There is a reason that all delta wings have their tips set so that at cruise their wingtips provide NO LIFT and in fact generally provide negative lift. It ain't for high speed performance either. Its called low speed control performance or lack thereof and maneuverability.

I know, I hate wiki quotes, but in this case they are correct and you can look it up in aeronautics books as well.

http://en.wikipedia.org/wiki/Tailless_aircraft

Read the longitudinal stability section.

Here is the best frontal picture I could quickly find showing the washout.

http://www.f-16.net/f-16_forum_viewtopic-t-10820.html Scroll down a little bit.

Enjoy

I believe the F4 washout is VERY noticeable at the break, but didn't quickly find a picture.