Dave wrote:
On 07/05/2011 19:37, tony sayer wrote:
In , dennis@home
scribeth thus


"The Natural wrote in message
...
The Medway Handyman wrote:
On 07/05/2011 06:59, Matty F wrote:
On May 7, 3:45 am, Roger wrote:
I need to replace the weights in some of my sash windows, because
the
existing ones aren't heavy enough. I need to use lead because less
dense
iron or steel weights would occupy more space than is available.

Depleted uranium takes even less space, and is probably cheap. I'm
not
sure how it should be cut though

Plus the added bonus of your window frames glowing in the dark :-)


DEPLETED uranium is NOT radioactive.

Shhh you don't want to tell everyone.
Especially as it is radioactive with a half life of about 4.5 billion
years.

Ah look at that a radioactive natural element that lasts "forever" I
wonder
how we should store it for safe disposal. ;-)


Is that the same grade of metal that thy use as stabilisers on the tail
of a Jumbo jet?..

Spent uranium is used extensively in the aerospace industry, mainly as
ballast, I don't know why it was used on the tail of a jumbo though.

High weight per unit volume. Think its aero balancing..reduces
possibility of tail surface flutter.


The ballast is used to ensure that the center of lift from the wings
coincides with center of gravity, otherwise you can end up with an
unstable aircraft.

Firstly not always why its used,. secondly centre of lift is always
where C of G is of necessity. That is not the issue. The issue is that
it is so with the aircraft in steady flight, rather than e.g. pointing
90 degrees down :-)

Its very easy to move the centre of lift: that's what the elevators are for.

The critical reason to move the C of G is to do with the differential
movement of the centre of lift with the planes angle. If the center of
lift moves forward as the pklane noses up, its deeply unstable,.



All aircraft have to be accurately weighed as one of the last phases
before its first flight. The aircraft is de-fueled at its correct flight
attitude and this information is fed into the flight computers.

??

Sounds like someone who has worked around an arcraft factoy with no real
understaninding of aerodynamics to me..