|Quoting apfpilot (Reply 30):|
But why is that a bad thing, you haven't provided any evidence.
|Quoting strfyr51 (Reply 41):|
the service ceiling has nothing to DO with the airplane's performance.
It's the internals like pressurization and just how high you can maintain an 8 psi cabin differential.
Cruise efficiency is determined by outside air density. As one climbs, the density drops, therefor less thrust is required. Since the outside pressure and density are dropping, with the temperature a constant in the stratosphere, a higher wing loading means about 10% more fuel burn at the 2nd half of cruise.
Getting to higher cruise altitude has *everything* to do with airframe performance after the 1st hour.
I worked on an engine where a 3" reduction in fan diameter reduced weight enough to allow earlier step climbs (and a reduction in nacelle drag and fractional improvement in fan diameter) had zero impact on long range mission fuel burn and improved shorter mission economics.
But it was because of a higher cruise altitude that mattered. Douglas built great planes. To achieve their cycle life they built a bit heavier *and* designed for a lower cruise altitude. This sacrificed range. At the end of the T-tails sales life, the lack of that little bit of range hurt sales. Because of the lower cruise altitude, more diversion fuel is required further eating into range.
Maximum cruise altitude in service is limited by the achieved climb rate at a given cruise weight. You are not allowed to carry passengers until flight test proves at each weight that climb rate. Now, I worked experimental aircraft, so we figured out the number and let another group bless operating altitudes. Its much more fun going beyond the rules.
Note: Many aircraft are operated in limited service beyond certification limits, but that requires an in cert test pilot.
|Quoting Revelation (Reply 44):|
When you look at the EJet/CJet market size compared to A320/B737 you can see who is in the right market.
Agreed. The smaller market is that much smaller.
|Quoting ltbewr (Reply 45):|
It wasn't small enough (under 100) for many 'commuter' airlines so could be operated by lower tier non-mainline (and cheaper) crews.
It was heavier than needed due to it older base engineering for its capacity so not as fuel efficient as 737's/318's.
It was close to some then current versions of the 737 (the weak selling -600) so didn't need the competition.
Many airlines wanted to limit the different types of models of a/c they have. The 717 was just one model too many for airlines.
That sums it up. It was too heavy vs. the E190/E195 which, as we see by the 100 seater *far* outselling the larger frame, was to keep costs down.
The E190 entry into service in 2004. Is it really any surprise 717 production ended in 2006?
Once a new generation of new small narrowbodies is in the fleet, I expect the resale value of the 717 to decline. Oh, HA needs the quick turn capability. DL will buy them too. But one day DL will buy something else. Just as UA is looking into a new plane, one day DL will too. I see the 717 staying in their fleet, but in the future a low utilization when RASM is elevated. Now, I'm talking future tense after the C-series and E2-190/195 are out in numbers. (Either or... One market segment, it is when quantity is out.)