Then regional jets arrived in force, and 1,105 of these were built between 19, along with 2,215 props.īut then all-jet fleets became a mantra for many regional operators. Between 19, 2,356 props were built and just 259 jets. Ultimately, turbofans swept them away.Ĭonsider regional aircraft. Aviation once embraced a more efficient form of propulsion-propellers-and considered embracing related very high-bypass propulsion concepts such as propfans and ducted propellers. But technologies from our industry’s past may offer paths forward, or at least a better balance of costs and risks. That will require billions of dollars to pursue uncertain solutions, with the strong risk of technological dead ends. The global civil aviation industry has pledged to reach net-zero emissions by 2050. With SAF, scalability is a big challenge, too. Hydrogen, electric and hybrid propulsion, sustainable aviation fuel (SAF) and other emerging technologies offer varying degrees of promise but there are serious questions about their feasibility and cost-effectiveness. Yet there is no clear path forward beyond incremental improvements with today’s technologies, and we are nearing the limits of what can be achieved with thermal efficiency gains. Furthermore, reasonable agreements with other computational results are indicated.Decarbonization is one of the biggest trends in aviation. It is also verified that the lift-offset conditions in forward flight are simulated using this established trim analysis. It is shown that the predicted hover performances of the torque-balanced coaxial rotors are in excellent agreement with the experimental data. Verification of the trim analysis method and validation of the prediction accuracy of aerodynamic performance are performed based on previous experimental and numerical studies in hover and forward flight using the lift-offset conditions.
The blade pitch angles of both upper and lower rotors are adjusted to satisfy the target trim conditions through the trim analysis by being loosely coupled with the CFD solver. Six target forces and moments, which are the thrust of the coaxial rotor system, the rolling and pitching moments for each upper and lower rotor, and the torque balance for yaw control, are considered as the trim conditions. The trim analysis is implemented using a rotorcraft flow solver, rFlow3D. A numerical simulation method of computational fluid dynamics (CFD) coupling with a trim analysis for coaxial rotor systems is described in this paper.
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