2 quick questions

[witchdoctor]

Hi guys,

Was recently asked by a colleague for the answers and I'm stumped.

Why do multi-engine turbines start the number 2 engine first?

What are the fins (vanes or strakes?) on the inside portion of the engine pods on most jet transports?

I suppose I must have fallen asleep during groundschool when these came up.

[BOAC]

Wot I wuz told:

Traditionally the battery on multi-engined pistons was on the starboard side hence less voltage drop if you start 2 first.

Fins designed to ensure engine will go under wing if it breaks away rather than over/through.

Stand-by for more 'reasons'.........................

[fruitloop]

Answer is correct for twins but if more than 3 start the outers first even on the 52

[gas path]

Why do multi-engine turbines start the number 2 engine first?

I don't believe that would be true for all multi engine a/c. Usually the first engine to be started would be the one with the hydraulic pump that supplied primary brake pressure.

What are the fins (vanes or strakes?) on the inside portion of the engine pods on most jet transports?

Called chines they are there to improve the airflow around the wing and they improve the stall margin by typically 5knots.

[Engineer]

There is no specified mandatory sequence of engine starting.

Individual airline requirements will generally dicate the starting sequence.

Taking in to consideration passenger boarding, elimination or reduce possible hydraulic system pump noise etc

[BOAC]

You wait 'til I catch up with that trainer! ..............

[GlueBall]

The right side usually is started first, as pax door/jetway is on the left side. In the case of a trijet like the DC10 or L10, usually the center engine is started first as it is closest to the APU pneumatic source.

[PleinGazSec]

Concur with Gas Path

[john_tullamarine]

From the sticky thread in Tech Log, you might find this page useful in understanding nacelle VGs on large engines.