The work to pre-fit the new top skin panel to the starboard side of the centre wing has been completed so that all the fuel tank bay top panels are ready for riveting once we have completed all the repairs on the wing aft of the rear spar. Both of the large panels overlap the circular ‘well’ in the centre around which there are large numbers of anchor nuts to fix not only the skin panels but also the semi-circular panels which seal the gaps around the edge of the ‘well’. (The name ‘well’ is used in an autobiography by a gunner/radio operator in Blenheim Mk Is & IVs in WW2 but is not referred to in any way in WW2 manuals for the Bolingbroke or Blenheim.) All of the anchor nuts have had their bolt heads cut/broken off at some time in the past leaving the now fully rusted threaded part in place and these have all been carefully drilled out and replaced with new anchor nuts.
At this stage we decided to clean out the ‘well’ and replace all the damaged wooden panelling and also the hinged doors that give access to the bomb bay below. Much of the panelling has already disintegrated and disappeared over the years so it all has to be replaced with new plywood panels.
We have started working on the damaged underside of the centre wing between the front and rear spar which also forms the top of the bomb bay. Many of the stiffener ribs in this area have been crushed flat in places and repairs to them are being done gradually in situ as their removal for repair would need the removal of fixings into closed boxed structures whose removal themselves would need some serious dismantling.
We had felt for some time that we would try to repair the damaged skin panels aft of the rear spar, particularly on the starboard side, in situ but it is clear that this is not practical as it is much easier to repair them on the workbench. Additionally removal of the 2 flap operating bell cranks which are both totally seized, is only possible after the skin panel above them has been removed so we have now drilled out the panels on the starboard side and will shortly start to extract the bell crank assembly.
Space has been a problem in the building with the rear fuselage and outer wings in situ severely limiting access to the centre wing in the horizontal position. We also need to have some scaffolding to work on the centre wing in the upright position but there is no space for it.
After discussions with BAE Systems they have offered us the use of half of an out-of-use building originally used by the airfield fire service and adjacent to the workshops we use now. This is big enough to store the rear fuselage and the outer wings together. We have been planning the move for some weeks but the appalling weather this summer in the UK has delayed the move as we do not want these components full of rain water. This move was eventually completed a few hours before distributing this news letter.
One of our volunteers has taken on the manufacture, in his home workshop, of the pilots seat which was probably taken by the farmer who bought 9048 in 1946. This is a complex piece of metal work but with the aid of basic dimensions taken from one of the Bolingbrokes at Duxford we believe we have enough information to be able to make a good replica. I hope to be able to show you some pictures of the progress in the next report.
Following supply of castings for the engine cooling gill system they have now all been machined as shown in the pictures towards the end of this report.
The fuel tank bay skin panels are now all in place. The starboard aft skin panels have been removed. The end of the innermost rib on the starboard side before removal of the skin panel (arrow in wing photo above) is shown below before removal. The rib end has been torn away and separated from the main part of the rib and the skin panel is substantially bent out of shape.
Most of this panel was never painted in manufacture (on the aircraft it was mostly covered over by the wing to fuselage fairing) and you can see that the Alclad material has suffered no corrosion at all in 70 years.
The ‘well’ is seen here from above before removal of the remaining woodwork. All the access holes in the floor should have hinged wooden doors for access to bomb loading equipment but they are all missing though some of the hinges remain. The wooden panel on the ‘well’ wall (top left) has some remaining leather loops which have petrified with age – these were used for storage of emergency rations.
Here is the largest surviving piece of the plywood ‘well’ floor which is in a very brittle state and mostly now only 2-ply as most of the 3rd ply has been eroded away over the last 70 years. Above it is a new plywood replacement. The other much larger floor panel only remains in bits and pieces.
The 2 flap operation units now visible in the starboard wing after removal of the skin panels. Their tubular bearings (which need to be replaced) can be seen above the arrows. To replace the bearings the whole assembly around them has to be removed from the wing.
￼￼￼￼￼￼￼￼Here are 2 ends of some of the centre wing under-floor stiffeners which are also part of the bomb bay roof. The left photo shows identical parts either side of the centre line – one in relatively good condition (right) and the other folded up and crushed flat as can be seen in the more detailed photo on the right. Though a very minor part of the aircraft they are very time consuming to repair - cut out the damage, make new parts and splice them in to the existing good structure. This is one of many such repairs we have to put in place.
During 2009 we reported that we needed to source many castings for the engine cooling gills operating system. Many of the gear drive casings were cracked and distorted. The latter were originally made from magnesium alloy, a material which while much lighter than the usual aluminium alloys used primarily for aircraft manufacture is more brittle and very susceptible to long term corrosion. The original casings (casing to the left at the bottom of the photo below) were die castings, but we have used much cheaper sand castings (sample to the right at the bottom of the photo below).
Some gill slides were missing and a few unusable due to cracks. The newly machined slides are shown below left. One of our volunteers has machined all these components in his garden workshop. The many fixing, pinning & shaft holes required separate holding tools for each hole as did the gill blade slits so the work has taken quite some time. Finally he machined 3 of the operating shafts one of which is shown on the left in the photo below right.
Project Manager, Bolingbroke 9048 Restoration