Vulcan - bone domes

[ScottBouch]

Ok, thanks, I do like to get it right where possible! Good to learn...

Yes L Adams is the company on mine too, I know the mask bayonet is called a Mk7 connector, the supply hose end may be different mk number.. I don't quite know..

Thanks again, Scott

[oldmansquipper]

Wow! - Didn`t realise how much fun could be generated by the mere mention of AR5...

[Tashengurt]

It's still a dirty word.

[ScottBouch]

I've just found the G-Suit connector for Vulcan / Victor crews that connects to the Oxygen hose of the Front Crew PEC, or the rear crew MSC! (Good to get the terminology right!)

Cheers, Scott.

[ScottBouch]

This photo shows my AR-5 and Vulcan front crew PEC as part of my 2011 CockpitFest display at Newark Air Museum.

Cheers, Scott.

[H Peacock]

I believe the same system was used on the Canberra PR9. There was only one oxygen pipe from the PEC that fed the pilot's mask, pressure jerkin and G- trousers. In the event of a high-altitude decompression the same over-pressure from the regulator was fed to all 3 pieces of AEA. The jerkin and trousers were there to stop the over-pressure bursting your lungs!

The slightly larger hole on the PEC was for the air ventilated suit (AVS), a wonderful piece of kit.

[ScottBouch]

On the PR-9, would that be the Mk4 seat in the nose, or the crew in "normal" positions behind? or all?

Was the PR-9 capable of higher altitudes than other Canberras?

Cheers, Scott

[HTB]

I can state categorically, having done three consecutive tours on 27 Sqn (which included several air sampling dets to Midway Island involving flights above F500), that g-pants were not supplied and therefore never worn during my time on the sqn , only the partial pressure jerkin.

Helmets - generally all crew wore G-type/Mark 1 bonedome combo with P/Q masks (wasn't the P and Q just a size indicator?).

Mister B

[Pontius Navigator]

HTB, that was corect. The cruical measurement was, IIRC, bridge of nose to chin. Even though I don't have the smallest conk I used the smaller Q mask.

Interesting what you say about the G-Helmet. It must have almost been a peer-fashion think or a refusal to supply the Mk2s.

In Cypus in the early '70s an increasing number of us acquired the Mk 2. Far more comfortable in the higher temps at low level. Initially we also carried the g-helmet so you could get your head into tight spaces such as for fuse changing and astro shots. I found astro was no problem nor were many of the other areas. I can't remember but I think I stopped carrying it in the end. I think on one trip I had to go down on the door and up to the JB343 (?) and 11P behind the nav crate. I think I had to dispense with a helmet altogether.

[ScottBouch]

According to the book 'Into Thin Air' by members of the Institute of Aviation Medicine or IAM:

The MOD had a policy of using a variety of different manufactures, so all eggs aren't in one basket. The original P mask was made by one manufacturer, and when need arose for a smaller mask, the contract was given to another manufacturer, and a new mask type allocated as the Q.


I can't recall which manufacturer was which without referring to the book.

Later variants on this mask included the V-Type, again was similar but used a green 'noise silenced' hose.

Cheers, Scott

[Tigger_Too]

Was the PR-9 capable of higher altitudes than other Canberras?

Ohh yes! Similar figures to the ones Mr. B was quoting for certain Vulcan profiles - and sometimes even a bit more!

[HTB]

PN

Re helmets: I can't recall any rear crew wearing Mk 2s, especially not on 27 where helemts were worn only for takeoff and landing (5-7 hours on a high altitude sortie would literally have been a pain in the neck - except for the nav rad who could use the R88 canera as a headrest).

Similarly for the two up front - take of and landing - otherwise they would have a tedious few hours of neck leaning inwards. I do recall that one or two wore Mk 2s, particularly the co-pilots, but it was not the norm.

Can't say I was ever offered the option of any other sort of helmet while flying Vulcans.

As an aside, I did a refresher/FJ lead-in course at Finningley, where I pitched up for the JP LL phase (why was that at the start instead of the end of the course?) with my G-type/Mk 1 ensemble (including wrong sort of tubes). The look of bewilderment and utter disbelief was a joy to behold; joining instructions? Any instructions? Nah. Just a brief call from the sqn - "when you finish the OCC course, go to Finningley...blah, blah, blah". What a way to find out you had a posting (to Chivenor) as the precursor to Tornado conversion.

I also recall that during the main nav course at Finningley we flew the LL JP (3) phase with G-type/Mk1, so was expecting the same for the JP 5.

Mister B

[Pontius Navigator]

Originally Posted by ScottBouch

The MOD had a policy of using a variety of different manufactures, so all eggs aren't in one basket. The original P mask was made by one manufacturer, and when need arose for a smaller mask, the contract was given to another manufacturer, and a new mask type allocated as the Q.

I suspect it was not as carefully thought out as that. More likely that a new contract was let and won by the rival company rather than it being deliberately placed.

An example of this was the early, 50s, cold weather flying gauntlets much prized by MT drivers. These were over the cuff gauntlets which differed from civilian leather gloves from having the lining sewn onto the leather so it was visible in the seams. The gloves were issued as gloves, left and gloves, right rather than a pair as they were sourced separately and the leathers were always different colours.

Later variants on this mask included the V-Type, again was similar but used a green 'noise silenced' hose.

Have you come across the 'med' masks? Initially they were made to order in a cream latex for those that suffered skin allegies from the standard masks. The proud owner had has to wear a number of different formula rubbers strapped to his arm to see which caused the least inflamation. A mask was then made to the appropriate formula.

Later a standard green med mask was introduced which was an effective one type suits most and was subjectively more comfortable than the initial black. Curiously the M-type was green

[Fareastdriver]

I had a Q1A Med mask. It was a different kind of black.

[ScottBouch]

Tigger_Too - Thanks, good to know there is an altitude diference between the PR-9 and other Canberras.

PN / HTB - on the subject of Mk2's.. I am aware that when they entered service they were ludicrously expensive, maybe this is why some units used the Mk1 for a while longer?

PN - Yes I have seen the cream / beige medical masks, but don't have one in my collection.. The facepiece is rather stiffer than a regular P/Q mask.

This is my Mk2A, it belonged to Len Dean, who was crewchief over the TSR2, Jaguar and Tornado prototyping at Warton / Boscombe. It may well never have flown, but used on many engine testing runs.

Here is a Vulcan Crew with a mix of Mk1 and MK2 helmets:

HTB - The JP mk3 (and Shackleton) used a constant flow / economizer oxygen system (non-demand), which needed the H-Type mask:

The M-Type Masks were early Pressure Breathing (non-demand) used with a pressure waistcoat (not Jerkin) on Canberras. I don't know of any other aircraft to use this setup (please let me know if there were others).

Rough evolution of Pressure / Demand Breathing masks:

(Please feel free to correct me on any inaccuracies)

J-Type - Based on the H-Type, but with manually adjustable sprung exhalation valve with aluminium knob at the front. The knob would have to be adjusted (3 settings) to provide different spring tensions on the exhalation valve, therefore providing different pressures in the mask and waistcoat to suit the altitudes.

M-Type Mk1 - Sealing difficulties of the previous J-Type led to a facepiece re-design, and the introduction of the returned lip. The exhalation valve is the same. Note green rubber, this one is dated 1955.

M-Type Mk2 - Improved comfort and sealing again. Same exhalation valve again. Note black rubber

A-13 - The RAF started using American Pressure Demand Regulators, they bought the masks to go with them, The A-13 or MS220001 was the RAF's first Demand Oxygen Mask. The exhalation valve is a Pressure Compensated valve, a small pipe into the supply tube provides pressure to hold the valve closed instead of using a manually adjustable spring for different altitudes, making it automatic.

This is a UK variant on the American design (different microphones). Used with Pressure Jerkins and without. Known for lack of comfort, heavy, and poor visibility, they were not popular. A later variant on this mask used a "Gabb" toggle harness instead of the earlier straps as seen here:

This is one of the American Variants of this widely used mask:

Another American Variant, this time on my APH-6 helmet:

N-Type - Pressure Demand oxygen mask, VERY little is known on this mask, it is mentioned in the book Into Thin Air, and it seems as though it was used for trials and pre-the P/Q. This is the only picture I can find of what I believe MAY be an N-Type mask. Worn by Roly Beaumont:

Also note the F-Type cloth flying helmet and unusual visor on his Mk1 helmet.

P / Q-Types - To replace the A-13 and M-Types in use. Pressure compensated exhalation valve working on the same principal as the A-13. These have been in use for the longest period of any of the masks, even used in Canada and Australia on American Gentex helmets! I believe the earlier black facepieces were natural rubber, and later / current Green facepiece of P/Q masks are made from silicone rubber to avoid irritation?

ADOM - Will this eventually replace all P/Q in service with the RAF?? only time will tell. There are currently a few in service.

Phew, that took some putting together! Like I say, please correct me where I'm wrong!

Cheers, Scott.

[Pontius Navigator]

We also used the H-mask on many types including Meteor, Varsity, Shackleton etc. You say it is a non-demand system. Now I thought that was the other way around.

As you breathed in an oxygen/air mix was inhaled through a bellows arrangement on the floor. If you didn't breathe it didn't flow.

With the Vulcan system there was a constant flow rate of 2mm to ensure a positive pressure through the mask. On emergency IIRC it increased to 4mm. As many crew flew with the mask dangling there was a constant escape of oxygen. It was for that reason the smoking was forbidden. A burning cigarette was quite spectacular as it would appear incandescent and burn out in a minute or so.

Also, at one time it was suspected that the air mix system might fail ON which would allow fumes into the mask if it was selected to emergency IIRC so we flew with it on 100%. The problem now was oxygen ear after prolonged use of oxygen.

I might be wrong here as it was a long time ago.

[ScottBouch]

Hey PN,

When I say constant flow, I mean the oxygen from the bottle is set to constantly flow. This was the way in WW2, but wasteful when not required, and not enough during heavy breathing (late night phone calls etc...).

SO the Economizer was invented... this device is the bellows you refer to:





Oxygen would enter the Economizer at a "Constant Flow" from the cylinder, leaving a nice reservoir there to breathed in. Upon exhalation, the economizer will refill from that constant flow form the cylinder. Typically a Mk11 regulator may have been used between the cylinder and the economizer:



The "Demand" systems did not use a local reservoir, instead, the regulator would allow a greater flow when the aircrew "demanded" it by lowering the pressure in his mask by inhaling, and not supplying oxygen when not needed.

The constant trickle flow you refer to could be the "safety pressure" referred to in AP129 (part 1, section 7, chapter 3):

"Up to 32,000 feet air is mixed with oxygen in proportions appropriate to the cabin altitude ; above 32,000 feet 100 per cent, oxygen is supplied. Between 12,000 and 40,000 feet the oxygen is delivered at a slight positive "safety pressure" (about 1 in. water)."

Check out my little blog on the subject, I've copied in a section of this AP about half way down the page: flightgear's posterous - Home

I mentioned the JP3 and Shackleton as they never were upgraded to a demand system, and used H-Type masks right until they were retired! As a side note, the Air Mix was achieved with the H-Type in a perculiar way: the inspiratory valve that looks exactly like an anti-suffocation valve used on later masks, actually uses a lighter spring and is for inhaling air into the mask to mix with the oxygen! Nice and simple!

Cheers, Scott.

[MANTHRUST]

WIWOChipmunks, first flight, instructor slid the canopy forward and hit me on the bone dome. Deplaned to SE and returned with an old cloth cap and goggles, this was the summer of '81, the old cap was a bit smelly but without it, that would have been the end of a not so beautiful career before it got airborne!
I remember my first flight with the Mk IV, better than any new fangled ANR nonsense.

[ScottBouch]

MANTHRUST - not a fan of ANR? What don't you like about it?

Just trying to learn as much as I can form you guys!

[tartare]

Thread drift - but now that it's out of service - is the ceiling of the final reconnaissance Canberra variant still classified - or can it be discussed openly?
I note Wikipedia says the B6 could reach FL48.
But I'd always heard rumours they could fly much higher - FL60-70 or such?
Aware there are a lot of urban legends out there - tall tales about Canberras nearly matching U2s etc.