For all you V force rear seaters, the ultimate in home entertainment

[NutLoose]

Imagine the fun you could have sitting at home whiling away the hours, think of the money you would save in heating your home as this would do it for you, the ultimate boys toy..

Navigation and Bombing System NBS
(H2S Mk 9A and Navigation, Bombing and Computer NBC)
used in V-bombers Victor, Vulcan and Valiant.

All wired up and running in a HOUSE!!!!!!!

Tatjana van Vark ~ Navigation and Bombing System NBS (http://www.tatjavanvark.nl/tvve/dduck0.html)


http://www.tatjavanvark.nl/tvve/vulc095s.jpg

http://www.tatjavanvark.nl/tvve/vulc080s.jpg


Now that dedication for you....... :D:D

[Grackle]

But look at the other things she has done! Amazing! ... but daft as a brush

[green granite]

What an amazing person. :ok:

[tartare]

Lads.... could one of you explain what this is?
I assume it's the back seat panel that allowed a nuclear weapon to be dropped? Or Blue Steel, or conventional weapons?
Which would all be done digitally today no doubt...

[Tankertrashnav]

Oh the Calc3 - the most amazing collection of cogs, wheels, levers, gizmos and whizzits ever assembled - and all to calculate the forward throw of the bomb, and thus the release point. When they finally realised it was redundant in the Victor tanker and removed it, the extra space made the cockpit seem positively roomy!

Tartare - in answer to your questions, basically "yes", "yes", "yes", and "without a doubt", but she wouldnt have half the fun playing with a digital one!

Ive always thought there was a fine line between genius and madness - not sure which side of the line this lady inhabits ;)

[Pontius Navigator]

Tartare, to follow through on Tankertrash,

Tatjana is trying to get a Calc 7. That was one piece of kit directly linked to dropping a nuclear weapon but only for the Valiant and Blue Danube. After 1965 it was well and truely obsolete so her chance of getting one will be vanishingly small.

The other thing she has not got, and does not know she hasn't, is either panel EY, EP or ER for the later nuclear weapons or a 90-way panel for conventional bombs. However these were not truely integrated with the NBS.

[psycho joe]

Just look, maintaining internal silence, until the meaning of my work becomes clear.


There's no doubt that the work is impressive, and I have a generally relative understanding of what this thing was designed to do in an aircraft; But I have to ask what if anything would this thing do when switched on in a house?...Other than generate some heat & maybe a humming noise. :confused:

[Tyres O'Flaherty]

Not that I would want to cast nasturtiums, but have you seen the pic of ''Tatjana'' from the home page ?


:eek:

[Bushfiva]

Ms van Vark has, in the past, made her own 40-rotor cryptograph, improving somewhat on the original German Enigma in that it supports punctuation. The workmanship on all her stuff is impeccable.

[Pontius Navigator]

But I have to ask what if anything would this thing do when switched on in a house?...:

Just like why did you climb the mountain?

Because she can.

I am not sure but I think the kit has been rearranged from its first layout. In some respects the layout is better than the trainer at Lindholme although a bench would add to it; give somewhere for the external offset box.

[peterperfect]

Fantastic kit. I guess it could all be done with an iPhone App these days ??

[The Oberon]

Mad as a hatter.

I quite agree that the internals of the calc 3 were fascinating but my favourite was the calc 5. 2 motors, 3 potentiometers, a length of steel tape, a handful of chopper relays and a couple of valve amplifiers. Result ? an electro mechanical Pythagoras machine that calculated Rp from Ht and Rs. Quite brilliant.

She also appears to be missing a Test set TS501

[tonker]

Mad maybe, HOT deffo:ok:

[Navy_Adversary]

All looks a bit 50s to me......:)

[cliver029]

...And our "proud boast" was that there was only one solid state component in the whole shebang when we did our L-Fitt Q AV- NB training.
And, you still continued to beat the nice people across the pond in the bombing comps didn't you:D

[Pontius Navigator]

but the square rooting pin-wheel was something else :)

and double sine-cos pots

[The Oberon]

"And, you still continued to beat the nice people across the pond in the bombing comps didn't you"

Ah yes, Giant Voice, when NBS fairies came to the fore, many happy memories. Mind you I believe that the chinagraph lines on the windscreen aligned with the bodge tape on the probe came in handy for low level targets.

[Roadster280]

Excuse my idiot question -

What was the point of having all this whirring secret gubbins in the aircraft? If its output was the bomb release parameters, and its input was position, track, bomb weight etc, this would lead to a finite set of results, so why not just tabulate all the possible inputs, and outputs, and then issue a set of tables? Even if it were equivalent to 30 telephone directories, it would have been much more reliable than such a complex system, especially airborne.

I used to have an ex-RAF radar tech as a colleague, and his comment was "H2S wasn't all that accurate, only a couple hundred yards or so, but it didn't matter, it was a nuclear bomb"!

[Pontius Navigator]

Excuse my idiot question -

What was the point of having all this whirring secret gubbins in the aircraft? If its output was the bomb release parameters, and its input was position, track, bomb weight etc, this would lead to a finite set of results, so why not just tabulate all the possible inputs, and outputs, and then issue a set of tables? Even if it were equivalent to 30 telephone directories, it would have been much more reliable than such a complex system, especially airborne.

I used to have an ex-RAF radar tech as a colleague, and his comment was "H2S wasn't all that accurate, only a couple hundred yards or so, but it didn't matter, it was a nuclear bomb"!

But we did indeed have tables but not as thick as your telephone directory. We would pre-calculate the forward throw in the even the computer through a wobbly or the system suffered a failure.

The cruical component was the radar and its ability to display a discrete aiming point. The theoretical accuracy (50%) for the system was 325 yards (IIRC).

When you say tabulate all possible inputs, it would take a finite time to check true airspeed, temperature, altitude, rate of change of altitude, groundspeed, drift angle, aircraft heading and so on, extract the forward throw and amend the release point.

The forward through was groundspeed times the square route of height divided by g plus +/- H dot (rate of climb) divided by g plus taw (a time value to allow for bomb ballistics), plus time advance (to allow for the lag in the system) with an addition for the range component of cross-trail, H tan lamda times the cosine of the drift angle.

Now a feature of the NBS, as an analogue computer, is that it could make all these calculations simultaneously which contemporary digital computers could not.

The system could cope with a rate of change of height of 50,000 feet per minute which was pretty impressive given that the Vulcan would climb at only 8,000 feet per minute or so.

One weakness was in the speed of ballistic computation as it would take 4.55 seconds for the Calc 3 to run a B-bank scan. The system would also open the bomb doors at 7 seconds before bomb release. To ensure that the computer didn't change the release point and try to release the bomb before the bomb doors were fully open the system would lock out at 10.55 seconds.

The timing was pretty impressive. Back to doing it using tables, the aircraft was flying at some 300 yards per second. A tenth of a second timing error equated to 30 yards. No, automatics were far more reliable.

[Roadster280]

PN - Thanks for the comprehensive answer. The 300yds/sec is the telling bit. If the accuracy of the system is roughly one second of flying time, then that answers it all.

The realtime nature of the analogue computer is also a plus, though obviously today's digital computers do the calcs so quickly that they appear to be simultaneous.

How did the system account for the various types of bombs and quantity? I should think dropping a single larger HE bomb would be a very different kettle of fish to dropping a stick of 21 on a target (eg Black Buck). In fact, DID the V-force drop larger single HE bombs, or was that option deleted in favour of nuclear?

[Tankertrashnav]

The theoretical accuracy (50%) for the system was 325 yards (IIRC).



Or could be as much as nine miles. Although I have to admit this was nothing to do with the H2S/NBS and more to do with the trainee nav radar misidentifying a Pennine valley, which unfortunately like the intended target also had a reservoir with a dam :(.

Still, that skewed my bombing results enough to get me a posting to tankers, so it was an ill-wind!

[Pontius Navigator]

How did the system account for the various types of bombs and quantity? I should think dropping a single larger HE bomb would be a very different kettle of fish to dropping a stick of 21 on a target (eg Black Buck). In fact, DID the V-force drop larger single HE bombs, or was that option deleted in favour of nuclear?

The Vulcan was designed to carry 12xmines which were larger than 1000lb bombs but this was never employed. By the 1950s the RAF had standardised on the 1000lb GP bomb. The early bomb was a Mk 7, realtively fat compared with all subsequent marks. In its Lancaster/Lincoln guise the Mark 7 had a short tail and a circular shield around the fins. This was too short for stability when dropped by the V-bombers to initially a reducing ring was used so that a Mk 107 tail could be fitted. This also reduced the effective bomb load. From 1964 we had the Mk 11 and Mk 12, one was cast iron for airburst fragmentation and the other was forged for penetration. The RN had the Mk 10 which was similar but had side pockets for the fuses rather than the RAF nose and tail. Side pockets were safer on a warship.

The trajectory for a bomb is initially flat and it travels forward at aircraft speed until it accelerates under gravity and travels faster downward. Even at very high altitude it will still have a considerable forward velocity component, ie it does not drop vertically. Calculation of the shape of the trajectory is simple, modelling that shape on an analogue computer is dificult. What they did was to model parts of the trajectory where it could be modelled as a straight(ish) line. This was done on the calc 3 and the setting of A and B bank switches to match the bomb type/height/speed of the aircraft. The particular bomb was modelled using a 'ballistic film' and you can just make out the film cassette on the calc 3 housing. In training we used to use 'bomb zero' or an ideal bomb. Later we switched to using real bomb types. IIRC the 1000lb freefall bomb film was a Type 48 or 48A. The latter was for use on the Calc 3a that was initially fitted to the Mk 2 Vulcan.

For stick bombing we would increase the forward throw by half the stick length. There was a setting on the Calc 3 where we simply set the stick length. The maximum value was 1400 yards which was modified by the Calc 3 to increase the forward throw by 700 yards.

We would calculate the actual forward throw using the time interval between each bomb. While the bomb distributor, the 90-way, could handle intervals as short as 0.09 seconds (I think), 0.18, 0.24, 0.3, 0.45 and so on (longer times would have been used for minelaying) there was a risk of jostle with settings less than, I think 0.24 seconds.

At 0.24 seconds and 480 kts, the interval would be 65 yards (I used accurate figures). The length of such a stick of 21 1000lb bombs would therefore be 1300 yards. If the target was a line feature, like a runway say 40 yards wide, the aircraft would have to fly at an angle so that at least one bomb would hit.

A warship would be a very difficult target for a high level attack as it is much narrower for a start and from 48,000 feet the time of bomb fall would be about 60 seconds. In that time a warship could move 400-600 yards away from the predicted impact point!

[lasernigel]

The trajectory for a bomb is initially flat and it travels forward at aircraft speed until it accelerates under gravity and travels faster downward. Even at very high altitude it will still have a considerable forward velocity component

Excuse my ignorance, but are you saying the bombs actually went supersonic whilst falling?

[Skittles]

No Laser, terminal velocity would prevent that from happening. It would speed up to a point, then the force of wind resistance would equal that of gravity, essentially, and it would fall at a constant speed.

[Pontius Navigator]

Yes, the bombs would go supersonic if dropped from a great enough altitude. The terminal velocity of a 1000lb GP bomb is 1800 feet per second, roughly mach 1.8. The 100lb practice bomb was very slick and its TV was 1600 feet per second.

More typically, the TV of the bombs from a Lancaster would be nearer 1131 feet per second. The 1000lb bomb has a drag coeficient of 0.9 which is not bad.

[Skittles]

Eh? Well that throws my admittedly limited, self-acquired knowledge into disrepute.

Glad to be proven wrong though.

In a further attempt to learn, which may in fact just compound my ignorance, am I right in saying that after the bomb blasts, there is a slight delay and a series of sonic booms? Depending on the bomb of course.

[threeputt]

PN

I don't remember all the maths but, I think you are talking a fair amount of hoop when it comes to supersonic bombs old chap.

3P:ok:

[Pontius Navigator]

W. J. Lawrence wrote about the Tallboy bomb in his book, No 5 Bomber Group:[3]
It was ballistically perfect and in consequence had a very high terminal velocity, variously estimated at 3,600 and 3,700 feet (1,100 m) per second (1,100–1,130 m/s or about 2,500 mph / 4,000 km/h)

Assuming that the Tallboy was indeed ballistically perfect (a 1000lb bomb has a drag factor of 0.9), to reach a TV of 3,600 feet per minute, time of bomb fall would be getting on for 2 minutes and it would have to be dropped from around 200,000 feet.

[Brian Abraham]

While the TV of a Tallboy was supersonic, what is not mentioned here is that the Lancaster was not flying high enough for the bomb to reach its TV
The poor old Lanc was never going to reach an altitude where the Tallboy could reach its TV assuming PN's numbers are correct. Even in a vacuum (zero drag) a body dropped from 20,000 is only just supersonic at 773MPH when reaching the ground (sonic roughly 750MPH).

[Pontius Navigator]

BA, not my figures, they were a quote from Lawrence.

[cliver029]

........The bulkhead plugs in the raydome went intermittent, (Plessey plugs if my fading memory is correct) and it took a megger to reproduce the fault on the ground.
.
Oh and a rubber hammer, I once watched an NCO who should have known better trying to fit a the tray back into one of the "cans" without realising it was in the wrong place and beating hell out of the tray to make it fit, until someone else put him out of his misery showed him the correct slot, and it still worked after all that abuse:\