In making a tactical approach two factors must be given first consideration:

For the shortest possible landing run (approaching over an obstacle), you must approach and land at the lowest safe flying speed. The landing must be simply a continuation of the approach, without a flare-out, or floating period.
For accuracy in the approach to the landing spot, you must fly at that airspeed which allows you a maximum of control of the glide angle through slight changes in airspeed.

In considering the first factor, the lowest airspeed at which you can safely make the approach is that which is barely above the stall. However, at this speed you have the least control of the glider. Any attempt to increase the airspeed by lowering the nose results in a partial stalling of the wing. A loss of between 50 and 100 feet of altitude, depending upon the gross weight of the glider, should, in this event, be anticipated. In addition, a turn attempted at this speed results in an immediate stall, and a falling away on one wing, since the ship is already too close to the stall speed to permit any increase in wingloading.

Normal Glide Speed
To determine how much above stalling speed to fly, consider the normal glide. The normal glide speed is that which results in covering the greatest distance for a given loss of altitude (assuming no-wind conditions).
The normal glide is the most efficient airspeed at which the glider can be flown. For the CG-4A, at its designed gross weight, it is approximately 85 mph lAS (72.6 mph CAS).
Since the glider, at any airspeed above the normal glide, is losing altitude at a greater than normal rate, such airspeeds must be considered as diving rather than gliding speeds.
In following the standard approach patterns there is no advantage in flying the maximum distance over the ground. In planning your ap-proach, figure on a glide much steeper, and therefore slower, than the normal glide.

Tactical Glide Speed
The glide speed which is standard for combat gliders is called the tactical glide. It is a speed approximately halfway between the stall and normal glide speeds.
Since the approximate figures for the stall and the normal glide speeds (calculated for the CG-4A at 7500 lbs. gross) are 60 and 85 mph lAS, respectively, the tactical glide speed is about 70 mph.
In playing the glide speed to obtain the desired rate of descent, you need vary your airspeed little more than 10 mph above or below the tactical glide to cover the full range of glide angles.
The use of the tactical glide gives maximum control over your glide angle, as follows:

To steepen your glide path, raise the nose a few degrees, decreasing the airspeed.
To flatten the glide path, lower the nose, increasing the airspeed.

Confusing Reactions
In playing the glide speed to control the glide angle, the desired results do not occur im~ mediately. For example, when you raise the nose of your glider to decrease the airspeed. and so steepen the glide angle, the first result is an abrupt leveling off, or even climbing, as the excess airspeed is dissipated.
Likewise, when you lower the nose to increase the airspeed and so lengthen the glide, the most noticeable immediate effect is a loss in altitude. These reactions are confusing and, unless anticipated, may make you think you have applied the wrong technique. When in danger of undershooting and the trees look close, you need plenty of will power and great faith in your own knowledge of aerodynamics to make the only correction possible and lower your glider's nose.

CG-4A Glider Pilot Training Manual