PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   2 quick questions (https://www.pprune.org/tech-log/137683-2-quick-questions.html)

witchdoctor 15th July 2004 08:56

2 quick questions
 
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.:O

BOAC 15th July 2004 09:06

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'.........................:D

fruitloop 15th July 2004 10:05

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

gas path 15th July 2004 10:32


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 15th July 2004 12:45

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 15th July 2004 12:59

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

GlueBall 15th July 2004 13:05

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 15th July 2004 15:51

Concur with Gas Path

john_tullamarine 15th July 2004 23:04

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


All times are GMT. The time now is 04:47.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.