Click on picture for close up.
Propellants stream from the prime drains of the X-15-3 immediately after launch on one of its first nine flights. Propellants were pumped through the plumbing of the XLR-99 rocket engine before launch to prime the engine for ignition, with the overflow directed through the prime drains. The tail of the X-15 is still in the shadow of the NB-52. Note the barely visible yellow NASA tailband. It was only applied to the left side of the tail during this period. The last flight of the X-15-3 with the ventral fin was mission 3-9-18 on August 14, 1962. Photo courtesy AFFTC/HO.