Please calculate the STAGNATION PRESSURE of the exit from the fan. A small business jet aircraft is flying at a true air speed of $428$ knots in ISA conditions at an altitude of

$18050$ feet.

Propulsion for this aircraft is provided by two small turbofan engines each of which, at this flight

operating condition, has a core mass flow of $5\mathrm{.}1k\frac{g}{s},$ a bypass ratio of $3\mathrm{.}3,$ fan pressure ratio of $1\mathrm{.}62$

and a fan polytropic efficiency of $91\mathrm{.}2\%.$

It may be assumed that:

Intake isentropic efficiency $=93\%$

There are no pressure loses in the bypass duct

The bypass flow propelling nozzle area is matched to this operating condition.

$1$knot$=0\mathrm{.}5147\frac{m}{s}$

$1$ foot $=0\mathrm{.}3048m$

For air, $=1\mathrm{.}4,R=0\mathrm{.}287k\frac{J}{k}g.K$

Calculate the stagnation pressure at the exit from the fan.

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