Mig-21Bis Airstart

[jackmckay]

How many times one can commit airstart? Why is that engine flameouts at mach 1.1 on medium-low altitudes?

[Esac_mirmidon]

I´m not sure but i think three times.

[Dehuman]

Depends how long you have the air start switch on for.

 

Engine can't take more than 1300kmh IAS at any altitude. Down low this is 1.1M up high it's 2.1M.

[asla36]

In order to fly at those speeds you use AB, and with AB your negative G tanks lasts a tiny amount of time. Thus you can starve the engine of fuel by an unnoticeable nose drop, if it lasts enough.

 

Though I am not sure, just my little conspiracy theories.

[humptydumpty]

I think flameouts are mach 1.3 and higher.

 

you need 500 kmph airspeed to restart and I think the relit is 3 times only.

 

Negavtive G / inverted flights will also cause engine out. don't do these maneuvers for more than 12 secs as I have noticed at 15 secs the engine out occurs , but it's been a long time since I flew the baby

[jackmckay]

I asked RL MiG-21bis test pilot (recently retired) about this feature and he said that there's limit on 5 relight iterations. I didn't ask about engine flameout conditions but under my opinion this should not appear valid due to use of cone extending mechanism and shock cone shift as air entering engine should mainly stay subsonic. Surge protection gills are also integrated on airframe. So why so much flameouts on high mach number?

Edited May 30, 2017 by jackmckay

[myHelljumper]

Depends how long you have the air start switch on for.

 

Engine can't take more than 1300kmh IAS at any altitude. Down low this is 1.1M up high it's 2.1M.

 

He said it.

It's not because you have an adjustable nose cone that you can go at any speed.