First I have to apologise for the lateness of this report. Illness towards the end of January followed by nearly 2 weeks in hospital in February and subsequent recuperation have combined to put me out of action for some time. Now I'm trying to catch up.
Since the last report in July 2011 we have made significant progress in the repair of the centre wing section. The top skins on the port side of the wing were nearly completed at the time of the last report and they are now ready for final riveting up. But this can only be done once all the repairs aft of the rear spar have been completed as the top skins on the wing overlap skins aft of the rear spar.
On the starboard side of the wing all the new tank support ribs have been assembled into the wing tank bay and with the aid of simple drilling jigs drilled off ready to take the skins. The skins have been cut out and most of the drilling out has been done. Prior to this the complete rib which sits between the tank bay and the landing gear bay was removed from the wing because it needed many repairs which were not practical in situ. The multiple damages to this rib enabled us to remove it from the wing by twisting and bending it. But it was realised that once repaired it would be physically impossible to reinsert the rib into the wing so a small section of the rib where it connects to the front spar was cut-off and repair plates were made and pre-drilled before reassembly. The following photographs show the ribs being installed and the wing with skin temporally in position for drilling out the rivet holes.
There are many areas of damage on the underside of the centre wing particularly on the port side of the rear spar. These look as though they have been caused by the wing being dropped onto rough ground at sometime in the past. Repairing has been quite difficult as we do not wish to remove a single large bottom skin panel aft of the rear spar on each side of the centre wing. But progress has been made and a number of in situ repairs have been completed. Particularly difficult are the pivots for the flap operating cable mechanism and associated pulleys all four of which are completely seized on their tubular bearings and in different positions so that if we left them as they are we would only be able to reinstall the flaps in different positions on each side of the aircraft. Removal of these pivots buried deep into the wing has been quite difficult. The first one we removed carries two pulley wheels which despite copious amounts of freeing agent and differential heating with torches we were quite unable to free. In the end we had to cut out the long tubular bearing that runs through the centre of the pulleys by slotting it with a hacksaw along its length on the inside and collapsing it in on itself in order to remove it. We have located a supplier in the UK where we can obtain exact matching diameter tubing from which we will have to new make new bearings for all four locations. With so many repairs needed in these areas it will be some time before we can finally rivet up the small top skin panels aft of the rear spar and then finally rivet up the large tank covering skins between the two spas. Some of the repairs are shown in the following photographs.
In between all these repairs we have also spent some time cleaning the rear and front spar surfaces paying particular attention to the steel components which have been treated with an anti-corrosion￼￼ ￼￼￼compound recommended to us by one of the major UK aircraft museums. With this treatment completed and all the aluminium surfaces cleaned to remove all loose paint and dirt, green primer paint has then been applied. Where the multiple laminations of the bottom spar booms point upwards we found that the original gaps between them had been filled with some sort of black compound much of which had disappeared over the years. This has all been removed and will be replaced with a modern commercial sealant. We assume that this sealant was in place originally to prevent any rain or condensation getting into the gaps between the steel laminations and causing corrosion.
￼￼￼￼￼Part of one of the small bomb bays from the port side of the centre wing before and after repair. Its removal from the wing was simplified by the ability to fold it around the damage splits, but re- assembly into the wing required it to be split in two and rejoined after the reassembly.
David Bradley 1st March 2012