787 Bleedless AC

[Yusef Danet]

So we know that the 787 will feature bleedless engines for fuel efficiency...

I understand electric starting, electric anti-ice, but how will it be air conditioned/pressurised?

Of course tapping off hot bleed air from your powerplant then cooling is not the most efficient way of seeing to our respiratory needs, but how are Boeing planning on doing it?

[Wizofoz]

Electrically...

[Yusef Danet]

Well, I didn't think it would be a coal powered Drayton-cycle engine, but how will it be done more economically than using compressor bleed/packturbines/heat exchangers?

[downwind]

Guys,

Also heard the cabin altitude in the 787 will be something in the order of 4000 above sea level instead of the normal 8000 above sea level, could they be using a newer vapour style aircon system???

What is the backup hydraulic's pressure for the FBW sytem of the A380, heard it was 5000 PSI?????
don't know not rated on any of the A3xx familys????

[767-300ER]

I just had a briefing by Boeing and the cabin will be 6000'.
The reason for the 6000' was that they can lower it from 8000 since the carbon-reinforced plastic can withstand the differential pressure, a metal cabin would have to be a lot heavier than the current cabins to get the strength required to sustain the pressure. The reason that an electrical press and a/c system is better is that with electrical systems you can match the demand and requirements much more closely. A pneumatic system is less efficient and a lot heavier and more complicated!

The fusleage barrel that they just rolled out in a single piece (7m x 5m or something like that) would have had 1200 pieces in a metal fuselage barrel and would have been held together by 40,000 rivets...so there are lots of reasons for the move to the carbon reinforced plastic (or is it plastic reinforced carbon ;-) )

[Herp]

Both the A380 and the B787 will apparently have Hyd systems pressurised to 5000psi. The higher pressure allows a smaller diameter pipe which in turn reduces weight.