B365

OTHER: Aerodynamics - Vibration - Rotor Induced

Reports reinforce the logical assumption that vibration (and noise) consume power, which could otherwise be applied to thrust. This presents a strong reason for eliminating the source of the vibration in lieu of the 'Band-Aid' approach of masking it.

Overview:

This is an attempt to evaluate the sources of rotor induced vibration in single rotor helicopters [1020], then the additional sources in twin rotor helicopters [1089] (the SynchroLite), and finally the additional sources in a twin rotor helicopter with absolute rotor rigidity (the Unicopter).

Sources of rotor induced vibration:

Vibrations affecting single rotor helicopter. [1020]

Air forces transmitted from the blades, through the hub to the fuselage.

Downwash on the Fuselage and Tail Boom.

Moments about the blades' feathering axes and transmitted through the pitch links to the cyclic stick.

Vibrations affecting twin rotor helicopters with aerodynamically interacting rotors (tandem, coaxial & intermeshing). [1089]

All 3 noted above.

Aerodynamic interaction between the two rotors.

Vibrations affecting twin rotor helicopters with absolutely rigid interacting rotors [1089]

All 4 noted above.

Dissymmetry of lift ( and drag? ~ already accounted for in single?).

Items:

OTHER:

	Name	Item
	General:
	OTHER: Aerodynamics - Vibration - Rotor Induced - Overview	1059
	OTHER: Aerodynamics - Vibration - Rotor Induced - Blade Vortex Interaction [BVI]	1094
	Analysis:
	OTHER: Aerodynamics - Vibration - Rotor Induced - Analysis of Single Rotor Helicopters	1020
	OTHER: Aerodynamics - Vibration - Rotor Induced - Analysis of Twin Rotor Helicopters	1089
	OTHER: Aerodynamics - Vibration - Rotor Induced - Rotor-to-Rotor Interaction	1296
	OTHER: Aerodynamics - Vibration - Rotor Induced - Analysis of Sikorsky ABC Coaxial	0893
	OTHER: Aerodynamics - Vibration - Rotor Induced - Analysis of Flettner FL-282 Intermeshing	1086
	Control:
	OTHER: Aerodynamics - Vibration - Rotor Induced - Higher Harmonic Control (HHC)	0793
	OTHER: Aerodynamics - Vibration - Rotor Induced - Individual Blade Control (IBC)	1060
	______________
	DESIGN: UniCopter ~ Vibration - Rotor Induced - Control - High Frequency Modifiable Tip Control	1544
	DESIGN: UniCopter ~ Vibration - Rotor Induced - Control - Embedded High Frequency Leading + Trailing Edge Flaps	1087
	Related Subjects: OTHER: Aerodynamics - Rotor Concept - Active Blade Twist (ABT) OTHER: Aerodynamics - Rotor Concept - Independent Root & Tip Control Electrotor-SloMo - Control Flight - Cyclic by Torque-Pitch

Information Specific to the Two Helicopters on this Web Site:

Unicopter ~ Vibration - Rotor Induced - Analysis:

Unicopter ~ Vibration - Rotor Induced - Control:

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SynchroLite ~ Vibration - Rotor Induced

Information on theWeb:

A COMPREHENSIVE VIBRATION ANALYSIS OF A COUPLED ROTOR/FUSELAGE SYSTEM

This is a 283 page 1999 dissertation by Hyeonsoo Yeo, Doctor of Philosophy at the University of Maryland. It is easy reading and looks to be very interesting and complete.

It can be located at; http://www.enae.umd.edu/pdf/students/PhD/YeoPhD1999.pdf. In addition, this dissertation has been stored on my computer, under the name [Vibration Analysis.pdf]

It is in the 'strange' type, but it appears to print out clearly.

Optimal Objective?:

To be able to vary the lift, and (possibly independently) vary the drag, at a number of different radii, and at a large number of different azimuths, with a very high response rate; driven by computer control, where its outputs are determined by recent inputs.

Hypothetical Means:

An extremely rigid spar, for setting the primary one per rev pitch angle, overlaid with a highly active and segmented airfoil, which is computer controlled.

Last Revised, August 11, 2010