What size nationality and registration markings are required for an amateur-built aircraft with a maximum speed of 180 mph?

The requirement for nationality and registration markings on amateur-built aircraft is dictated by FAA regulations. For an aircraft with a maximum speed of 180 mph, the appropriate size for the nationality and registration markings is 3 inches in height. This adheres to the regulations laid out in 14 CFR Part 45, which specifies the requirements for identification marking on aircraft.

Understanding these requirements is important for ensuring compliance with regulations, especially for amateur builders who must adhere to specific guidelines to receive airworthiness certificates. Markings that are too small would not be easily visible from a distance, which is a critical factor for safety and identification purposes. Therefore, 3-inch markings are specifically chosen to ensure that they are large enough for proper identification while still being practical for the aircraft's size and design.