Key-frame animation starts slowly and reaches a max speed and never slows down but ends abruptly

If anyone could please help me make simple wind turbine animation, I would be grateful.

All animations are ultimately controlled by curves, where “keyframes” represent explicitly-designated points along these curves and all others are interpolated in some way between them. The default is to use a smooth curve which automatically provides for “in and out.” But, it can also be “linear” (a direct diagonal line) or “constant” (stair-steps).

There’s a separate curve for every variable that is being animated, and, in Blender today, “everything can be animated.”

For a wind-turbine, of course it depends on just what you want it to be doing. “Constant” or “Linear” interpolation is often just the thing to use for mechanical motion. (Machinery that is speeding-up or slowing-down normally does so at a constant rate of acceleration, not “ease in/out” as creatures do.)

So, perhaps if you want the turbine to speed up, run, and then slow down to a stop, set four keyframes: one at “frame #1,” one at the point of maximum acceleration, one at the frame where slow-down is to begin, and a final one at “frame #last.” Use Linear interpolation between all of these points. (If there’s some point where an automatic “speed brake” kicks in, just add another keyframe at that point in time.)

Ok thanks for info!!!