Tiltrotor aircraft combine the vertical takeoff and landing capabilities of helicopters with the speed and range of fixed-wing airplanes. Modeling their transitional flight dynamics, particularly the role of rotor flapping, remains a challenge. This paper develops an analytical framework that incorporates first-order rotor flapping and nacelle tilt dynamics into tiltrotor simulations. Using small-angle assumptions and blade element theory, the model captures the coupling between rotor flapping and body angular rates across different nacelle tilt angles. Results indicate that the influence of flapping dynamics is more noticeable in configurations closer to helicopter mode, particularly within 30 degrees of nacelle tilt from this regime. In these conditions, the rotor blades experience higher effective angles of attack, amplifying rotor-induced moments. As the nacelle tilts toward airplane mode, the incoming airflow approaches more from above the rotor plane, reducing the blades’ effective angle of attack and, consequently, their contribution to flapping dynamics. The study also highlights that nacelle tilt rates introduce gyroscopic precession and transient moments, which are more pronounced during fast transitions or asymmetric maneuvers. While heavier tiltrotors like the XV-15 show limited sensitivity to flapping dynamics in airplane mode, trends in lower-speed and rotor-dominated conditions emphasize the need for accurate modeling of flapping effects. This is especially relevant for lightweight tiltrotors and urban air mobility vehicles, where reduced inertia amplifies rotor-induced responses. These findings suggest that including flapping and nacelle tilt dynamics in flight dynamics models can improve predictions of handling qualities, particularly during transitions between flight modes.

The AerGo is a recreational ultralight water-aircraft, designed to be transportable by bike and operated without a license. This report outlines its concept, characteristics, and feasibility.

The AerGo features a biwing design with swept wings, closed by vertical plates at the tips. It has a constant wing chord of 0.79 m and a wingspan of 12 m. The aircraft is powered by two six-bladed propellers mounted on the top wing and driven by electric engines. The lower wing is attached to a buoyant hull, stabilized by side floats. A paddle is used for taxiing and docking on water, as the aircraft is designed exclusively for water take-off and landing. The pilot sits inside the hull and controls pitch by shifting weight on a swing. Roll control is achieved through wing warping, and yaw by rudders. The total empty mass is 44.7 kg. A multipurpose trailer system facilitates storage, transport, and deployment. The AerGo is designed for single-person assembly and operation and is safe to fly for over 270 days per year.

A market analysis of ultralight aircraft reveals a European fleet of over 25,000, with 500 in the Netherlands. While most ultralights are custom-built, successful models like the Woopyfly and Lazair have seen large-scale production. The AerGo’s mobility, ease of use, and hydrodynamic capabilities position it competitively. A conservative estimate projects annual sales of 20 units, with 25% for the Dutch market and 75% for Europe. Expansion to North America is a future opportunity.

The design is driven by weight and energy efficiency, with batteries forming a significant part of the empty weight. The primary energy requirement comes from cruise flight, optimized through airfoil selection. The NACA 6415 airfoil, chosen for its high lift coefficient at zero angle of attack, minimizes drag and maximizes cruise efficiency. The hydrodynamic model, based on DSDS data, estimates a take-off speed of 9.9 kg and a 170 m take-off distance. The computed climb rate is 1.43 m/s, reaching a cruise altitude of 150 m in 105 seconds.

The engine and battery design prioritize take-off power while ensuring a minimum flight time of 60 minutes. With a cruise speed of 15 m/s, the AerGo has a range of 40 km. The pilot’s longitudinal position, optimized at 1.6 m, ensures stability. The upper wing has a positive stagger of 0.45 m forward, creating a seesaw effect that smooths weight-shift control. Roll is controlled by wing warping, and yaw by rudders placed at the wing tips. A 15° wing sweep enhances rudder effectiveness, allowing safe operation on a single engine.

The aircraft’s lightweight structure consists of a skin-on-frame design, with a nylon-covered carbon fiber wing weighing 11.3 kg and a dacron-covered carbon fiber hull at 4 kg. Noise reduction is achieved with six-blade propellers, keeping levels below 40 dB at 100 m distance. Approximately 74% of the aircraft is recyclable, with a carbon footprint of 800 kg CO2 per unit.

At an estimated price of €20,000 per unit and annual sales of 20, the break-even point is 9.5 years, with a projected return on investment of €700,000 after 12 years. Further analysis is required on cost budgeting, structural impact resistance, and user assembly instructions to ensure feasibility.