MBU-12 setup

[Fouga23]

Yeah, I would also go with the 60/P!

[CAPFlyer]

Thanks for the input.

Problem is finding a suitable A-21 regulator. The one on Ebay was a real veteran from some unamed conflict.

Do you have any leads?

I'd get the one Ebay or try and make contacts within the RCAF Hercules community and see if they've got a line on what they do with theirs when they retire them. Just because it's a veteran doesn't mean it's somehow sacred and can't be used again.

Otherwise, contact Cobham and see what they say - http://www.cobham.com/media/64991/ADV10482.pdf

[Ollie]

Yeah, that's what I thought. I'll get the one on Ebay and have someone take a look at it.

Thanks!

[RickH]

The bottom of the CRU 79 regulator is an open threaded hole. It was originally designed to take the threaded portion of the upper part of a REDAR hose ( R.E. Darling Co. ) The lower connection is an odd connection peculiar to the US Navy. The radio connections run through this connection to a corresponding female spring loaded connection that runs through the seat kit which in turn plugs in to another hose that runs to the pilot servicing console.

There are other chest mounted regulators that can be had on Ebay. Try to find some that have a switch for 100% and Dilute. Most of the Navy regs are not demand, they just blow. The later regs are designed for LOX or gaseous O2.

In short, while it's not impossible to plumb all of this together, it will take a litte work and imagination !

[Ollie]

I tried my A-21 regulator with my old USAAF Type A-14 mask and the connection fits. Now, I can always use that connection on the MBU-12 hose.

I do have a dilemma regarding the fittings to reduce the diameter from the bottle to the regulator. I'm torn between using aviation stuff or welding stuff. I'm concerned about electrical conductivity...

What do you think?

[The Inspector]

Don't forget-NO ORGANIC COMPOUNDS unless you want a face full of fire

[Ollie]

Yes, that's my number 1 fear.

[CAPFlyer]

If you choose to go the welding supply source, just make sure you're buying oxygen fittings. It'll all have left-hand threads and it'll be all brass with dry-lube seals. As it's designed for 100% pure oxygen, it'll be as good or better than what you'll be able to find aviation side. My grandfather spent his entire career selling cutting/welding equipment to steel mills for Linde and then ESAB, so I got pretty well immersed in all that stuff. Heck, I might have the fittings you need in his barn, but the shipping alone will cost more than you going and getting it locally.

[The Inspector]

Don't forget-NO ORGANIC COMPOUNDS unless you want a face full of fire

I mean on ANY threaded surface like threads, reducers, anything that aviators oxygen ( which is 99.99% dry and pure) can come in contact with, no vaseline, anti sieze agents, oils. There is a lubricant that Boeing uses and should be available commercially, it's a very light purple tint and pours like corn syrup. It's used exclusively to lube 02 threaded parts, check with your gas passer or a medical supply store.

Boeing factory oxygen assembly kits (wrenches and torque wrenches) come from a tool room and are immersed in a freon bath between uses.

Don't use medical oxygen as the moisture in the gas WILL freeze and you'll work up a big sweat trying to suck an icecube through the feed line. No moustache wax either!!!

[shrike]

No moustache wax either!!!

I have limited experience with oxygen, but I can attest to the flammability of moustache wax. I lost a perfectly good handlebar to a zippo and a freak gust of wind.

Last edited by shrike on Tue Mar 05, 2013 3:35 pm, edited 1 time in total.

[Ollie]

Thanks guys,

if I'm going with the welding supplies, it'll be stuff for O2 only.

To be continued when I get the mask...

[CAPFlyer]

Boeing factory oxygen assembly kits (wrenches and torque wrenches) come from a tool room and are immersed in a freon bath between uses.

Having worked around oxygen with my grandfather and using acetylene quite a bit (which is more flammable than 100% oxygen), while such precautions are great for initial build-up of such a system to ensure no contamination of the system and prolonged life, it has little to do with flammability.

As long as you're using brass or soft, no-spark metals, you will not cause a fire with O2. Just make sure all the fittings are clean prior to assembly and you'll be fine. The welding 02 fittings should not require ANY lubrication or sealing. If you have questions about it, ask the welding supply guys. They'll provide the right kind of sealant and/or tape to you. Don't guess with it.

[Ollie]

Roger wilco.

Of course, pictures will be made available.

[Ollie]

Here's the CRU-60/p attached to the A-21 regulator. It fits just great.


CRU-60/p by comiquaze, on Flickr

My guess is that the small fitting is for the anti-G harness?

[bombadier29]

My guess is that the small fitting is for the anti-G harness?

It hooks to the high pressure bail out bottle on the parachute.