Work Day 18th September 2021

T86

More painting of the aerial assembly, especially the hard to get at places. The aerials are on their back for this latest painting session. The two photos below show before and after painting of the waveguide assembly fed by the receiving dish.

LCP

Refitted the small telecoms unit on the test equipment mounting plate. A half hour job that took two hours! Reason, the golden rule of re inserting screws from removed units was not observed so could not find the original mounting screws. The photo below shows the comms which has been corrosion treated and repainted and the test equipment on the mounting plate.

The simulator had not been run for a few weeks so was switched on at the end of the day. Unfortunately a few faults were immediately apparent:

  • The FT81 monitor gave no display so the boot up process could not be monitored.
  • Yet another power supply RIFA filter capacitor went up in smoke
  • … and the simulator failed to boot

For the past few simulator sessions the FT81 had no vertical sync on switch on but eventually settled down, so is the ‘no display’ related? It has been removed for repair as has the 15V 8 Amp power supply.

The failure to boot appears to be an intermittent problem with the digital Output box but needs investigating further. The Argus was loading the software, according to its activity LEDs but without the FT81 it couldn’t be determined at which stage the boot up was stalling. Possibly reseating cards will fix but with limited time this will be a job for the next visit.

Simulator Booting

The green LED on the ME1461 flickers on loading software as is normal and the processor LEDs then look to be in a loop waiting for something. There are no LEDs on any of the Digital output cards and the displays were showing the firmware display – no Bloodhound boot display. When fiddling about removing the FT81 I turned around and the Bloodhound boot display had magically appeared, there were also a total of three LEDs on a couple of Digital Output cards. A reboot simply showed the firmware display again and no boot up display. On the occasion when the boot display did show I pressed the Simulator button but nothing happened. Finally; when the boot displays appeared the Mode Change Not Allowed message was NOT present which means the Argus is seeing the required inputs. All four CHARGE channels are also OK. I don’t think the power supply with the blown RIFA is responsible. Problem with the PeriBus card on the digital output box (maybe).

Pete H

Work Day 11th September 2021

T86

Finished hand crafting the temporary pedestal roof covers to use when working on the aerial system once the roof is painted.

Top coated the pedestal roof with NATO Green. If the T86 was repainted before its end of service life it would have been NATO Green, I assume. The pedestal roof will receive two coats of NATO Green and the black for supports and the base of the actual pedestal. See photo below.

Away from Cosford restoration of removed fittings continues. The latest items to be restored are the two viewing windows for the course and fine elevation synchro dials.

LCP

A job that been on the ‘to do’ list for a while is to remove the duct cover that is below the test equipment holders on the wall in front of M Rack. The cover is secured by screws which are rusted in. The last screw was drilled out yesterday and the cover removed.

Quite a few hidden treasures found as below

A good clean was carried out and new securing screws will be fitted which will involve the re tapping of holes.

The telecoms box fitted to the test equipment rack has been refurbished and will be refitted once the duct cover is replaced. The ‘box’ is brown and has been resprayed brown but not in the original shade. Near enough will do in this case.

The spare monitor is now in the LCP and will replace the U/S monitor when lifting power is available.

Away from Cosford the refurbishing of fittings continues. And returned to the LCP are the securing plates for the leather straps that secure the canvas roof awning, new leather straps and the securing plates for the canvas covers over the roof joins.

Pete H

Workday 21st August 2021

T86

Our main focus for the day was the replacement of the three ‘on-launch’ waveguide horns at the corners of the T86 cabin. When our T86 was recovered these were missing, literally snapped off the cabin walls shearing the securing bolts and waveguide sections feeding the horns. This was probably down to the attention of metal thieves many years ago before the radar came into our care. Fortunately we were able to recover three replacement waveguide horns from a derelict T86 on the North Luffenham airfield and these are now being fitted. Dave and Pete’s task was to restore the mounting bolt holes for the horns and deal with the sheared studs and twisted waveguide ends.

Mounting and waveguide connection.
Initial fit of one of the horns

This restoration task is work-in-progress. To enable the restoration of mounting holes a repair kit has been created as shown here.


The T86 aerial assembly was tilted back to enable further access for painting. Note. Several assemblies from the aerial system have been removed and restored ready to be refitted.

LCP

It can be confirmed that the display fault is due to a U/S monitor. A spare will be taken to Cosford this coming Saturday and if time allows some fault finding will be carried out.

Pete H

Activity Update to WE 20th August 2021

This is a compendium update of activities up to August 20th

T86

The Tx and Rx reflectors have had a coat of black paint (for now), see accompanying photo.

We are nearing the conclusion of the refurbishing and painting of the aerial assembly and pedestal platform but it does seem like a never-ending task due to all the waveguide runs and inaccessible places. Still to do are reassembly of all the items removed, JA aerial, In-Flight aerial etc. which is a two-man job.

Some parts of the aerial system also require the aerials to be tilted back to finish the painting; this to is a two man job; one on the brake switch and one on the hand crank to wind the aerials in elevation. Moving the aerials in bearing is not a problem, as long as the brake is off!

Aerial positioning and control (bearing) Part 1

In the odd moments I get I’m still trying to unravel the mysteries of the bearing brake system and the associated sector, end stop and limit switch operation. A total of 14 microswitches (I think). I know what switches should operate and when but that’s the start of the problems in that the synchro dials that indicate the mils of the aerial position do not tie up with the physical position. SJ operates at the vehicle centre line (straight out over the rear of the cabin) and the corresponding mils should indicate ‘0’ but they don’t, they indicate 24xx or something around there. Is it a set up problem? Of course when operating the T86 operationally you never actually checked the mils reading for aerial positions, or I can’t remember doing it. This photo shows where the various microswitches are located, they reside on the rotating pedestal shaft, the Bearing Stop Unit and the Switch Unit Bearing (the Geneva Mechanism and it microswitches sit below this unit).

Also see the Pedestal Assemblies drawing here.

Aerial positioning and control (bearing) Part 2

To add to the headache….. With the aerials at ‘0’ and SJ is operated (closed) by a small spigot on the main pedestal shaft the Sector the Limit and Sector lamps are out on the Pedestal End Stop Indicator out, sounds correct. So why is the SA /SB Lamp on, this lamp should only be on in an end stop? Why is the Limit Override lamp always on? Operating the Limit override switch on the console makes no difference but the Limit Override lamp goes out if the Bearing Brake is applied on the Console. I haven’t found a description of when the lamps come on and in which sequence (yet). Only answer is to finish my redrawing of the circuits controlling the lamps on the Pedestal End Stop Indicator.

I read up on a couple of APs; the story you get depends on which AP you read.

AP 1: Move the aerials to the Datum Zero Line on the trailer and if required release the clutch under the coarse mils dial and adjust to zero.

AP 2: Move the aerials to the Centre Line. Check the micro switch(s) operation at the mils they operate at and allow for any difference from the mils reading at the Centre Live from zero (implying the mils are not zero at the centre line).

Here is the engraved notch on the pedestal shaft that indicates the Centre Line.

The first thing I don’t understand is: When moving the aerials to around 200 degrees (CW or CCW) the Limit lamps light and with a bit more movement the Sector lamps light. That doesn’t look right to me hence the checking of the mils dials to see if I was actually at the centre line when starting or if I was 360 degrees out. The mils reading is not desperate if not zeroed but I currently can’t relate it to the mils at which the microswitches operate. The Sector lamps are illuminated by SC/SD in the Switch Unit Bearing while the Limit lamps are illuminated by SM/SN on the pedestal shaft.

All I want to achieve are some straight forward notes for us and anyone in the future who will be moving the aerials and what the indications mean but mainly to prevent someone ripping out the cable winder.

The clockwise and counter clockwise sectors of the aerial movement in bearing checked. Outer sector indicators on the console checked, see below.

A suspected fault with two indicators on the pedestal indicator unit remains to be investigated.

Protective wooden covers were constructed for the pedestal roof as painting of the roof commences. New duck boards have been constructed for the roof but these will only be fitted once restoration is complete, see accompanying photo.

LCP

Simulator run up for a check and all booted correctly. The simulator was left to run while other work was carried out.

Returning to check the simulator I found a fault had occurred on one of the display monitors (Technical Supervisor position).

The monitor is not suspect but a CHARGE (video display processor) Pixel Store is the more likely fault and I will swap the CHARGE Pixel Store with a spare, or extend the fault finding, spares are available.

Pete H

Work Day 31st July 2021

T86

Many small tasks progressed with, painting the waveguide desiccator clamps black, sections of not easy to access waveguide, also a start made painting the waveguide supports on the aerials.

Stripping old paint off the stainless steel positioning spigots on the aerial beam was carried out.

A problem with repainting the aerial assembly is that it shows up items we would not have considered for refurbishing. An example; the Perspex covers for the aerial elevation position indicators, see below.

The metal covers and the Perspex viewing windows have been removed for refurbishing away from Cosford and the corrosion shown in the photo will be treated before reassembly. Usual problem with refurbishing such items, dirt and old paint.

No apologies for another photograph of the aerials.

LCP

The remaining ‘R’ clips have at long last been fitted to the roof support struts! A spare Harrison X150 amplifier in the LCP has been removed for testing. We have a total of three X150 Boost Blast amplifiers, originally thought to only have two!

The simulator was not run yesterday.

Away from Cosford

LCP:

A few long outstanding tasks remain to be tackled and a start has been made. The LCP roof join canvas securing clamps are being refurbished and painted. This photo shows three of these clamps, stripped of paint.

They are copper bars with brass on one side and besides old paint they are heavily tarnished. The clamps must have been nice and shiny when new! There are 33 of these clamps (I suspect there are a few spares). Also being refurbished are the alloy plates that secure the leather retaining straps for the canvas roof cover. Needless to say the original overall canvas roof was not with the LCP and the canvas roof join covers have completely rotted.

T86:

For the future display and moving of the T86, plus current refurbishing work, it is important to understand aerial movement, braking, aerial removal and pedestal retraction. The aim is to interpret the information contained in T86 APs and create a set of notes on these topics relevant to the operations just described. Currently, -24V supply has been restored (not using the original D Rack and F Rack power supplies) so that indicators, pedestal microswitches and aerial brakes operate. This photo shows the Pedestal Indicator Unit, the lamps indicate aerial positioning and overrides.

A priority task is to document when these lamps come on in relation to the bearing position indicator, dials graduated in mils. One example, the Limit Override lamp stays on irrespective of operating the Limit Override switch on the console (D Rack). Why? The T86 APs have wiring diagrams and testing procedures but we do not have information on the processes and procedures we need – unless we don’t have the right APs!

Pete H

Work Days 19th and 24th July 2021

19th July

T86 Pedestal Roof

More rubbing down before applying a primer. As the pedestal roof is steel I used a vehicle chassis primer so it’s now a nice overall grey.

Next visit I intend to cut some ply that we have liberated and cut it to size to give the roof surface some protection as we continue to work on the aerials. We have a circular saw but to cut the shape required I have now invested in a new reciprocating saw with plenty of spare blades!

I was getting a bit concerned about the damage to the hardwood rubbing strake on the T86 doorway caused by the steps. Some handy scaffolding just the right height provided a staging at the T86 door.

One job which I never get around to is sorting out all the T86 bits (mainly from the aerial assembly) that have been refurbished. To this end there are now several plastic storage boxes in the LCP for the purpose of getting them all together. Once sorted I can stop worrying about things like ‘where are the waveguide desiccators, they must be here somewhere’.

LCP Door Seal

The Engagement Controller’s escape door still has its seal attached which has now been removed. Pulling/cutting the seal away from the door (the seal is fixed to the door and not the cabin) left all the original Bostik glue in place which was removed using an abrasive flap thing on a drill. Once cleaned all remains of glue on the inside edge of the door in which the seal sat was primed with an etch primer. One photo shows a detail of the seal before removal (not in a good condition) and the second a view of the complete door with its edge primed. Note the door mat in the photo. The problem; the original ¼ round seals are no longer available so a search for a suitable alternative is under way.

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The simulator was run up and ran for a good period. No problems in the boot sequence, no errors on the FT81 and the displays were all good. The simulator ran perfectly. Long may it continue.

24th July

It was good to be joined by Pete M and Ian for company and we got lots done. Pete and Ian did the work while I got on with collecting together previous refurbished items, mainly from the T86, which were spread around in various boxes in various places. Lots of items found which I hadn’t seen for a long while like the clips for the RF Receiver cover.

T86

Pete M has made an excellent job of repairing the hole in the steel roof below the pedestal.

The hole was caused by severe corrosion caused by water collecting on the roof which was held there by debris, mainly rotting leaves, trapped under the wooden decking slats while the T86 was in open storage. Our location ruled out welding a patch over the hole so a steel plate was riveted and sealed with a weatherproof adhesive sealant.

Ian prepared and primed the base section of the pedestal.

The lighting in the hangar could be better so Ian did mutter something about painting by torchlight! Now the base is primed we can look to replacing the Radar Absorbing Material (RAM), a rubber sheet made into a sandwich with a metal mesh. Ian finished the pedestal base in good time so he then set about painting the RAM on the pedestal frame using a rubberised roof sealing paint.

The original RAM was left in place but its surface was cracked due to the many years in the open and exposure to the elements. The first task in restoring the RAM is to skim it with weatherproof sealant and lightly rub it down before painting with rubber repair paint. Result, it looks like new.

LCP

The Harrison X150 amplifier was replaced with a spare on the basis that it’s good practice to give spares a good run, the original amplifier remains serviceable. We have a third X150 spare which will be tested next week.

Following his roof repair Pete M set up an exercise on the simulator to emulate engaging Concorde! He will refine the exercise after getting hold of accurate Concorde performance data. A good test of the exercise will be to track Concorde as a crossing target through zero doppler. The simulator remains serviceable.

Pete H

Mid-Week from ‘3rd Line’

CHARGE:
I’ve now dismantled the CHARGE test rig so I can get some space back in my office. Only one task remaining and that is our spare CHARGE controller has a defective AVX capacitor somewhere on the PCB. The controller works fine but across the +5V the resistance is 37 ohms which we can live with on a spare for now, should be around 150 ohms. I’ve tried a new technique but yet to prove it, using this temperature gun.

The gun works fine so in principle a low resistance AVX will get warm/hot so I should be able to detect the faulty capacitor. Problem is that some adjacent TTL chips all get hot under normal operating conditions so could mask a faulty capacitor. One day I’ll revisit this controller and see if I can detect the problem before unsoldering each AVX in turn until I strike lucky.

Harrison X150 Amplifier (Boost Blast):
As mentioned last Saturday I have removed the installed X150 Amp as it looked decidedly tatty (the LCP must be looking pretty good if I’m doing this sort of thing). Here is a photos collection for you to refer to.

Harrison X150 and X300 Top Cover
X150 Front Panel
X150 Internal
X300 Front Panel (original)
X300 Internal (original)
X300 Front Panel (modified)
X300 Internal (modified)

The case of the spare X150 has previously been opened but I assume it is
serviceable so will take it to Cosford on Saturday and await we will give it a run. We also have two X300 amplifiers which could be used in an emergency when fixed as they have U/S labels on them. Also, both X150 and X300 amplifiers regularly appear on eBay.

One X300 is interesting as the original innards have been stripped out and two ‘new’ ILP audio amplifier modules (one for each channel) have been fitted; it has unacceptable hum while the other has one channel U/S. I can test once I
get some test leads organised.

We do not have component-level schematic diagrams for these amplifiers yet, only the functional schematics on the lids; perhaps someone out there can locate copies for us.

Pete H.

Work Day 10th July 2021

Type 86 Radar:

As mentioned previously I’ve now actually started on filling the corrosion dimples on the cast iron work on the pedestal roof. A rub down of the filler (a chemical metal filler used for car body repairs) will proceed a repaint. The filling is being carried out in stages so will take a few weeks. Two photos here show before and after filling.

Last week I applied corrosion treatment to the waveguide desiccator securing clamps so this week they have been primed ready for a top coat. Photo below.

The waveguide desiccators have already been refurbished and are in a box ‘somewhere’ on site.

I have completed the refurbishing of the noise tube covers (photo beolw) from the RF assembly. The colour is Dark Admiralty Grey. The original paint was badly faded due to exposure to the weather when the T86 was ‘stored’ by the RAF Museum with the RF receiver cover removed!

Corrosion on transformers in the RF receiver, treated last week, have now been painted.

Here is another photo of the Aerial Assembly as restoration progresses.

Launch Control Post:

All the hex button head rack screws on the computer and I/O racks in the LCP have been replaced with slotted screws. The hex button headed screws were affected to varying degrees by corrosion. Photo below of new rack screws.

The original Harrison X150 audio amplifier is looking decidedly tatty so has been removed. A spare, which hasn’t suffered from surface carrion, will be fitted on the next work day.

Off Site:

The CHARGE Pixel Store recently repaired still had an unserviceable AVX capacitor; indicated by a low resistance of a few ohms between +5V and 0V . The only way to resolve the fault was to unsolder each AVX capacitor in turn and check its resistance. I had high hopes that this trial and error approach would find the defective capacitor without having to desolder them all, unfortunately the fault went down to the last capacitor checked!

Pete H

Work Day 1st July 2021

The first job today was to make a skirt for the pedestal to stop the grot dropping in when we work on the aerials. I’d finished the internals of the pedestal with red oxide and don’t want it to get dirty! The ‘skirt’ is shown in below.

Most of the day was on corrosion treatment, preparing the clips for the
waveguide desiccators and the pedestal roof. The plan for the pedestal roof is to use body filler to fill the masses of small dimples on the cast iron work . A repaint will then give a smooth surface rather that allow water to settle in the dimples -should it be exposed to the weather again. I also removed some fittings from the aerial system to refurbish at home. The aerials are looking good but apologies for getting me in the shot !

Here is the state of the T86 aerials when we recovered it and after the first clean.

I plan to get organised on the T86 drawer handle sand other bits that need re-chrome plating this coming week; here they all are.

As you can see there are a lot of items to be done and this work doesn’t come cheap. Donations towards it being undertaken would be most welcome, thank you.

Pete H

Work Day 26th June 2021

On Site
Time today was spent on the T86 with cleaning, corrosion treatment and some painting. The plastic corrugated cable hoses on the aerial assembly have now been cleaned with sugar soap and rinsed. A task needed as dirt was filling up the corrugations in places!

An inspection/alignment cover was removed in the base of the pedestal and the accompanying photo shows an exposed gear wheel covered in a granular form of corrosion (rusticles?).

The granules can be scrapped to loosen them and then vacuumed out carefully avoiding the oil bath. Only this one section of the gear wheel was visible but once the team are back on site the aerials will be moved to check and remove any further corrosion granules.

The base of the pedestal continues to be cleaned and red oxide painted.

Away from Cosford
We have an unserviceable CHARGE Pixel Store, a spare is available so the simulator is not affected. To fault find a Pixel Store a test rig is set up to use one using a serviceable CHARGE card to drive one display.

We do not have any test software or routines to test CHARGE cards so the approach is to set up the test rig and create a set of reference waveforms (screen shots from a USB driven scope) at key points in the card’s logic We then swap the U/S card and look for differences. This process is usually reiterated a few times but has been successful in fixing two Pixel Stores in the past. With a U/S Pixel Store fitted the monitor display has lines laid over the firmware display as seen below .

The firmware display appears in the LCP prior to the Bloodhound software booting and is generated by CHARGE, not the Argus 700 computer.

Pete H