Raytheon, a defense contractor with a presence in Tucson, earlier this week said it had acquired drone maker Sensintel Inc. Terms of the acquisition were not disclosed. Tuscon-based Sensintel was founded in 1989 and had 50 employees, who will become part of Raytheon Co.'s Missile Systems business. The acquisition wasn't expected to materially impact Raytheon's quarterly or full-year earnings. "Sensintel's expertise in unmanned aircraft systems solutions makes it a natural fit with Raytheon's…