The multidisciplinary nature of rotary-wing aeromechanics poses a daunting challenge for the design of practical modeling and simulation software that is accurate, efficient, and maintainable. This paper describes the design strategy for the US Army’s Helios software, which features a lightweight Pythonlanguage integration framework combined with well-defined interfaces to link together various...

We report the results of the dynamics of a three dimensional lattice of dipolar molecular rotors where the unit cells consist of a dipolar phenylene ring rotating about an axle stabilized by stationary triphenyl groups. The molecules are synthesized such that the lattice may be customized to elicit novel and useful physical phenomena. Using dielectric spectroscopy and H NMR, we demonstrate rapi...

A broad class of soil fungi form the annular patterns known as 'fairy rings' and provide one of the only means to observe spatio-temporal dynamics of otherwise cryptic fungal growth processes in natural environments. We present observations of novel spiral and rotor patterns produced by fairy ring fungi and explain these behaviors mathematically by first showing that a well known model of fairy...

We investigate the control of the dynamics of a periodically kicked mechanical rotor in the presence of noise. It was recently shown that the system dynamics shows the characteristics of a complex multistable system. We demonstrate that it is possible to stabilize the system at a desired attracting state even in the presence of considerable noise level. As control strategy we use a recently dev...

Vibration derived from the main rotor dynamics and imbalance causes premature wear to the aircraft components, and can cause pilot fatigue. While improvements have been made in rotor track and balance (RTB) techniques; there is room to enhance the quality of the recommended RTB adjustments. One aspect that limits the development of RTB algorithms is the difficulty in quantifying the performance...

We describe the preparation of a compound whose molecules consist of two metal sandwich stands carrying tentacles with affinity to metal surfaces and holding an axle that carries a dipolar or a nonpolar rotator. The dipolar rotor exists as three pairs of enantiomers, rapidly interconverting at room temperature. When mounted on a gold surface, each molecule represents a chiral altitudinal rotor,...

This paper considers the problem of a nonlinear L2-disturbance rejection design for a laboratory twin-rotor system. Since the rotor blades present fixed angle of attack, control is achieved by using the rotor speeds as control variables. This mechanical device features highly nonlinear strongly coupled dynamics. The control is developed considering a reduced order model of the rotors obtained b...

We examine the effect of the initial atomic momentum distribution on the dynamics of the atom–optical realisation of the quantum kicked rotor. The atoms are kicked by a pulsed optical lattice, the periodicity of which implies that quasi–momentum is conserved in the transport problem. We study and compare experimentally and theoretically two resonant limits of the kicked rotor: in the vicinity o...

Control of a helicopter is complex, and includes cross coupling of forces and balancing of forces. While sophisticated and advanced controllers can achieve stable control, good mechanical design can reduce the problems and hence make tuning the control loops easier. In this paper, we argue that a coaxial-rotor design solves a number of problems that make control of a four-rotor helicopter diffi...

A description is given of a multi-body dynamics rig for testing a novel rotor fluid film bearing system. The design included a composite rotor supported on a stationary central shaft, with loading applied by non-contacting electromagnets. The shaft included hydrostatic bearing pockets and continuously adjustable hydrodynamic bearing segments. A technique is described for deriving displacement c...