The Master was furnished with a constant-speed propeller, which was interchangeable between Rotol and de Havilland units. The Kestrel engine of early-built aircraft incorporated various auxiliary drives to power both vacuum and hydraulic pumps, along with an air compressor and a 500-watt electrical generator. Cooling for the water and oil systems was provided via a duct running underneath the fuselage. Fuel was housed in a pair of fuel tanks, each containing up to 36 gallons, accommodated within the wings; the oil tank is mounted behind a fireproof bulkhead while the water tank is mounted in front of the engine. The retractable undercarriage is operated via two separate hydraulic systems along with a hand-pump as backup; the brakes are also hydraulically-actuated.