Text in force at CAR3-14: from CAR3-0, effective 1 Nov 1949. OCR text
(c) Structural clearance.
(1) One inch radial clearance between the blade tips and the airplane structure, or whatever additional radial clearance is necessary to preclude harmful vibration of the propeller or airplane.
(2) One-half inch longitudinal clearance between the propeller blades or cuffs and stationary portions of the airplane. Adequate positive clearance shall be provided between other rotating portions of the propeller or spinner and stationary portions of the airplane. FUEL SYSTEM