J/K,

Here is a side view drawing of a Kruger leading edge flap on the 727, 737.

http://img15.imageshack.us/img15/6505/27krueger229.jpg

And here is a photo of the same flap on a R W 737...

http://img713.imageshack.us/img713/6571/kruger73780067.jpg

Here is the L E flap on the 747...

http://img822.imageshack.us/img822/858/variablecamber.gif

These are all forms of Kruger L E flaps.

My question is:

First, why the mix of Kruger and slats on the 727 & 737?

Second, why does the 707 and 747 have only Kruger L E flaps?

J/K, if you would like to answer, be my guest.  ;)

Uploaded with ImageShack.us