Posted for "Bill Harrelson" <n5zq@verizon.net>:

 Adam,

 I too obtain my induction air from the engine plenum.  I believe that
tapping the high pressure environment above the engine is better than tapping
the high speed environment of a ram tube. I use a conical K&N filter. Not
seen in the photos are carbon baffles that surround the air filter from the
front and prevent any air from entering the filter directly from the intakes.
 This deflects ice, bugs and debris that might otherwise be able to get to
the filter. With the baffles, air must enter the filter from behind.  I get
substantial manifold pressure rise with IAS increase and the filter remains
mostly clean.

 Bill Harrelson
 N6ZQ  IV  600 hrs





> -----Original Message----- From: adam@validationpartners.com
> Sent: Tuesday, September 09, 2014 7:43 AM
> To: Lancair Mailing List
> Subject: [LML] Bellmouth intake design
>
> I currently have a simple wire screen over my throttle body. Intake air
> is drawn from the high-pressure cooling air in the engine plenum.
> However I recently read that a straight intake pipe which draws air
> without the benefit of ram pressure is inefficient. Some air gets drawn
> in from the sides and has to make a sharp 90-degree bend. This results
> in a ring of low pressure air which "chokes" the intake somewhat.
>
> Hot rodders have long understood the benefit of smoothing the intake air
> using a bellmouth inlet (sometimes called a velocity stack). Bellmouths
> are also installed on jet engines when they are run in a test stand (see
> attached photo).
>
> So my question is, can someone point me to any drawings or papers which
> spell out the optimum shape for a bellmouth? Just has we have
> specifications for NACA scoops and airfoils I imagine someone did the
> research for air intakes.
>
> Once I have a CAD drawing on hand, this seems like a good candidate for
> 3-D printing.
>
> Thanks,
> Adam Molny
> Legacy N181AM, 295hrs
>
>
>
>
>
>
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