(R_m) is the minimal achievable turning radius of the model in specific units based on the system of units used.

(2/ρ) can be read as 2 over ρ (rho), as shown in the formula, or 2 divided by ρ. The / symbol is used for divided by or sometimes read as "over".

The symbol ρ (rho) represents standard air pressure in this formula.

Standard air pressure: "According to the International Standard Atmosphere (ISA) values—15°C at sea level—the density of dry air is at:
-In Metric units: 1.225 kg/m^3
-In Imperial units: 0.0765 lb/ft^3”
15°C is 59°F

1/c_LM creates a constant as 1.1 is used for the maximal lift coefficient (c_LM), which Andrej describes as the mean value between 1.0 and 1.2 for the majority of wing profiles for models without additional high-lift devices, thus the constant is 1 divided by 1.1 = 0.909 (rounded to the nearest thousandth)

Using the formula with an example:

Note:
The SI units used for the calculations are kilograms (kg) and square meters (m²).
The Imperial units used for the calculations are pounds (lb.) and square feet (sq. ft. or ft²).

Example Plane: Weight (mass): 50 oz. with a 500 sq. in. wing area
50 oz. / 16 oz. in a pound = 3.125 lb.
500 sq. in. / 144 sq. in. in a square foot = 3.472 sq. ft.
50 oz. / 35.274 oz. per kg = 1.417 kg
500 sq. in. / 1550 sq. per square meter = 0.323 m²

Note: The units have been dropped from the computations that follow for clarity.

Imperial R_m = (2 / 0.0765) x 0.909 x (3.125 / 3.472)
R_m = 26.144 x 0.909 x 0.9 = 21.4 feet (rounded to nearest tenth)
SI R_m = (2 / 1.225) x 0.909 x (1.417 / 0.323)
R_m = 1.632 x 0.909 x 4.387 = 6.5 meters (rounded to nearest tenth)

To verify that the answer in feet, 21.4 feet, and the answer in meters, 6.5 meters, are equivalent minimum radius turns, the feet unit needs to be divided by 3.281, the approximate number of feet in a meter. 21.4 feet divided by 3.281 is approximately 6.5 meters, rounded to the nearest tenth.

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