ERJ-145 JSX airplane model. Embraer began working on 50 seat regional jet concepts in the late 1980s. The original EMB145 (now renamed ERJ-145) concept was launched in mid 1989 and was essentially a stretched and jet engined EMB120 Brasilia. Features of this design included a straight wing with winglets and the two turbofans mounted forward of the wing as on most low wing turboprops. This design would have seated 45 to 50 passengers and featured 75% commonality with the Brasilia. In that configuration cruising speed would have been 740km/h (400kt) and range with a 4500kg (9920lb) payload 2500km (1350nm).
But by 1990 Embraer was studying a modified design with less commonality to the Brasilia as wind tunnel testing revealed that the original configuration would not reach its design performance objectives. Changes to this interim design included a mildly swept wing (wing sweep of 22.3°) and conventional below wing mounted engines.