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 Post subject: AAF A-8A Sextant
PostPosted: Fri Feb 27, 2009 5:03 pm 
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Location: Panama City, Florida
I recently acquired an A-8A Sextant to add to my small collection of military memorabilia.

Can anyone tell me what a No. 10 Unit Cell (battery) is? Does it equate out to a modern battery? Or are there reproductions available? I googled myself blind with no luck.

Also trying to find anything that describes the different parts of the sextant and what all is supposed to be in the box. Right now the box has the light tube in the lid, two of the 3 spare bulbs in the bottom portion of the box and the sextant. There is 4 slots for batteries (Bordered in Yellow), and three small holes for sosmething (there's a small rod in one right now). And a small bracket for holding something in place on the left forward portion of the box (Bordered in Red). I'd like to make the box complete.

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Mike in Florida
USAF Aircrew Life Support (Retired)
"Your Life Is Our Business"


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 Post subject: Re: AAF A-8A Sextant
PostPosted: Sun Jan 29, 2012 4:22 pm 
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ffuries

Are you still looking for answers on this?
I realise you post is over 2 years old....
I have an A-8A and presently restoring it to working order.


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 Post subject: Re: AAF A-8A Sextant
PostPosted: Mon Jan 30, 2012 8:00 pm 
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Location: Panama City, Florida
Yes still looking for some answers, I know the big round holes in the front of the box are for the batteries. The thumb screw is where the spare bubble chamber goes (Won't find any of them from what I understand), then there are the 3 holes, one of which has a steel bar/rod in it, what are the other 2 for? Plus it looks like my bubble chamber will need to be redone.

Mike

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Mike in Florida
TSgt USAF Retired
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"Your Life Is Our Business"
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 Post subject: Re: AAF A-8A Sextant
PostPosted: Tue Jan 31, 2012 10:32 am 
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Mike

OK here goes.

First, the A-8A is a wonderful device because it is one of the few airborne sextants that allows to work with either the bubble as an artificial horizon or without the bubble, using the visible horizon. Still, don't think you're rich.... the sexant sells on ebay under $100. :?

Your device looks in absolutely great condition. Also, the fact that you have some tools and spare bulbs in the box is quite rare. From the shiny cable in the lid of the box, I have the impression that the device has been restored to some degree. Originally the cable is rubber, and by now must have become hard and brittle. NOt easy to see from the picture though. The tube in the lid is the battery holder, not the light tube. The light bulbs are in the device itself. You could also check the spare bulbs to see if they appear old & original, or a modern replacement.

The batteries you described as "No. 10 unit cell"...that's just one more denominator for what are very ordinary type D batteries at 1.5V. You can buy them in any nearby electronics shop. (http://en.wikipedia.org/wiki/D_battery). They are used to light up the bubble or the drum for reading the value at night, as you set with the obvious switch on the sextant.

On the left is indeed the stow area for a spare bubble assembly. These are hard to come by. There is a bubble assembly installed in your sextant: see your last-but-one photo: the metal round part with single screw under the telescope (right side of picture).

This bubble chamber should probably be redone indeed; i.e. refilled with a liquid to create a bubble. This is not very difficult; I did mine just last week. If you are comfortable with tools and work carefully, it's no big deal. My biggest difficulty was in obtaining all the materials required. The liquid is xylene, and you'll need a hypodermix syringe+needle, a bit of shellac flakes, pure alcohol (96% ethanol) for dissolving the shellac. Tell me if you want to go this way and I'll help you best I can.

The tools on the left are supposed to be three. Although I have none, I believe they are (see picture 17 in the manual you have)

1. Counter lock wrench (to be found under the name plate, which you can slide away to the right)
2. Adjusting wrench (you seem to have this in the box)
3. Screw driver

Actually you can live & work without those perfectly well, but I understand you want it complete for display purposes. Can't help you there. Again, those are quite rare.

Additionally, under the metal clamp (top left of the box) goes lense paper for cleaning, any photo shop will sell you this.

Don't worry about sending the manual, I have that. I do not have the July 1945 Navigators Information File. Not sure what it is, but sounds interesting.


Eric


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 Post subject: Re: AAF A-8A Sextant
PostPosted: Tue Jan 31, 2012 11:45 am 
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Location: Panama City, Florida
The NIF file, is a manual for navigators it covers everything and anything.

Section 1 Is about how to submit reports about the sextant, manual, etc.
Section 2 Dead reckoning, pilotage, and radio aids.
Section 3 Celestial.
Section 4 Tactical operations.
Section 5 Crew duites.
Section 6 Navigation weather.
Section 7 Emergencies.

Section 3 has the star charts and everything in it, really cool manual, interesting reading.

As for the batteries, I found some vintage battery labels on the internet and printed them on label paper, and applied them over modern batteries. Looks pretty dang good in my opinion.

All the bulbs, the ones intalled in the sextant and spares in the box are original, missing only one spare bulb.

Got lense paper from when I was working on NVG's before I retired, didn't even think of that.

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Mike

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Mike in Florida
TSgt USAF Retired
Jan 86 - Sept 08
Aircrew Life Support
"Your Life Is Our Business"
(122X0, 1T1X1, 1P0X1)
NRA Life Member


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 Post subject: Re: AAF A-8A Sextant
PostPosted: Tue Jan 31, 2012 11:55 am 
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Very nice Mike!

Great job!

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 Post subject: Re: AAF A-8A Sextant
PostPosted: Tue Jan 31, 2012 12:08 pm 
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Location: Panama City, Florida
Thanks the330thbg, I would love to take all the credit for it but CINC Household (AKA the Wife) came up with the ideal. I found the labels, I printed them, she trimmed and applied them, gave them back to me and said there, now you have old batteries just like you. Still have 2 spare labels (printed) and the doucment to make more if I need to.

Mike

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Mike in Florida
TSgt USAF Retired
Jan 86 - Sept 08
Aircrew Life Support
"Your Life Is Our Business"
(122X0, 1T1X1, 1P0X1)
NRA Life Member


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 Post subject: Re: AAF A-8A Sextant
PostPosted: Tue Jan 31, 2012 6:39 pm 
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Thanks for posting this. I have a number of the USN A-12 bubble sextants. I also have a box of the battery holders with original cloth-covered cables attached if anybody is missing theirs. Thanks for posting the repair information- very useful.

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 Post subject: Re: AAF A-8A Sextant
PostPosted: Wed Feb 01, 2012 6:58 am 
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Forgotton Field

For the A-12 and others, a highly acclaimed repair & overhaul guide is available here: http://sextantbook.com/category/my-bubb ... n-manuals/

Eric


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 Post subject: Re: AAF A-8A Sextant
PostPosted: Tue Nov 19, 2019 4:27 pm 
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I happened upon this old thread. I also have an A-8A sextant, but no manual!!

Does anyone out there have one they would scan for me??

Thanks,
Peter


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