It's cute and pedantic. But also only true when the engine is moving at low
speeds. An intake moving at speeds of transonic and above produces massive
drag.
On Apr 1, 2016, at 10:30 AM, Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
No, it's more that the interior and leading edges of the intake, and thus the
engine face, are under low pressure. High pressure in back, low pressure in
front, forward thrust.
"The intake produces (most of) the thrust" is just a way of saying that, if
you calculate the thrust by integrating pressure over the exterior of the
engine+housing+intake, there are cases where the largest factor is the
reduced pressure at the intake. Never mind that what's actually producing
that reduced pressure is the engine's work in ejecting masses of burned
fuel+air at high velocity out the back, "the intake produces the thrust" is a
cute, mathematically-correct way of stating the matter (and boggling
bystanders.)
Something similar applies to calculating rocket thrust. One way of figuring
losses from atmospheric back pressure is to integrate pressure over the
interior and exterior of the rocket nozzle - the atmospheric pressure on the
exterior (largely forward) is essentially the thrust lost from operating in
other than vacuum.
Henry
On 4/1/2016 8:53 AM, Paul Mueller wrote:
Really? So the material between the intake and the engine mount (say on
a wing-mounted turbojet like on a B-52) is under tension, and if the
intake broke free it would go shooting forward? I'm not saying that's
wrong, I just don't understand that.
On Fri, Apr 1, 2016 at 1:30 AM, Troy Prideaux <GEORDI@xxxxxxxxxxxxxxxx
<mailto:GEORDI@xxxxxxxxxxxxxxxx>> wrote:
It's a tricky statement to make in a universal sense. In terms of
turbojets, the intake is the part that produces the thrust.
Troy
>>
>> Henry
> It is all about _Intakes_ !
>
> All intakes produce drag ( missleading! in correct terminology
they "are energy sinks" ).
> You expect to recover and efficiently add energy in the process.
> So many processes that work that way around :-)
>
> uwe
>
