Stinson Model U airlinerStinson Model U airplane model. The Stinson trimotored Model U was basically a transport type high wing monoplane with seating arranged for 10 passengers and a crew of two. Often called a sesqui plane (wing and a half) because of the thick lower stub wing that the new Trimotor used to mount the recently developed Lycoming transport type engines of 240 hp each. The design made for a much cleaner aerodynamic configuration, despite its increased bulk.