Bomb Bay Jack Attachment

Glad to be of help Peter. Herewith another picture and a diagram from AP2062A.

Some identified items: 10 – pieces of fuselage

Keeping the pictures going, as requested, here are several fragments of fuselage found amongst the wreckage. A few are identifiable. Attached are pictures of (1) a piece of fuselage former with the notches for the stringers running down the length of the fuselage; (2) a similar piece, differently shaped, from the bomb bay door frame together with a circular piece for the bomb bay jack attachment; and (3) one unidentified piece which could be from the bomb bay door. It has serial numbers 11F3715 and 3F4537 impressed on opposite sides. Does anyone have any ideas on this last one?

Some identified items: 9 – Segment of altimeter dial

Many thanks WV-903. The only pictures I have been able to find show more pointed saw-like teeth – nothing that looks quite like the buckle piece we have.

In the absence of any responses to my request for any photos of the fuel piping in situ, the next item is a piece which appeared with others as item E on photo W3 (post #22). It is the internal pressure setting dial for the altimeter. This was one of the six main instruments on the pilot’s main flying instrument panel which together enabled the pilot to fly ‘blind’ in bad visibility.

This took some while to identify, with early suggestions being that it was a pressure gauge of some sort, perhaps connected with the hydraulics, as the readings visible on the fragment ranged from 800 to 880. But it didn’t match any of the known dials. I stumbled across the picture attached below and suddenly all was revealed! It was a pressure gauge, but not of the type suggested.

The full dial was calibrated from 800 to 1040. Both these readings can be seen in the aperture at the bottom of the altimeter dial pictured to the left of the piece found. The main altimeter dial with its three pointers must have been a little confusing for pilots, and was probably easily misread with one pointer sometimes partially obscuring another (as appears to be the case here with the small pointer probably hidden under the large one). The smallest pointer read the height in 10,000ft intervals; the intermediate one in 1,000ft intervals; and the largest and longest at 100ft intervals – crucial on landing!

I am very far from being an expert in these matters and what follows is probably an unsuccessful attempt to summarise very briefly what I have gleaned from the internet. It may be of some help to those non-experts like me who want to understand the function of the air pressure dial.

To determine the height of an aircraft an aneroid barometer measures the atmospheric pressure which decreases in a known manner as height increases. This is translated into the height recorded by the altimeter which needed to be set by reference to the prevailing atmospheric pressure at ground level, and it was the internal gauge that was used to do this. In simple terms the aneroid altimeter measures the external air pressure and is calibrated to show this in accordance with a mathematical model as an altitude above sea level.

Without getting too technical, on a mission, particularly at night, it was important that all aircraft flying in close formation used the same initial pressure setting on their altimeters in order to avoid mid-air collisions. Although absolute height above sea level might vary from the indicated height by virtue of changing weather conditions, the relative height of each aircraft in a formation, as between each other, would be constantly recorded on their instruments as long as they all started with the same calibrated pressure setting on take-off. This would (presumably) either be the actual recorded pressure at the airfield, or by using the standard British pressure setting of 1013.2 millibars (now hectopascals), equivalent to 29.92 inches of mercury (as used in American instruments).

It is only too easy to see how mid-air collisions and misjudged landings occurred in poor visibility.

Now all is clear (?) – thank goodness for computers in modern aircraft!!!

Anyway, what has been found is part of the altimeter internal calibration dial.

Some identified items: 7 – Magneto sprung strap and Aerial plug board fitting

WV-903, it was a good spot by you in the first instance that identified the split cotter – much appreciated. There have been no immediate responses to my suggestion about the seat belt buckle, so on to the next item which I hope will prove a little less difficult!

One of the unidentified items on photo T2 (post #35) was number 13 which I queried as possibly being an “electrical spacer”. It was on the trestle table next to a magneto casing sprung strap, and there is another similar broken piece on photo T4, next to item 19. Enlarged photographs of the two pieces are attached, with a close up in the bottom row showing where the magneto strap was positioned.

During my recent visit to Duxford, while looking at the various installations in the Radio Society hut, I noticed an aerial plug board. On a limited number of early installations in wartime aircraft, an aerial selector plug board was fitted instead of the aerial switching unit Type J. The connections of the plug board are shown in figure 7 from AP2548A. A photograph (taken with the consent of the Radio Society people) of the plug board at Duxford, standing on the top of an R1155 receiver is attached along with the diagram.

My so-called “spacer” would appear to be one of the fittings marked “HF” and “MF”. I am not sure of their function – perhaps not only to maintain the space between the long plug sockets, but also to label which was which – nothing too complicated? I should have asked while I was at Duxford – but maybe a radio enthusiast will be able to confirm?

As I have already mentioned, ED908 was built by A.V.Roe in early 1943 and was therefore likely to have been fitted with the earlier type of equipment. Until seeing the plug board at Duxford, I had wondered whether this is what the pieces were but, now that I have seen them, they appear to be the right size, so my guess is that they probably are what I am suggesting.

Seat belt buckle?

The lack of responses to my last post suggests that there is nothing more to add to our search relating to items 27 and 31 which has gone round in circles back to where we started, although we may have narrowed down item 27 to a non-standard fitting (perhaps a repair) on the front gun turret! Many thanks to all those who have contributed to the discussion.

I wonder whether our “hook” from post #205 may be part of a seat belt harness. It seems to be right shape and is clearly a broken fragment. I don’t have much information about these except that they were probably used by the rear gunner, wireless operator and navigator. I have seen references to a “Q” type seat belt. If our piece is from such a harness it would need to have a hole at its base to fit into the locking device, but this area is completely surrounded by encrustation, so without some further work to clean it up, we cannot tell. Can anyone provide any information about the use of these seat belts?

Thanks again, Air Ministry – sorry to put you to additional trouble. Hopefully Peter will now agree?