Section Washout Location

[Karén Melikov]

Hi, all.

Does washout location denote the distance from the root of the given section?

Thanks.

Kare'n

[Rob McDonald]

It specifies the distance along the chord (x/c) about which the rotation happens.  0 -- Twist about the LE.  1 -- Twist about the TE.  0.25 -- Twist about c/4.

In an interesting (to me) phenomena of aerodynamics, lets assume that you're using twist to achieve some lift distribution.  You can use twist to achieve any arbitrary lift distribution -- and it doesn't matter the point you choose to twist the airfoil about.  However, the twist distributions will be different.  I don't know of any study that has looked at the subtle differences in aerodynamics for two wings twisted to the same load distribution, but about different points.

Rob

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[Karén Melikov]

Rob,

about which point does twist usually occur, as a general rule (if there is one)?

Thanks.

Kare'n

суббота, 14 июня 2014 г., 11:37:33 UTC-4 пользователь Rob McDonald написал:

[Rob McDonald]

I don't know that there is a rule, but it is something that can be determined by 'other' considerations.

For example, if your aircraft really wants a straight LE, then twist it about the LE.

On the other hand, many aircraft hang the control surfaces off of the rear spar.  It may simplify the design of those mechanisms to twist about that line.

Rob

[Karén Melikov]

Thanks, Rob!

суббота, 14 июня 2014 г., 11:50:17 UTC-4 пользователь Rob McDonald написал: