Received-SPF: none
 receiver=logan.com; client-ip=211.29.133.166; envelope-from=lendich@optusnet.com.au
Message-ID: <000f01c57a03$f4c66360$526b1fd3@george>
From: "George Lendich" <lendich@optusnet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1021775@logan.com>
Subject: Re: [FlyRotary] Re: Single Rotor Research
Date: Sun, 26 Jun 2005 14:03:05 +1000
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

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 radiused
> 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.
>
> --
> This is by far the hardest lesson about freedom. It goes against
> instinct, and morality, to just sit back and watch people make
> mistakes. We want to help them, which means control them and their
> decisions, but in doing so we actually hurt them (and ourselves)."
>
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>