Did You Fly The Vulcan?? (Merged)
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The AVSCU was quite an artful piece of work - a truly analogue item.
For those who may wonder, it was the Automatic Variation Setting Control Unit, which converted a True Heading to Magnetic Heading.
The aircraft's longitude position rotated a plastic (Bakelite?) representation of the world's magnetic variation and the latitude moved a sliding contact arm up and down the surface. A plunger contact moved in and out and the deflexion provided the magentic variation value corresponding to the lat/long.
At least, I think that's how the 'dog turd on a stick' worked!
Nowadays I have the entire global magnetic variationin a 2.73 Kb database file....
For those who may wonder, it was the Automatic Variation Setting Control Unit, which converted a True Heading to Magnetic Heading.
The aircraft's longitude position rotated a plastic (Bakelite?) representation of the world's magnetic variation and the latitude moved a sliding contact arm up and down the surface. A plunger contact moved in and out and the deflexion provided the magentic variation value corresponding to the lat/long.
At least, I think that's how the 'dog turd on a stick' worked!
Nowadays I have the entire global magnetic variationin a 2.73 Kb database file....
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Far prefered the NBS Vulcans with the large black radome for a nose than the silly ones with the rounded boob look, with a pimple and poker stuck out. It looks so effete. The black radomed ones looked like they were meant for business, not for swanning around the sky playing lets pretend.
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The black radome looked so old-fashioned - as did shiny paint.
The TFR pod and probe showed that the aircraft meant business. TFR-ing was quite hard work at 300ft! We didn't use the AAR probe for its intended purpose when I was flying the Vulcan, but it made taxying easier as it was a good reference - and was also a good standby bombsight!
The TFR pod and probe showed that the aircraft meant business. TFR-ing was quite hard work at 300ft! We didn't use the AAR probe for its intended purpose when I was flying the Vulcan, but it made taxying easier as it was a good reference - and was also a good standby bombsight!
I don't own this space under my name. I should have leased it while I still could
Magnetic to True. There were pendulously suspended flux valves near the wing tips that sensed the earth magnetic field. This was corrected by the setting on the AVSCU. The 'melted candle' was actually dental wax. In 1964 the magvar drum was for, IIRC, 1949. Not long after there was a great leap forward and we got one for about 1956; I don't know if there was ever a later version.
The Calc 5/5A housed the triangle solver. This wonderful device had a height carriage that drove a slug to represent the aircraft height. There was a horizonal slug that was driven by the CU626 inputs to represent the range of a contact. A metal tape ran between the two. Now the clever bit. The hypotenuse on the metal tape represented the radar slant range to an object. What was needed was the actual plan range. By a suitable system of feedbacks (NBC Techs please expand) the horizontal slug would move and a pickoff on a potentiometere would feed the appropriate voltage to the Calc 1 and 2.
I gave my copy of the NBS Master Block Schematic to the RIN so I can't check now.
The AVSCU was not, AFAIK, in the Calc 5 but was a separate unit.
For odd boxes how about the little wind dubbry switch and desyns by the Nav Panel?
The Calc 5/5A housed the triangle solver. This wonderful device had a height carriage that drove a slug to represent the aircraft height. There was a horizonal slug that was driven by the CU626 inputs to represent the range of a contact. A metal tape ran between the two. Now the clever bit. The hypotenuse on the metal tape represented the radar slant range to an object. What was needed was the actual plan range. By a suitable system of feedbacks (NBC Techs please expand) the horizontal slug would move and a pickoff on a potentiometere would feed the appropriate voltage to the Calc 1 and 2.
I gave my copy of the NBS Master Block Schematic to the RIN so I can't check now.
The AVSCU was not, AFAIK, in the Calc 5 but was a separate unit.
For odd boxes how about the little wind dubbry switch and desyns by the Nav Panel?
Last edited by Pontius Navigator; 17th Feb 2011 at 08:56.
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In civilian use, the "Automatic Variation Setting Control Unit" is today the MagVar tabular database in the non-volatile memories of the Flight Management Systems. It is next due to be updated in 2012, when it will only be two years out of date. (The current MagVar tables are about 11 years out of date). The separate GPIs used their own integral MagVar conversion cam to help them continuously plot Long/Lat long before the advent of Inertial Reference systems, but circuit flying tended to get them into a groove, if you see what I mean. 
Last edited by Blacksheep; 17th Feb 2011 at 08:06.
I don't own this space under my name. I should have leased it while I still could
If we are talking Vulcan, the GPI6 took its heading feed as a true input from the corrected MFS and later as a true input from the HRS which was a free-running gyro.
IIRC the AVSC was a part of the compass system. The plotter would set the magvar and deviation (if any) on the MI and the AVSC pickup would then be set on the appropriate magvar contour. The magvar drum would then take lat and long feeds from the nav system (GPI? or NBC?). Longitude was set by rotation and latitude by radial movement of the pickup. The north pole was at the centre and the south pole at the edge.
As the OP suggested, it took some brainwaves to come up with those ideas. The NBC was made by EMI back in the late 40s and early 50s.
IIRC the AVSC was a part of the compass system. The plotter would set the magvar and deviation (if any) on the MI and the AVSC pickup would then be set on the appropriate magvar contour. The magvar drum would then take lat and long feeds from the nav system (GPI? or NBC?). Longitude was set by rotation and latitude by radial movement of the pickup. The north pole was at the centre and the south pole at the edge.
As the OP suggested, it took some brainwaves to come up with those ideas. The NBC was made by EMI back in the late 40s and early 50s.
I don't own this space under my name. I should have leased it while I still could
Mig, I would go along with that. I do know it was in the NBS Master schematic and as the Nav Panel had the L/L dials that would be logical. Also of course the NBS reliedi on True north whereas with the GPI4 the Plotter could, if he wished, revert to A/A or Grid.
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The things you find!
Summary. The Military Flight System Compass installation in the Vulcan B Mk 2 provides a satisfactory gyro-magnetic compass system for navigational use. The Track Control Unit provides a useful and accurate navigation aid. The large amplitude Northerly phugoid instability, and the loss of gyro datum in turns, reduces the usefulness of the system and could degrade weapons system accuracy. Modifications to overcome these deficiencies are recommended.
http://www.dtic.mil/cgi-bin/GetTRDoc...f&AD=AD0339998
Summary. The Military Flight System Compass installation in the Vulcan B Mk 2 provides a satisfactory gyro-magnetic compass system for navigational use. The Track Control Unit provides a useful and accurate navigation aid. The large amplitude Northerly phugoid instability, and the loss of gyro datum in turns, reduces the usefulness of the system and could degrade weapons system accuracy. Modifications to overcome these deficiencies are recommended.
http://www.dtic.mil/cgi-bin/GetTRDoc...f&AD=AD0339998
The AVSCU cam was definitely in the Nav Panel, the ones I remember were made from resin, the last version I remember was 1964.
P.N. The Pythagorus machine was indeed in the Calc 5, but my memories of it differ slightly from yours, the height was known, from the CU 585, the Slant Range (RS) was known from first ground returns, 10.4 micro secs = 1 radar mile. The RS and Height motors adjusted the tape which in turn rotated the Plan Range (RP) potentiometer. The voltage from the RP pot was then used for a number of things including distorting the IND 301 timebase so that the picture gave Range Plan and appeared as a linear 1, .5 or .25 mill map.
As for the Wind Unit you mentioned, the servicing schedule for that unit had the following statement " Set the Stop/Start switch to Start, simultaniously starting the stop watch", bit of a mouthful.
P.N. The Pythagorus machine was indeed in the Calc 5, but my memories of it differ slightly from yours, the height was known, from the CU 585, the Slant Range (RS) was known from first ground returns, 10.4 micro secs = 1 radar mile. The RS and Height motors adjusted the tape which in turn rotated the Plan Range (RP) potentiometer. The voltage from the RP pot was then used for a number of things including distorting the IND 301 timebase so that the picture gave Range Plan and appeared as a linear 1, .5 or .25 mill map.
As for the Wind Unit you mentioned, the servicing schedule for that unit had the following statement " Set the Stop/Start switch to Start, simultaniously starting the stop watch", bit of a mouthful.
Last edited by The Oberon; 17th Feb 2011 at 13:23.
I don't own this space under my name. I should have leased it while I still could
Mig, indeed I have corresponded with her.
Forget, fascinating. At that time we used to practise an evasive bomb run with a 45deg AOB turn at 1.5g through 45 degrees, reverse after 15 seconds through 90 deg, reverse after 30 seconds through 90 degrees, reverse after 15 seconds through 45 deg and roll out on bombing heading 60 seconds or so from bomb release. It would be flown at around 0.86 and 48k.
This was rather more violent than the A&AEE trial.
I recall that the answer from Smiths to the question: "How far may the system precess during these manoeuvres?" was "no more than 180 degrees."
Forget, fascinating. At that time we used to practise an evasive bomb run with a 45deg AOB turn at 1.5g through 45 degrees, reverse after 15 seconds through 90 deg, reverse after 30 seconds through 90 degrees, reverse after 15 seconds through 45 deg and roll out on bombing heading 60 seconds or so from bomb release. It would be flown at around 0.86 and 48k.
This was rather more violent than the A&AEE trial.
I recall that the answer from Smiths to the question: "How far may the system precess during these manoeuvres?" was "no more than 180 degrees."
I don't own this space under my name. I should have leased it while I still could
The only thing I would disagree with was height from the 585. One did a radar height finding on the 585 which was used to determine the D-factor from 1013 and hence calibrate the system for true height. The 585 also had the target height dial too which was a further correction to determine height above ground.
A radar height finding had to be carried out near the target and over Russia flat areas suitable for height finding were depicted on ULAC - uniform level area charts. These were Lamberts charts a a scale of 1:2,188,000 and really useless for anything else. They were also classified Confidential.
Change of height was pressure driven although it may well have fed back to servos in the 585 for feed to the calc 5.
A radar height finding had to be carried out near the target and over Russia flat areas suitable for height finding were depicted on ULAC - uniform level area charts. These were Lamberts charts a a scale of 1:2,188,000 and really useless for anything else. They were also classified Confidential.
Change of height was pressure driven although it may well have fed back to servos in the 585 for feed to the calc 5.
Thread Starter
The large amplitude Northerly phugoid instability...
If the MFS/HRS switch was selected to HRS and the the plotter dialled in the correct value (which was non-SOP for approaches - you were supposed to fly on MFS), you could fly very smooth and accurate approaches though!
I often wonder what the Vulcan would have been like with modern avionics and fuel/CG management - and perhaps even fly by wire?
Astonishing technology for its day though!
There used to be a rumour amongst "us fairies" that crews preferred to fly with the Blue Steel nav system slaved in as it was better than the platform system, any truth ??
I don't own this space under my name. I should have leased it while I still could
Oberon, I was FF but I believe you were right. The BS had a low grade stable table but was fine as long as it had nav updates and doppler feeds.
Once we got the HRS then it was a whole different ball game 0.25deg/hr drift rate even without FMA and input of ke and kn. It was far more serviceable than BS and always there!
Once we got the HRS then it was a whole different ball game 0.25deg/hr drift rate even without FMA and input of ke and kn. It was far more serviceable than BS and always there!
I don't own this space under my name. I should have leased it while I still could
A heading error of 0.25/hr at 480 knots equates to an azimuth error of about 2 nm/hr. Given a flight time of 6.5 hrs that could give an uncorrected error of 13 miles - well within the accuracy requirements for the H2S to update and acquire the target.
However the mission was a night mission with the availability of astro. The norm was a fix every 40 minutes but over that length of sortie it is likely they would have dropped to one fix per hour. Terminal errors, given a serviceable doppler and HRS would have been no more than 10 miles - about half the error of the dop/HRS alone.
Given a good autopilot and calm conditions at astro could have been better than that.
However the mission was a night mission with the availability of astro. The norm was a fix every 40 minutes but over that length of sortie it is likely they would have dropped to one fix per hour. Terminal errors, given a serviceable doppler and HRS would have been no more than 10 miles - about half the error of the dop/HRS alone.
Given a good autopilot and calm conditions at astro could have been better than that.
I remember taking a Jaguar over the pond to Goose en route to Nellis. We flew as a pair of Victor tankers and all the way over we were getting fixes from the Jag mate, who had the luxury of INS. It was a bit galling that the combined efforts of 4 navs (using essentially the same kit you had in Vulcans) couldnt do as well as one pilot reading off a dial, but that was a glimpse of the future for dedicated navigators, I suppose.
Btw the weekend at Nellis (well, Las Vegas) was very good - better than working for a living, as we used to say!
Btw the weekend at Nellis (well, Las Vegas) was very good - better than working for a living, as we used to say!
V Force reunion 2012
The last reunion in April 2010 was generally regarded a great success, and as we are all getting on a bit it was thought that perhaps we better not wait another 6 years before organising another. Newark Air Museum were keen too, so we have decided to go ahead. The next reunion will be held on Saturday 28th April 2012. This is just advance notice, we aren't doing bookings for a while yet, but I will be getting the reunion website up and running fairly shortly. This will have all the info you will need and I will be posting a link to that on here. Just a reminder that the reunion is for all ranks, aircrew or groundcrew, who operated the Valiant, Victor or Vulcan, together with their families, so please help by passing the word on to any of your former comrades who may not otherwise get to hear of it, and make a note of that date now.
Mods - I hope you wont mind me posting an identical entry on 2 threads, just want to reach as many as possible - pity we dont have a Valiant thread.
Mods - I hope you wont mind me posting an identical entry on 2 threads, just want to reach as many as possible - pity we dont have a Valiant thread.
Tanker
Would the 2012 reunion only be open to RAF personnel?
I worked for 10 years on Vulcan for a civilian contactor and would love to attend (availability willing).
Would the 2012 reunion only be open to RAF personnel?
I worked for 10 years on Vulcan for a civilian contactor and would love to attend (availability willing).