The times I have used the F2Whirble include:
-6 on 1, their favor.
-Attacking vulchers who attempt it, and the ack didn't kill those D. VII's for some reason.
-For fun!
After all, a plane sitting on the ground is very easy to kill, especially with the easy flamings of planes. I fly the F2B for its versatility, speed, and maneuverability. The rear gun is an added bonus.