Coax Wind Resistance Grease

Bill Coleman AA4LR aa4lr@radio.org
Wed, 19 Feb 97 12:00:50 -0500


>From:        k4sb@avana.net
>
>The most expense in operating an airliner is fuel. My company also figured 
>out if you didn't paint the thing, ( I think they used a 727 for this ), you 
saved 460 
>pounds of weight, and God only knows how much money for the paint. ( I seem 
to remember it
>was about $45 a gallon )

Sounds about right for Imron (an extremely durable polyurethane paint).

>don't much remember the end except they now could translate the fuel 
>savings from not having the weight of the paint. And it was considerable....

Yet, most airliners paint part of their planes for marketing reasons.... 
Quantas has the coolest paint jobs.

>And as to anyone who thinks the surface of an aerodynamic shape doesn't 
>matter, you should
>have seen original test flights of the F-104 ( which was an AF plane, but 
>conducted at
>Navy Oceana. That beast had specially fitted covers to protect the front 
>surface of the wing.
>One of the tests they did was to put a grease mark on the front of the 
>wing....The thing
>was absolutely unable to get airborne on a 15000' runway. 

The F-104 is a completely different animal than coax in the wind. Now, if 
you had coax in a wind twice the speed of sound, you might have something 
there.

>Now coax is round and smooth. ( at least all I've ever seen. The ONLY way 
>you could reduce
>the drag would be to employ the Magnus principle. The is the principle 
>that caused all those
>little dents to be placed on golf balls, and why commercial airlines have 
>exposed rivet heads 
>on the wing and body.

The airliners I've seen use only flush rivits in the wing surface. Even 
the bodies are mostly flush. My Cessna, on the other hand, has rivit 
heads all over. 

The best way to reduce coax drag would be to fit a long extension that 
would gradually taper the shape of the coax on the downwind (trailing) 
side. But you'd somehow have to rotate it or allow it to freely turn so 
that it was always downwind.

Probably much easier to install a stronger tower....



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@radio.org
Quote: "Not in a thousand years will man ever fly!"
            -- Wilbur Wright, 1901


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