----- Original Message -----
From: "Tord S Eriksson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Friday, May 18, 2001 7:30 PM
Subject: Re: Tandem-winged Planes
> There are a few issues involved here.
>
> The front wing must stall before the main wing,
> which, in a lowdrag installation often is solved
> by having wider chord on the rear wing (thus lower AR),
> usually combined with higher loading on the front wing.
> The same airfoil can be used, but low pitch airfoils are
> most likely recommended.
>
> According to Boeing research, refered to in one
> of Darrol Stinton's books, the lowest drag
> can be had for three-surface aircraft, where manouvering
> is done with a conventional tail, but trimming is done
> with the front wing.
>
> As the front wing can only be used for pitch adjustments,
> that is no ailerons or elevons, roll authority might be low.
> Anhedral on the front wing might be wise, and dihedral
> on the rear. Often you see sweep on the rear, combined
> with wing-tip fins.
>
> So sweet-stalling front wing, combined with low drag airfoils,
> should result in a plane with low sink rate as the average
> wing-loading is lower than a similar conventional plane.
>
> Tord S Eriksson
> www.tord.nu
>
>
> Tord S Eriksson
> www.tord.nu
>
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