SASS question.

["Juan Pablo" jpculasso]

Good Afternoon, friends.

A new home made small SASS is in the final stage of construction.
My question regarding the aluminum piece covering part of the nose.
What are the real efect  tof the piece in the recording?
Is it necessary close the back of the sass? if yes, is it necessary full fi=
ll the internal space with phoam?
In my larger SASS rob plans I did not put nothin on it.
Many thanks for your answers.
My best,
Juan Pablo.