Is Spinner Required on PA28-181 ?

[SuperCrash]

I have a 1977 Archer II PA28-181 The spinner came off in flight. Luckily nothing else was damaged, but I was curious if it can be flown without the spinner until a new one can be found.

Where do I look to determine if the spinner is required on my aircraft?

Thanks in advance

 

[kamikaze]