Results 131 to 140 of about 599 (185)

Airfoil-Section Rotor Blades

2015
The work done in the previous chapter is further extended to the design of a two-cell airfoil cross-section which is a more realistic model of the helicopter rotor blade. Optimum actuator placement, the effect of the current active twist concept on key characteristics such as blade loads, aeromechanical stability and trim controls is investigated ...
Ranjan Ganguli, Dipali Thakkar, Sathyamangalam Ramanarayanan Viswamurthy   +2 more
openaire   +1 more source

Optimal Design of a Smart Conformable Rotor Airfoil

Adaptive Structures and Materials Systems, 2002
An optimization method has been developed for the design of a smart conformable rotor airfoil with distributed piezoelectric actuators. A conformable airfoil is proposed as a substitute for trailing edge flaps used for helicopter vibration reduction by achieving high frequency camber variations.
Roberto A. Sarjeant, Mary Frecker, Farhan S. Gandhi   +2 more
openaire   +1 more source

Design Optimization of a Controllable Camber Rotor Airfoil

AIAA Journal, 2008
A conformable airfoil is proposed as an alternative to trailing-edge flaps used for active helicopter vibration reduction through high-frequency changes in camber. The design consists of several compliant mechanisms of predetermined topology that are placed serially within the airfoil along the chord, aft of the leading-edge spar.
Farhan Gandhi, Mary Frecker, Andrew Nissly   +2 more
openaire   +1 more source

Rapid Estimation of Airfoil Aerodynamics for Helicopter Rotors

Journal of Aircraft, 2008
Semi-empirical methods have been proposed to extrapolate airfoil aerodynamics at high Reynolds numbers and at transonic Mach numbers. The theory has been compared with the available wind-tunnel data for some rotorcraft airfoils, the NACA 0012, the NACA 23012, the SC1095, and the SC1095-R8. An iterative procedure around Mdd allows the calculation of the
openaire   +1 more source

Robust aerodynamic optimization of morphing airfoils for helicopter rotor blades

17th AIAA Non-Deterministic Approaches Conference, 2015
This paper presents a robust aerodynamic optimization framework for the design of a morphing airfoil for helicopter rotor blades. The adoption of a conformable geometry is considered to cope with the variable flow conditions encountered in forward fight with the objective of increasing the aerodynamic performance on the advancing and retreating sides ...
FUSI, FRANCESCA, QUARANTA, GIUSEPPE, GUARDONE, ALBERTO MATTEO ATTILIO, P. M. Congedo   +3 more
openaire   +3 more sources

Jet circulation control airfoil for VTOL rotors

Journal of Aircraft, 1969
Based on the potential flow theory calculation, the capacity of the air supply, the limitation of the internal pressure of the model and the limitation due to the compressibility effect of the jet stream at high velocities, the elliptical airfoils of 18 and 12% thickness ratios were designed and constructed.
openaire   +1 more source

Numerical Simulations of the Adverse Effects of Rain on Airfoil and Rotor Aerodynamic Characteristics

Proceedings of the Vertical Flight Society 78th Annual Forum and Technology Display, 2022
There is a significant interest in improving the performance of rotors under adverse operating conditions. However, there is a very limited understanding of the performance implications on 2D airfoils and rotor blades under adverse effects of rainfall.
Aishwerya S. Gahlot, Ritu M. Eshcol, Lakshmi N. Sankar, Richard E. Kreeger   +3 more
openaire   +1 more source

Roughness Sensitivity Considerations for Thick Rotor Blade Airfoils

ASME 2003 Wind Energy Symposium, 2003
In modern wind turbine blades airfoils of more than 25% thickness can be found at mid-span and inboard locations. In particular at mid-span aerodynamic requirements dominate, demanding a high lift-to-drag ratio, moderate to high lift and low roughness sensitivity. Towards the root srtuctural requirements become more important.
R. P. J. O. M. van Rooij, W. A. Timmer
openaire   +1 more source

Effects of Ballistic Damage on the Aerodynamics of Helicopter Rotor Airfoils

Journal of Aircraft, 1998
Experiments were conducted to estimate the effects of ballistic damage on the aerodynamics of helicopter rotor airfoil sections. The lift, pitching moment, and drag were measured on nominally twodimensional blade specimens with representative prescribed and actual ballistic damage.
Keith W. Robinson, J. Gordon Leishman
openaire   +1 more source

The Impact of Advanced Airfoils on Rotor Hover Performance

26th AIAA Applied Aerodynamics Conference, 2008
the blockage effect on the aerodynamic characteristics. The computed dynamic stall characteristics correlate well with experimental data. In general, the results of airfoil with slat show improvement in the lift characteristics and suppress the negative pitching moment in all dynamic cases.
openaire   +1 more source