RV-1: single example of a modified Stits SA-3 Playboy built by VanGrunsven in 1965 and modified with a 125 hp (93 kW) Lycoming engine, larger tail, modified cowling, modified fuselage and a custom metal wing[8] RV-2: wooden flying-wing sailplane prototype that was never completed[9] RV-3: single-seat kit aircraft, aerobatic, debuted in 1972; genesis design for rest of the RV series[9] [10] RV-4: two-seat kit aircraft, tandem seating, aerobatic, bubble canopy[9][11] RV-5: single example of a small metal single-seat aircraft that was originally flown with a half-Volkswagen engine and then with a two-stroke Rotax 447 engine[9] RV-6: two-seat, side-by-side seating aircraft, aerobatic; the most-built model of the RV series and likely the most popular kitplane ever produced[9][12] RV-7: modernized kit with similarity to the RV-6, with longer wingspan and larger rudder, aerobatic; replaced the RV-6 model[9][13] RV-8: two-seat tandem seating, aerobatic aircraft, with larger cockpit and greater overall size than the RV-4[9][14] RV-9: two seat, side-by-side aircraft; non-aerobatic, with larger wing and more docile handling qualities than others in the RV line[9][15] RV-10: largest of the RV fleet with four seats, non-aerobatic, tricycle landing gear only[9][16] RV-11: single-seat motorglider; under development until c. 2012[17] RV-12: two-seat, side-by-side light-sport aircraft,[18] updated to RV-12iS variant in 2017 [19] RV-13: designation not used[20] RV-14: two-seat, side-by-side aerobatic aircraft, considered similar to the RV-7 in design but larger and roomier[21][22] RV-15: future high-wing, back-country capable aircraft[23][24]