|
Kelly,
Ah so! I wasn't aware of that one and was hoping
Lynn would make some comment.
Yes your right the top edge of the exhaust port is
correct.
I had spoken to Lynn in the past on the bottom edge
( leading edge) but not the top edge - I didn't know he suggested to slightly
radius that edge - if he did I can't remember.
If we are singing from the same sheet of music -
radiusing the top edge, does increase exhaust flow
characteristics. See attached drawing.
Jump inhere if you wish Lynn!
George ( down under)
George and All,
I do not follow !!
I am familar with Lynn's suggestion to add slightly more
radius to what I call the top edge of the exhaust port.........Are you
suggesting
additional work to this edge ?? Perhaps a simple drawing would
help my simple
mind visualize what you are suggesting !!
--
Kelly Troyer
Dyke
Delta/13B/RD1C/EC2
--------------
Original message from "George Lendich" <lendich@optusnet.com.au>:
--------------
> Ernest,
> Let me try again.
>
The leading edge is already radiused or sloped to enhance flow into the
> exhaust port, Lynn has suggested a further streamlining of that
edge helps
> evacuate the exhaust.
> The top ( following)
square edge helps to block the exhaust from entering
> the inlet
area.
> Now the suggestion to me was to slightly radius this top
edge.
> My thinking it would help draw in some inlet charge and
that's not so good.
> However he has said he gets good performance
from doing that mod.
> I'm unsure !?
> George ( down under)
> > George Lendich wrote:
> >
> > >
> > > It would also seem that if you radiused the following
edge of the
> > > exhaust outlet, it provides better exhaust
flow and less contamination
> > > of the inlet charge at idle.
> > > For your digestion!
> >
> >
>
> OK. I'm about done digesting, so...
> >
> > This is
completely logical, under the theory that the sharp edge will
> >
trip the exiting airflow into turbulence. Clean air always flows
>
> faster. I keep thinking about the exhaust inserts. Ed has the opinion
> > that they must be eating up horses to give the noise reduction
by
> > causing back pressure. But what if the inserts work like a
fowler flaps
> > and just helps the gas to exit is an orderly
manner vs all turbulated?
> > Aren't laminar flow aircraft
typically quieter than turbulent flow ones?
> >
> > Has
anyone compared the noise produced before and after an exhaust has
>
> been radiused?
> > Has anyone attempted to 'shape' the
inserts so that it has a radiu sed
> > leading edge and a tapered
trailing edge (ie, aerodynamic)? I know
> > they're not very
thick, but their thickness is a significant portion of
> > the
overal exhaust ports size.
|