How? This actually doesn't violate any laws. You can remote fire all day long as long as it isn't full auto.
Virginia is the master of laws that are vague enough to mean exactly what they need to mean in each circumstance. Given that helicopters real or toy are wont to depart controlled flight at any old time I think this could apply if any bullet went where it shouldn't. A reckless prosecutor could try to make it apply better. Ceding muzzle control to aerodynamics and radio frequency has hazards.
§ 18.2-56.1. Reckless handling of firearms; reckless handling while hunting.
A. It shall be unlawful for any person to handle recklessly any firearm so as to endanger the life, limb or property of any person. Any person violating this section shall be guilty of a Class 1 misdemeanor.
Then there's this. I know that this section does not aim at helicopter mounted pistols but it is vague enough that the remote activation other contrivance could be twisted to be the guy with the remote, even though he meant to come into contact with it. Especially if you hand it to your buddy and he 360s it with the rudder and accidentally kills himself.
§ 18.2-281. Setting spring gun or other deadly weapon.
It shall be unlawful for any person to set or fix in any manner any firearm or other deadly weapon so that it may be discharged or activated by a person coming in contact therewith or with any string, wire, spring, or any other contrivance attached thereto or designed to activate such weapon remotely. Any person violating this section shall be guilty of a Class 6 felony.
Far out I know, but you've got to think like a well greased lawyer. And a flying armed helicopter is not in the range of "normal" to the 12 half-witted "Peers" you're going to get.
Beyond that the issue of remote activation for me is worrisome with the BATF. Even if it's a linear servo, if you could get the thing in any way to electrically rapidly cycle then there may be trouble. I would only do it with a servo that would travel one way and stop until you released the switch, or better yet you had to reverse the switch to a third position to make it release. If the BATF has hacksaws to make your evidence "fit," it stands to reason they have soldering irons.
I've got some way out there remote firing ideas myself, just have to puzzle them over to make sure demonstration is legal.
But I still want the helicopter. Under my legal worry, deep down I am still the kid that fired all my estes rockets on quite acute angle trajectories. :D With terminal enhancements. :D :D