We're still waiting for the Ka-50s to show up for the helo-to-helo dogfights.
The Z has AIM-9 as well. For as rare/nonexistent as helo air-to-air is, I'd think helo-mounted Stingers would answer the mail.
While they were airframe tested and wired for the Alpha model 64 we don't carry (and thanks to the CMWS mod can't carry) Stingers on the Longbow. However... RF Hellfires are capable of Air to Air shots.
Doesn't retreating blade stall come into play at those airspeeds? What effect does that have with the axial rotor system?
Retreating blade stall is basically a growth of the "No Lift Area" on the retreating blade side of the rotor system. Eventually what small area of the retreating blade is still creating lift and control imputs are not enough to effect the dissimilarity in lift being created by the advancing side. It'd be like as a fixed wing airplane's speed increased if somehow you could make the right wing span increase while the left wing decreased (opposite wing sides for Euro helicopters). By Using a Coaxial Rotor system you negate this. You also save on the parasite effect of a tail rotor stealing torque away from the aircraft. This is especially critical at the high power settings we use when we are hot high and heavy. You can over torque the aircraft simply by letting the aircraft get into a high yaw rate where the sudden use of tail rotor authority to arrest the rate creates a transient torque increase and goes above the aircraft limits. However you pay for this by adding the weight of an additional rotor system which creates its own set of issues such as weight, drag, complexity, etc. The KA-50 for all its lauded ability is a very heavy helicopter without nearly the payload of similar weight class attack helicopters.
Bleeding edge speed with attack helicopters is often much more effected by flat plate drag than by the rotor system going into retreating blade stall. The only way Im gonna see Vne in an Apache carrying an FCR and a respectable load is to put the aircraft into a steep dive.