Found and Explained Official on MSN

The experimental F-15 that taught the F-22 how to fly

The F-15 STOL/MTD and later F-15 ACTIVE turned the Eagle into a remarkable testbed for thrust vectoring, canards, digital ...
The F-15 STOL/MTD, and later the F-15 ACTIVE, were among the most unusual Eagle variants ever built. Experimental platforms, operated by NASA and the USAF, these specialized F-15s were used to test ...