re-reading your original post, when you mention "engine stall", where you refereeing to the flow of air in the compressor being interrupted or the engine shunting down? I ask because you mention flame outs and stalls and the same time. I do believe the F-86 engine in DCS might not be completely modeled yet. Edited March 25, 2015 by mvsgas 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...
Cool Breeze Posted March 25, 2015 Share Posted March 25, 2015 IMHO you are dealing with fuel starvation. I have had a few instances in the past were the rpm stuck at 70% even though the throttles were advanced to full power. Generally from very rough handling of the Sabre. Backing the throttles down to idle, then slowly advancing them back up to full power solved the issue. "For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return." Leonardo Da Vinci "We are tied to the ocean. And when we go back to the sea, whether it is to sail or to watch - we are going back from whence we came." John F. Kennedy Link to comment Share on other sites More sharing options...
Robin_Hood Posted March 26, 2015 Share Posted March 26, 2015 IMHO you are dealing with fuel starvation. I have had a few instances in the past were the rpm stuck at 70% even though the throttles were advanced to full power. Generally from very rough handling of the Sabre. Backing the throttles down to idle, then slowly advancing them back up to full power solved the issue. I have had a lot of that (rpm stuck @ 70%), not sure what is happening there, but I'd love to know. 2nd French Fighter Squadron Link to comment Share on other sites More sharing options...
skendzie Posted March 26, 2015 Share Posted March 26, 2015 Something a manual should resolve. Too bad Belsimtek's priority for manuals seems to be at the bottom of the list. Who needs a manual to fly a jet anyway. Link to comment Share on other sites More sharing options...
Nevyn Posted March 26, 2015 Share Posted March 26, 2015 Something a manual should resolve. Too bad Belsimtek's priority for manuals seems to be at the bottom of the list. Who needs a manual to fly a jet anyway. Manuals????? Whats that??? hehe.:music_whistling: Link to comment Share on other sites More sharing options...
Buzzles Posted March 26, 2015 Share Posted March 26, 2015 I have had a lot of that (rpm stuck @ 70%), not sure what is happening there, but I'd love to know. That's compressor stall I think. Easy to replicate: when you're on the ground and idling, just slam the throttle forward and back a few times and you'll find it tops out at 70% with the throttle forward until you drop back down to idle for a while. Fancy trying Star Citizen? Click here! Link to comment Share on other sites More sharing options...
mvsgas Posted March 27, 2015 Share Posted March 27, 2015 That's compressor stall I think. Easy to replicate: when you're on the ground and idling, just slam the throttle forward and back a few times and you'll find it tops out at 70% with the throttle forward until you drop back down to idle for a while. I have not tried myself, but if the RPM is not moving, it should be a "stagnation" ( Non- recoverable stall) 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...
BlackLion213 Posted March 30, 2015 Share Posted March 30, 2015 IMHO you are dealing with fuel starvation. I have had a few instances in the past were the rpm stuck at 70% even though the throttles were advanced to full power. Generally from very rough handling of the Sabre. Backing the throttles down to idle, then slowly advancing them back up to full power solved the issue. Thats pretty classic compressor stall behavior, called engine RPM "hangs". If the RPM remains low with the throttle advanced, the TIT should rise and the engine could either flame-out or catch fire. I don't know the endpoint with the DCS F-86, maybe I should buy it and find out! Sounds like accurate engine behavior. I've read a lot about this in the context of the TF30 in the F-14A, not sure how different things would be in the F-86's turbojet. -Nick Link to comment Share on other sites More sharing options...
golani79 Posted October 22, 2015 Share Posted October 22, 2015 (edited) But if the engine flames out due to fuel starvation it shouldn´t just restart if you go back to normal flight? Bought me the F-86 in another Sim too and if this happens you have to attempt an air start. In DCS the engine every time starts itself - no matter what. I´ve never needed an air start in DCS. Shouldn´t be the case now should it? This behavior is still the same in 1.5 Here are 2 passages from the F-86F manual (not the DCS one - think it was already posted here somewhere). Engine Failure The majority of jet-engine flame-outs are the result of improper fuel flow caused by fuel control system malfunction or incorrect operating techniques during certain critical flight conditions. The engine instruments often provide indications of fuel system failures before the engine actually stops. If engine failure is due to malfunctions of the fuel control system or improper operating technique, an air start can usually be accomplished when time and altitude permit. Compressor Stall Compressor stall can occur at any altitude as a result of rapid advancement of the throttle while operating on either the main or the emergency fuel system. Although the possibility of such compressor stall is considerably reduced during operation on the main fuel system, it can occur in case of main fuel regulator malfunction or improper fuel scheduling, o rat low airspeeds even though the regulator is functioning normally. Compressor stall is likely to occur during any rapid throttle advancement while operating on the emergency fuel system or the emergency fuel system in standby. This is because the emergency fuel regulator schedules fuel as a function oft he compressor inlet pressure (altitude and airspeed) and throttle position, thus affording no acceleration fuel schedule for stall protection such as that provided by the main fuel regulator. Stall occurs when rapid throttle advancement injects more fuel into the combustion chamber than the engine can use for acceleration at the existing rpm. The burning of this additional fuel increases the combustion pressures. As these pressures increase, they create a corresponding increase in the pressures against the compressor discharge air. This increase of pressure against the compressor discharge air results in a breakdown oft he airflow through the last stages oft he compressor, which ist he condition known as compressor stall. As a result oft he stall, the mass airflow through the compressor is reduced, causing a reduction in airflow through the turbine; thus the energy available to the turbine wheel is decreased. A roaring, pulsating noise and heavy vibration usually accompany compressor stall and may precede any engine instrument indication of changing engine conditions. In addition to the pulsating noise and vibration, the following signs of compressor stall may be present, depending upon the severity oft he stall: rapidly rising exhaust temperature, failure oft he engine to accelerate, a long flame from the tail pipe, and loss of thrust. If the engine is allowed to continue operating in this stalled condition, the increased temperature oft he burning gases will cause serious damage tot he hot section (combustions, turbine, and exhaust sections) oft he engine, resulting in possible engine failure. If stall is encountered during a rapid engine acceleration, action should be taken to eliminate it as follows: 1. Immediately retard throttle to IDLE. 2. If exhaust temperatures stabilizes at a normal value, readvance throttle slowly, while carefully monitoring exhaust gas temperature. If the exhaust temperature continues to drop after the throttle is retarded, a flameout has occured and an air start should be attempted. Edited October 22, 2015 by golani79 >> DCS liveries by golani79 << Link to comment Share on other sites More sharing options...
domini99 Posted October 31, 2015 Share Posted October 31, 2015 I can easily replicate the stall, including the typical banging and fluctuating RPM/fuel flow in-flight, after that it'll get stuck at 70%rpm. If someone needs it, I can replicate it and upload a video here Link to comment Share on other sites More sharing options...
Paganus Posted October 31, 2015 Share Posted October 31, 2015 Hanging at 70% is partial compressor stall. Link to comment Share on other sites More sharing options...
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