Coop wrote...
> >Perhaps you could windmill start it by putting Dorothy in front, full
> >power, brakes on.
[quoted text clipped - 5 lines]
> I could be wrong..... but I suspect it would take more than 130hp to
> get one of those big jets winding over fast enough to start....
Apologies for the late post, catching up.
When we operated a gas fired plant that ran PW FT4C (aero derivative) engines,
they had an air driven starter which spun N2 up to 1,800rpm for 30 secs before
fuel/ignition. The air supply was a 2 Mpa compressed air system with about 4 air
receivers about 3m tall by about 1.5m wide. It had enough reserve to start all
12 engines.
The starters that the aircraft use must be beauties, if those engines require
similar conditions to enable them to fire and not having to rely on external
carts.
matt weber - 10 Mar 2010 00:14 GMT
>Coop wrote...
>
[quoted text clipped - 19 lines]
>similar conditions to enable them to fire and not having to rely on external
>carts.
Actually you can calculate what it takes based upon the 787 electrical
requirements.
http://www.boeing.com/commercial/airports/acaps/787electrical.pdf
says you need 180kVA. If you assume a 100% power factor (unlikely) and
100% efficiency (you can get close)
180,000/746=241 hp for a 65,000 pound thrust class engine.
Coop - 11 Mar 2010 09:17 GMT
>>Coop wrote...
>>
[quoted text clipped - 26 lines]
>
>180,000/746=241 hp for a 65,000 pound thrust class engine.
Q E D :-)
Coop