A few years ago I was galvanised by the closure of Millom to take this shed on as a restoration project
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The fuselage wooden shell has now been stabilised, repaired where necessary and returned to the correct shade of blue that it left Air Trainers Ltd in mid 1950s.
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During it’s time with the ATC unit it had been modified to a simple flight simulator by first removing the radio simulation equipment then the engine simulation gear along with prop rpm/carb heat controls.
Cut and shut had been carried out on the panel and a “stuff it where it fits” installation of replacement instruments.
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The main panel has now been repaired/refurbished, instrument positions corrected and link trainer instruments used to replace non simulator components. A temporary structure has been fabricated to hold the P.12 compass. A new face plate will be installed into the ASI to give the correct 20 – 300 knot device for the piston trainer variant.
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Now the request.
The top right quadrant of the panel has two empty holes which should be filled with two identical fuel contents gauges. To date I have failed to source the correct instruments to install in this space. Anyone got any leads for instruments up for disposal?
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The above page from the AP shows the correct version of fuel contents gauge needed.
Also missing is the Boost Gauge and any source for this would be gratefully received.
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Again the instrument is shown on the above AP page.
Regards
Ross
By: WG-13 - 25th January 2014 at 18:54
Back in the mid-1970s there was a complete D4 with 152 (City of Hull) Sqn ATC, but they had neither the space to operate it, nor the skills to restore it, sadly. I’ve often wondered what became of it.
By: Ross_McNeill - 25th January 2014 at 11:49
Cheers for the encouraging words gents.
I’m hoping to sow a seed which will see some slumbering Blue Boxes return to wheezing life in a few museums.
There was a comment on this forum that a Vampire and a Link Trainer was the standard starter pack from the RAF for a fledgling museum. The numbers of preserved Link examples gathering dust in either a corner or a rapidly reducing floor area of museums all over the world bear witness to the accuracy of this comment.
What I would like to sow is the thought that the D2/D4/ANT example lying dormant is actually a fairly simple device, very robust in construction/design that would form the ideal nursery restoration for trainees.
Materials and parts are basic fabrications that lend well to bench tasks for unskilled workers and can form part of a training lesson in both woodwork and electrical trades.
So think about letting the newbies cut their teeth on the Links – they are just sitting gathering dust (both the Links and possibly the newbies!).
With basic functions returned the museum gains a movement simulator that complements and shows genesis of the modern flight sims that can found everywhere. Running costs are minimal compared to modern hydraulic movement platforms and maintenance is in line with the family business of Mr E Link – player pianos.
I’ll continue to show a cosmetic restoration on this more complex D4 giving the basic details from the AP.
Over the next few months I will start on the base and column followed by the motion vacuum bellows.
Go on museum gents – think about it and what it could bring to your collection.
Regards
Ross
By: Wyvernfan - 24th January 2014 at 17:34
Always good to see refreshingly ‘different’ projects coming together. Nice one !
Rob
By: Fouga23 - 24th January 2014 at 16:24
Nice resto! 🙂
By: Ross_McNeill - 24th January 2014 at 15:13
Fuselage Control Box
The cockpit showing fuselage control box prior to removal and inspection.
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Electrical signals in the Link Trainer are divided into power, analogue control (teletorque signals), digital control (on/off signals) and audio (r/t and w/t).
Showing its American roots the main voltage used is 115 VAC but supplied at 50 Hertz for UK use.
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115 VAC power along with control and audio signals from the base are passed to the trainer fuselage via a rotating slip ring column in two multicore cable bundles (33 cores and 12 cores). The two multicores are terminated in two Jones type sockets.
The fuselage control box has corresponding chassis plugs and is the primary distribution/marshalling point for all the trainer electrical functions.
Where possible the power is left at 115 VAC but three sets of transformers located within the fuselage control box are used to provide 32 volt teletorque power, 12 volts for the undercarriage indicator lamps and 12 volts for the cockpit/instrument lamps. 32 VAC for the ultra violet instrument panel lighting comes from the teletorque supply.
Nine relays are located in the fuselage control box all being used to switch audio signals from the various radio devices in response to pilot selected controls.
Internally the bulk of the panel comprises of terminal strips for the power, control and audio signals while externally mounted on/off switches are provided for master power and blower.
Three R type dimmers are provided for level setting of Instrument/Cockpit and U/V lamps. A glide path setting potentiometer is also mounted beside the dimmers but this control is set by the instructor before the trainer is used and cannot be altered by the student.
All electrical signals to and from the fuselage control box are via multicore plugs allowing distribution cabling to be rapidly replaced and taken to the bench for fault finding.
The fuselage control box was removed from the fuselage to allow inspection and repainting of the internal fuselage woodwork.
Previously Link D4-030 had been modified to remove the w/t radio aids and this had been achieved by removal of the external control boxes and cabling to the fuselage control box leaving the bulk of the internal switching and power terminations intact.
The r/t circuit had been modified to use a modern external intercom and two relays had been removed to enable external headset/mic sockets to be added to the fuselage control box. Wiring for the relays had been cut short in the looms but left in situ to the terminal strips.
[ATTACH=CONFIG]224888[/ATTACH] (Fuselage Control Box showing non standard intercom mods)
With so much of the electrical distribution intact it was decided replace the removed relays with modern equivalent, until period relays can be sourced, and to joint/extend the cut wiring looms before carrying out resistance and megger checks to see how sound the original wiring was.
Despite the prolonged period of humid storage no significant defects were found with only a few terminals needing to be opened up, cleaned and remade. Function of the relays was tested by application of coil voltage and “belling out” the contact wiring. Voltage from all three transformers was proved by multimeter to be within original design limits.
One small section of fascia was stripped to treat defoliation corrosion before being primed and re-sprayed.
On completion of works the fuselage control box was reinstalled into position on the starboard side of the cockpit and a temporary 110 VAC supply from a safety tool transformer for testing purposes made off onto the terminal strip.
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The first circuits to be made live on the restoration were the cockpit/instrument lamps and the blower giving a satisfactory project achievement boost when for the first time a response is seen to switch flicking.
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A small thing in project restoration terms but the first signs of life function returning.
Ross
By: Ross_McNeill - 18th January 2014 at 13:49
In the previous post I mentioned that the installed ASI had the wrong fascia and would be replaced.
The ASI signal system in the Link is a teletorque system where the rotor of the airspeed transmitter is mechanically displaced as a result of derived airspeed.
The mechanical movement induces a voltage in the star connected windings of the transmitter which is passed by 3 core electrical wiring to the remote instruments mounted on the pilot panel and the instructors desk console.
At the remote instruments similar star connected windings mirror the initial induced voltage and cause a mechanical rotatation of the pointer in the same manner as the transmitter.
The pointer will move until the remote instrument winding voltage matches the induced voltage in the transmitter.
This gives a standard instrument that can rotate in any direction and is not constrained by scaling or limit on the number of turns.
This means that a teletorque remote instrument used in the link is of the same electrical connection and design regardless of the system it is used to display.
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Since I could not find a suitable ASI it was necessary to produce a facsimile ASI for use in the restoration.
I selected a remote bearing teletorque instrument as the basis for the facsimile ASI purely because there were three in the spares cupboard. Any instrument could be modified in the manner described below.
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The nearest equivalent dial I had to hand was from a Mk IXE ASI
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The two instrument dials were of different diameters and prevented direct fascia exchange.
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With the donor fascia removed it was easily photographed and then the image reduced in size by photo manipulation software (Photoshop) to give the desired size.
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On other instruments I have used Photoshop to alter the colours of the numerics and scales from fluorescent dial images to better match Luminous dials, used these in the donor housing to give radiation free instruments that are visually identical and installed them into public access cockpits.
Cut and paste of scales and numerics from other images can also be used to recreate instrument dials that are proving impossible to obtain.
Once happy with the dial image it is printed out on SemiGloss Photo Paper in a standard inkjet printer then cut to size.
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The dial image could have been silk screen printed onto a new metal fascia blank but for my purposes I reversed the teletorque dial and pasted the printed image directly onto the surface.
The pasted fascia was then installed into the teletorque instrument using the original mounting screws and holes, pointer replaced and checked for free movement and the glass sealed.
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As long as the printed image is protected from strong sunlight it will last a reasonable time before fading but with the image on file it is a simple task to print a new image and replace the faded one in the instrument.
Ross
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January 9, 2014 at 11:44 am