Howard Hughes' XF-11 was a prototype reconnaissance aircraft made for the US military.  The XF-11 used two of the most powerful airplane engines on earth, had a 100 + foot wingspan and weighed nearly 58,000 lbs. It was designed by Howard Hughes to be the highest flying and fastest reconnaissance airplane in the world. On July 7, 1946, with Howard Hughes at the controls, the first test flight resulted in a crash that nearly cost Hughes his own life.   After being airborne for over two hours, one of the huge contra-rotating propellers on the starboard side began to lose oil and fail. This made the XF-11 pull violently to the right.  Hughes did all he could to save the crippled plane but, unfortunately ended up crashing and taking out three homes in the process.  The plane was destroyed and the crash nearly killed Howard Hughes. on its maiden flight.