Alex launching a model rocket we built together. The conditions were excellent with a wind speed of 5 kph (3 mph). We used three engines for this session: B4-4, B6-4, and C6-5. This rocket was created with a multiple-fin design, representative of the Nike ground-to-air missiles that were used in US defence for years. From 1954 to 1974 certain US cities were ringed by Nike missile sites, intended to protect against attack by enemy bombers. The first versions of these missiles were armed with high explosive warheads, so they could bring down the target even with a near miss.