 In 1947 , before the flight testing of the prototypes was completed , 30 production aircraft were ordered . They incorporated an ejection seat and a redesigned vertical stabilizer as well as two auxiliary fins , one towards the tip on each side of the tailplane in an attempt to improve the directional stability of the aircraft . The fuselage was lengthened to fit additional equipment and the wing had fillets added at the rear junction with the fuselage . 
