Makes total sense,jet engines don't care what altitude they're at only that
you go fast enough to feed their voluminous intake needs. Little to do with
aircraft aerodynamics other than the same 'go fast enough' needs.
K
On Mon, Mar 1, 2021 at 3:56 PM Kevin Ho <rebelwithoutajob@xxxxxxxxxxx>
wrote:
This might be totally OT, but the reason why airliner service ceilings are
often below bizjet ceilings is actually really boring: oxygen requirements.
Aircraft are required to be able to generate sufficient passenger operation
to for the entire descent down to a prescribed series of altitudes in case
of depressurization. To fly higher you need to either descend faster or
carry bigger oxygen generators.
I used to fly an aircraft that had one ceiling as an airliner, and a
different, higher ceiling when certified as bizjet. The bizjet
configuration simply had a different passenger O2 system.
Often the other system is a variable too - if the speed brakes are inop,
you are often restricted to a lower max altitude.
Kevin
On Mar 1, 2021, at 4:42 PM, Henry Spencer <hspencer@xxxxxxxxxxxxx>wrote:
derivative, same wing and engines but shortened fuselage -- could be up
On Mon, 1 Mar 2021, roxanna Mason wrote:
The point is 40KFt is at commercial jet altitudes and some business jets
like the Lear 24 service ceiling is 51KFt.
Indeed, if memory serves, a 747SP -- the specialist long-haul 747
near 50k at the end of a long flight. (They ended up needing to add ozone
filters in the cabin air inflow, because up there at the edge of the
stratosphere, the ozone concentration in the incoming air was starting to
become noticeable.)
Henry