OPT's "flight simulator"

Given the challenge here.

5 unbroken double unders
10 unbroken double unders
15 unbroken double unders
20 unbroken double unders
25 unbroken double unders
30 unbroken double unders
35 unbroken double unders
40 unbroken double unders
45 unbroken double unders
50 unbroken double unders
45 unbroken double unders
40 unbroken double unders
35 unbroken double unders
30 unbroken double unders
25 unbroken double unders
20 unbroken double unders
15 unbroken double unders
10 unbroken double unders
5 unbroken double unders

Result: 15:42