Resources Contact Us Home
Dual piston drag damper for rotary-wing aircraft rotor

Image Number 5 for United States Patent #6676074.

A drag damper for use on a rotary wing aircraft rotor comprises a body defining two variable volume chambers linked by a piston. The chambers are filled with fluid and are connected by a restriction port (35) and by a channel (32) of larger cross-section than the restriction port. A secondary piston slidable and pressure-tight piston is fitted in the channel and loaded by an elastic bias (34). The equivalent mass of this secondary piston (33) and of the fluid which it displaces, and the stiffness of the elastic bias (34) are such that the secondary piston is resonant in the channel (32) at the rotation frequency of the rotor, to filter the dynamic component at this frequency of stresses applied to the damper (20). Furthermore at the natural drag frequency of the corresponding blade, the elastic bias substantially blocks the secondary piston (33) in its channel (32), and the flow of fluid between the chambers (29, 30) of the damper (20) takes place mainly via the restriction port (35) calibrated to provide substantial damping at this frequency.

  Recently Added Patents
Surfcraft fin
Viruses lacking epithelial cell receptor entry
Base station apparatus and communication control method
Signal processor and signal processing method
Light-emitting element, light-emitting device, and electronic device
Washing machine
Materials for organic electroluminescent devices containing substituted 10-benzo[c]phenanthrenes
  Randomly Featured Patents
Spiral earring for double-pierced ear
Assay for porcine circovirus production
Electrooptical device, electronic apparatus, and method for producing electrooptical device
Ink-jet printing apparatus, control method thereof, and data processing apparatus and method
Method and system for printer suggested training
Display poncho
Adjustable point looping tool for rug making
Apparatus for rounding and conveying onwards sheet-metal blanks for can bodies
Railroad track trailer
Apparatus and method for reducing vibrations of a structure particularly a helicopter