Work Day 7th July 2018

Three tasks carried out in the LCP this week. The replacement of firmware on the SCSI controller with a later version which we been able to obtain, refitting the Argus 700 monitor on the front of the computer rack and adjusting the Vertical Sync on the Jamming Assessment monitor which involved removing the monitor from the display console so that the vertical sync pots could be accessed. Here is the monitor, now with a stable picture again after adjustment.

Jamming Assessment Monitor wm.jpg

The monitor panel was not part of the operational LCP and has been fitted for future software work.

Computer Racks with Monitor wm.jpg

The plan is to repaint the internal walls and roof of the LCP, the original colour being Cockpit Green. After fifty plus years plus the internal paint is engrained with dirt and faded as illustrated in this photo showing a test section of the internal wall.

LCP Paint Test wm.jpg

Note the contrast in colour but the fresh paint is still wet. The accesses covers for the fluorescent (now LED) lights in the LCP roof have been repainted and can be seen in the photo of the covers being repainted.

The Simulator was run up and remains serviceable, this was also a good test for the new SCSI firmware.

Dave carried on doing a first rate job on prepping the wheel arches. Unlike the cabin structure the wheel arches and the rest of the chassis is steel and not alloy so corrosion is a significant issue besides the flaking paint and dirt. See below for the results of Dave’s work on one of the wheel arches. Dave also treated the corrosion with an inhibiter, most being applied to corrosion but also to his overalls!

T86 Wheel Arch Prep for Painting wm.jpg

A lot of work on refurbishing ‘parts’ from the T86 is taking place away from “2nd Line” (so 3rd Line = Home!). These include chiller and air condition covers. Once the corrosion, loose paint etc. are removed, they are returned for painting.

T86 LCP Items Repaint wm.jpg

Two further images are included to illustrate the sort of problems being treated. Corrosion between a steel latch and alloy cover and perished metal RF/Insect shield. In the case of the latch it will be removed from the cover, both being treated and repainted before re assembly. The original metal shields will be replaced with plastic insect shields as the T86 will not be transmitting again!

T86 Mod Cover Detail 4 wm.jpg

T86 Mod Cover Detail 5 wm.jpg



Workday 30th June 2018

At long last we are starting to put paint back on the T86 radar instead of taking it off! Unfortunately this doesn’t mean that all the repaint preparation is complete, it isn’t. What was achieved was the priming of the T86 trailer’s wheels, a specialist vehicle chassis primer was used, a task that took several hours. The six wheels are now ready for a top coat and are looking good after removing loose paint, vegetation, corrosion and then corrosion treatment. The photo below shows the result of the day’s work which also included priming the receiver cover from the aerial assembly.

T86 Wheels Rx Cover Primed wm.jpg

OK, so there are seven wheels in the photo, one is a spare we have acquired. An interesting point on the wheels. When the T86 was recovered it ended up with one wheel from a T83 radar and while the T86 wheels are bog standard steel the T83 wheel is bronze!!!

The tyres are another matter, several have perished quite badly (not surprising for their age) and replacements are being sought, part worn is OK as the T86 trailer is no longer road legal. Tyres are: Dunlop B6 10.00 x 15 14 Ply.

One of our many challenges has been to find the correct paint colour for touch up and repaints in the T86 cabin, drawer fronts etc. It is not RAF Blue Grey! Anyway, a couple of tester pots were procured for what was determined to be the nearest match and the results are shown in the photo. There are two colour ‘splodges’ on the piece of trunking cover in the image, A = Dark Admiralty Grey and C = Dark Camouflage Grey, the light grey is primer and nothing to do with the colour match test. One challenge being the grey paint used in the T86 cabin does have slightly different shades depending on what the item is! In the photo the ‘test piece’ of trunking is laying on a cover from C Rack and to confirm that Dark Admiralty Grey is the correct match there is a splodge on the cover between two rivets – can you see it?

T86 Internal Colour Matching wm.jpg

Workday 16th June 2018

After having a big sort out and tidy up of our materials and stores it was back to the paint prepping of the radar. Pete H treated corrosion on four of the six wheels ready for priming. Pete J getting the best job of the day, using GUNK to degrease one of the wheel hubs, before running out of GUNK! Pete J then carried out further corrosion treatment on the radar. Neil continued for yet another week prepping the aerial assembly.

The last activity of the day was to check the simulator. Two weeks ago we broke the software while trying to access the operating system (OSC245) from the Bloodhound application. Basically, at boot the operating system could be entered but the Bloodhound software not run. We had no other option but to reload the software from ¼” tape. Two tapes are used, one for the System Volume and Start Disk the second for files known as Section 1. The first tape was reloaded but the second tape failed to load. Fortunately just loading the first tape restored to software needed to run the Bloodhound software. A piece of good luck as it preserved the engagement sectors, site parameters and a ‘no illuminate’ arc for the T86, settings entered by us on the standard distribution of Bloodhound software.

Whilst repairing the ME159 Monitor Panel a fault we have seen before showed itself again – corroded lead-out wires on crystals and crystal oscillators; in this case a 19.6608MHz oscillator.   This is the panel in question.

Argus Steady State.JPG



“Yellow River” – Type 83 Radar

These photographs were kindly donated to us by  Mr Ernest Miller. They show a “Yellow River” Type 83 Bloodhound Mk1 Radar and were taken at at the test site near Leicester, about 1959. Ernerst said that the site was in the middle of the sewage farm which did tend to keep visitors away.

image003 wm.jpg


A basic drawing showing the major components can be seen here:

A YouTube video showing the radar deployed at RAF North Coates is here:

Two references to doucments held in the National Archives are:
Ref: AVIA 6/1914 Effect of carcinotron jamming on radar type 83 (Yellow River) – 1960
Ref: AVIA 54/1507 Equipment Radar A.A. No.3 Mk.9, `Yellow River’: development – 1947-57


Workday 19th May 2018

The plan is to complete all the prep work for a repaint of the T86 this summer still holds good. The work being undertaken is thorough and includes the removal of the cabin wheels and treating the chassis corrosion.

Wheel removal
Removal of the wheels from the cabin has proved to be challenging, that is until a torque multiplier was acquired, Pete M’s comment was ‘this is a dream’ following previous weeks that were spent creating all sorts of leverage systems to try and release the wheel nuts.  Here shows the torque multiplier in action.

T86 Removing Wheel with Torque Multiplier wm.jpgOnce the wheels are removed lose paint and corrosion is removed from the wheels, leaf springs, brake drum etc, all becoming much easier. Pete M in action on a leaf spring below.

T86 Removing Corrosion - Leaf Spring wm.jpg

The T86 cabin wheels are in a poor condition due to their age and the extended period the cabin has been in the open. The tyre rubber is perishing and corrosion on the wheel hubs is severe but not terminal. The accompanying image shows the inside of wheel after removal, not much paint left and a decent amount of vegetation! The T86 cabin will not be made road worthy as it does not comply with current vehicle regulations etc. but it will still need moving short distances and the perished tyres will not be suitable for that purpose in the longer term. We are therefore on the lookout for part worn 10.00 15 tyres – please anyone?

T86 Wheel Original Condition 2 wm.jpg

Replacing the cabin floor
Dave and Pete J have replaced the front cabin floor which can be described as a precision job. The first image shows the floor fitted before moving on to priming. To complete the new floor the lino, or a more modern version of, will be laid over the wood with metal fillets to cover joins on the wheel arches.

T86 New Floor Front Cabin 2 wm.jpg

T86 Floor Primed Front Cabin 1 wm.jpg

Preparing the aerial assembly
Neil continues with what looks to be a never ending task of rubbing down all the aerial system components and the rats nest of the wave guide assembly.  Here is Neil being ‘embraced’ by the aerial system!

Refurbishing components
Many of the smaller components are being refurbished off site as they are easily transported! Two accompanying images show the handles for the receiver cover and the pedestal support pillars from the rear of the cabin, before and after paint stripping.

T86 Rx Cover Handles wm.jpg

T86 Pedestal Anchors wm.jpg

F16 (400Hz) Power Supply
We gave the power supply a good soak test on Saturday by connecting its output to 115V incandescent bulbs; it ran for several hours without a problem. ge. At a date to be decided a test run of driving a few synchros will take place.

T86 F16 on Soak Test wm.jpg

After several weeks of being U/S the LCP (simulator) was run up and as per last week remains serviceable with the exception of a vertical sync issue on one monitor which has been shelved to get on with other work.

Pete H

Type 86 400Hz Power Supply

The TF16 400Hz power supply in the T86 radar is now working!!!

As previously reported our member Pete M put in a lot of effort to develop a 400Hz power supply with the aim of running the radar simulator in the LCP. However, the large synchros proved to be too much of a load for Pete’s power supply. So Pete H thought he would have a go at resurrecting the T86’s 400Hz supply (location F16).

A note of caution, it is early days and the power supply hasn’t yet had a full load and soak test  but the attached images of meter readings show the F16 voltage and frequency output parameters.

F16 Output AC wm.jpg      F16 Output Hz wm.jpg

Whilst the T86 was in the care of the RAF Museum capacitors were removed by contractors who were tasked with removing any components in the T86  containing polychlorinated biphenyl (PCB) a toxic chlorine compound.  Not only did they remove those but  also all the electrolytic capacitors from the F rack power supplies!!

F16 Caps Removed wm.jpg

The loss of the electrolytic capacitors was no big deal as due to their age all would probably allneed replacing anyway. Several replacement capacitors are ‘near enough’ the same values of the originals, e.g. 10uf being used to replace 8uf which are not available at the correct working voltage. Here we are with the replacements fitted

F16 Caps Replaced wm.jpg

For the initial switching on of the 400Hz supply we connected it to a variable auto transformer (Variac) and wound it up gradually to 230V AC. The frequency and voltage of the output can be adjusted but after several minutes the voltage dropped by 15 V. Investigation showing that the 26V DC that is supposed to be across the output of the bridge rectifier was actually 33V. The mains input had to be wound down to 190V on the auto transformer to achieve the 26V DC and at that voltage everything became stable.

These two images show the wiring of the input transformer in the power supply  and its circuit diagram. The primary windings are giving too much voltage on the secondary so we shall experiment with the links to obtain the required voltage on load.

F16 Transformer Primary Wiring wm.jpg

F16 Transformer Taps wm.jpg

We have noticed that the power supply gives off a fairly loud 400Hz tone. Not sure if this is normal as in a working radar it wouldn’t have been noticed!


Workday 12th May 2018

The warmer weather means working outside so one of our priorities was completed. Treating all the new plywood floor panels with preservative.

T86 Floor Panels Following Preservative Treatment wm.jpg The next stage is to fix these panels to the cabin floor. All panels are secured in place by being bolted through the floor, new bolts have been procured as the originals were completely corroded and had to be cut out. The forward section of the cabin floor was also painted ready for the refitting of the wooden panels. The accompanying photo shows the repainted cabin floor, apologies for the poor quality image it will be replaced next week.
T86 Cabin Floor Primed.jpg

The simulator has been unserviceable for several weeks following a period of the hangar being very damp and cold, there is no heating in the hangar and we cannot leave heaters/dehumidifiers switched on when not working there.

I’m pleased to report that the simulator is now serviceable again following a replacement main GX processor in the Argus 700 computer.

One other minor issue is the Jamming Assessment display which has a vertical sync problem. The plan is to check and adjust locally and replace if necessary.