There were several solutions, each with advantages and disadvantages. Mounting the gun on the upper wing where it would fire over the prop meant that you couldn't readily clear the inevitable jams. Then there were the pushers, which gave a clear field of fire ahead but were generally unsatisfactory for other reasons.
I liked the solution of having a passenger with a shoulder fired machine gun. He had to be real careful not to shoot the wings off or shoot the pilot...or the prop. That would take some guts...and trust.
But not very competitive with the fokker in terms of maneuverability. Or even speed, I think, for that matter.