Warbird Information Exchange

I hope this is the correct sub forum for this since it does apply sort of, if its not please move it.

But anyways. As the title says, i need some help on headsets.

Right now, I'm a private pilot going for my Instrument rating which will be followed with a commercial license, CFI/CFII, Multi and MEI hopefully by June/July. However, I'm also a member of an aviation museum which flies a Fairchild C-123K Provider, OV-1D Mohawk and L-21. I'm hoping to officially begin flying as part of the crew for the C-123 this summer and will be needing a headset compatible to it.

I have been looking into getting a good headset and have my eyes set on the Bose A20. I really like the capabilities and features of it over the light speed. However, I have two questions i need resolved though before i can get any headset.

1)What type of plug do i need on my headset? I know that on our C-123, the jacks are all a single pin. I asked the guys that fly it now and they don't know what type of plug it is because they just use their headsets they had from the military.

Is this plug the "Helicopter single plug" or is it the "six pin" style plug? Also, because i will be using this headset for both military and civilian aircraft, which way is better to convert the plugs? would it be better for the single pin go into the dual pin converter, or is it better for the dual pin be converted into the single pin? or are both equally as bad/good?

2) As i was asking about the pins, one of the crew members mentioned about the headsets being different internally for military headsets vs civilian. I knew this because we thought my current headset might have been military since my brother gave it to me and he works on P-3's, but forgot about it until he brought it back up and didn't take it into account when looking at headset originally... Jack (the guy i was talking to) said he has a David Clark set that has a toggle on the one side that lets him switch between the two types. is this feature available from any other manufacturer?

So Any idea on what headset would be good for me? I have a set of David Clamps now, but don't care for them too much.

Thanks, Tyler

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Tyler Pinkerton
Active Member of Air Heritage Inc. of Beaver Falls, PA.
Aircraft: C47B, C-123K, Fairchild F-24, Funk Model B, L-21B, T-28B, T-34B
Static: F-4C Phantom II, F-15A, T-3 Provost

Hey Tyler, welcome over to WiX. You coulda just asked me in one of the other forums we both frequent.

From my limited knowledge, Helicopter headsets and military headsets use the same plug style (single pin), but the difference is impedence. Civilian usually uses like 300 ohm while military uses like 70 ohm. I don't remember for sure. However, this difference can cause problems with the units working properly if you put the wrong one on the wrong system.

Anyway, my personal suggestion to you would be to get the David Clark H10-13H. This is essentially the same headset the USAF issues to its transport crews today. Alternately, you can call David Clark and see if they have a conversion kit for your current headset, I know they do for my H10-13 (fixed-wing) and the price isn't really bad.

I would also suggest that you look into investing into an HGU-55/P helmet with comms. With a full ANR boom mic setup configured for military impedance (i.e. for the C-123), you're looking at $1400 new, but being in back of the plane you'll be glad you have it. You could also probably find surplus HGU-55/P's setup properly for quite a bit less, but make sure they've got the right setup with military impedance and single plug because if not, you may find it won't work.

There are guys on here who are more versed in this stuff than I am though, so they probably know secrets I've not looked into before.

Although many claims are made by the manufacturers and there are many excellent noise cancelling systems out there for modern aircraft, I haven't come across one yet that will work in a B-25, B-17 or any of the fighters. The noise levels are just too much for any of them. David Clark with good sealing gel earpieces seem to do the best. I wear helmet when flying fighters.

Tyler,
I'd strongly suggest a helmet for the military aircraft you listed. They do a bit better for sound attentuation than headsets plus you'll have at least some head protection.

Easiest way to go. Have a headset for your civil flying and a helmet/headset setup for military systems. (Military uses 19-ohm speakers vs 300-ohm for civil aviation. Different mics as well)

For helmets, IMO the most underrated helmet out there is the SPH-4. Relatively inexpensive and readily available. No modifications needed for military work -- correct plug and impedence.

The HGU-55 is a nice helmet -- considerably lighter than the SPH-4 -- and more modular in its design. I can switch between civil/military/helicopter is less than 5 minutes. I have an extra set of earcups already containing mil-spec speakers and two different drop cords (2-plug GA and single plug mil/heli). Basically I can pull out the earcups and in shell wiring and replace with whatever configuration I require. Same for the drop cord. The same can be done with HGU-26/33/68/84.

I have a Lightspeed Zulu and I am very impressed with how it performs. I have flown with it in the B-25, DC-3, B-17& T-6. It has handled all of those airplanes almost flawlessly. There can be a little bit of breakup at takeoff power, but once I throttle back to METO or climb power it works great. I have flown with a few people that have tired to use a Bose headset, and they have all had issues with them. I've even used the blutooth function on the headset with my iPhone to call someone on the ground (I was pilot NOT flying at the time FYI.) Our B-25 has both two pin (on the flightdeck) and single pin (rest of the aircraft) connectors. You can buy an adaptor cord to use the single pin with the headset. Of course all four of the above airplanes have either sigtronics or garmin intercomms, so if the plane you are flying still uses stock military intercomms there might be issues. That would be a question for a tech rep.

Hope this helps.

Patrick Mahaffey
B-25 "Pacific Prowler"
C-47 "Southern Cross"

Last night I was wearing my "clunker" pair of David Clark H10.30s in the King Air 350. WIll use them tomorrow in the Learjet and they worked great this week in the CItabria and C-172. I use them because they work in everything I get called to fly or crew.
A lot of the ANR's don't work in warbirds. If you wear sound cancelling in the T-34s with those augmentor tubes you will still have ringing in your ears. The noise cancelling headsets usually don't work in the warbirds, aircraft with radial engines, and open cockpit or aircraft that are fun to fly with the windows open like the Maule M-7, or Supercub.
My suggestion if you're going to be doing all the flying you are talking about is to get something non-sound cancelling and with volume control volumes for each ear. Sometimes aircraft have weird harmonics depending on the exhaust location, which windows are open and even the propellor and wind noise.
Last, use double hearing protection. I use 33db ear plugs from Home Depot and then adjust the volume on the headsets. THe military aircraft always have press to talk switches on the throttle or stick. Many civilian aircraft have voice activated or "hot" intercoms. These pick up the engine noise and funnel that noise straight into your ears . THe Super Decathlon and CItabria are set up fom the factory that way. IF you are in the training environment or have the door off, your ears will be ringing after every flight.
FWIW, I'm also looking for a set of noise cancelling headsets for the turbine stuff I fly. Most people have either the BOSE A20 or the Lightspeed ZULU. Those that have both have told me they prefer the LIghtspeed.BOth are very nice if you fly with the windows closed! Good luck.

I'll 2nd that as I wear Bose in the Challenger but I found out that they don't work in T-6's as Chuck Gardner smiled and said "told you so". I sent me HGU-55 to Gibson & Barnes as suggested by Jim Harley for the CEP kit. When it returns I hope for better hearing and less missed calls...

Fly Safe

As an owner of 2 of those military DC 10-76 headsets that I have modified I can tell you this.

The single plug NATO headsets come in 2 flavours. The first is the helicopter types. The other is fixed wing headphones. They both have a higher impedance earphone than the civy headsets. Not a problem going from military use to civy but getting a civy unit to work on a military system might cause volume issues.

The microphones are different, however, in that the helicopter uses a dynamic mic while the fixed wing units use a similar mic to the civy units. The reason is that the radios for the helicopters are army units (FM) and are, from an historical point of view, more modern. The fixed wing microphones are, due to historical reasons, emulating carbon microphones that have been around since the beginning of radios in aviation. When helicopters first appeared they were are for the most part still part of the army ops and the radios used in the army (FM radios) are only from the time of WW2 when they first came into being. These units have dynamic microphones.

For those who want to know the technical details the headphones are 300 ohms (as opposed to 8 ohms for civys) and the fixed wing unit microphones are approximately 200mV@80dBc and the rotary wing mics are approx 5mV@80dBc.

Mark (the hard-core flying electronics engineer)

Mark, I think you have your resistances backwards. Civil units have 300 ohms, military runs on 19 ohms, that's direct from David Clark and Gentex.

I wear a pair of David Clarks in the 1900s. If you were going to just do the occasional flight after you get a private, I'd say go cheap, but since you want to get a commercial, a pair of DCs are great. I personally think the Bose are overated. Sitting next to a pair of PT6s all day, non noise canceling headsets are just fine. Remember with the noise canceling, they ommit sound to cancel the other noise, but you can't hear it. Low frequency sound, like a dog wistle. Sometimes I wear ear plugs underneath which helps more when they're needed, especially on the ramp. Don't go overboard.

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"According to the map, we've only gone 4 inches."

The single military plug for aircraft is called the U-174/U. I have used a military headset in a civilian (2 plug) aircraft by using an adapter with an impedance converter for the mic. (The earphones will work fine regardless). It worked great in several aircraft with modern radios such as Garmin GNS430 or King KX155 and didn't work in another with older, more persnikity radios. I assume a single plug aircraft (not helicopter) headset would be easy to find on eBay and the converter can be purchased, tried out, and returned if it doesn't work.

Although this item may not be an exact match, you can start here and also try google for more vendors:

http://www.marvgolden.com/mg-14-militar ... apter.html

Ken

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"Take care of the little things and the big things will take care of themselves."

Thought I've seen adaptor plugs in either radio shack or on sportys.

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"According to the map, we've only gone 4 inches."

Whoops... You're right. I should have noticed that...

Thanks

Mark

Tyler are you in Pittsburgh? Many years ago I was a crew member on both the C-123 and the L-21 at Air Heritage.

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Chris Henry
EAA Aviation Museum Director

I worked at David Clark for 7 ½ years, great company and costumer service.

Phil

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A man's got to know his limitations.