corrugated ailerons and flaps...

[152captain]

A question from an aspiring PPLer (flight test next week). What is the reason behind having corrugated ailerons and flaps on many of the GA aircraft out there?

[Intruder]

Strength with economy of manufacture?

The corrugations would decrease the need for internal ribs. They might also decrease spanwise flow to a small extent...

[Tinstaafl]

As Intruder says. The ribs provide strength & stiffness simply, cheaply & lightly.

Have a look at the thickness of a C150/152/172 aileron & try to work out another cheap way to achieve the same result.

Damned if I can, other than some sort of honeycomb. Might be cheap enough now, but I doubt it wasn when these types were designed.

[DOC.400]

Look at a Ju 52 if you get the chance!!

[Genghis the Engineer]

Also tends to reduce the tendency for crossflow, which improves control effectiveness. But mostly the stiffness.

G

[152captain]

Thanks for all the info, I guess that's why some rudders are that way too,

much obliged,

152

[ 06 January 2002: Message edited by: 152captain ]</p>

[152captain]

BTW, I looked up the JU52...wow...now I get it...

152
<a href="http://www.airliners.net/open.file?id=207308" target="_blank">JU52</a>

[ 06 January 2002: Message edited by: 152captain ]</p>

[Deaf]

Increased Stiffness. The stiffness of a sheet is proportional to the cube of the thickness and the corrugation increases the effective thickness. For a less simplistic explanation look up "moment of inertia".

Try creasing a sheet of paper in a similar manner and notice the difference in stiffness.

[Shaggy Sheep Driver]

It's to tip a load of rainwater down the neck of the student doing the pre-flight when he waggles the ailerons.

Character building, don't you know!

SSD