Deceleration drum assembly containing air guides

In combination with a folding machine of a web fed printing press, a deceleration drum assembly, comprising:

• a deceleration drum disposed in the folding machine, said deceleration drum having a plurality of rotary grippers, said rotary grippers gripping, decelerating, and overlapping signatures;
• a guide surface assembly containing at least one guide surface member;
• said guide surface assembly providing a fluid flow for transporting the signature in a contactless manner above said guide surface assembly;
• and
• said guide surface member having at least one recess formed therein and including at least one sensor disposed in said at least one recess, said at least one sensor outputting sensor data determining at least one of a height of the signature above said guide surface member, an air pressure under the signature, and a position of the signature in regards to said guide surface member.