WWll Spifire Pilots

[harrier]

Every month it is my pleasure to have lunch with the SAAF Association in Cape Town. Some of the members were Spitfire pilots during WWll and one of them mentioned that they would fly as high as 35 to 36 thousand feet to try and have a go at Junkers 88s flying at 40 thousand.
The Spits were obviously unpressurised and although on 100% oxygen were using the old wartime oxygen masks.
How long would one expect a young fit man to stay conscious at 35 to 36 thousand feet?
He says that he never suffered any noticeable effects except for the intense cold and a big headache after landing. He is still a hale and hearty 89 year old.

[Dan Winterland]

On oxygen, they will stay as conscious as long as the oxygen flowed. However, at about that altitude, there isn't enough partial pressure of oxygen for the blood to absorb enough. Modern regulators start to feed in higher pressure oxygen to maintain the level. I'm pretty sure they wouldn't have had pressure breathing then - the masks wouldn't support it. They said they had no ill effects, but the msymptoms of anoxia (lack of oxygen) are very innocuous and modern pilots are tought that they may not recognise it in themselves.

If the oxygen failed - time to unconsciousness depends on the individual - but typically at that height it will be in the order of 20 to 30 seconds.

I suspect they would be suffering some form of decompression sickness (DCS) - which would account for the headaches. Modern RAF regs prohit unpressurised flight above 25,000'. And even with this limit - I've experienced the onset of DCS at this regieme. We know a lot more about aviation physiology now.

Of course, they could have been flying Mk VI or Mark VII Spitfires which were pressurised - but only small numbers of these marks were produced.

[Tankertrashnav]

I'd concur with what Dan has said. Like him, I underwent decompression training at the RAF Avmed centre where we were rendered hypoxic, and we were given simple tasks to carry out after the oxygen supply was cut off, writing down the five times table or something similar, which quickly became harder than differential calculus! What was noticeable was how quickly full consciousness returned when the oxygen supply returned, a matter of a few full breaths and all was normal.

Again, as Dan says, even on 100%, without pressure breathing, trips to 40,000' would have to be very brief, and if the oxygen failed unconsciousness would have occurred within seconds at that height.

[VIProds]

Alec, My 92 year old PRU Spitfire pilot friend said that the optimum height to take good photographs was about 30,000ft. He would also travel to and from the targets at this height.

The cockpit was heated but not pressurised, so he used to fly in just his battledress & submarine polar neck sweater. He knew the consequences of bailing out at that height, but on 6 hour plus sorties comfort was more important.

On one sortie, he got as far as Bordeaux, when he noticed that he had used 3/4 of his oxygen supply, so had to fly out to sea & reduce his altitude so that he could get back to St Eval in Cornwall.

The only time that he had headaches, was the usually the morning after, having spent the evening proping up the bar !

[green granite]

I can't remember which book it was in but there was the tale of the squadron pilots just after the end of the war in Europe, when they had no real purpose to their flying, climbing to see how high above 40,000' they could get their Spitfires and quite a few claimed to have suffered from headaches and some from chest pains, The station doctor was not amused.

[SCAFITE]

The Highest kill of WW2 was done in a Spitfire MK VII which was a MKV fitted with a Merlin 60 series engine and extended wing tips and fully pressurised. The Spitfire shot down a high flying Junkers JU86 at 46,000 foot. The Germans gave up high flying Recce sorties after that as it came as a bit of a shock to be had at that hight.

Spitfire MK VII was a imporved Spitfire MK VI which was not very good and needed the pilot to be bolted and sealed into his cockpit. The system used on the Spitfire MK VII was used again on the Spitfire PR MK XIX which could at a push operate at 50,000. PRXIX were PR version of the Spitfire MK XIV which again was a Spitfire ML VIII fitted with a Griffon engine.

Previous record was 41,000 in a modified Spitfire MKIX before the MK VII entered service flown by F/O Prince Emanuel Galitzine of Special Service (High Altitude) Flight Northolt, September 1942

Before anybody asked why did the MK VII enter service after the MK IX, basic interceptor Spitfires in Fighter Command during the war were as follows in order they entered service.

MK I/II

MK V

MK IX Stop gap Fighter (MK V fitted with a 60 series engine) until the MK VIII (new airframe) entered service but the RAF in the UK were so happy with the MK IX that they did not need the MK VIII.

MK VII (MK V fitted with 60 series and extended wing tips)

MK VIII These were given to the USAAF and RAF sqns in the Middle and Far East.

MK XIV (MK VIII fitted with a Griffon 5 bladed) to shoot down VI or Diver Patrols)

(Note) Spitfire MK XII was again a MK V fitted with a early short Griffon with 4 blades but was very rough and only served in 2 Sqns one being 91 Sqn for only about 4 months or so before being replaced with MK XIV March 1944.

(Note) Spitfire MK XVI (the new one being restored for the BBMF) this was a Spitfire MK IX fitted with a US Built Merlin from the P51D due to the fact at that time we could not build enough Merlins with production demands for Lancaster and Mosquito. These were mainly used in ground attack roles, but in their low back version used to replace Spitfire MK IX in the air combat role towards the end of the war.

Lanacaster lovers note Lancaster B Mk I is a Lanc fitted with British Built Merlins, B Mk II Fitter with Bristol Radials and the B Mk III Lanc fitted again with US Built Merlins.

[NutherA2]

How long would one expect a young fit man to stay conscious at 35 to 36 thousand feet? The Meteor 7 was unpressurised and fitted with an oxygen economiser system (no pressure breathing assistance); IIRC we were limited to 38,000 feet with no time limit imposed; we used to start our spinning exercises from that altitude. A less well recognised problem at the time was aircrews' vulnerability to decompression sickness which could occur when exposed to cabin pressures above 25,000 feet for extended periods.

[Fareastdriver]

NutherA2

I will second that.

[henry crun]

NutherA2; I can't remember the limitations for the Meteor 7, but for the pressurised NF Meteors I have the upper limit of 43,000ft lurking in the few grey cells left.

Was it a later mark of economiser system, or is my memory is playing me false again ?

[Wander00]

Did we not fly the JP to 35,000 ft unpressurised, and I seem to recall that at 40,000 the Canerra B2 variants were pressurised only to 25,000ft. Don't recall anyone reporting altitude sicknes symptoms, but then we wouldn't would we!

[NutherA2]

Henry, when using oxygen economisers on high flow the max permitted altitudes were, as I recall, based on 38,000’ being the level at which, using 100% oxygen, the ambient pressure was only just sufficient to provide sufficient pressure within the lungs to provide the minimum required level of oxygenation to the blood stream (equivalent to 10,000’ without an oxygen system); unpressurised aircraft were therefore limited to 38K.


Pressurised aircraft were permitted to fly at higher levels since it was assumed that in event of sudden decompression, the pilot could descend to below 38k within his time of “useful consciousness”. Sadly my little grey cells have lost track of the file where this higher limiting altitude was once recorded, but I think that for the Vampire T11 & FB5 and Meteor 8 it may have been 45,000’. I would be happy to be corrected by anyone with a better memory than mine.

For later aircraft such as the Hunter & Javelin, fitted with the pressure demand regulator, the limitation was 48,000’ unless you were a space cadet wearing a pressure jerkin.

It’s late at night and all this typing has left me a bit hypoxic, so I think I’ll go to bed.

[cazatou]

Wander00

I don't think the Mk3 Jet Provost got to 35,000ft very often but the Mk4 would do so with ease. The problem we had at SORF was that we had a new course every 2 weeks - 25 Courses a year - so we would do the major part of the high level flying in a very condensed time frame at very regular intervals.

[sharpend]

Yup, I sometimes flew to 35,000' unpressurized in the JP4.

Additionally, I flew the Canberra B15 often at 45,000' with b**er all pressurization and once cruise-climbed it to 62000' over the Indian Ocean to get over Cbs. Biggest problem was in the UK/FRG winter though when the cannopy totally iced up and one had to land looking through a tiny 'DV' window.

[Tankertrashnav]

My Avmed lectures are a bit of a hazy memory sharpend, but 62,000' in an unpressurised a/c, even with a pressure breathing mask would seem to me to present some physiological problems. I recall being told on here that the Canberra guys who set up the world altitude record of over 70,000' in the 50's wore a suit rather like that subsequently worn by U2 pilots. I assume you were in normal flying suits, so were there any after affects?

[Dan Winterland]

The rules when I was in the RAF were no flying unpressurused above 25,000' and some sort of pressure jacket was required above 50,000'. Safe - perhaps over safe - but cases of DCS have occurred as low as 20,000'. While I was in, the JP3s were limited to 25,000' and the presuurised JP5s to 36,000' Flying the Tucano, we could climb pretty fast up to 25,000' and then no further, even though other oprators limit it to 34,000' - which it has no problem acheiving. But even at 25 in the cruise, I have had pains in my elbows, knees and knuckles. Descending just 2000' would stop this.

The Victor K2 which Tankertrashnav and I flew was limited to 49,000 due to the oxgen supplies coming from the Mk17F regulator which would supply pressure breathing, but the limit came because of the pressure suit rule, a thousand feet being added for the venturi effect of the slipstream. In it's bomber role, it used to climb to over 60,000' and in the recce version, over 65,000'. In the latter, the guys used to wear pressure jerkins - partial pressure suits which covered the torso only.