Tom Killeen was a pioneer of monocoque design, and one of his specials, the Hillman Imp-based K18, was initially scheduled to enter production as the Rycam Mirage. In fact, it formed the basis for the production Scorpion. The bodywork was a semi-monocoque fiberglass structure (a later version featured steel instead). There was a tubular steel roll-cage surrounding the cockpit area, which dictated high sills. Pop-up headlamps and gullwing doors were fitted but they were poorly conceived. The rear-mounted engine was a twin-carburetor 998cc Imp Rallye unit developing 65bhp, good for 95mph (153km / h). It is believed that only 11 were made, but the design was later revived as the Kestrel Scorpion.