Bellanca Decathlon:

The airplane that I fly is a 1979 Bellanca Decathlon CS, 8KCAB.  It's got a 150hp Lycoming AEIO-320E1B aerobatic engine. A main feature of the aerobatic engine is a system that supplies oil to the oil pump when the engine is both upright and inverted.  The CS stands for "Constant Speed" propeller.  A constant speed propeller will maintain a constant RPM with changing airspeed.  The RPM is set by a knob in the cockpit.  During the airshow, the RPM knob is set full forward at about 2750 RPM.

Everything installed on the airplane is either from the manufacturer or has an STC (Supplemental Type Certificate), so its a completely certificated airplane that does not require an Experimental category airworthiness certificate.  The aileron spades installed at the root of each aileron use air loads to lighten the stick force required by the pilot during rolling maneuvers.  Also installed are Hooker Harnesses with a belt ratchet, which provide a very secure seating position for negative g flight.