Hummingbird Hovering

Hummingbird Hovering
The simplest (but still complex) explanation goes something like this: The wings function quite like a helicopter that has two blades; these rotate in opposite directions less than 180 degrees; then they stop, reverse their pitch, and begin moving counter to the original rotation; the process is reversed again, and so on. The effect is to create only lift and no rotational movement. If it were possible for a helicopter to function this way, it wouldn't need the tail propeller. Sikorski was said to be inspired in part by the hummingbird when he invented the helicopter.

The wing muscles of a hummingbird represent a disproportionately large part of the body mass--perhaps up to one-third or so--when compared to members of other bird families. They can provide nearly equal power on both the forward and backward strokes, making the helicopter analogy pretty close.

The wings of a hummingbird are different in another way: elbow and wrist joints are fused, and only motion about the shoulder is possible: in effect, the wings are large "hands." The wing motion is powerful and controllable.

Picture a hummingbird with beak straight up and tail straight down. In this position, commonly seen when a hummer feeds at a fuchsia blossom, to remain motionless the axis about which the wings rotate must align with the roll (central) axis of the bird, resulting in pure downward thrust. The hummingbird has control of the angle between the axis of wing rotation (direction of thrust) and the body axis, permitting the thrust to be directed and cause motion in any direction; up, down, forwards, BACKWARDS (the only bird that can do this!), or to either side.

In level flight, ruby-throated hummingbirds can attain maximum speeds of 25 miles per hour or possibly more. During power dives, some species have been recorded at more than double that.

Going back to the helicopter analogy, the wings do not stay exactly in a plane when moving forward or backward. Instead they move downward slightly during the stroke, slow down, then during the reversal lift up somewhat, and begin the reverse stroke. Viewed from the side, the wingtip traces out a modest figure 8, looking a bit like the symbol for infinity.