zorgonThe exact shape of the panel has been another of the big mysteries for me too. In fact, I had been in touch a while ago with the Canada Aviation and Space Museum in Ottawa where they have KB 944 (RAF) alias Avro 683 Lancaster X, manufactured in 1945.
One of the Curator’s assistant’s Erin has been kind enough, with the permission of the Museum Curator, to look into many detailed questions I had about the BA panel and to take some measurements. I just heard back from her today. One of the guys (I’m sorry I don’t have his name to give him credit) who crawled in and took a whack of photos and measurements for me, drew up the attached sketch. He has clearly given this some thought and he seems to think, it is actually a parallelogram. I was thinking that maybe it was only one side that was angled differently and there were two 90 degree corners. I’ll also attach a very clean pic of the panel from him, face on. The gadget layout again varies slightly from other Cdn. examples I’ve seen. I note the bomb release button appears to have two (or four?) wires but, it also has two possible outlets, the 2nd being the 5D/525. Oh, to be a fly crawling around the back wiring of that panel!
I would have never thought to ask for diagonal measurements to get the degree of corner angle but there may be other ways to estimate that. Having good diagrams of the rib set-up would be a start. Can one assume the aircraft ribs are parallel at this point? Do you think the panel sits horizontally at 90 degrees to the ribs?
Then there is the right side, towards the skin which can’t be fully seen as it’s behind the rib. Without original diagrams or having a panel outside of the aircraft and available to measure, it’s going to be very tricky to get that shape accurate. The other wrap-around sides look to be 1/4 to 3/16″ in depth but I think the Nanton Lanc is closer to 1/2″ – as measured from the front face.
I’ll have some additional information from the Nanton Lanc (Mk.X FM-159) BA panel analyzed shortly and we’ll see if that info clears things up or just adds to the confusion.
Later,
Wayne
zorgonHi Fleet16b:
In response to “I have an actual mould that was used for making these stop watch holders”.
Wow! What a desirable item to have; a great find. Could you post a few pictures? Particularly of the (reverse) impression of the lettering. I think I have see a few different examples of the raised format so perhaps they were made under contract by a few companies?
Maybe, rather than you finding a replacement formula, you should try to find a company that makes traditional real rubber items and have them do a limited run with your mold (put me down for one too). I believe someone in Britain did this a few decades ago in both black and white versions and those particular high quality replicas were still selling for a hundred to 150 quid or so (or a gazillion Canadian Dollars) recently. I guess it depends on how authentic one wishes to be. Certainly silicon and the modern urethane’s would do the trick, look great and last much longer but they’re just not, … “real”.
Ya, 3D printing. I guess I have to get with the program. It’s hard for an old phart.
Thanks,
Wayne
zorgonHi All:
Thanks for the interesting and educational link Brian. Not surprisingly, it is complicated chemistry but interesting to read that Castor oil might be the preferred compound in restoring some of the initial properties of the old rubber. Retaining tensile strength, shape and providing a lasting rejuvenation are all of course critical considerations.
It would be great if there is still anyone left who worked at the plant near to where Air Ministry lives who remembers anything about the initial manufacturing process or compounds that went into rubber manufacture during the war; it’s probably buried in a book somewhere. I believe latex purity wasn’t foremost on their minds, as would be expected, during wartime manufacturing. It’s amazing any of these watch holders have survived actually. I recall seeing one rubber holder on eBay a few years ago, in the original box, that looked almost in mint shape and it sold for over $200 as I recall.
Peter, I’ve seen your Halifax instrument panel and it is wonderful, detailed and accurate creation, congratulations on that project.
Thanks to all for the feedback and images,
Wayne
zorgonI’ve noticed the different options too; either five or six connectors across the top but not always in the same positions. Sometimes it’s the right side end one, facing the panel (AN3102-16-9P, 4 pins), that is missing (G for George (A07006) Australia and KB944 in Ottawa). It could depend on the combination of pre-selector, the version of the Distributor (i.e. 5D/664) and the bomb release button wiring and maybe the actual bomb sight fitted to the plane. I believe, but I’m not sure, that the far right plug might be for the inertia switch Klixon if used. Ya, I’m not sure either but I think it’s a protective safety device, maybe added latter on in the war. Initially I thought this had something to do with extraterrestrial warriors! Maybe a safety device to disarm the bombs should the plane experience rapid momentum changes? Perhaps someone will weigh in on this.
The bomb release button is another contentious item. I’ve seen them usually sold with two wires (also used in photography as triggers). Often on BA panels, they fit into a plug (5D/525), which can accept up to 5 wires via a 2, 3 (5D/517) or 5 (5D/519) pin male plug configurations, … depending. In fact, I’d hazard a guess that 99% of the “bomb release” buttons sold in the last few decades weren’t actually ever used for that purpose at least on the Lancaster but they are the best available substitute.
Maybe we’ll just have to build something that looks pretty!
Opinions and/or corrections to any of the above are more than welcome.
W.
zorgonHi Andy & all:
Below (or attached?) is a page, presumably from a Canadian manual. Sadly I can’t recall who sent this to me but I think it was from a British source. I too had assumed the British and Canadian connectors were identical.
I also note that I had assumed the connectors mounted on the panel were female but at least in one example I have seen, they are male. Attached is an image of the female, “Z” Amphenol connector at the end of a wiring harness, AN 3102 20 – 16P (9 pins) which plugs into the panel.
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You’re right Andy, it seems detailed info is hard to find. I hope to rectify that over the next while on this form once I can confirm some numbers, photos and diagrams.
Cheers,
Wayne
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zorgonHi Andy:
My Lanc BA panel has been on hold for a few years, pending a few components, including the connectors. I had made the list below list some time ago. I suspect my reference numbers are for the Cdn Lanc but maybe it will be of some use?
I too have yet to find even one of these exact, original connectors but maybe soon. Somewhere I have a page that references the connectors to the numbers if that will help.
AN 3102 Connectors needed for Bomb Aimers Panel
All Female
• X AN 3102 20 – 15P 7 pins
• Y AN 3102 20 – 16P 9 pins
• Z AN 3102 20 – 16P 9 pins
• F42 AN 3102 16 – 9P 4 pins
• F41 AN 3102 24 – 7P 16 pins
• F158 AN 3102 18 – 8P 8 pins
• F43 AN 3102 14S – 9P 2 pins
• F46 AN 3102 14S – 9P 2 pins
• F44 AN 3102 14S – 9P 2 pins
• F3 AN 3102 16 – 11P 2 pins
Cheers,
Wayne
zorgonShielding for 226Ra dials on WWII Instruments
If we assume that the radium paint in luminescent dials is in “secular equilibrium”, a state where all of the daughter isotopes are in balance W.R.T. their natural production and decay processes, the average gamma energy emitted is around 830 keV.
To shield this level of gamma activity one commonly uses a term, “Half Value Thickness” (HVT); that is the amount of a material that will reduce the measured activity by one half. Similarly, there is the unit, TVT, tenth value thickness or the amount required to reduce incidence activity by 90%, down to 10% of initial levels. For 226Ra, the HVL of lead is about 14mm (0.55”) and the TVT, 42mm (1.65”).
I guess that’s the bad news. The good news is that one can theoretically still allow something like a panel to be safely viewed behind special “leaded glass”. The bad news is that to shield down to a socially acceptable level (open for argument) of, say, 10% initial, the thickness of the leaded-glass required would prohibit it from being done, both from a weight perspective as well as a cost which I would suggest be in the many thousands of dollars (or pounds).
Bottom line, using small amounts of lead will help to reduce the gamma emissions from a luminescent dial but not sufficiently to prevent it from being detected by either the Postal or Courier system where sensitive gamma detection equipment may be utilized. And it’s only going to get worse. Major International ports and border crossings are starting to incorporate a new generation of detectors using muon tomography and GEM detectors. Basically, it won’t matter how much shielding you incorporate, a radioactive source inside a package will still be detected. Thanks (I guess) Homeland Security.
As I see it, the only way around this for panel-builders and instrument collectors is going to be to reach some agreement with the Nuclear Protection folk in conjunction with the shipping industry.
I’m not an expert. Once again, a caveat that my data may be out of date or incorrect as I haven’t double checked this with colleagues.
Wayne Logus
zorgonHi P&P:
Wow, lots of really good and very pertinent questions. One could write a chapter on each and still not cover everything adequately. I won’t even tackle the specific questions now.
It seems to me we have a complex dynamic that consists of 1) Theory, 2) Health Protection rules and regulations and 3) Real world situations. The boundaries between these variables are blurred and everyone is going to have a different opinion on which to emphasize. This thread may not be the ideal form to discuss this in detail; it’s a bit of a tangent from the initial query by OneEightBit.
Perhaps the most important thing that readers can take from this whole discussion is that it’s not a black and white issue. It certainly won’t hurt to increase ones theoretical knowledge about Radium and radioactivity, nor become more familiar with existing rules and laws governing what is legal vs. what might be tolerated. I am unaware of what discussions regarding radium instruments, displays, aircraft in museums, etc. have gone one with the IRR99 in Britain, the CNSC in Canada or the equivalents in other Countries. It has to be, in part, a lack of manpower and priorities with the Regulating Agencies, that regulations and guidelines in the strictest sense of the word, haven’t been enforced. It is my understanding that some are trying to work within the system to create an acceptable and legal way of shipping instruments with radium painted dials but it is anyone’s guess when, if ever, a compromise might be reached.
I’ve attached a well-known chart , thanks John, on the decay scheme of 238U (from whence Ra is extracted and purified) to help explain why the problem goes beyond just “Radium”. Of course, our gauges only have isotopes “downstream” from Radium. We know that one of the decay products is 222Rn, a gas, which decays giving off a nasty alpha particle (bad for lung tissue and perhaps the 2nd leading cause of lung cancer outside of smoking). jb154 has pointed out that even the outer bags housing radium gauges become contaminated after time. Radon, a natural material found in many soils, in turn decays to a whack of other isotopes. 214Bismuth, in particular, has isotopes with very high gamma energies (600 keV to about 2.5 MeV) which can plow through a lot of material before they are stopped. An eighth inch of lead will reduce the gamma radiation from these higher energy particles but not even by half.
When Radon undergoes decay, some can escape and the daughter isotopes can end up some distance from the “sealed” gauge. Basically, surfaces will eventually pick up some radioactive component depending on the distance from the gauge or panel. That means the glass cover, the body of the gauge, the bag, the box, the walls of the room, etc. If you store a radium dialed instrument in a room for a long time, you will be able to detect residual activity on materials in that room long after the instrument is removed. Is it significant? Do we need to worry about it? There is no absolute “right” answer; it’s statistical, but less is better in this case. That’s a whole new discussion.
My apologies to those who already know all of this and for any theoretical errors I’ve made or incorrect explanations. Rephrasing or edits are welcome.
zorgonAnalysis of WWII Instruments with radium painted dials
I thought it would be prudent to take a closer look at a representative sample of early WWII Allied instruments with radium-painted dials and obtain some actual measurements. The two aspects investigated and reported here are the isotope of radioactive material used on the dials and the maximum dose rate emitted from the units (i.e., the source of the radioactivity and its magnitude).
The gauges and instruments investigated were:
# Description, Stores Ref #, Version, Year, Dose rate at contact (mR/hr)
1, Altimeter, 6A/1203, Mk XIVB, 1941, 4.8
2, RPM Indicator, 6A/1203, Mk IVB, 1940, 2.5
3, Rate of Climb, 6A/942, Mk IB, 1941, 3.5
4, Boost, 6A/16581, Mk IIIM*, 1943, 1.9
5, Oil Pressure, 6A/570, No XIE, 1943, 3.8
6, Compass (RCAF), 6A/0.726, P8, 1944, 1.6
( 1 mR/hr = 10 micro Sv/hr)
A calibrated Keithley survey meter (Model 36100) was used to measure the radiation dose from the instruments. At 1 metre the dose rate from each instrument was equal or less than ~0.1 mR/hr but this is still a significant level and many times above background. The dose rates on contact with the glass dial faces are listed in the table above. The younger generation will want to convert these to the current SI units of µSv/hr or mSv/hr. As mentioned by others, even a single unshielded instrument will stand a high likelihood of being detected by the newer International mail and courier transportation monitoring systems.
~~~~~~~~~~
To determine the isotope(s) of radioactive material used in the dial paint I went to the University of Alberta SLOWPOKE Nuclear Reactor Facility. The reactor is used as a source of neutrons for elemental analysis via neutron activation analysis (NAA), and for radionuclide production, research, and teaching. The Facility has several high resolution, highly sensitive gamma-ray spectrometers used to analyse radioactive materials derived from many different sources. The SLOWPOKE Director, Dr. John Duke, performed all the measurements and my thanks to him for his time and comprehensive explanations. The hyper-pure germanium detector of the gamma spectrometer we used was of modern design and the associated PC-based multichannel analyzer (MCA) operating software by APTEC was used to collect and identify the radionuclides present in the various cockpit instruments. The Facility frequently analyzes Naturally Occurring Radioactive Material (NORM) from the 238U and 232 Thorium decay series, and has on hand numerous reference standards to confirm the spectrometer energy and efficiency calibration.
Radium-226 (half-life = 1600 yrs.) is itself a decay product of 238U the most abundant isotope of uranium. Because of its long half-life and differing chemical behaviour Ra can readily be separated from its U source. Radium-226 has numerous “daughter” products (other isotopes, radioactive themselves, that are created when the radioactive ‘parent’ decays). Examples of 226Ra decay products include gaseous 222Rn, and gamma-emitting 214Pb and 214Bi. In addition to 226Ra emitting a characteristic gamma-ray of its own gamma-rays emitted by the latter two radionuclides in particular serve to “fingerprint” or confirm the presence of the long-lived 226Ra to which they owe their existence.
Results and Conclusion. As suspected and confirmed by others on this topic in past articles and for example the clean-up at RAF Carlisle in the 90’s, the only long-lived radioisotope found in any of the instrument dials examined was 226Ra (together with its short-lived progeny). Based on the absence of any gamma-emitting daughter products of 228Ra it is safe to say that there was absolutely no evidence of 228Ra being used in any of the instruments analyzed.
An image of the display of a spectrum from one of the instruments tested is attached. Basically, all units tested had identical spectra (in regards to the gamma-ray photopeaks present). In all instances 226Ra was confirmed as the source of the radioactivity in the instruments, as evidenced by its gamma-ray photopeak at 186 keV together with the numerous gamma-ray photopeaks from its gamma emitting decay products 214Pb and 214Bi. Of note was the complete absence of the gamma-ray photopeaks at 583 and 911 keV from 228Ac, the immediate daughter product of 228Ra, confirming the absence of 228Ra in these instruments.
My personal feeling is that we should treat the instruments with respect, limit the time we are in close proximity to them, keep them stored in areas which are ventilated and not adjacent to where people spend long periods of time, i.e., where they live or work. We need not eliminate them from properly controlled displays and personal collections if we adhere to the principle of ALARA (As Low As Reasonably Achievable). In addition, it would be prudent that one never open the units and risk contamination of themselves or the immediate environment. Special care must be given to units that are damaged, where the glass is missing or broken, or when there is a chance that remnants of the dial paint can escape the enclosure. Using gloves, the units should be sealed in Ziplock bags and disposed of in a safe manner which is yet to be universally determined.
Wayne Logus
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