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Depleted Uranium used in Aircraft construction

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Depleted Uranium used in Aircraft construction

Old 5th Oct 2008, 22:21
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Depleted Uranium used in Aircraft construction

Was watching a program on the dismantling of a 747 and they mentioned that the wings had a certain amount of Depleted Uranium used in the construction on the spars ( I think ). To what extent and what benefits does this metal have over normal aviation grade Aluminium?

Sorry if this is the wrong forum, but it seemed a relevant technical problem of some sorts.
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Old 5th Oct 2008, 22:36
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Thank you. Just the answer I was looking for.

Is this a common practice in the industry then? Just wondered if my Citation was likely to have it in? In case I ever feel the need to make an armour piercing bullet at short notice
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Old 5th Oct 2008, 22:38
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My RV-8 uses Lead

Although that's becoming as un-eco friendly as Uranium I suppose

NoD
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Old 5th Oct 2008, 23:45
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Snoop

747 classic originally used Depleted Uranium in the flying controls for balance. It could be found in the elevators, rudders and outbd ailerons. It was also originally fitted in the early JT9d nose cowls (different amounts depending whether the cowl was for an inb'd or outb'd position) again to reduce flutter.
The maintenance practice for it was to ensure the paint was intact and they weren't corroded.
JFI we had a visit from the NRPB sometime after the loss of PA103 as they were interested on roughly how much there could have been fitted.
Made a damn fine door stop or rivet block though
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Old 6th Oct 2008, 02:10
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I suspect that depleted uranium was very inexpensive as well, or more specifically, less expensive than lead. Certainly much less expensive than tungsten--which is a pretty close match in density.

I have a little family story to tell here. My father was a chemical engineer who worked in the development of the standard acrylonitrile production process in the late 1950s. One of the candidate catalysts used uranium. At that time, if you wanted any uranium at all, you went to the Atomic Energy Commission. He told me of the raucous laughter at the other side of the table when his team inquired as to whether they could be confident of being able to obtain enough of the material. The general public at the time had no idea at all of how big the tailings pile must be.
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Old 6th Oct 2008, 03:30
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It's already been answered, but below is from the Maint Manual.
Also, during the replacement program from uranium to tungsten - quite a few of the old uranium weights ended up in "scuba diving belts"
Lotsa weight but no where near as bulky as lead.
There's nothing, and I mean nothing that an aircraft engineer can't find another use for.


RUDDER/ELEVATOR BALANCE WEIGHT - REMOVAL/INSTALLATION
1. General
A. This procedure includes removal and installation of balance weights for
the rudder and elevator while control surface is still installed on the
airplane. Balance weights can be made of tungsten or depleted uranium.
WARNING: THE RUDDER AND ELEVATOR MUST BE PROPERLY BALANCED AT ALL TIMES.
AN OUTBOARD ELEVATOR OR RUDDER THAT DOES NOT MEET THE
REQUIREMENTS SPECIFIED IN 51-80-02 OR 51-80-03 OF THE
STRUCTURAL REPAIR MANUAL CAN PRODUCE UNDESIRABLE FLUTTER AND
DYNAMIC INSTABILITY WHICH COULD AFFECT FLIGHT SAFETY.
B. Depleted Uranium Balance Weights
(1) Some balance weights on outboard elevator and upper rudder are made
from depleted uranium, which is a naturally occuring uranium that
has been "depleted" of most of the isotope U235. This remaining
low-level radioactive uranium, similar to other heavy metals, is
toxic if ingested, absorbed, or inhaled into the body. Those
weights are identified with legends permanently stamped into the
surface of each weight, to assure special handling during
maintenance. Protective coatings have been electro-plated on the
weights to contain the depleted uranium. If those coatings are
penetrated, certain precautionary measures are required to minimize
the small health risk.
WARNING: REWORK, SUCH AS FILING, SANDING OR MACHINING, THAT WOULD
DAMAGE THE PLATING OR REMOVE ANY BASE METAL IS PROHIBITED.
INHALATION OR INGESTION OF FILINGS, DUST, ETC., FROM THE
WEIGHTS MAY BE HARMFUL.
(2) Limited repair of damaged or corroded weights can be accomplished
safely if the procedures in subject 51-20-03, hazardous materials,
of the Structural Repair manual are used.
(3) Replacement of uranium balance weights with tungsten balance weights
can be obtained from Structural Repair manual (51-20-03).
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Old 6th Oct 2008, 05:50
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Just wondered if my Citation was likely to have it in? In case I ever feel the need to make an armour piercing bullet at short notice
Might depend on the model Citation but recall one of our engineers saying he had to go to the gun shop to buy bullets of a particular calibre as thats what the particular model Citation used for balance weights.
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Old 6th Oct 2008, 08:40
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Don't tell the Feds.............they'll be stupid enough to impound all Citations as Terrorist Related weapons!!!
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Old 6th Oct 2008, 11:08
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Looking at an atomic weight chart, it seems the weight of Uranium is 7 to 8 times the weight of aluminium. Tungsten (which now replaces depleted Uranium is about 6.8 times). The Uranium on our old 747's was removed many years ago.
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Old 6th Oct 2008, 15:28
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Originally Posted by Brian Abraham
I recall one of our engineers saying he had to go to the gun shop to buy bullets of a particular calibre as thats what the particular model Citation used for balance weights.
Wouldn't that have been shotgun pellets? I would have thought they'd be easier to handle, weigh, install, etc.
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Old 6th Oct 2008, 15:43
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Depeleted Uranium (DU)

IIRC this caused a "problem" when the KAL 747F crashed at Stanstead about 10 years ago. The recovery took a while as they had to dig some tonnes of earth to recover the lost DU ballast weights.
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Old 6th Oct 2008, 16:12
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Note that there is a very well known metal whose density is a rather exact match to those of depleted uranium and tungsten, which unlike tungsten is plastic and easy to work, won´t corrode and is nontoxic, environmentally friendly. Only its price is iffy.
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Old 7th Oct 2008, 09:28
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Now here's a thought for any nuclear scientists out there. Is it possible to put the "mojo" back into depleted uranium? (pardon the Austin Powers ref but it seemed the most appropriate!)

PB
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Old 7th Oct 2008, 11:00
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You may be thinking of this pasty Breeder reactor - Wikipedia, the free encyclopedia Put a glow in those pasty cheeks.
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Old 7th Oct 2008, 11:28
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I think the Wessex or Puma had nickel plated depleted uranium weights in the rotor tips, but it is going back a bit..........

Certainly several fighters used it in the Ammunition for the Guns due to its weight.
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Old 7th Oct 2008, 23:20
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The Convair 600/640 had weights on the horizontal tail that I heard were DU. As I recall, not a CG issue but vibration damper.
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Old 8th Oct 2008, 03:17
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IIRC this caused a "problem" when the KAL 747F crashed at Stanstead about 10 years ago. The recovery took a while as they had to dig some tonnes of earth to recover the lost DU ballast weights.
when the 747 crashed into a large block of flats in amsterdam a few years ago there was a story in the press it was carrying some radioactive material ,this was by the look of it d/u that had been heated up to a great degree and at that became radioactive
Typical hysteria from people that hear the word "uranium" but somehow never hear the word "depleated".

I worked with and around "depleated uranium" for years and as of my last physical about three months ago I and perfictly healthy for a man my age (old), what ever that means?
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Old 8th Oct 2008, 07:53
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glhcarl
I believe you are correct about the relative safety of depleted uranium. As long as it remains in one big solid chunk. However, if it becomes vaporised, or broken into fine particles, and can be breathed in, then it is a very different matter entirely.

I rather doubt that the temperatures or mechanical forces available in an aircraft crash are sufficient to achieve this. (Anyone know different?) But when DU is fired as armour piercing ammunition this does happen, and this is a recognised hazard on recent battlefields.
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Old 8th Oct 2008, 08:04
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The famous Mirage III fighter our Air Force just put to retirement (1 piece still flying for private use) used depleted Uranium in its structure.

It was mainly in the speedbrakes and I think in the engine.

Dani
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Old 8th Oct 2008, 09:00
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ghlcarl,
I'm sorry but I simply reported that "the authorities" felt it necessary to dig the stuff up rather than leave it at the crash site. Not hysteria or any other thing. I personally do not have any trouble with DU or nuclear power. Try to read the words an not add extra meaning that wasn't there.
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