What is DMMS?

DMMS is Defined Minimum Manuevering Speed. 

Remember the law: "Don't Stall". The following video is profound.

First, generally it is accepted that flight (other than flight during short final close to the ground) should occur with a 30% margin of safety above stall speed. So knowing 1.3 x Stall Speed from the plane's POH is important information to memorize. 

An additional safety factor is adding in the necessary increase of speed required in a banked turn (30%) so DMMS is defined as 1.4 times stall speed.  (Use this for the "Clean-No Flaps Stall Speed)

For N998SC, my Cubcrafters Sport Cub, DMMS is 56 mph.  NEVER fly this plane at a speed less than 56 mph except on short final when close to the ground and the runway. 

And, in the event of an engine failure, especially during climb out after takeoff, you will need to agressively and instinctively push the stick forward to keep the plane from slowing below DMMS.