Convair X-11

The Convair X-11, originally designated XSM-16A, was the first test vehicle of the Atlas intercontinental ballistic missile programme. The German article calls it the first test environment for the Atlas missile, with the more developed Convair X-12 following as the second. Twelve X-11 vehicles were built and tested in a series that ran from 11 June 1957 to 3 June 1958. The first three were used only in static ground tests, numbers four and six were destroyed in launch accidents, and all the others completed their test flights successfully. Unlike the three-engined X-12, the X-11 had only one engine. The article gives no further technical data, so dimensions, thrust and range are not stated here.