Hobart Sorrell built Dr. I (Fokker triplane) ¾-scale replica 1957. Subsequently formed Sorrell Aircraft Co. Ltd, flying SNS-2 Guppy biplane (1967), SNS-7 Hiperbipe aerobatic biplane (March 1973) and SNS-9 Exp II 2-seat sport/trainer (22 May 1985); also produces microlights.