I found the video of them starting up that engine for the first time more interesting:
Re: Elmo V. Jet Engine
Posted: Sun Nov 08, 2015 9:27 am
by Colonel
Gosh, that's a familiar turbine. Cpt
Crunch - I didn't know you had that
type rating!
PS It really bugs the crap out of me
when people describe jet engines as
developing "X" horsepower.
Sigh. This is 'way worse than petty
grammar or spelling mistakes. They
just don't get the physics.
-- EDIT --
High school physics time. Yes, you
knew this stuff, and it's your job as
a pilot to educate the rest of the
population as to the difference
between thrust and horsepower.
A turbo-jet or (more modern and
efficient) turbo-fan engine, merely
[i][b]BLOWS[/b][/i].
That's all it does. As in the video
above, you can bolt one to the ground
and run it up and people who "half get it"
will claim that no power is being developed,
and they don't "get" the physics either -
air has mass, and if you don't believe
me that a stationary jet engine is developing
lots of power at 100% RPM, stand behind
it and get back to me on what you learned.
So, a turbo-jet/fan engine develops (and
is rated in) pounds of thrust of air that it
can shove back. Or if you're a Liberal, it
digs a hole in the air, and falls into it.
Contrast that with an engine (opposed
piston, radial piston, turboprop) which
has a shaft that it turns. It's output is
measured in HORSEPOWER.
Let's look at some basic Newtonian
physics definitions:
FORCE: (eg thrust, a push of some sort)
FORCE x DISTANCE: WORK
WORK / TIME: HORSEPOWER
See the difference between thrust and horsepower?
Thrust is a very simple measurement of force,
used for jet engines.
Horsepower is a much more sophisticated measurement
of work performed in a given time, which is more
naturally used to measure the output of an engine
with a shaft that is rotated with a specific torque
at a given RPM. Note that distance does not have
to be linear - it can be circular : two Pi Diameter,
you might recall.
Rather arbitrarily, a horsepower is defined as 550 lbs
being raised one foot in one second, which is what an
old dude called James Watt observed about a million
years ago.
Anyways, I hope this helps. Understand the difference
between FORCE, WORK and HORSEPOWER because that's
what you're going to be controlling and relying on for
the rest of your pilot career.
Re: Elmo V. Jet Engine
Posted: Sun Nov 08, 2015 7:34 pm
by Strega
[quote]both slowing down the air and increasing its static pressure and therefore mass flow rate[/quote]
Interesting....Is that how they teach math in AME school?
Re: Elmo V. Jet Engine
Posted: Sun Nov 08, 2015 8:30 pm
by Strega
Im not going to explain anything to you... youre the expert...
Although I didnt know an adiabatic cycle was "magic" to increase massflow...
Re: Elmo V. Jet Engine
Posted: Sun Nov 08, 2015 8:41 pm
by Strega
Yes... and I dont baffle those with "bullshit over brains"