Is this an experimental oxygen mask?

[Bob Hudson]

The MBU 5/P oxygen mask is fairly common, but I've got a couple modified ones I can't figure out. Basically it's the standard MBU-5/P with a hinged lever. The straps that hold the mask to a helmet (or to a headset with suspension straps as in my photo below) are attached to a locking lever that is hinged to the mask. If you pull on the end of the lever it releases tension on the lever and the mask falls away from the face, but stays strapped on. To put it back on it's you just place the mask on your face and pull down on the lever so it locks in place and tightens the strap.

 

Here's two photos showing it in the up and down positions:

 

 

 

I have looked all over and cannot find any photos of another MBU-5/P with this quick donning system, but tonight I did find references to tests of this type of system.

 

One of these reference is a 1961 report by the Aerospace

Medical Laboratory:

 

"DEVELOPMENT OF ORAL-NASAL MASKS,

OXYGEN, MC-1 AND MBU-5/P"

 

The MBU-5/P is basically the MC-1 made available in four sizes. Part of the development process involved a "quick-donning mask harness."

 

The report describes some of the designs:

 

"One design is shown in figure 5. The harness has, at the front of the mask, a lock with a

cam-action type lever to permit adjusting the mask to any desired position and tension. To provide

maximum comfort at low altitudes, where pressure breathing is not required, the lever is left in

the up position (left view, figure 5). At higher altitudes, where the mask must provide a tight seal

against the face, the lever is moved to the down position.

 

The harness design shown in figure 5 was received favorably by many pilots during flight

testing. Several others, however, reported the mask would not remain stable during the g-forces

encountered during flights and during tests conducted on the centrifuge. To overcome this

deficiency, a new suspension was designed (figure 6). In this harness, a single straD was routed

across the nose section of the mask shell, through the quick-release connectors, and under the

mask shell chin section. A buckle was installed on the strap for adjusting the harness. The single

strap allows the mask to be moved easily into position for a comfortable fit over the face. A lever

for controlling the fit of the mask was not practical with this harness."

 

When they got to the MBU-5/P the evaluated other possible quick-donning designs:

 

"Various proposed harness systems designed to convert the MBU-5/P mask to a quick-donning

type have been evaluated. Figure 15 shows one harness system with the HGU-2/P helmet. The

sequence used in donning the mask is shown in the figure. Harness tension may be adjusted by

moving the slide buckle on each cord to the helmet connector and by turning the knurled knob at the end of the mask lever."

 

Here's photos from that report showing this lever design.

 

 

That lever is similar in principle to the ones on the two MBU-5/P helmets I acquired: it's wishbone-shaped and attached the mask so it can swivel up and down. Here's the one on mine.

 

 

 

Okay, so back to my question: was this an experimental design? Again, I can find no other photos of anything like this except in the above quoted report. Elsewhere I did find this description:

 

"MBU-6/P - Experimental Quick Donning Pressure Demand Oxygen Mask; not mass-produced; succeeded by MBU-9/P & MBU-10/P"

 

After I found that I wondered, is this an MBU-6/P mask? Because the basic components of mask, hardshell and microphone would have been the same, it would be logical that an experimental MBU-6/P could have been just an MBU-5/P with an added lever. I will note that the pilot who had had saved these from USAF days also had a rare DH-5 experimental prototype helmet so he apparently did get involved in test programs.

 

Then again, maybe someone out there can point me to where I've missed some obvious indication that this type of mask with lever was commonplace.

 

[USMC_GAU-21]

Bob,

 

I found another website that listed all of the "experimental" masks and designations.

 

MBU - Breathing Oxygen Masks

(1) (No information)

MBU-2/P Oxygen Mask

MBU-3/P Oxygen Mask; used with HGU-9/P; replaced by MBU-5/P

MBU-4/P Oxygen Mask

MBU-5/P Oxygen Mask; manufactured by Gentex

MBU-6/P Experimental Quick Donning Pressure Demand Oxygen Mask; not mass-produced; succeeded by MBU-9/P & MBU-10/P

MBU-7/P Experimental Pressure Demand Oxygen Mask; intended to replace MBU-5/P; not mass-produced

MBU-8/P Experimental Oral-Nasal Shaped Constant Flow Oxygen Mask; intended for emergency use on transport aircraft; not mass-produced

MBU-9/P Experimental Quick Donning Pressure Demand Oxygen Mask; based on commercial mask manufactured by Puritan Corp.; successor development program to MBU-6/P; not mass-produced; succeeded by MBU-10/P

MBU-10/P Experimental Quick Donning Pressure Demand Oxygen Mask; based on commercial mask manufactured by Sierra Engineering Co.; successor development program to both the MBU-6/P & MBU-9/P; mass-produced and used on C-141 (and similar transport aircraft)

MBU-11/P Smoke Mask; existing smoke mask by Scott Aviation with added two-way electronic communications

MBU-12/P Pressure Demand Oxygen Mask; manufactured by Gentex

MBU-13/P Chemical/Biological Protective Oxygen Mask

MBU-14/P Pressure Demand Oxygen Mask (based on MBU-12/P); used with HGU-68/P

MBU-15/P Pressure Demand Oxygen Mask (based on MBU-12/P)

MBU-16/P Pressure Demand Oxygen Mask (based on MBU-12/P)

MBU-17/P Pressure Demand Oxygen Mask (based on MBU-12/P); used with HGU-68/P

MBU-18/P TAERS (Tactical Aircrew Eye Respiratory System) Mask

MBU-19/P Protective Integrated Hood/Mask; manufactured by ILC Dover; part of AERP (Aircrew Eye/Respiratory Protection) System

MBU-20/P "Combat Edge" Jet Pilot Oxygen Mask; manufactured by Gentex; used with HGU-87/P as part of A/P22P-16

(21) (No information)

MBU-22/P "Combat Edge" Jet Pilot Oxygen Mask (improved MBU-20/P); manufactured by Gentex; used with HGU-86/P

MBU-23/P Enhanced Pressure-Demand Oxygen Mask; manufactured by Gentex; used with HGU-68/P; replaced MBU-5/P

MBU-24/P "Combat Edge" Jet Pilot Oxygen Mask (sometimes referred to as MBU-24/P22P-16); manufactured by Gentex; used with HGU-87/P

 

I found it interesting that one of the experimental masks listed was developed for C-141 crews. Isn't you guy a C-141 Pilot? :think:

[Bob Hudson]

I found it interesting that one of the experimental masks listed was developed for C-141 crews. Isn't you guy a C-141 Pilot? :think:

 

Right - after bombers he flew C-130's and C-141's.

 

This mask has the standard hard shell found on normal MBU-5/P's plus over that it has another shell which has the attachment points and lock for the lever. This is a Sierra Eng. item with the ID "Assy. No. 450-375" A Google search brings up just one reference and that's for an old Ebay sale whose details are no longer available. And, again, I have looked at scores of MBU-5/P photos online without seeing this lever mechanism.

[Bob Hudson]

Well, someone on Ebay answered the question of what it is for, but not why you don't see these when rummaging through MBU-5/P images online:

 

"I don't believe these were experimental, they were used more than that. I have a 1984 Army Aviation Life Support Equipment manual and it shows this quick don setup listed as an alternative mounting method of the MBU-5 to the SPH-4 helmet. The helmet's or in your case the headset's mic cord is plugged into the masks cord. When the mask is in the worn position, the mask mic is hot and the boom mic is cold. Pulling that black handle and releasing the mask kills the mask mic and makes the boom mic hot again. I believe for USAF use they were used by airlift crews with the H-157 headsets or HGU-7 helmets."

 

That is in fact an H-157/AIC headset/microphone that it's attached to in the photos. I had wondered about the purpose of the small micro-switch that is triggered when the the lever is lifted.

[cscmc1]

I know this is an old topic, but I, too, had one of these masks (many years ago). I see them every so often; they're not super-rare. Mine was attached to an SPH helmet that I traded for.

 

That said, let me know if ever you're ready to part with one of your standard bayonet-mount MBU-5's. I have a really nice MBU-12/P that I'd like to trade in order to match up the '5 to an older helmet I have. Thanks!

[mohawkALSE]

Well, someone on Ebay answered the question of what it is for, but not why you don't see these when rummaging through MBU-5/P images online:

 

"I don't believe these were experimental, they were used more than that. I have a 1984 Army Aviation Life Support Equipment manual and it shows this quick don setup listed as an alternative mounting method of the MBU-5 to the SPH-4 helmet. The helmet's or in your case the headset's mic cord is plugged into the masks cord. When the mask is in the worn position, the mask mic is hot and the boom mic is cold. Pulling that black handle and releasing the mask kills the mask mic and makes the boom mic hot again. I believe for USAF use they were used by airlift crews with the H-157 headsets or HGU-7 helmets."

 

That is in fact an H-157/AIC headset/microphone that it's attached to in the photos. I had wondered about the purpose of the small micro-switch that is triggered when the the lever is lifted.

 

 

Very old topic but just browsing through and now I'm laughing. That answer from ebay was written by me.

 

I have a couple of these mask setups. Ive seen a handful of pics on the net of them but I cant recall any of it being used actually. Seems like they were just carried along for the most part.

[phantomfixer]

here is one from Dover AFB from 1972-1974 from the inspection stamps...kinda neat mask...

[phantomfixer]

tag

[phantomfixer]

...

[Bob Hudson]

I love how a seven-year-old thread can come to life I visited a forum recently that doesn't let people post to older threads but I think it's great that topics can grow over the years.

[phantomfixer]

I agree...allows for continuity....

 

When I saw your thread and read how the mask saw little use, I thought I would post this one....the mask, I believe was not meant to be worn continually like a fighter pilot MBU-5/p and helmet...this design was for decompression...when the aircraft depressurized in the event of an emergency..thus the quick don... they were hung around the aircraft, in strategic locations, just in case...

 

so in this respect, they saw continual service, with limited actual use