It has been mentioned elsewhere, but I will say it again, the Vulcan was flying before PCs and GPS, you could not get route information on your PDA. PDAs had not been invented.

Photo from Jimmie Robb of rear crew.

With this page I leave myself wide open to a few hairy old Plotters getting back to me with some comments on how I’ve got it wrong.  Please do, but include the right answers!

In the pages below this section some of the equipment used by the Navigators will get some level of detailed description, but for this page I will just say that the nav team receive inputs that show them their height, speed across the ground, heading, drift and their Lat & Long position. To enable them to keep the position updated in the event of errors, or to check that the equipment is working correctly they also have the facility to take ‘fixes’ using the H2S radar in the Nav Bombing System, RDF, Tacan and astro. Using a mix of these the team should be able to navigate accurately and put the aircraft in a position to deliver a weapon on an assigned target. The section below is an outline of the basic ‘problem’ that the Navigator Plotter is constantly solving.

The basics of navigation are quite simple; if you head out on a specific compass heading then if you know your speed and how long you have been flying for, you will be able to calculate your position at any particular time. This basic navigation model is made complicated by a natural feature of the world we live in, wind.  We are all used to wind, and we know from the weather forecasts that at any one point the wind has a direction, normally expressed as the point of the compass from which it is blowing, and it has a speed, for air and sea navigation this is expressed in nautical miles per hour (knots) rather then miles per hour as in a car.  So at any point the wind can be expressed as a vector such as 090 degrees at 40 knots, i.e. if we are flying due north then we have a wind blowing on our right hand side at 40 knots.  It is trying to blow us off course. As anyone will know who has flown to the USA, a wind on the tail on the way home can make the journey time a lot shorter. The effect of the wind on the track of the aircraft, and its groundspeed is at the root of the navigational problem. 

The photo above was sent to me by Jimmie Robb, he is in the centre of the photo. He has taken the shot by putting the camera in his Nav Radar area and taken the shot on self timer, the shot shows the Plotter station, and that of the AEO at the top.  Jimmie says the Plotter is Ash Weaver and he believes the AEO ic Viz Nagan who died of a heart attack playing squash at Scampton. From the Plotters map it looks like they were doing a high level navex starting from the Lincolnshire coast to the islands off Scotland, then south to a point west of the Wash, as the end of the exercise, then turning for home. This was probably a night astro sortie.  The Plotter’s Dalton nav computer is just under Robbie’s hand where he is pointing.  Modern youth’s with their PC’s would not recognise this as a ‘computer’!

Most people watch the TV weather forecasts at some time or other, one thing that is immediately obvious is that the weather varies within a country, and other geographic areas, consequently the wind speed and direction changes as you move around, and normally the temperature changes as well.  But weather is not two dimensional; it changes with height as well as distance. For any point on the ground, as you climb vertically the first thing you notice is a change in temperature, usually it gets colder as you climb.  On top of that the wind speed and direction will also normally change in the vertical plane.  If navigation were totally automated these natural effects could all be compensated for by the ubiquitous computer. Even without a modern digital computer the Vulcan navigation system could cope with these changes when all equipment was working correctly and the aircraft was within radar range of accurate radar or Tacan fixes.  The problem became difficult when the equipment malfunctioned or the aircraft was out of range of accurate fixing aids, such as radar or Tacan.  In these situations the Plotter had to spend a lot of his time attempting to calculate an accurate wind and the effect this had on the aircraft position as it was likely to be different from the wind he had used in his flight planning. Any wind used in flight planning was the best ‘guestimate’ of the Met Officer, and anyway, even if accurate at the time of calculation, it would have changed during the time of the sortie.  During flight planning the Met Office would have given the crew their best prediction of the winds at various points in the climb to operational height, the winds at various points around the planned aircraft track for that sortie, and if low-level was to be part of the sortie then the Plotter would also get winds for the descent from high to low-level as well as predicted winds around the low-level route.

The diagram below [not to any scale] shows a simple flight plan route, all at high level, all over sea but with three radio beacons ‘X, ‘Y’ & ‘Z’. These beacons will give the crew a radio bearing but no range information, we will also assume that the aircraft will be outside radar range, and astro is not possible. The only information available to the Plotter is the flight plan winds and the radio beacons.  The leg from ‘A’ to ‘B’ requires a track of 045^o and the distance is 600nm, planned groundspeed is 600 knots so if there is no wind the aircraft can fly a heading of 045^o and will arrive at ‘B’ in 1 hour.

The plotter intends to take two fixes on this leg, each 20 minutes apart, so that he can update wind data and his position.  Assuming that there is no wind then if he leaves point ‘A’ at 12.00 he would expect to be 200nm along track at 12.20, the ‘green blob’ on his track. At 12.15 he takes a bearing from beacon ‘Y’ saying that he bears 260^o from the beacon, he can draw this as position line ‘a’(p/l ‘a’).  As he intends having a position check at 12.20, then this position line needs to be moved along track by a distance equivalent to 5 minutes. At a groundspeed (g/s) of 600 kts. the 5 minutes equates to 50nm.  This movement gives position line (p/l) ‘a1’.  At 12.18 he does the same with beacon ‘Z’ getting a bearing of 190^o which he plots and moves 2 minutes along track, or 20nm.  The intersection of the two p/l’s ‘a1’ & ‘b1’ gives him his new position as of 12.20. Because the wind is not zero as he had used in flight planning, this new position will not be on track, in fact it is to the left of the ‘green blob’ position. The difference between his expected position at 12.20 (based on flight plan data) and his calculated position will give him an indication of the wind that he has experienced for the last 20 minutes, say 070^o at 35 kts.  Using this he can calculate the expected wind for the rest of the leg to position ‘B’ and so calculate a new heading and ETA for the turning point. 

The new track he requires is the dotted blue line to position ‘B’, let’s say this is 047^o from his fix position at 12.20, fedding this into his nav computer with the wind at 070^o at 35 kts.and an airspeed of 600 kts he will need a heading of  048.3^o and his groundspeed will be 568 kts.

This procedure would be repeated at planned intervals all the way round the flight plan track. All other things being equal the Plotter should be able to calculate fairly accurate winds, allowing an accurate ‘overhead’ at point ‘A’ at the end of the exercise.  Under normal conditions the Green Satin would be giving accurate inputs of groundspeed and drift to the Nav system, as would the Heading Reference System.