The Germans did, during WWII with the Ju 287. Then the Soviet Union captured the Ju-287 prototypes, along with the FSW configuration design, and subsequently developed the Tsybin LL-3. Then the United States and the Soviet Union developed their own prototype aircraft with FSW configurations. Grumman X-29 Sukhoi Su-47 Berkut
12 posted on 08/31/2009 5:37:49 PM PDT by myknowledge
(F-22 Raptor: World's Largest Distributor of Sukhoi parts!)