Work Day 23rd October 2021

T86

The last piece of RAM was fixed to the base of the pedestal.

The next work day will see the joints between panels sealed as well as bottom and top edges. Care is taken to ensure there is no possibility of water ingress under the RAM as was happening before restoration took place.

Work is now focused on treating corrosion, priming and painting the T86 chassis starting with the wheel arches and running gear.

It is obvious that the chassis and underside of the cabin has never been repainted since new, little of the original paint remains.

Preparation of the tow bar for repainting was completed.

The following photograph shows an unusual angle of the aerial assembly. As is the norm, any item that can be removed for refurbishment has been including the cover for the top junction box. Note. All cables for the aerial assembly are in their stowage positions and no attempt will be made to reconnect to the junction box due to the condition of the plugs and sockets.

LCP

The simulator was given a run and is serviceable. That said there was one mysterious trip of the main RCD. Simulator run up again and all ‘S’. The suspicion is that the trip was caused by earth leakage through a RIFA filter (EMI Suppression) capacitor in one of the power supplies, a well-known problem. The X2 metalized paper RIFA capacitors are being replaced gradually with alternative polypropylene (MKP) X2 capacitors that have a polypropylene (MKP) dielectric, a dielectric more resistant to our damp location. If time allows a RIFA replacement program will take place over the winter months.

Post Script

Never one to sit still Pete H managed to squeeze in a few hours the following day, Sunday 24th October! [Ed]

I cleaned up the chassis under the wheel arches best I could and found the original chassis ID label, you can make out some of the details:

Rubery Owen 7 ½  ton radar, FV2624(A). F.V. R.D.E Spec 926L? Cont. A31183GW

The Swedish chassis label is mounted on the from of the trailer, also attached.

Rubery Owen still exist so I’ll ask them if they have any archive information on the chassis.
(https://en.wikipedia.org/wiki/Rubery_Owen)

Pete H

Could Bloodhound Have Shot Down a Concorde?

It’s not all hard work at Cosford during restoration days with our Bloodhound Mk2 Launch Control Post seen above.

Last Saturday time was taken out to create and run an exercise to engage a high-level threat by a Soviet TU-160 bomber which has performance parameters close to that of Concorde.

It is believed that Concorde was used in a Cold War exercise to simulate such an attack. There was certainly a Concorde chase down the North Sea at some time when a Lightning was the only fighter at the time that could catch and overhaul Concorde.

Note that images below were not from this particular engagement simulation.

Initial  conditions set in the simulator for the exercise were:

Echoing area: 20 square metres (it’s a big bird)
Bearing: 350
Height: 56k feet
Range: 60 miles
Track: 120
Speed: 1150 knots (approx. Mach 2 at 56k feet)

HOLDFIRE
Showing an RAF Bawdsey Missile Engagement Zone

Section at full readiness, missiles prepared and ready to fire.

Engagement: 

FREE TO FIRE
Showing an RAF Bawdsey Missile Engagement Zone

The missile was fired at a range of about 55 miles. and the radar doppler would have been displayed to the Engagement Controller

An example radar doppler display showing missile and target

The interception occurred about 80 seconds later, just before the target went zero doppler and the target would have been destroyed.

NOTES:

  • Increasing the initial bearing or range or decreasing the track towards 90 degrees would put the engagement OUT OF FUEL RANGE. Even with the initial conditions above, there is a VERY short window of opportunity to acquire the target and get the missile away before the engagement exceeds the fuel range.
  • Reducing the initial range to 45 miles would put the engagement more comfortably within missile fuel range and likely result in an interception in a tail chase (receding Doppler)

    Pete Murray

Postscript:

There was an exercise with Concorde and yes we did have a successful  engagement. Trouble is I can’t remember if I was at Green section RAF West Raynham or Yellow  at RAF Bawdsey. The missile had a longer fuel range in a tail chase due the change in its Navigation constant. 

Robert Findlater

Work Day 16th October 2021

T86

First job of the day was to finish the task of re mounting the three On-Launch waveguide horns attached to corners of the radar cabin. A task complicated by several sheared bolts. See accompanying photo, a close up of the underside of a mounting plate for one of the On-Launch horns.

The next task was to refit the Radar Absorbent Material (RAM) to the base of the pedestal. The type of adhesive was discussed, a choice between a contact adhesive and adhesive sealant. The problem with a contact adhesive was that it is a ‘one chance’ solution to position the RAM so the sealant alternative was chosen. See accompanying photos of the adhesive sealant being applied and sections of RAM finally glued back in position on the pedestal base. Adhesive sealant will be applied to the edges of the RAM material to prevent water ingress.

Once the RAM is in place the next task is to refurbish its outer surface. Due to age the rubberised outer surface has become badly cracked in places, see accompanying photo.

To refurbish the RAM a skim of rubberised adhesive is used to fill the cracks and once dry will be lightly rubbed down before receiving a coat of rubberised paint. All RAM material on the T86 receives this treatment.

Work has progressed well on the aerial system and pedestal so work has recommenced on refurbishing the T86 chassis starting at the front of the cabin which means the towing arm. See accompanying photo of the towing arm complete with ‘tools for the job’.

The refurbish starts with removing engrained dirt, old grease and lose paint.

LCP

The simulator was given a good run with a simulated engagement and remains serviceable.

Pete H

Work Day 9th October 2021

T86

Yet more painting of the aerial assembly which is like a miniature Forth Bridge. Top surfaces are now complete so next week the elevation of the aerials will dropped to zero degrees to finish the job.

With the painting job finished the next task is to re fix the rubberised absorbent material to the base of the pedestal. See the accompanying photo showing the rubberised panels roughly positioned.

The photo also shows the temporary plywood roof covering to protect new paint work while restoration work is carried out.

Work on the T86 will now move to the cabin and chassis, The cable hatch has been primed and the internal surface will be painted white.

The cable outlet for the Ward Leonards on the rear of the cabin has been repaired with fibreglass as it was badly corroded. The repair will be filled to give a smooth surface before painting.

What is required is for the chassis work is another order for Hydrate 80, a corrosion treatment product! Anyone have some going spare?

LCP

The simulator was given a good run and remains serviceable.

Two tasks continue away from Cosford:

  1. The creating of a manual as a fault finding guide. Several illustrative photos were taken of the Argus processor.
  2. Investigating the preplacement of the FT81 monitor with an LCD screen. Some evaluation work has taken place to convert the slow scan video of the FT81 to drive a modern LCD monitor, work on this will continue over the next few months. Anyone with experience with converting 15kHz CGA type video to standard VGA/HDMI, please get in touch.

Pete

Work Day 2nd October 2021

A bit of a wet day and this time of year it can be warmer in the hangar than out so the doors were closed, unfortunately that adds to the gloom.

Tasks planned were further work of refitting the on-launch waveguide horns, yet more painting on the aerial assembly and make a start on refurbishing the tow bar and finally checking PeriBus fault conditions and the errors shown on the FT81.

T86

See accompanying photo of the mounting plate for one of the on-launch which illustrates just one of the problems, a sheared bolt (lower left) that required drilling out. Such damage was caused by metal thieves whole removed the original horns when they gained access to the airfield at Cosford. There is no such thing as an easy job!

Accompanying two photos show a detail of the restoration work on the aerial system. The first shows the condition of the aerial assembly before restoration and after a clean.

The second photo shows the aerial system today. Note that assemblies have been removed for refurbishment on the second photo.

Work has now started on the chassis of the T86 with a start made on the tow bar. Usual problems with corroded bolts to be removed without shearing!

LCP

The simulator Is serviceable again after replacing the FT81 monitor and one of the console display monitors. While a few monitor spares are available to maintain the simulator but it is all too obvious that thirty five year-old CRT monitors will not run indefinitely, also several components to repair CRT monitors are no longer available, Line Output Transformers being just one but critical example. Maintaining such obsolete monitors is not a practical proposition with the non-availability of parts so work has started on how we might have to replace CRT monitors with modern displays. Easily stated but the Bloodhound simulator monitors have video signals that are incompatible with modern displays.

Another project underway is the creating of a ‘Fault Finding’ manual for the Bloodhound simulator so those with no experience can have guidance with resolving faults. See the accompanying screen shot of the FT81 monitor showing errors. What is it telling you?


Pete H

Work Day 25th September 2021

Today was all about getting the simulator running and having a good tidy up in the LCP. The last runup of the simulator resulted in three faults:

  1. RIFA capacitor blew on a G15 8S (Amp) power supply
  2. FT81 U/S no display
  3. Simulator would not boot

The blown RIFA on the G15 8S power supply was replaced away from Cosford and refitted today.

Investigation of the FT81 indicates a U/S Line Output Transformer. A spare FT81 was fitted in the LCP. Components for the FT81 are a long time obsolete and not available which means that an alternative, ‘modern’, display is needed at some time. Work has commenced on the technical requirements for an LCD replacement for the FT81. One day it will be needed.

No attempt was made to run up the simulator until some preventative maintenance had taken place. In this case reseating the PeriBus converter card for the Digital Output box, suspected problem for the simulator not booting. The simulator now booted OK but a couple of CHARGE errors appeared on the FT81. Removed three of the four CHARGE channels, DexIT’d the connectors and all was ‘A’ OK on the next simulator boot. (We swear by DeoxIT Gold for contact cleaning but it is mighty expensive!)

The simulator now serviceable again.

One of the display monitors had previously developed a horizontal deflection fault. Rseating the connectors in the monitor made no difference so it was replaced. Replacing monitors is normally a two man job but after setting up a special jig it was slid back on to its runners without any problems. The faulty monitor will be repaired off site. See photo of monitor being refitted perched on top of a tyre!

Lastly, A major tidy up of the LCP. It probably hadn’t been tidied up since the inside of the cabin was repainted.

A couple of photos of the inside of the LCP attached, as it was left today.

Pete H

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