Conceived as a motor glider and sport touring aircraft, the RF-4 was introduced in 1966. It is of all-wood construction and is fully aerobatic. The landing gear consists of a monowheel gear which retracts forward into a fibreglass cowling. The main wheel has a brake which is manually operated. There is a small steerable tailwheel and wing-mounted outrigger wheels.
An RF-4D was flown by Mira Slovak across the Atlantic Ocean while participating in the May 1969 Daily Mail Air Race. The flight won a £1,000 prize offered by the London Evening News for the best performance in the race by an aircraft under 5,000 lb (2,268 kg) gross take-off weight. The main landing gear fork is an ongoing maintenance issue, with regular replacements needed.