If you have access to Avsig then you can find a downloadable Excel
spreadsheet in the library that will do all the hardwork for you to whatever
size you want.
Duncan McFadyean
-----Original Message-----
From: Fergus Kyle <fkyle@bigwave.ca>
Date: Thursday, January 06, 2000 8:43 PM
Subject: NASA Duct....
>Cheers:
> I always wondered where the info on the NASA (was NACA) inlet duct
>design was to be found and was ready to assail the local library when I
>stumbled across details in Tiny Bingelis' "The Sportplane Builder".
> Anything to do with aeronautics is bound to be written backwards, so I
>set to and have devined a design for an inlet duct to feed a 2in. (51mm)
>internal Diameter airduct. At present it is just the shape of the inlet,
>so must be revised to suit the ductwork subsequent. Also, I haven't
>divined the surrounding structure to compensate for loss of integrity
>due to the incursion.
> The basis refers to selection of aspect ratio (length/width) of the
>surface inlet as 3 to 5. I set out at 4, but it seems too long and thin,
>so have opted for 3:1. Thjis produces a shape length of 8.144 inches and
>max. depth of 1 inch and appears more in keeping with photos I've seen.
>(Ratio of 4:1 is 10.25in by 1.57in deep).
> Unless someone has better dimensions/choices, I will fax (I can't scan
>yet) a copy of fullsize design for kneeheight inlets for cockpit cool
>air each side, on request. Failing acceptance of my size/shape, will
>happily send formulae for your own design and the steps involved - which
>if you are as old and bent as I, mught save a few minutes puzzling......
> Better stuff? Anyone?
>Happy landings
>Ferg #A064
>
>
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