X-29 Tuft Photo

[Jonfliesgoats]

The picture of the X-29 at the top of this page shows pieces of yarn stuck all over the X-29.  Even today, with supercomputers that can simulate fluid dynamics, going flying and looking for which pieces of yarn wiggle and which don't is an effective way to find where there is turbulent flow around a plane.

The lump of techno-junk on the tail is a parachute.  During stall tests, if the airplane becomes uncontrollable that parachute dangles stabilizes the plane by effectively dangling it from the tail into the relative wind.  The pilot can then release the chute and recover the plane.

Anyway, here are some cool photos from the eighties.

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-008-DFRC.html