Vulcan Limit

[Brian Abraham]

Reading “the Vulcan Story” by Tim Laming and surprised to see under altitude limitations “There is no height restrictions on the aircraft because of airframe limitations. However, the maximum operating altitude is limited by the oxygen equipment as follows: ……..”
It then tabulates the various combinations with 56,000 feet cabin altitude being the maximum. With a maximum pressurisation differential of 9 PSI surely the bomber boys would have bragging rights over the Lightning altitude attempts on a recent thread. What was she capable of? I’m sure in true military fashion some one must have attempted the official limit plus a bit.

[4Greens]

There are a number of aircraft that are altitude limited by cabin/oxygen. The limits are based on the depressurised case. This is, of course, more likely in military aircraft that may suffer battle damage. It is not always practical to wear full pressure suits!

[BEagle]

The Vulcan was certainly capable of such heights when light, the problems being:

1. There were 2 types of oxygen regulator. The Mk17 could not deliver the required overpressure at such heights, being capable of a maximum of 30mm Hg overpressure. However, although the Mk21 could deliver up to 50mm Hg overpressure, it was necessary to wear a counterpressure pressure jerkin and anti 'g' suit in order for the crew to cope with such high levels of pressure breathing.

2. In the event of loss of the cockpit canopy, aerodynamic suck could reduce cabin altitude by 5000 ft, so to lose the canopy at 50000ft gave a cabin altitude of 55000ft.

3. The aeroplane was so aerodynamically clean, that it took too long to descend from high level to a height at which the Mk17 regulator would cope. So, if you decided to fly at 56000ft and were to lose the canopy, the time of useful consciousness would be less than the time it would take to descend to a safe level.....

Did people bust the limit? I've been up to above FL510 with one captain who decided that the chance of losing the canopy or experiencing explosive decompression were infinitessimal. No-one had ever suffered either problem in the past. The aeroplane flew quite happily and we turned with 45 deg AoB watching a pair of F4s trying unsuccessfully to get a firing solution.

[ionagh]

I thought that the margin between cruise speed and stall above FL55 could have been a limiting factor? I'm sure there couldnt have been much latitude for error.
The Frightening was just that little bit quicker at altitude.

[Aeronut]

Anyone heard of coffin corner?

[A2QFI]

I flew the PR9 and that too had a major problem losing height after any cabin pressure loss. We sometimes flew in the gear mentioned by Beagle plus the Taylor pressure helmet, a very uncomfortable bit of kit in the Middle East! At extreme altitude the problem really was turning - the outboard wing would get near to MCrit and the inboard wing would get near to stalling and control was marginal to say the least.

[BEagle]

Aeronut and ionagh, the delta-wing Vulcan did not suffer from 'coffin corner'. There was no such thing as 'low speed buffet boundary' or a conventional stall - at high AoA the drag simply increased until level flight was no longer possible with maximum continuous thrust. The only aerodynamic limit was the release to service maximum permitted IMN of well over M0.9.

[Brian Abraham]

Just found that 61,500 was reached during test (4-3-1959) of the first production B2 (XH533). Still, what do you think she would have been capable of BEagle?

[FJJP]

I still had 300fpm climb rate at FL550 going over a line of thunderstorms which lay between the Great Lakes and Florida en route Offutt to Goose. The ac would probably reach in the order of FL600 before the roc reduced to 100fpm [at a guess].

It was only 27 Sqn who wore the special pressure kit whilst on spec ops, although quite a few ac were fitted with the Mk21 regulator.

[Pontius Navigator]

Beags memory has slipped slightly, the Mk 21 delivered 70 mm pressure. We only switched to the low altitude Mk 17 after 1965-66 when our high level lkit was withdrawn.

The NBC Calc 3A had height range of 17200-60000 feet which limited our ability to conduct computed bomb runs below 18000 feet. About 1968 the Mk 1 Calc 3s were retrofitted to the Mk 2 Vulcan which gave us the same height range for ballistic computation at 7200-50000.

This meant we could now do 2G attacks (popup to 8000 feet). By this time we were doing laydown attacks and did not need to use the Calc 3 for ballistic calculation.

FJJP, I concur with your height, we got 555 over Glasgow at about 120k on an air test and gave up with a ROC of about 300-500.

I have just done some ODM work and was surprised to find the height over target would be only 530-540. Once the 21000 lb load had gone we could continue to cruise climb to 560.

Aerodynamic suck was not an issue in the mid 60s and was only 'invented' after the switch to the Mk 17 regulator and the suggestion that we limit our upper level to 450.

The Lightning, with the 21F regulator and the Taylor helmet could go to 660.

It wasn't the aerodynamic suck that worried me but the 45000 feet free fall if we had to bail out.

[Yellow Sun]

IIRC there was an issue with the Mk21 regulator delivery pressure which limited alt to 470 without pressure clothing. Paradoxically, the lower delivery pressure of the Mk17 allowed an alt. limit of 490. The definitive answer is no doubt in the loft!

YS

[passpartout]

So what did 27 sqn do that meant they had to go that high?

[BEagle]

You do not need to know.

[charliegolf]

Secret trials of:










nosebleed remedies!

CG

[The Rocket]

Good old "Captain Cold War" to the rescue again;)

Defending our secrets from the Russian hordes:ok:

[jindabyne]

Hunting for the foxes

[BEagle]

The Cold War may be over, but certain classified operational capabilities may still be required.

Such as sowing chemtrails to subjugate the lower orders. Oops, b*gger. Black Omega alert!

[charliegolf]

I have a 25 year old Black Omega, and it still keeps really good time.

CG

[Jackonicko]

"So what did 27 sqn do that meant they had to go that high?"

He thinks that you don't need to know.

"The Cold War may be over, but certain classified operational capabilities may still be required."

He obviously doesn't know, or doesn't know that 27's role and secondary role have been described in detail in a number of publications. Rather than provoking his angina it's obvious from the role and from the kit that these jets were sometimes seen carrying.....

[BEagle]

...were clearly chemtrail sowing devices.

The front bomb bay tank was isolated and filled with reagent Alfa. Reagent Bravo and the mixing device were installed in a standard bomb bay pannier. Dispensing devices were installed in the redundant 'window' hoppers.

Allegedly.

[Busta]

Beags,

Now you've blown the gaff, send me your address I'll have to come round and shoot you.

Nothing matters very much, most things don't matter at all.

[passpartout]

Whatever.:*

Some capability gap we've had to endure.

Anyway. Will never forget the first time I saw a Vulcan. One flew over my house in about '74. Was mightily impressed, even if I didn't know what it was back then. I guess it was about FL005.

[BEagle]

You probably did know at the time, but soon afterwards the chemtrail subjugation effect would have made you forget......

[passpartout]

No, I was 5.:ok:

[Busta]

I can still see all those pretty colours

[Blacksheep]

Dispensing devices were installed in the redundant 'window' hoppersWhich is why 27 never came home with loads of duty free when they went on overseas detachments... :}


...Ooops, another cold war era secret slips out of the bag.

[FJJP]

Nah - you could get 30-40 cases of scotch in the bomb-aimer's position.

Oops! Bu**er, let the cat out of the bag...

[BEagle]

Plus several sets of golf bats in the recuperator bays....

'Mongo' once brought back a complete ride-on lawnmower back in a tin triangle - but declared it. That miserable b*gger 'Farquar the Revenue' (remember him, busta?) charged him car tax on it, as well as duty! Although he did later get it back when he explained that he was hardly likely to drive it up Lincoln High St.!

[HTB]

Pontius Nav - Re the Calc 3 and low level laydown, I vaguely remember having to wind the height down to -500ft. Whether this was to frig the ballistics or to "interface" with the Calc 5 to produce a radar picture which would otherwise consist of a a big empty hole in the middle I do not recall (which is probably why I spent more time on 27 than most!).

BEags - A ride-on lawn mower! Ha! A certain AEO sqn ldr brought back a full size billiard/snooker table (from Singapore I think), as well as the usual assortment of camphor wood furniture and sundry items for consumption. You mentioned "g-suit" in earlier post; not in my time, not in the sense of the sexy leg warmers that are now to be seen. We were equipped with the partial pressure jerkin for high level ops, an inelegant but comfortable shoulder to crutch infaltable body warmer; all the usual LSJ accroutrements were incorporated and it came in a dashing range of coulours - well, grey or gray. Not to counteract g-forces, but to keep vital organs inside the chest cavity in case of rapid decompression. Highest? In excess of 560.

And if you really want to know what 27 did back in the seventies...dig out copies of the Lincoln Echo, where we usually found details of a forthcoming short-notice deployment before notification by official channels. Or one could have read the national press of the day to find out who was doing what in places distant and foriegn. Nor were we the only ones doing it.

Those things hanging from the wings were in fact pre-production laser guided photon torpedoes with hyper-drive pulse motors:p

[Dan Winterland]

The Victor K2 was limited to FL490 as well due to the Mk17 regulator. However, the K2 had short wingtips, uprigged ailerons to move the centre of pressure forward to preserve fatigue life and the AAR pods as well as the underwing tanks which were fixed on the tanker. This meant that 490 was pretty much it's max altitude although I flew one up to 520 and a bit once.

The short tips on the K2 gave a span of 117'. The B2 (bomber) had medium tips giving 120' and that could reach FL630 once the underwings were dropped. But a clean SR2 (recce) with the long tips bolted on giving a span of 123' and no underwings could reach FL670! The SR2 with 543 Sqn did the secondary role before 27 took it over.

But at altitude, the K2 handled like a dog. At light weights, the engines could push you up to a height that there was only about 2 knots between the buffet boundary and the high speed buffet. This meant turning was nigh impossible. One way round the problem was to switch the autopilot rudder channel off and steer it with your feet, thus keeping the wings level!

[O2thief]

Plus several sets of golf bats in the recuperator bays....
'Mongo' once brought back a complete ride-on lawnmower back in a tin triangle - but declared it. That miserable b*gger 'Farquar the Revenue' (remember him, busta?) charged him car tax on it, as well as duty! Although he did later get it back when he explained that he was hardly likely to drive it up Lincoln High St.!

Only things we put in the recuperator bay's were Salmond or Char (from the BX in Goose Bay). Golf Clubs far too important to be frozen! Once got a BL Mini in the 4000lb pannier!.

[orionsbelt]

http://www.famousvulcans.co.uk/xh537.htm

'8th May 1978
Delivered to 27 Squadron as a Vulcan B2 MMR. The MMR role was to maintain a alert standard through out the North Sea, keeping an eye on the UK`s oil fields and acting as a early warning for any USSR ships entering our waters. As well as that 537 would pick up any distress signals from ships, something that the Nimrod does these days. 537 could also be fitted with air-sampling pods, a task inherited from Victor SR2s of No 543 Squadron.'


take a look

[HTB]

Aaah. Air sampling pods, were they. No wonder we could never get a firing solution.

And that's not the only thing 27 inherited from 543; many of the ancient aircrew also moved over. One paricular crew made up entirley of ex-543, with the exception of the co-pilot, who at the ripe age of 45 brought the average crew age down to about 53 (although at the time they looked more like 73). God bless the "Gindits".

[Pontius Navigator]

Yellow Sun, my log book tells a different tale.

On 5 May 64 I was banged to 560 for 15 secs. The following year, just in case I had forgotten what fun it was AMTC did it again but to 520 for 15 seconds. And again the following Jul for good measure.

Th enext time I had the pleasure of practice dying was with the F4 regulator to 48k for a mere 3 seconds.

Buggers hadn't finished as they banged me from 25k to 45k for the Nimrod in 1975.

These were 'true' pressures and one presumes that this is the same pressure one would have experienced for real at, say 500, if the lid blew with aerodynamic suck.

Thinking about it, I think that aerodynamic suck was probably over played. If we had had to bail out we would have jumped before the lid was blown off. Possibly the open door might have created suck but the effect would have been of very short duration.

Similarly when the pilots blew the lid a double bang would follow soon after. The chances of the lid coming off? It never did and when the Victor crew tried it by accident it didn't come off dspite their best efforts.

HTN, I will have to think about low level bombing tonight - like counting sheep.

[The Real Slim Shady]

'Scuse me HTB...I resemble that remark.

I was the Gindits co pilot and I wasn't 45 then!!!!

Bottle of Gordons and a six pack of tonic in my Navbag for the Captain when we shutdown on the first nightstop on a Ranger: sadly, no longer with us, but a wonderful guy, described by our Plotter as "A garrulous old b*st*rd at the best of times".

[Pontius Navigator]

HTB,

<<Re the Calc 3 and low level laydown, I vaguely remember having to wind the height down to -500ft. Whether this was to frig the ballistics or to "interface" with the Calc 5 to produce a radar picture which would otherwise consist of a a big empty hole in the middle I do not recall (which is probably why I spent more time on 27 than most!).>>

We did not use ballistic computation for the 2F or the 2J. We would calculate the FT and then fly the groundspeed to achieve the correct values. I think you are right about the height being set for the Calc 5. It was, I seem to remember, set on the CU585 for the Calc 5 as you surmised.

FT for the 950 was about 400 yards and for a 2J at 350k about 1.2 miles I seem to remember.

[HTB]

TRSS

Depends which of the co-pilots you were! Do allow a bit of artistic licence (exaggeration) for effect. Bless him, the little nav plotter taught me the rudiments of golf on an isolated Pacific island where the major hazard was lage nesting/waddling albatross. Are you the one who went to work for BAe at Tabuk?

PN

I hope that helped in getting off to sleep - it worked for me on the OCU!:ugh:

I'll dig out my logbooks at the weekend to see if I can provide some real info for the thread topic.

[The Real Slim Shady]

HTB,

Tabuk??? Not me. I was JM's last co pilot until the Sqn disbanded.And the plotter's golf in the Pacific was legendary, after he clobbered the bird wit his tee shot!

[radarnav]

The Victor K2 was limited to FL490 as well due to the Mk17 regulator. However, the K2 had short wingtips, uprigged ailerons to move the centre of pressure forward to preserve fatigue life and the AAR pods as well as the underwing tanks which were fixed on the tanker. This meant that 490 was pretty much it's max altitude although I flew one up to 520 and a bit once.

The short tips on the K2 gave a span of 117'. The B2 (bomber) had medium tips giving 120' and that could reach FL630 once the underwings were dropped. But a clean SR2 (recce) with the long tips bolted on giving a span of 123' and no underwings could reach FL670! The SR2 with 543 Sqn did the secondary role before 27 took it over.

But at altitude, the K2 handled like a dog. At light weights, the engines could push you up to a height that there was only about 2 knots between the buffet boundary and the high speed buffet. This meant turning was nigh impossible. One way round the problem was to switch the autopilot rudder channel off and steer it with your feet, thus keeping the wings level!


A clean Bmk2 (BS) could go there too. Any tales?

[Pontius Navigator]

This next bit is really sad.

Setting up for a normal, high level, computed bomb run would require the nav rad to do a radar height finding. The scanner would be tilted down and the radar/nbc height switch on the CU585 set to radar. The aircraft would be flown at a steady height over a level surface. If this was a plain the terrain height would be put on the CU585 target height dial.

The radar height would then be adjusted until first flicker on the neon. The radar/nbc switch would be put back to nbc. The calc 3 height would be checked against the radar height and used if it was correct. It was fed from the pressure system and was corrected for pressure by setting a D-factor.

This height was then used to feed the calc 3 ballistics and also the calc 5 height carriage for the triangle solver to get the range marker to mesure plan range.

If the calc 3 was u/s the radar/nbc switch would be set to radar and the height voltage would be sent to rotate the calc 5 y-axis shaft and set the correct height.

At low level, below 7,200 feet the calc 3 would not calculate the correct ballistics but the difference between plan and slant range was insignificant. I think I am correct in saying that we left the switch on nbc and, as I said earlier, used a calcuated g/s and height for achieve the correct release point.

Nerdish? Sorry about that.:p

[charliegolf]

Very interesting. Everyone knows there's more to it than

fly over, drop the bomb, fly away.

But folk rarely explain. Ta.


CG

Do you have to come and kill us all now?:uhoh:

[diginagain]

PN and others (and BEagle, I suppose), thanks. Despite all of the banter that you've entertained us with, I guess we'll never know just how fortunate we are that you never had to put your skills to use.

Or cuff it, for that matter.

[FJJP]

Pontius, I remember it well; when it came to do the calcs, I was glad I faced forward!

The modern bomber has it easy - put the cross-hairs on the tgt on the tv screen, select automatic and the computer does the rest for a boring DH every time. Computer fails? Even easier - turn round and come home!

No system available for manual reversion of any kind...

How many ways of releasing bombs from the flatiron?

[BEagle]

Well, we had the SFOM sight and Time Delay Unit from the co-pilot's bomb release - which was all but useless. My preferred method at low level was to press the centre console bomb release when the target was more or less under the No3 RPM gauge.

Accurate enough for the odd DH - and certainly accurate enough for a bucket of sunshine!

We used the Type 2 (All Aids) attack for preference - He Who Sees Controls! But this did rely upon the Nav Radar being told to wait until we'd overflown the visual IP before giving his steer corrections - we wouldn't select the MFS selector to 'Bomb' until the IP. In poor vis the Nav Radar's information was used, converting to visual only if the co-pilot could see enough to take over the attack visually.

[Pontius Navigator]

The best was 'no picture', then 'no shift - LP 6', 'shift but no homing - LP 3A', 'homing no ballistics - LP1B', 'No markers - LP 4?', 'Basic with shift but no markers', and finally 'Basic' with no shift and no markers just a heading marker if lucky.

Oh, and the type 2 (normal), 3 (BS), 5 (T4 bombsight) and 6 (T4 sighting head but no computer).

I make that 11 without all the tactical variants.

Yes, thanks Beags, I forgot the SFOM. One Akrotiri crew swore by radar line, visual ranging whereas the rest of us would do visual line radar ranging. They had a pretty good average on the raft using their method - 300 feet. Then again so did 8 of the other crews at 300 feet. One crew had 280 and the 10th had 320.

[LateArmLive]

I wouldn't say the modern day aircraft can't go 'rev', FJJP, there are 10 different bombing modes in my current jet. Each of them is practiced regularly to make sure we can use them all accurately, and you may be surprised to find that we can still get very good results with the "rev" modes.
p.s.
Loving the Vulcan dits, I think it was the reason I got into the RAF in the first place after seeing one make my little brother cry at an airshow!:E

[ORAC]

I seem to remember a certain RAF exchange pilot found out about SHar rev modes when he bombed the Ark...... :E

[Yellow Sun]

And let us not forget that wonderful piece of British engineering ingenuity, the Copilot's Visual Bomb Sight (CVBS).

YS

[Gainesy]

So, was the actual visual bomb sight ever used; I mean the one "downstairs".

[Lyneham Lad]

My preferred method at low level was to press the centre console bomb release when the target was more or less under the No3 RPM gauge.
Accurate enough for the odd DH - and certainly accurate enough for a bucket of sunshine!

Hmmm, low level release of a 'bucket of sunshine' :eek: Wouldn't a LABS manouevre have been used?

[Pontius Navigator]

Lyneham Lad,

The best we would have done with the Yellow Sun was a programmed release in the climb, 15 deg in the case of the Vulcan 2.

Was the T4 bombsight ever used in anger? Yes. The Valiant force was not cleared to use the NBS at the time of Suez and all, bar one sqn, used the visual bomb sight. I understand the results were not exactly sparkling. One rumour I heard was that there had been no allowance for stick length. The T4 was fine for point bombing but needed a sighting head correction to release earlier to place the stick on target.

One sqn used the NBS and I am told achieved acceptable results. Setting the stick length was a 'simple' dial up system on the Calc 3 - apart from the Calc 3 not being that easy to access.

[BEagle]

Lyneham Lad, no, we didn't use a LABS manoeuvre. For 2 reasons:

1. The bucket wasn't that big really.

2. It wasn't supposed to go bang until after we'd left the vicinity. Of course, we would never have known if that was just a story made up to give us some hope of surviving....

[Pontius Navigator]

Beags, you are of course talking of the little one and not Yellow Sun. It was a BIG B*ST*RD and designed to go bang on impact. The only separation was your speed and time of bomb fall.

LABS was designed so that the Canberra, et al, could deliver an airburst (or groundburst) ballistic bomb from a low level entry rather than a pop-up or straight and level high level manouevre.

A really lulu was the 2D attack designed for the V-s to drop the Red Beard or Violet Club as they could not loft it. Low level entry and a sedate climb to 27 000 feet - wings level following the steering commands all the way.

Way to go!

[MMEMatty]

What sort of accuracy could you normally achieve, both from High Altitude and Low Level when dropping the bomb?

And also, did it really matter how accurate you could drop (except to yourself of course)

Matt

[Pontius Navigator]

Laydown would have been close enough to ensure the target would be in the crater - say 200-400 yards.

2H - Popup to 10500 feet was problematical. Initially the data would consistently drop the bomb about 3000 yards long. Bit too far out. The Mk 1 guys, against orders, practised using the automatics. Initially it was thought the Calc 3 could only handle a 3000 fpm climb as this was the 'test' rate of change of height in 'primary check'. It was then discovered that it would have worked in a Lightning as it could handle 50k/min. Accuracy improved to 500-600 yards with the occasional 'low' release. 10500 was supposedly the minimum safe escape release height. If you cocked up the initial POP and climb then . . . some crews dropped in training at 8500 Ooops.

Pre-low level, the high accuracy would have been about 400 yards for a straight and level attack. For an evasive bomb run somewhere between 800 and 2000 yards depending on experience of the crew and, to quote the SOP,

"It is possible that the appearance of the target may be considerably different from that planned due to earlier strikes."

To these accuracies you might also like to consider that Bomber Command research Branch had determined a combat degradation factor of 75% based on WW2 and the Korean War - the pucker factor. I don't know how that worked out for GW 1 or GW 2. Certainly the results in GW 1 looked better than plus 75% degradation.

In comparison, I believe that the US ICBMs were also in the 500 yards area compared with the opposition where their accuracy was said to be in miles.

[Tim McLelland]

I suppose I should be happy that somebody bothered to read my book! I will be including the Aircrew Manual in my new Vulcan book, although this time I should have loads of extra space, so hopefully I can persuade a former Vulcan driver to add his comments at the appropriate places!