[books] aircraft and engine

On Wed, 06 Jun 2007 11:35:55 GMT, Ron Hardin
wrote:

...

That the turbine is spinning doesn't matter to the objection. The exhaust going
to the rear spins it up, the exhaust going to the front slows it down. Net effect,
zero. How does the exhaust keep it spinning?

The compressor in front provides a wall of air as dense as 6 times
standard pressure - so the expanding hot air behind it finds it
energetically advantageous to go backwards, which reinforces the wall
of air

Brian Whatcott Altus OK

Brian Whatcott wrote:

On Wed, 06 Jun 2007 11:35:55 GMT, Ron Hardin
wrote:

..

That the turbine is spinning doesn't matter to the objection. The exhaust going
to the rear spins it up, the exhaust going to the front slows it down. Net effect,
zero. How does the exhaust keep it spinning?

The compressor in front provides a wall of air as dense as 6 times
standard pressure - so the expanding hot air behind it finds it
energetically advantageous to go backwards, which reinforces the wall
of air

Brian Whatcott Altus OK

But that back pressure slows the turbine, just as surely as going through the blades
backwards would. Equivalently, the compressor is doing more work the more you ignite
the fuel. What keeps the turbine from slowing to a stop and then everything just
blowing out both front and back?

--
Ron Hardin


On the internet, nobody knows you're a jerk.

On Wed, 06 Jun 2007 13:19:36 GMT, Ron Hardin
wrote:

Brian Whatcott wrote:

The compressor in front provides a wall of air as dense as 6 times
standard pressure - so the expanding hot air behind it finds it
energetically advantageous to go backwards, which reinforces the wall
of air

Brian Whatcott Altus OK

But that back pressure slows the turbine, just as surely as going through the blades
backwards would. Equivalently, the compressor is doing more work the more you ignite
the fuel. What keeps the turbine from slowing to a stop and then everything just
blowing out both front and back?

If I arrange to share the motive power between compressing input air,
and accelerating exhaust air, the compressor is a load. and
accelerating the exhaust is a load.
The compressor does not normally stop if I supply energy as fuel.
And the exhaust does not normally stop if I keep supplying fuel.

Brian Whatcott Altus OK

Brian Whatcott wrote:
But that back pressure slows the turbine, just as surely as going through the blades
backwards would. Equivalently, the compressor is doing more work the more you ignite
the fuel. What keeps the turbine from slowing to a stop and then everything just
blowing out both front and back?

If I arrange to share the motive power between compressing input air,
and accelerating exhaust air, the compressor is a load. and
accelerating the exhaust is a load.
The compressor does not normally stop if I supply energy as fuel.
And the exhaust does not normally stop if I keep supplying fuel.

The question is, though, why the combustion products don't just blow
out both ends. _All_ the turbine blades are compressors, from the point
of view of the gasses.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

On Thu, 07 Jun 2007 10:26:40 GMT, Ron Hardin
wrote:

Brian Whatcott wrote:
But that back pressure slows the turbine, just as surely as going through the blades
backwards would. Equivalently, the compressor is doing more work the more you ignite
the fuel. What keeps the turbine from slowing to a stop and then everything just
blowing out both front and back?

If I arrange to share the motive power between compressing input air,
and accelerating exhaust air, the compressor is a load. and
accelerating the exhaust is a load.
The compressor does not normally stop if I supply energy as fuel.
And the exhaust does not normally stop if I keep supplying fuel.

The question is, though, why the combustion products don't just blow
out both ends. _All_ the turbine blades are compressors, from the point
of view of the gasses.


Ah, I see Ron's issue - thinking that a compressor blade is
functionally identical to a power turbine blade. Their curvatures are
different with respect to the airflow, in fact.

But I have spent too much time on this question

Regards

Brian W

Brian Whatcott wrote:

On Thu, 07 Jun 2007 10:26:40 GMT, Ron Hardin
wrote:

Brian Whatcott wrote:
But that back pressure slows the turbine, just as surely as going through the blades
backwards would. Equivalently, the compressor is doing more work the more you ignite
the fuel. What keeps the turbine from slowing to a stop and then everything just
blowing out both front and back?

If I arrange to share the motive power between compressing input air,
and accelerating exhaust air, the compressor is a load. and
accelerating the exhaust is a load.
The compressor does not normally stop if I supply energy as fuel.
And the exhaust does not normally stop if I keep supplying fuel.

The question is, though, why the combustion products don't just blow
out both ends. _All_ the turbine blades are compressors, from the point
of view of the gasses.

Ah, I see Ron's issue - thinking that a compressor blade is
functionally identical to a power turbine blade. Their curvatures are
different with respect to the airflow, in fact.

But I have spent too much time on this question

Well, you might try the idea of leverage. Together with the fact that
more gas goes out than comes in, to keep it from falling afoul of
some law preventing perpetual motion machines.

--
Ron Hardin


On the internet, nobody knows you're a jerk.