On Tue, 01 Jul 2003 08:40:51 GMT, Guy Alcala
wrote:

JB wrote:

True enough, it does burn more fuel, but possibly not enough to be an issue.
Actually, in domestic ops, the RR is the most thirsty of the engines.

Some numbers:
767-200 PW
Fuel to climb to FL330 (at 155,000 kgs start weight) 3280 kg
Cruise at FL330
@ 155k, 5086 kgs/hr
@ 130k, 4510 kgs/hr
@ 110k, 3994 kgs/hr

767-300 GE
Fuel to climb to FL330 (at 155,000 kgs start weight) 3010 kg
Cruise at FL330
@ 155k, 4940 kgs/hr
@ 130k, 4476 kgs/hr
@ 110k, 3982 kgs/hr

The numbers are for a .79 cruise, and reduce by just on 400 kgs/hr (for
both) if you are holding.

The 767-300 has a bit less drag than the -200, so I would expect a GE
equipped 200 to be slightly worse than these figures. You can't use a 300,
as there will be tail clearance issues with the boom refuelling gear.

Do you happen to know why the -300s have less drag? Offhand I'd expect the
opposite, given the larger wetted area.
larger wetted area, but the aircraft is transonic and the longer
fuselage increase the 'fineness' or ratio of cross section to length,
which tends to reduce drag in the transonic and supersonic regimes.
Relatively few notice just how Long (and thin) Concorde actually is.
It is about 2 meters shorter than an a330-300!