STOL Cruiser Aircraft

A new STOL (Short Take-Off and Landing) aircraft in the LSA (Light Sport Aircraft) category, with a maximum take-off weight of 600 kg, is now entering production. Marketed as the STOL Cruiser, this aircraft was developed through close collaboration between Direct Fly s.r.o. and the Department of Aerospace Engineering at the Faculty of Mechanical Engineering, Czech Technical University in Prague, with support from the Technology Agency of the Czech Republic under the EPSILON Program.

Thanks to a tailor-made high-lift system and an aerodynamically optimized design, this aircraft achieves significant fuel savings compared to other STOL aircraft in the LSA category, making it both more economical and environmentally friendly. In this category, aerodynamic efficiency is often overlooked, leading to either very low cruise and maximum speeds, limited range, or high fuel consumption. The common approach to achieving higher performance in existing STOL aircraft certified in the LSA category is the use of more powerful engines (typically 140 hp or more), which increases acquisition costs, fuel consumption, and reduces payload capacity. Furthermore, most current STOL aircraft configurations rarely allow for carrying payloads heavier than 30 kg, making them more suited for recreational use rather than practical transport.

The uniqueness of the STOL Cruiser lies in the comprehensive design approach combined with advanced manufacturing technology, which is uncommon in the LSA category. The aircraft’s concept was shaped by the need for high flight performance while also considering technological constraints, particularly those of tool-free manufacturing methods. This approach minimizes production costs compared to traditional riveting techniques. As a result, the STOL Cruiser enters the market as a cost-efficient aircraft with an unprecedented combination of flight characteristics in this category, allowing for significantly more economical and environmentally friendly operation. Unlike other STOL aircraft, it offers performance levels closer to those found in heavier aircraft categories.

The aircraft is a fully metal, single-engine, two-seat high-wing design with a conventional tail configuration. One of its main advantages is exceptionally short take-off and landing distances, thanks to its low stall speed. Additionally, the STOL Cruiser boasts a relatively high cruise speed, which is uncommon in this aircraft category. Another key benefit is its spacious cabin, making it highly versatile and capable of transporting oversized cargo that is rare in this segment, such as a stretcher for a reclining patient. With a total fuel capacity of 100 liters, it offers extended range and endurance.

The aircraft features a self-supporting, trapezoidal wing equipped with an efficient two-part Fowler flap system on the trailing edge. The leading edge incorporates slots, with the inner slot linked to the flaps for enhanced safety, while the outer slot extends automatically at high angles of attack. The semi-monocoque fuselage consists of a load-bearing skin, bent stringers, and pressed bulkheads.

Compared to its competitors, the STOL Cruiser offers a significantly broader range of operational speeds while requiring substantially less engine power. Equipped with a 100 hp engine, the STOL Cruiser delivers the following performance:

• Maximum speed: 220–225 km/h
• Minimum speed: 40 km/h (depending on engine mode)
• Cruise speed: approx. 180 km/h

The maximum-to-minimum speed ratio is an unmatched 5.5 in this category. Additionally, it provides an exceptionally spacious luggage compartment capable of holding up to 60 kg of cargo. Despite being a tailwheel aircraft, it offers excellent visibility on the ground, enhancing operational safety.

Since most competing STOL aircraft in the LSA category rely on engine power rather than aerodynamic efficiency to achieve higher performance, the STOL Cruiser holds a clear advantage in both operating and acquisition costs, where engine power requirements play a crucial role.

In collaboration with:

Contact:

Ing. Milan Dvořák, Ph.D.

Department of Aerospace Engineering FME CTU in Prague

E-mail: milan.dvorak@cvut.cz

Phone: +420 224 353 288