Common system fails during flight

[Wexler]

Hello,

 

I am new to AJS-37 and wondering what are common system fails (not bugs). I am aprox. at 1/4 of the manual now so maybe I will learn something here, meantime we can discuss why that happens.

 

So far the common fails for me are:

 

1) when flying on In-flight idle throttle, when the speed drops to stall (under 260 kph) the engine die and doesnt function. There is also sound of knocking on the metal but no damage visible. What is the cause?

 

2) When going full afterburner and going as high as possible, somewhere about 16 km height the engine die, successfuly started it on 3rd time but without afterburner function.

 

Any idea why that happens?

 

Thanks

[Lieuie]

The first one is probably a compressor stall. As for the second I am not sure, someone else will have to chime in.

[Knock-Knock]

When exceeding 22 degrees of AOA, you will hear these bangs. Its a compressor stall, as Lieuie already mentioned. And if you dont correct, the engine will more than likely quit.

 

As for the high altitude, I believe that is called a flame out. Viggen - the AJS, doesnt like high altitude. Its ment to be flown on the deck.

[Wexler]

Thank you. I can now imagine the physics in it.

[LazyBoot]

Input interpretation:

convert 16 km (kilometers) to feet

Result:

52493 feet

 

That does seem somewhat high.

[frosen]

When exceeding 22 degrees of AOA, you will hear these bangs. Its a compressor stall, as Lieuie already mentioned. And if you dont correct, the engine will more than likely quit.

 

As for the high altitude, I believe that is called a flame out. Viggen - the AJS, doesnt like high altitude. Its ment to be flown on the deck.

 

Well, the engine should not die at 16 km if you don't stress it so it flames out because high AoA. A clean aircraft should be able to go well beyond 16 km (according to the Swedish original SFI (the aircraft flight manual)) although it wasn't recommended because if the engine flames out at that altitude you lose the cabin pressure which will boil your blood and kill you if you don't have a special high altitude flight suit.

 

The problem or module bug is that the afterburner fails at around 14 km (don't remember exact altitude from the top of my head) and it's not possible to reignite it at lower altitude or even at ground level - that shouldn't happen! It has been reported by me and several others but to my knowledge the devs haven't acknowledged it.

 

(Just to be clear about the afterburner use at high altitude, it is however correct that it shouldn't be possible to start the afterburner above let's say 14 km (depending on a lot of variables) but that is not what I refer to above.)

[Jediteo]

High-altitude engine behaviour and performance is on the to-do list.

[frosen]

High-altitude engine behaviour and performance is on the to-do list.

 

Sounds good! :thumbup:

[Wexler]

Another fail (bug?): When i lost left back wing in dogfight, the aircraft behave like nothing happend. I didnť mention even for couple of minutes. Flame is comming from end of the wing which is actually not on aircraft, seems very weird. At least, the left wheel werent here for landing :-)