1296

Item 1296

OTHER: Aerodynamics - Vibration - Rotor Induced - Rotor-to-Rotor Interaction

Thoughts:

The problem?

The additional vibration of this configuration, over the single rotor configuration, might be partially the result of rotor-to-rotor aerodynamic interaction (downwash & downdraft). The note in patent 2,455,866, which was for a servo-flap on the leading edge only, seems to confirm this ~ see; OTHER: Helicopter - Outside - Intermeshing - Kaman - H-43 Huskie ~ Patents

The Solution (to this specific cause only)?

Reduce the intermittent localized spikes in the downwash, which are experienced in the lower blade, at varying azimuths and elements. I.e. reduce the intermittent decreases in the blade's localized angle of attack.
Currently available, partial solutions (in addition to the 1-P cyclic and flapping):

Solutions (static):	How:
Distribute the thrust more evenly along the span of the blade.	Increase the blade's static twist and taper. Note that twist or excessive taper may result in blade-blade contact.
Distribute the thrust more evenly about the area of the disk.	Increase the number of blades.

Future solutions:

Solution (dynamic):	How:
Replace the simple 1-P cyclic control with two (@ root & @ tip) 1-P cyclic controls.	Will improve the blade's thrust at its azimuths. Active Blade Twist,--
Develop the means of having a fast (>>1-P)) and localized (various locations along the span) means of changing the blade's pitch.	Will improve the blade's thrust at its azimuths and radial elements Leading and Trail Edge Enclosed Flaps.

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Last Revised: February 3, 2007