Actually, Mr. Osborne, acceleration is rate of change of velocity. A small difference, perhaps, but a significant one.
Speed is a one-parameter variable. Velocity has two parameters - speed and direction, since it is a vector. In this way, an object circling a point (e.g. conker on a string) is maintaining a constant speed but, since its direction of travel is constantly changing, it is accelerating towards the fulcrum at all times.
Next, when an aircraft departs the runway, its horizontal acceleration is decreasing, but its speed is still increasing. Part of the upwards motion is trading horizontal kinetic energy for upward, part is lift action from aerodynamic surfaces.
But enough of this rubbish. The point most people have made is that after problems on lift-off, you get the aircraft to the speed at which it is aerodynamically most efficient. This could be considered to be two different speeds, however. If you have objects to clear, you would aim for best angle of climb, until clear of the objects. Once that is achieved, trim forward for best rate of climb. In a simple piston twin, this is blue line speed. Any speed in excess of these figures is simply wasted, and possibly disastrously so. First and foremost in your mind should be to get the aircraft away from the ground.
Put simply:- Nobody ever collided with the sky.
[This message has been edited by HugMonster (edited 16 August 2000).]