CANBERRA – PR.3 – WF922 – RESTORATION LOG

Canberra PR.3 WF922 at Midland Aviation Museum – Update June 2005

Malcolm Lambert

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June 2005

Because of the nature of these continuing, in-depth, renovation reports, this and subsequent articles will tend to address more specific and detailed areas of the project. Hopefully this will allow the reader to become more acquainted with the areas of the aircraft that are not generally seen by the normal museum visitor. In my opinion these areas are probably as important in the process of recovering and maintaining an outdoor exhibit in good condition. One of our unsung aims is of course to try and inspire future generations to maintain these machines in as good a condition as time and money allows. This is not just specific to WF922, but to any preserved aircraft that the reader can possibly give help with, help that will fire the imagination of younger generations causing them to approach their nearest aviation outlet and volunteer their services. If this can happen, the current custodians will have the satisfaction of knowing that their work is being continued by the next generation of enthusiasts and that their, if not “national”, treasures are in safe hands for the future.

Wing Equipment Access Panels

Back to the job in hand. To keep this account chronologically accurate this update will concentrate on the spring period April to June 2005. April however was not a good month for outside work with continual downpours and high winds. No one in their right mind climbs up and works on the wet topside of an aircraft unless they are paid handsomely to do it (or are in “Government Service”). But the wind can often dry out a soaked aircraft in a very short time. As I had a lot of work to do on the main wing equipment panel fixings I took every opportunity to prop up the steps and get the drill out as soon as the weather permitted. Because the aircraft had stood for some nine years at Marshalls and the previous Major servicing was probably some three years before that, when the time came for the museum to remove this panel, a lot of the panel screws had firmly rusted themselves to their anchor nuts. The museum members were left with no option but to drill the heads off to remove the panels. Now the time of reckoning had come for those rusty anchor nuts (on the equipment panels anyway). One by one, on both the port and starboard, side the anchor nuts were replaced. My only concession to working on a non-flying aircraft was that I used Pop rivets instead of solids to secure the replacement anchor nuts. This was occasionally allowed in service but had to be recorded and rectified at the next major servicing (good old ASF). Quite a few of the anchor nut locations were located in almost closed box sections and would require major disassembly to put solids in anyway. Others on the leading edge strips were in completely closed box sections. On these the rusted screws had to be carefully drilled out and re-tapped, not easy and I broke quite a few cobalt drills in the process. In the end I had a 100% success on all four of the panels which even I was surprised by. Of course every one was put back with copious amounts of oil to keep them rust free for the foreseeable future. But I do have the panels off fairly frequently anyway to gain access to other parts so they are kept in an “in use” state.

WingPnl
WingPnl

Wing Equipment Access Panels

Luckily about the same time I was working on the access panles the museum took delivery of some 16 SWG L72 sheets of duralumin enabling me to fabricate a new upper wing port inner equipment – panel roughly a metre square. The badly corroded magnesium alloy sheet, that had been put on at some time by museum members, was consigned to the recycle bin. When the new panel was painted and stencilled it looked as good as the original would have done back in 1952. Just these couple of jobs took about three weeks of work but hardly a soul will ever see or know about.

Whilst the equipment panels were off, a small but important job was the fitment of the forward wing attachment bolt. Its purpose I suppose was to stabilise the front of the wing to prevent any flexing as it is only a half-inch nut and bolt, nowhere near the size of the main attachment pins on the main spar section. Nonetheless they were missing from both sides of the aircraft. Both sides took less than an hour to fit, including the re-fitting of the panels, as, thankfully, the bolt holes were perfectly lined up.

Fwd wing bolt brkt

Forward wing attachment bolt showing empty bracket (left pic)
and with bolt fitted (right pic)

On a slightly different tack I removed the one to four filler caps to free them off and clean them, one of the reasons for doing this was to establish which fuel tank it was that Marshalls had removed. This aircraft had obviously acted as a donor for another of their aircraft for quite a few bits and pieces. It wasn’t rocket science to use a torch and see what tank was missing and it turned out that it was the number three tank. This is obviously not on my itinerary for replacement, but if ever tanks become available the museum would at least know which one it needed. With the fully working filler caps re-fitted and then covered with speed tape to keep the rain out they should be good for a few more years. The number five tank cap I know has almost disintegrated and will have to be replaced when one becomes available

G4B Compass and Mileage Recorder
Not much work has been done internally in the last few weeks but one job that has been was the replacement of the noisy G4B pilot’s gyro compass with a brand new item from the 1960s. This runs very quietly compared to the old. Also, the replacement doesn’t cage itself on rundown and send the compass card spinning wildly for about five minutes.

F95 Cntrl
Fitted
G4B Compass and “Miles Gone” Indicator

A “miles gone” indicator was obtained and fitted to the navigator’s panel (again as per WE139), although to be completely honest I haven’t a clue as to where to wire it up to at the moment. Like most of these things however it will be fathomed out eventually when I find the correct wiring diagram. A new cockpit light was fitted above the navigator’s Green Satin indicator as well. This was to bring WF922 more in line with Hendon’s WE139 interior photos clearly showing a lamp in this position.

Seat and Pilot’s Harness
A chance visit by an ex RAF armourer showed me how to reset the fired barometric release on the pilot’s seat to enable me to fit the harness ends in to the seat’s harness release clip. This, along with a completely new harness release cable and clip was fitted because the fraying of the outer metal sheathing on the old one was a risk. This now means, that you can safely strap someone in to the seat – and release them too if you want!

Baro Release
Harness
Barometric Release Unit and Pilot’s Seat Harness

The only other internal job tackled this time was the re-working of the pilot’s lighting dimmer panel to incorporate the emergency lighting circuit. Details of this system were not available when I did the initial wiring up of the panel last year. This emergency lighting circuit is powered by a feed from a small 3 volt wet battery located in front of the rudder pedals. When in use it powers two yellow lights either side of the main instrument panel and a feed to the emergency compass light.

Underwing Root Fillets
Now a job that I had been dreading but it eventually it worked its way up the priority list. I needed to undertake the manufacture and fitting of the port and starboard under wing fillet strips between the wing and the fuselage, (to hide the join so to speak). Originally made out of one strip of metal about 2.5 inches wide at its widest point and about 10 feet long, it was a puzzle over the best way to restore these fillets. An original one-piece fabrication was out of the question so I made it in two lengths with a smaller, 5 inch strip for the very rear section. This method put the new fabriction within the capabilities of the museum’s guillotine and made the initial cutting job that little bit easier. Nothing is ever simple though and the making of these strips was a true fitting job because the width of the strip varied as it progressed aft to take account of the tapering fuselage shape. A great deal of measuring, filing and trial fittment was involved which, of course, included trying to sort out (and drill and tap) which of the anchor nuts were still usable to hold the strip in place. All of this going on at a very awkward height that had you kneeling one minute and legs straddled to reduce your height the next. Thankfully, as with most things that are persevered with, the task was eventually finished.

Port
Starboard and Port Under-wing Fillet Strips

The strips were then primed and painted to match the rest of the underside of the inner wing section. Because of the high strength factor required for flight, the pitch of the screws on these strips was about one inch apart. WF922 obviously doesn’t need this strength factor for these root-fillet strips now so I settled on about four inches of pitch and just attached by screws on the wing side. The anchor nuts attaching the fuselage fillet strips have not weathered well and to replace them would mean taking the wing off – and I am not about to do that! The topside strips are in place and they will require some work done on them to secure them more firmly. This task will be tackled during the next phase when I have replaced my worn-out cobalt drill bits.

Undercarriage Fillet Doors
Small main under carriage fillet doors are attached to the engine cowling and cover the gap between the upper end of the oleo leg and the cowling after retraction. These doors, on both sides, had previously received a coat of paint, but I did notice that they had quite a few corroded rivets in need of replacing. So out came the drill again and all the rivets that were showing signs of distress were removed or the holes cleaned out of the missing rivets as required. Originally these were solid rivets, closed, I expect, in the comfort of a dry production line environment with pneumatic rivetting equipment. No such engineering luxury on an outdoors static airframe though. For replacement nicely countersunk Pop rivets were used to fix the double-skinned doors together again. Additionally, a small strip of metal had to inserted as a repair on the port door lower section to strengthen an area where corrosion had opened a rivet hole and split the metal. After it had been all sanded down, primed and painted it looks like part of the structure that was always there.

Before
After
Main Undercarriage Fillet Doors – Before and After Treatment

You can gather from the detail of renovation reporting here, (explained in the opening paragraph), the depth of recording in this and following reports are going to. Apart from just being a Log of my activities on WF922 it is hoped that these Progress Reports will serve to encourage other renovation and refurbishment enthusiasts of the UK’s aviation heritage. Enthusiasts who possibly, if they were in my position, would go down the same route given the same goals but perhaps for one reason or another cannot participate in the physical side of things. It must be remembered however that all this work on our PR.3 Canberra, WF922, is taking place on a static museum exhibit. It is NOT an attempt to get it into airworthy condition again, not even an attempt to make it taxiable. Some of the measures taken and repairs carried out are cosmetic and I wouldn’t want anyone to think otherwise.

High Energy Ignition Unit (HEIU)
Keeping the upper equipment panel screws exercised, as mentioned earlier, the starboard outer panel was removed to enable the fittment of a new High Energy Ignition Unit (HEIU). This had been removed some months earlier because it kept blowing fuses when the re-light was tried. With this fitted and tested the ignition units now function correctly when either a start cycle is selected or the relight buttons pushed. (Once again it makes a satisfactory “clicking”. Webmaster)

Pipe Cladding and the Cut Loom
Whilst delving inside these panels it is always interesting to note where the water collects and drill small holes to allow it to escape if it is forming in large quantities. I also take the opportunity to squirt oil over all the screws, nuts, and pivots that, who knows, might perhaps be removed at some time. Whilst I think about it when I had the inner panel off on the starboard side, I did start on the replacement of the jigsaw of fibre glass hot air pipe cladding. Obviously when it was removed some 21 years ago no one thought that anyone would be stupid enough to want to replace it so it was just piled in a heap inside the panel along with all the jubilee clips – but at least “they” kept it, that’s the important thing. I still have a few pieces “spare” but I suspect they belong in a similar position under the port inner wing equipment panel. Whilst in that area I removed the starboard main electrical feed that goes from the wheel well forward bulkhead direct to the main control panel. Or it did before it was sawn through close to the wing break. A pity really because it only took me five minutes to undo it correctly and unless the wing was hanging on the crane there was really no excuse that I could see for cutting it through. Now here, we are talking of a seriously thick cable capable of carrying some 400 amps so it is going to be a challenge to be able to reconnect it satisfactorily. Once again a purist would want to replace the whole run, with belly tank down etc. I took the view that it could be classed as a “Battle Damage Repair” that would suffice until the next major servicing. Although it might never take any current again I am satisfied that a good repair was made. I am going to try to get the use of the correct hydraulic crimping tool and terminal ends or splice, it may take a while as I only ever saw and used the tool once in 22 years of service and they were always held on a one per station basis. Made by Amp I think, they have been taken over by an American company but feelers will go out. Failing all of that I might make a sleeve out of copper tube and try soldering it.

Glass Fibre Cladding and the Cut Electrical Loom

Anti-Collision Light
Another one of those small but constantly visible jobs was the correct fitment of the underside anti collision beacon, if you study the recovery of the aircraft from Marshalls I don’t think the beacon was fitted at that time and the mounting might have received a small knock during the move as I noticed the area was misshapen when I first inspected the aircraft. I had made a start on correcting this but because of weather had had to give up. A renewed effort was made and the lamp was eventually persuaded to fit and all three mounting screws were safely screwed home. Just one of those finishing touches that gives a lot of satisfaction after completion, and yes it still works.

Anti-Collision Light Fittment

Painting
I have deliberately kept the subject of the painting of the aircraft until the last section of this report because it’s a very boring subject to write, and I therefore assume, to read about, but progress was made on the top of the wings and fuselage and it’s now presentable, I would hesitate to use the words finished. A lot of the stencilling has been redone or recovered after masking and a start has been made on painting the underside of the wings outboard of the engines. I wouldn’t say the painting is the best but my philosophy is that if it protects I am achieving my aim, if it looks good then that’s a bonus. Like any good masterpiece if you look at it very closely in minute detail it doesn’t give a true perspective of the overall appearance from a distance where it is best viewed. My last word on the matter, except that the colours for the dayglow and camouflage seem to have passed muster with the photographers of the aviation community and this is unfortunately rightly or wrongly how non flying renovations are almost always judged. Anyway I am hoping that the webmaster will display some of his latest photos of the aircraft (OK. See below. Webmaster) to show that the painting is fulfilling both functions of protection and presentation to my best ability.

Shining

External Views (Click pic for larger image)

Main Wheel

Starboard Main Undercarriage and Wheel

The work continues. For example, some time in the future the tip-tanks have to be removed to allow the wing-tip navigation lights to be properly serviced. But that’s all for this report. Now that you are acquainted with the refurbishment process, come and see WF922 at the Midland Air Museum, you will get a warm welcome.

Malcolm Lambert
Midland Air Museum
June 2005

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