P 10 Compass

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Airspeed
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P 10 Compass

Post by Airspeed »

Hi all,
Just a brag about my latest acquisition.
Another 14 detailed photos on the website below.
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Kevin Farnell
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Re: P 10 Compass

Post by Kevin Farnell »

I've got one of those. My parents saw it at an antiques fair some years ago and bought it for me. The box contains several date stamps (WW II era) and I did consider trying to find out which aircraft it may have served on. I'm not too sure where its hidden at the moment but I'll try and dig it out.

Kevin
Stratospheric traces, of our transitory flight.
Trails of condensation, held in narrow paths of white...

Airspeed
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Re: P 10 Compass

Post by Airspeed »

Hi Kevin,
Hope you can find it. :)
Just a word of warning:
I previously thought that concerns about radioactivity in instruments applied only to post war.
Whilst digging up info. on my old P4, I came across many forum posts.
Apparently, "they" added radium powder to the luminous paint, to boost its luminance.
It didn't work anyway, and in fact made the paint deteriorate more rapidly. The brown "red" on my wires is typical indication of the radium.
Some people, me included, thought that the loss of luminance may mean that it had lost its radioactivity.
Not so. The disintegrating paint means that microscopic particles of radium are floating around inside the bowl under the glass. Opening the glass leads to the risk of inhaling or ingesting the particles. You are right if this seems a bad thing. Don't mention this to Mrs Airspeed. :shhh:
So, what made me open it?
Firstly, I was ignorant of the dangers.
Secondly, this is what it looked like on the ebay listing, and when it arrived here.
"Move along, nothing to see here."
Image

Kevin Farnell
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Re: P 10 Compass

Post by Kevin Farnell »

Thanks Mike :thumbsup:

I was aware that there was a radiation issue with the faded 'glow-in-the-dark' paint. Like your compass, the 'crosshairs' on mine are a faded beige colour.

Radium (Ra) decays by the loss of an alpha particle to Radon (Rn). An alpha particle is basically a Helium (He) nucleus, i.e 2 protons and 2 neutrons but stripped of the 2 electrons. As such, alpha particles readily ionise and can therefore be blocked by just a centimetre or two of air. As Radium is a solid, the main risk is if you were to inhale any particlles, or touch them. Even then, they would need to undergo radioactive decay whilst in contact with you to cause any problems, The half life of Ra is around 1600 years but that of Rn is just 3.8 days. Ra is a gas and also an alpha particle emitter. It is therefore easily inhaled, with a higher risk of the alpha particle ionising in contact with the lung.
Radon decays to Polonium (Po), which as well as being radioactive, is also extremely toxic.You may recall the death of Alexander Litvinenko in London back in 2006. Allegedly poisoned with Polonium by a KGB agent.

But, before we get too gloomy regarding the Radium on our compasses, we need to consider the amounts and these are tiny. I watched a documentary a couple of years or so back. In this, people working in aircraft factories during WWII (where the paint was splashed all over certain aircraft parts) were painting it on their faces and hands (being unaware of the danger). They received massive dosses of radiation - you can guess the consequences.

A couple of years ago I went to an airshow and one of the stands had several of these WWII compasses for sale. If there was any significant risk from these items, I very much doubt they would be allowed to be traded.

So, enjoy owning your compass. Just treat it with a little respect.

Sorry for the Science lesson, but I'm a Scientist and I loooooove Science.

Regards

Kevin
Stratospheric traces, of our transitory flight.
Trails of condensation, held in narrow paths of white...

Airspeed
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Re: P 10 Compass

Post by Airspeed »

Hi Kevin,
Appreciate your science lesson. Though I was keen on the idea of it, I failed badly at school.
The concern is, as you mention, inhaling or ingesting micro particles once the glass is removed, and that's exactly what I did. I'm not losing sleep over it at present, and if I did take any on board, I doubt that there's a thing I can do about it now.
Something else I discovered, the "P" denotes a pilot's compass; there are also "O" prefixes for observers.
Ii the 1960s, I worked in an office attached to a gasket making factory, where pallets of asbestos sheet were everywhere; often sat on the stacks and ate lunch. :wasntme:

Kevin Farnell
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Re: P 10 Compass

Post by Kevin Farnell »

Hi Mike

Please, don't lose any sleep over it. You come across far more hazards throughout your life than this is ever likely to pose. Everything from crossing the road, driving, sunburn, cosmic background radiation, coronavirus etc, etc.
Forget it. Crack open a nice cold beer or pour yourself a glass of your favourite tipple. Oh wait. we're told that that's bad for us now!
I've got a cold beer open and I'll raise a glass to you!

Cheers :cheers:

Kevin
Stratospheric traces, of our transitory flight.
Trails of condensation, held in narrow paths of white...

airboatr
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Re: P 10 Compass

Post by airboatr »

Airspeed wrote:
15 Feb 2020, 01:20
, and that's exactly what I did. I'm not losing sleep over it at present, and if I did take any on board, I doubt that there's a thing I can do about it now.
Rumor has is it'll make your penis grow a foot.

... have fun finding a middle shoe.

.... :worried:
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Airspeed
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Re: P 10 Compass

Post by Airspeed »

airboatr wrote:
15 Feb 2020, 03:51
Airspeed wrote:
15 Feb 2020, 01:20
, and that's exactly what I did. I'm not losing sleep over it at present, and if I did take any on board, I doubt that there's a thing I can do about it now.
Rumor has is it'll make your penis grow a foot.

... have fun finding a middle shoe.

.... :worried:
Blast! They only have left footed penis boots at the local saddlery. :|

airboatr
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Re: P 10 Compass

Post by airboatr »

.... 8) :doh:

:lol:
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