Well, engineering judgement tells me that your drag
increase is still too low. Now I'll just have to prove
it by looking at that report, or elsewhere.
Sounds like a good project for the long holiday
weekend, or I could just work on my Cozy ... it will
be a tough call!

Ron

--- Ed Anderson <eanderson@carolina.rr.com> wrote:

>
>  Ok, Ron, I went back and looked at the drag aspects
> again.  It looks like
> the calculation was accurate, however, I think this
> will put it into a
> better perspective than before.
>
> The frontal drag at 120 mph for the 1 square foot
> radiator (using just the
> frontal area - no drag coefficient) was
>
> 37.63 lbf/ft^2,  the "internal skin" drag of the 4"
> thick radiator was 6.7
> lbf/ft^2.  The skin drag for the 1" thick rad was
> 4.28 lbf/ft^2.  So
> comparing the 6.7 with the 4.28 was where I came up
> with the 58% increase in
> skin drag.
>
>  However, adding  the frontal and skin drag factors
> for the "total" drag, I
> get 37.62 lbf/ft^2 + 4.28 lbf/ft^2 = 40.98 lbf/ft^2
> total drag for the 1"
> rad. For the 4" rad  37.62 + 6.7 = 44.32 lbf/ft^2,
> so based on that it
> appears that the total drag was increased by
> 41.90/44.32 = 5.5% more total
> drag for the 4" radiator than for the 1" radiator.
> It might be a tad bit
> less than that due to the 5% decrease in mass flow
> on the frontal area of
> the thicker rad.
>
> At least that is the way it appears to me.
>
> Ed
>
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:  
>
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>