Engine start process questions

Date:         04 Jun 97 13:03:58 
From:         richn@sdd.hp.com (Rich Nute)
Organization: Hewlett-Packard, San Diego Division
Followups:    1 2 3 4 5 6 7
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A jet engine is started by:

1.  Spin the turbine up to some rpm.

    How many rpm?

    The spin is either by an electric motor (for small
    engines) or compressed air (for larger engines).

    Does the electric motor also serve as the generator?
    What is the approximate gear ratio between the
    electric motor and the turbine?

    How is the spin air injected into the engine?

2.  Inject fuel.

    How is this done?

3.  Ignite fuel.

    How is this done?

In the cockpit, what are the engine start controls,
and what are the pilots' jobs during engine start?
Doesn't one pilot keep a hand on the engine fire
extinguisher?

Thanks,
Richard Nute
San Diego