Pilot's helmet?

I'm hoping some of my fellow hams in here are pilots who would recognize this helmet and let me know some specs on it. I've tried it on and it does a fantastic job of blocking outside noise interference. I was thinking it'd be cool to wear in the shack sometime. I could just close my eyes and imagine I'm flying! The questions I would have though are what kind of connector is this on the end? It's kind of like a 1/4" stereo connector but shorter and TRRS. Also what impedance for the earpieces and mic? So I'm picturing building a converter box with a socket to plug it in to, and then some kind of matching to the proper impedance for mic and headphones to my rig. I'm also thinking the lightning bolts will help with DX!

 

Also any idea what the metal brackets on either side would have been for? They adjust in and out but could also get in the way of the eye shield that comes down. Would this have been a helicopter pilot's helmet?

 

Yikes! Found the plug and those things are pricy!

The mating jack for it is 9.51 which is not too bad considering

 

And found the mic element manufacturer but no info on the specific PA-4 element. There is a PA-5X and if it's anything like it, this project will be a bit more complex as it is
an amplified noise canceling microphone requiring a DC voltage supply of 9-28 volts. Also does not specify impedance. There are also available foam windscreens.

 

The earpieces are 19 ohms each not sure if they are wired in series with each other, parallel or with 4 connections on the plug, possibly even stereo.

 

So what kind of circuit would I need for an amplified noise canceling microphone? Would also need to implement some sort of PTT. This is going to be a fun project!

 

That is a Navy HGU-33 flight helmet (fixed wing), early 80's or later vintage, Gentex has been the main government vendor for decades. The mic is an electret element that requires a bias voltage. As I recall the typical impedance for the systems is 600 Ohms.

It is not directly compatible with civil aviation intercoms nor amateur gear.

You would either need to use transformers/or transformer adapter cords(which are available) or replace all the parts to match amateur gear.

Gibson & Barnes is a high quality aviation equipment company. They have replacement parts, as well as adapter cords, and can repair or reconfigure your helmet.

I'll let you dig around on their website for info and specs. There are a few other vendors on the web who provide lower cost services and parts. You can probably find spec and modification tips on google. bill (several thousand hours in this helmet).
http://www.gibson-barnes.com/dept-293811/Hgu33-Helmet-Parts.html
http://www.gibson-barnes.com/dept-293804/Helmet-Communications.html

p.s. This helmet is light weight and only intended to protect the pilots head from light blows agains the canopy and cockpit. Do NOT use it as a motorcycle helmet. It won't provide good protection.

p.p.s. The ratcheting metal pieces are are part of the oxygen mask suspension.

p.p.p.s. With both O2 fitting and boom mic this could have been used in fixed wing like T-34C TurboMentor, T-28C, P-3 Orion, S-3 Viking, C-130, E-2C Hawkeye, perhaps USMC OV-10 Bronco. Tactical jet crews wear O2 masks at all time and don't need a mic boom.

 

Found the answer for the brackets - oxygen mask! So this would have been for high altitude flight use. Might just take those brackets out for day to day use. Edit - KA0HCP beat me to the punch while I was posting this one.

 

What did you fly in? And thank you for your service! No motorcycles for me. I prefer several thousand pounds of steel wrapped around me for protection!

 

Your are 100% right