Many thanks for your confirmation MerlinPete, much appreciated. It seems that we have now ruled out just about everything that might be possible to have been fitted to the Lancaster. So we are probably looking at something from a different source – either from a wartime vehicle or perhaps along the lines you suggest. Food for thought!

Good to hear from you, Air Ministry – and many thanks for confirming that the Lancaster wartime wheel was AH2238.

Mystery object No.12

It seems that we are heading away from this being Avro – if we have ruled out the carburettor itself and also the hydraulic system, then the only thing that looks remotely possible that I can see in AP2262A related to the pneumatic system is the slow running cut-out in the Mk.III version, but I have no idea at all what this would look like, or something connected to the radiator shutters. Maybe we are indeed looking at Renault or perhaps even something from an abandoned Volkswagen staff car – the allied forces re-occupied the area only about a month after ED908 came down.

Item No.11: Rib No.17

Thanks very much for the extract from your Spare Parts Schedule. I can now see everything clearly. However I am slightly confused by the nomenclature where the description under the port nose portion (1/F.4537) is “Less the following:-“, as if what is then listed, including our part 11/F.3715, is not there !!

We can only speculate about why our part shows the number 3/F.4537 – perhaps your list relates to the Mk.I version of the Lancaster and this was changed for the Mk.III ?? However , as I said in post #380, it is looking increasingly likely that we do have a piece of the port wing which would make sense if the port and starboard sections were re-numbered ‘3’ and ‘4’ for the later version.

I hope the weather in northern France has been better than we have just experienced in the south of England. It may be a little time before Laurent has the opportunity to return to his clearance work at location 12. I should mention that the flexible brake hose (item 41) was found a short distance away from location 12, not at the bottom of the hole, so it would seem that, as might be expected, some pieces were scattered on impact.

More to follow after I hear again from Laurent.

Many thanks for the confirmation, Peter. Do you know whether ‘AH’ numbers are all wheel related? Or maybe WV-903 or Air Ministry can confirm this? Even better would be if the number of our piece could be found in one of their lists, but if these are all post-war, we may be out of luck. If anyone is able to provide more information it would be much appreciated.

WV-903, Peter,

I am very grateful for all the time and effort you have both put in to try to identify our mystery item. Unless somebody else comes up with another suggestion, I think the best we can say is that, based on Peter’s picture of a Lancaster wheel, we have a possible wheel hub pneumatic attachment with a butterfly valve. In the absence of any wartime diagrams of the wheel showing what the brake exhaust valves looked like and how they were fitted, as WV-903 says, uncertainty must remain.

As promised, here are the photographs (from both sides) of the second brake shoe and two spring plates which fit into the slots at either end of the shoes which were found at location 12. One of the spring plates probably belonged to the first shoe found. The pattern of the holes for what I think are called ‘nibs’ to prevent movement between the brake shoe and the lining is clearly visible on the outer surface, as are signs of wear. To assist non-technical followers of this thread like myself, I have inserted ‘labels’ on the attached picture of a brake drum pointing to the items WV-903 has been describing and to the brake shoes and sprung plates. As WV-903 has explained, the drum fits into the cavity at the centre of Peter’s picture of the wheel. Whether this part of the braking system is substantially unchanged from the wartime version, I do not know, but hopefully it helps to explain the basic arrangement of a multi-shoe drum brake from which Laurent has found two shoes with the brake linings still attached.

WV-903, Peter,

I have been searching the internet and have found a number of archived pre-war and wartime Flight publications.

One from August 1942 refers to the undercarriage of the Avro Lancaster as having Dowty shock-absorber struts and the wheels and tyres being Dunlops – somewhat curiously a diagram of the whole aircraft refers to the undercarriage oleo legs and hydraulic wheel brakes (as already discussed, AP2062A dated April 1943 clearly refers to pneumatic brakes). Another publication from June 1932 refers to a new Dunlop pneumatic brake and, interestingly, to inlet and exhaust valves. To what extent this may be relevant to the development of an aircraft braking system during WW2 and our piece I do not know, but I thought I would pass on the information.

Having looked more closely at the third diagram in post #396 for Wheel AH8405 and Brake Unit AH8269, I see that item 2, which although not wholly clear from the cutaway diagram and positioned differently from the five items in Peter’s picture looks a bit like our piece and is described as a ‘valve housing’. Could we be looking at an exhaust valve? Or is this something connected to tyre inflation?

For clarification, I assume our piece has been ruled out as being the wrong shape for the Merlin’s twin carburettor and that this can be eliminated from the possibilities?

……….

I believe the wartime wheel type may have been AH2238.

Thanks very much for that very detailed explanation WV-903 and for the pictures which have helped to give me an idea of what we may be looking at. I have found the diagram of the pneumatic system in AP2062A which I can see operates the wheel brake units as you describe.

I remain confused as to precisely what we are looking at in Peter’s picture of the wheel hub. The piece found looks so much like the motor vehicle carburettor fitting I have pictured in post #393, but what are the fittings in Peter’s picture? There are five of these diamond-shaped items interspaced with what look like five bolt fittings, and they are certainly shaped as if containing a butterfly valve: the enlarged picture appears to show a small hole in the centre of the fitting, rather than a solid bolt. Would I be right in assuming that the brake drum would fit into the cavity on the nearside of the hub in Peter’s picture? It is a little difficult to get an impression of the depth. Peter, maybe you can confirm?

Also, WV-903, can you please tell me how the pneumatic system controlled the air flow to the brakes – would it have had butterfly valves to allow the build up and release of pressure? And if so, where would the valves have been positioned? You have said that our piece could be an air passage duct, but you are convinced that it is not for the brakes. I note, as Peter mentions, that all your diagram examples are post-war and appear to be for the Mk.VII version of the Lancaster or later – is it possible that the Mk.III might have been configured differently?

ED908 was one of an Avro batch built from November 1942 to June 1943, and it entered service in around April 1943. If our ‘VJN 9 42’ mark does represent a date of September 1942, this might well be what we would expect. And I keep on asking myself the question, what was the piece doing next to some Lancaster brake shoes 5 feet under the ground if it was not part of the aircraft? The alternative seems to be that it is a piece of discarded wartime rubbish – is this likely?

Lots of questions, and no definite answers.

Laurent is clearly a little doubtful about the piece, but it does appear to have a butterfly valve arrangement. It seems as if the mystery may remain unless he is able to dig a bit deeper and maybe find a piece of the main wheel. Let us hope that he is successful.

I have been in touch with Laurent regarding our mystery piece No.12. He says: “WV-903 a raison, moi aussi , j’ai étudié l’objet N°2, on croirait un boitier papillon ou une admission d’air! Il est possible que cette pièce n’ appartient pas à notre avion!” which loosely translated says that he thinks that WV-903 is right: he has also looked at the second object which he thinks is a throttle body or an air intake. (”Boitier papillon” seems to translate as “Butterfly box” or “Throttle body”.) He is also uncertain whether the piece is from the aircraft.

Laurent has told me that the undercarriage created a deep crater when it came to earth and that the hole that was left was filled with rubbish after the war. With the help of a friend, he has cleared out the rubbish – mostly old bottles – from the crater, which is about 1.6m or a little over 5 feet deep. Could our piece therefore be something of wartime vintage which was discarded at that time? But it was found next to the brake shoe. Laurent had thought that he might find pieces of the wheel and struts, but he is now beginning to think that perhaps the substantial parts were removed for use as scrap metal at much the same time as the rest of the fuselage.

It has apparently been raining almost continuously in the last few days, and so he has not yet returned for further exploration. In the meantime, shortly after the outset of the search, he has found another brake shoe and two spring attachments. I will post photographs separately after the discussion on the present item has concluded.

I attach four pictures. At the top left is Peter’s picture of a Lancaster wheel. At the top right is another picture from a different wheel showing the hub in a little more detail. The bolt holes WV-903 mentioned are spaced in between the five pieces which look like ours. At the bottom left is our piece. At the bottom right is a picture of a carburettor. It is now readily apparent why WV-903 could see the similarity with our piece. But we have pipes, a spring, and a curious grille-like attachment.

So, back to basics. What we have looks highly likely to be something within which sat a butterfly valve. What could be a throttle shaft is the piece running across the large hole, as seen in the picture of the carburettor with the pale yellowish circular butterfly valve in position in the gap. Would a drum brake system also have used similar butterfly valves to control the hydraulic flow as the brakes were applied? Pieces like this are what we seem to see in the top two pictures. So are Peter and WV-903 both right – our piece has the features WV-903 describes, but it is situated in the wheel hub and comes from the brake system???