Engine start sequence

Silly question, but is it a realistic feature of the Mig-29 that you can't start the second engine until the first has completely finished starting up? Doesn't matter if I start left or right first, the button to start the other won't do anything until first one is idling. On the Su-33 you can start the second engine at any time during the start up of the first, or fire up both at the same time.

Silly question, but is it a realistic feature of the Mig-29 that you can't start the second engine until the first has completely finished starting up? Doesn't matter if I start left or right first, the button to start the other won't do anything until first one is idling. On the Su-33 you can start the second engine at any time during the start up of the first, or fire up both at the same time.

The MiG-29 only has one APU - there is an APU selector switch, which determines which engine it engages("left" or "right"), so its realistic that you cannot begin to start up the second engine at any time during the start up of the first.

The manual(RL) states that, during manual start-up, you need to allow some 10 seconds interval after the APU disengages from the first engine, before placing the APU switch to the second and IIRC also that you should allow the first started engine to spool up to idle before pushing the start button for the next.

There is also an automatic start-up option(APU switch set to position "both"), where both engines are started in sequence automatically - its the most commonly used and is faster, since the above mentioned APU power down/up interval is determined precisely by the system.

Thank you! I thought it might be something like that but good to get the details of the procedure. I don't mind watching the engine spool up then pressing another button, not like I'm doing anything else at that point in time.

So then the Su-25T and Su-33 (only other planes I've flown) must have 2 APUs to allow simultaneous engine start up?

IF you press right shift and home, both engine will start by themselves in the RL sequence, right and left.

The MiG-29 only has one APU - there is an APU selector switch, which determines which engine it engages("left" or "right"), so its realistic that you cannot begin to start up the second engine at any time during the start up of the first.

But: There is two engine gearbox, for each engine and they can be interconnected with a clutch. See attachment.

The manual(RL) states that, during manual start-up, you need to allow some 10 seconds interval after the APU disengages from the first engine, before placing the APU switch to the second and IIRC also that you should allow the first started engine to spool up to idle before pushing the start button for the next.

Almost :) But at 50% the APU disengages from the engine, the rest of the spool to idle is on its own power, as already ignited. I also remember an instructor pilot telling me they start the second before the 1st reaches idle rpm. but thats ancient memories and that might be on quick ready alert which might differ...

But: There is two engine gearbox, for each engine and they can be interconnected with a clutch. See attachment.

Yes thats how it works :) . There is only one APU - when you set it to start the left engine(manual start-up procedure), it engages the gearbox of the left engine via a clutch. In order to proceed to start the right engine, you must wait for the APU to automatically disengage from the left engine(gearbox), then allow some 10 second interval for it to power down, before placing the APU switch to the right. The interval is to ensure synchronisation of APU with gearbox.

Almost :) But at 50% the APU disengages from the engine, the rest of the spool to idle is on its own power, as already ignited.

Correct :)

I also remember an instructor pilot telling me they start the second before the 1st reaches idle rpm. but thats ancient memories and that might be on quick ready alert which might differ...

I am also writing from memory and re-reading the Luftwaffe manual, it actually says that the 10 sec interval is automatically imposed in the automatic start-up mode(both engines), while it says that during manual start-up, the first started engine must run in idle for 40 seconds before proceeding to start up the second.

Are you sure that he wasn't referring to automatic start-up?