Engineers at the Central Aerohydrodynamic Institute named after N. E. Zhukovsky (TsAGI) have proposed a way to reduce the takeoff and landing distances of regional turboprop aircraft. Specialists have received a patent for the mechanization of the root part of the wing with increased lift, the solution is designed for operation from short runways of suburban airfields.
The development describes a configuration of a Fowler flap and additional elements — a rotating Krueger flap and a spoiler.
The engineers set precise geometric parameters of the profile and working angles of deflection to enhance the wing's lifting properties during takeoff and landing. The configuration allows for several schemes — a basic one with one flap and extended versions with front and rear mechanization.
What changes in aerodynamics
Calculations and tests showed an increase in the maximum lift coefficient. With the "adaptive" scheme, deflecting the spoiler downwards allows for a greater flap extension and stabilizes the flow. This increases efficiency at high angles of attack and expands safe approach modes.
TsAGI calculated that aircraft with such mechanization will be able to operate from runways 800–1000 m long with a steep glide slope. This opens up basing outside major hubs and reduces the load on hub airports.
It should be noted that serial regional turboprop machines use simpler schemes. For example, aircraft of the ATR family and Bombardier Aerospace projects do without advanced leading-edge mechanization. The new scheme is aimed at shorter runways and a dense regional network.