An aircraft comprising: an airframe; a rotor system (604a,b) coupled to the airframe , the rotor system (604a,b) being operable to exert a vibratory force on the airframe ; and a vibration attenuation system comprising: two or more batteries to supply power to the rotor system (604a, b); and elastic devices coupled to the two or more batteries and the airframe , the elastic devices being configured to attenuate a vibratory force of the airframe based on facilitating oscillation of the two or more batteries ; wherein a first elastic device of the elastic devices supports a first battery of the two or more batteries at a first location along a length of the airframe , the first location corresponding to a local maximum displacement of a first normal mode of the airframe ; and a second elastic device of the elastic devices supports a second battery of the two or more batteries at a second location along a length of the airframe , the second location corresponding to a local maximum displacement of a second normal mode of the airframe ; wherein the first elastic device has a stiffness tuned to the frequency of the first normal mode and the second elastic device has a stiffness tuned to the frequency of the second normal mode. an airframe; a rotor system (604a,b) coupled to the airframe , the rotor system (604a,b) being operable to exert a vibratory force on the airframe ; and a vibration attenuation system comprising: two or more batteries to supply power to the rotor system (604a, b); and elastic devices coupled to the two or more batteries and the airframe , the elastic devices being configured to attenuate a vibratory force of the airframe based on facilitating oscillation of the two or more batteries ; wherein a first elastic device of the elastic devices supports a first battery of the two or more batteries at a first location along a length of the airframe , the first location corresponding to a local maximum displacement of a first normal mode of the airframe ; and a second elastic device of the elastic devices supports a second battery of the two or more batteries at a second location along a length of the airframe , the second location corresponding to a local maximum displacement of a second normal mode of the airframe ; two or more batteries to supply power to the rotor system (604a, b); and elastic devices coupled to the two or more batteries and the airframe , the elastic devices being configured to attenuate a vibratory force of the airframe based on facilitating oscillation of the two or more batteries ; wherein a first elastic device of the elastic devices supports a first battery of the two or more batteries at a first location along a length of the airframe , the first location corresponding to a local maximum displacement of a first normal mode of the airframe ; and a second elastic device of the elastic devices supports a second battery of the two or more batteries at a second location along a length of the airframe , the second location corresponding to a local maximum displacement of a second normal mode of the airframe ; wherein the first elastic device has a stiffness tuned to the frequency of the first normal mode and the second elastic device has a stiffness tuned to the frequency of the second normal mode. <EOS>