From MusiCAD

A quintuplet is much like a triad but consist of 5 notes in time of 4 or 3.

You can make a quintuplet-note out of an ordinary note with the use of <alt-5>. Please note that you should always make sure that 5 quintuplet notes (or equivalent) are used together, to make a more common not-value . Quintuplet notes have durations like 1/10, 1/20 or 1/40, so 5 quintuplet 1/8 notes form one ordinary quarter note. You can promote a quintuplet note to an ordinary note by the use of <F6> just like you can with a triad-note

quintuplets in different durations an time signatures

Unlike a triplet-note which duration is well defined, a quintuplet-note will have a duration that can differ due to the [[time signature] in use. The same written note will have a duration of 1/10 (in a 4/4 meter) or 3/20 (in 3/4 meter). The number of beams used is a bit arbitrary... The edit-command [ToggleOther] will force one beam less.

see also