Andy Ross writes:

 > There's a tunable TSFC number that you can play with.  The engine
 > model isn't smart enough to vary fuel consumption with condition
 > (real engines have variable TSFC's under different situations).
 > But as long as the number used is correct for cruise there
 > shouldn't be too much difference over a long flight.

This is probably obvious, but according to my study materials for the
instrument rating, the efficiency of a jet engine depends on the
temperature differential between its combustion and the outside air
temperature -- that's why jets are very efficient flying near the
tropopause at around -60 degC, but burn more fuel for less power in
warmer temperatures (i.e. lower).  Is YASim taking that into account?

 > You could also check the throttle setting in the cruise parameters.  I
 > think I have most of them at 100% right now (max speed numbers, as
 > opposed to cruise numbers), lowering that should lower overall drag
 > and improve cruise-regime fuel consumption.  As always, the best
 > numbers to use are ones from a POH, if anyone has them.

The 747 YASim config file has the throttle at 0.75.


All the best,


David

-- 
David Megginson, [EMAIL PROTECTED], http://www.megginson.com/

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