Hello everyone my name is Dan and I work for Gibson & Barnes. You are correct that Gibson & Barnes does not sell fixed-wing helmets for use in helicopters.
I will do my best to explain Gentex and G&B’s position in this regard.
Fixed-wing helmets are different from helicopter helmets because the mission and flight conditions are different. Fixed wing helmets are small and light because of the high g forces often encountered. Their earcups are small because fixed-wing cockpits aren’t usually as noisy and the sound encountered is higher frequency which is easier to attenuate.
Helicopter helmets are larger because they have thicker shells and energy-absorbing liners and they have large-volume earcups that are necessary to attenuate low frequency sound. Rotor blades generate lots of sound with a frequency of 250HZ. Helmets involved in helicopter accidents usually receive multiple impacts so it is important that the helmet remain on the wearer’s head. .
The most protective helicopter helmet in the world is the helmet worn by the Army, Gentex’s HGU-56. It isn’t the world’s coolest helmet but it is a good design.
The Coast Guard’s uses the SPH-5 because it doesn’t interfere with their flotation collars. It is almost as protective as the HGU-56.
The Navy and Marine Corps use the HGU-84 with a bungee-visor. It looks like a fixed-wing helmet but offers a lower level of impact protection and sound attenuation.
Helmets features are trade-offs like everything else in aviation. You can’t have a small, light, cool-looking, highly protective, highly sound-attenuating, cheap helmet. Something has to give.
I’m not a pilot, but if I were, I’d wear the HGU-56.