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
Processing biomass
Radio communication system, transmission apparatus, reception apparatus, and radio communication method in radio communication
Sonic fast-sync system and method for bluetooth
Metal melting apparatus and method for melting metal
Acoustic measuring instrument
Human embryonic stem cell methods and PODXL expression
Method and apparatus for internet on-line insurance policy service
  Randomly Featured Patents
Radiation image read-out method and apparatus
Device, kit and method of applying polish to tip of nail
Low energy surface bonding system containing a primer with long open time
Surface mountable air towel
Differential device
Reforming system, fuel cell system, and its operation method
Selenium removal from water
Sideboard for futon bed
Injection blow molding process for forming a package exhibiting improved child resistance
Applicator to provide uniform electric and magnetic fields over a large area and for continuous processing