Having just read pilotmike's answer I have to correct him in turn!
Vmd
is coincident with L/Dmax in level flight, both occur at the lowest point on the drag curve. Flying at Vmd means you will be flying at the AofA for best L/D ratio, which is typically 4°. Neither will flying at Vmd give the best endurance in a glide or cruise as suggested. Vmd gives the best
range in a glide or cruise (piston); it is minimum
power (Vmp) that gives best endurance.
Note: Vmd and L/Dmax are at a tangent to the
power curve; they're at the bottom of the
drag curve. Maybe this is where the point is being confused?
To summarise:
Best endurance for a piston, power on or glide, is Vmp which is slower than Vmd.
Best range for a piston, again power on or glide, is Vmd (the bottom of the drag curve) which is also coincident with L/Dmax.
