Pitot locations vary depending on engineering convenience, but in
general somewhere near the front end of the helicopter, pointing
forward, matters not much where unless the bubble shape influences
airflow (vs, for instance, bernoulli).

Static can be on side of fuselage, but another good place is in some
wide-open space over the engine or behind the transmission.

Low-speed (less than 35 knots?) accuracy, however, is just plain
terrible for any pitot system mounted anywhere, the extremely low ram
pressures at those low speeds are woefully sensitive to minor changes
in angle of impact of the airflow, making it nigh impossible to get a
good reading.

The only remedy I've seen is at the engineering-test-pilot training
school at the Nat'l Test Pilot School in Mojave, CA, on a 206: a 24"
dish-shaped pod, non-rotating, above the main rotor (looking something
like the radar pods on the OH-58 for target aquisition), with a
rotating cuff (100 rpm?) containing multiple pitot tubes (or so it
appears), electronically instrumented with pressure transducers to
look at the DIFFERENTIAL between forward-moving side of disc and
rearward, the arithmetic sum (hey, at last something simple, 3-1=2)
being the airspeed. Quite accurately.

The quickie tour I got was brief on this, I may be misrepresenting
portions of the mechanism. Whatever. Certainly you won't find one on
ebay.

The total absence of real accurate IAS data throughout the rest of the
helicopter fleet is a flaming pain in the butte, there are so many
useful things we could teach and learn and do if we just knew
accurately, for instance, how much translational lift we were getting--
or even exactly when we achieve zero airspeed in OGE hover. But there
seems to be no way to get that info easily, so the entire industry has
gotten used to doing without it--even though a gyroscopic HSI costs
around $3000, nobody sees a NEED for 10 or 20-knot airspeed accuracy.

Not that it would free us from the grim realities of the h-v
curve . . .