14 CFR § 61.316

If you hold a sport pilot certificate, you may act as pilot in command of an aircraft that, since its original certification, meets the following requirements:

A maximum stalling speed or minimum steady flight speed without the use of lift-enhancing devices (VS1) of not more than 45 knots CAS, except for airplanes, which must have a VS1 speed of not more than 59 knots CAS at the aircraft's maximum certificated takeoff weight and most critical center of gravity.

A maximum seating capacity of two persons, except for airplanes, which may have a maximum seating capacity of four persons.

A non-pressurized cabin, if equipped with a cabin.

For gyroplanes, a fixed-pitch, semi-rigid, teetering, two-blade rotor system.

For powered aircraft other than balloons or airships, the loss of partial power would not adversely affect directional control of the aircraft and the aircraft design must allow the pilot the capability of establishing a controlled descent in the event of a partial or total powerplant failure.

For helicopters, they must be certificated with the simplified flight controls designation.

For gliders, fixed or retractable landing gear.

For powered-aircraft other than a glider, fixed landing gear except as provided in paragraph (b) of this section.

For powered-aircraft other than a glider, a fixed, ground-adjustable, or an automated controllable pitch propeller except as provided in paragraph (b) of this section.

If you hold a sport pilot certificate, you may act as pilot in command of an aircraft that has retractable landing gear or an airplane with a manual controllable pitch propeller if you have met the training and endorsement requirements specified in § 61.331.