STOL Stall Speed MPH Calculator

STOL stall speed: V = √(2·W / (ρ·S·CLmax))

STOL (Short Take-Off and Landing) covers aircraft built for very short fields, where stall speed becomes the floor on both liftoff and touchdown. Read the formula V = √(2·W / (ρ·S·CLmax)) and you can see two ways to bring the minimum flying speed down: lighter wing loading (W/S) and a higher CLmax from large flaps, leading-edge slats and vortex generators. The Piper PA-18 Super Cub gets off the ground in about 100 m at roughly 40 mph (35 kt). The Helio Courier stays controllable below 30 mph (26 kt). And modern bush-flying machines such as the Carbon Cub EX-3 have logged takeoff rolls under 20 ft (6 m) at the Valdez STOL competition in Alaska. These airplanes are what make backcountry flying possible in Alaska, the Patagonian Andes and the Brazilian Amazon strips.

Applications

Think bush flying across Alaska, Patagonia and the Amazon, medevac flights into remote strips, supply runs to off-grid villages, sport STOL events like the Valdez Fly-In, and operations under ANAC RBAC 91 / FAR Part 91 off unpaved fields.

FAQ

Is STOL the same as VTOL? No. A STOL aircraft still needs a short ground roll, while VTOL machines such as helicopters, the Harrier, the F-35B and eVTOLs lift off vertically with no roll at all.

What CLmax do real STOL aircraft reach? With flaps and slats out, somewhere around 2.4–3.0. STOL prototypes fitted with blown flaps have pushed CLmax past 5.

Does altitude affect STOL performance? Yes. At higher density altitude the air is thinner (less ρ), so the true stall speed climbs and the ground roll gets longer. That is one of the main limits for Andean strips above 3,000 m.