Originally Posted by
Collective Bias
I always thought lateral and horizontal vibration was the same. What would be the diffrence, or is lateral another word for roll vibration?
CB
CB,
I have come to appreciate on this forum that a helicopter is a collection of vibrations that come together to form a flying machine. The best any engineer can do is to make sure they don't coincide. The local aerodynamics are best off not affecting the various blade flexural modes, the blade flexural modes are best off not affecting the cabin modes, the cabin modes are best off not affecting the seat modes and acoustic modes. The pilot is best off being vibration tolerant.
Lateral generally means side-to-side, but can be taken loosely as horizontal. As a blade flexes it's mass to hub radius alters so you get coriolis vibration, normally solved with lead-lag dampers. Depending on the general layout of the machine all of these can cause either lateral or roll vibrations. I understand the theory, but that is not the same as a lifetimes experience solving helicopter specific problems.
Dave,
I imagine Sikorsky are internally justifying the engineering budget on a conservative market. If helicopters had not been developed there would be no helicopter market. I imagine that once the machine practically proves it's capabilities, market growth will be exponential...
Mart