Zippy,
The "banging" sound you hear, I bet is the stall horn, it sounds more like a clicking sound, unless you have it turned up real loud. I replaced mine with a 1936 Chev arooga horn, and try to fly within the specs of my aircraft, to avoid it going off.
The spining you see is your aircraft losing air flow over your wings. because you are going to slow (stall horn tells you that.
This is no bug, its like flying a real aircraft, unlike the arcade type flight sims (AW3 & FA2) this baby is for big boys!
Mr.ED
Pony Pilot
Knight