The N.V. Vliegtuigbouw 013 Sagitta is a Dutch mid-wing , single-seat Standard Class glider designed by Piet Alsema and produced by N.V. Vliegtuigbouw .
The N.V. Vliegtuigbouw 013 Sagitta is a single mid-wing , Dutch-seat Standard Class glider designed by Piet Alsema and produced by N.V. Vliegtuigbouw .