Rotary Engine wrote:
The local aluminum radiator supplier recommends the plastic tanks ( on his
website) before I contact him, what is the recommendation on the plastic
tanks - I heard they were prone to failure much more quickly than the full
aluminum ones. I'm sure the racing people use full aluminum, perhaps for
that reason.
George (down under)
Plastic tanks have been used since the 1970s. They are reliable. I
would never use one in an airplane, though, because the few ounces of
extra weight is a small price to pay for the significantly greater
strength of aluminum tanks.
Keith Wood
Most hard plastics in cars last about ten years here in Socal and then
become
brittle and crack easily. I am no expert on plastics by anybodies wildest
imagination but I think it is a process called out gassing. If you can
smell it--- it is out gassing. Certain compounds are leaving the plastic
changing its mechanical properties.
Non metallic objects going into space are tested by cooking them in a
vacuum chamber. One example I know for sure is the Space Shuttle
tires. Black "rubber" hoses and is another material that
self destructs over time. According to Cummins engine manufacturer
silicone hose does not. That is also a reason why new cars have a smell.
I would never ever use plastic rad tanks. One crack could kill you.
--
Paul Lamar ...No rotor no motor.
That isn't what causes plastics, in general to become brittle with age. It
is mostly attack from ultraviolet light. Plastic isn't like rubber in that
they add oils and other "plasticizers" to reduce hardness. I think you
should stick to the aluminum tanks, I don't think you even save any weight
with the plastic tanks. I've also seen people take the plastic tank
radiators that have the right core and make their own aluminum tanks for
them.
Steve Brazil
Ultraviolet light may affect some plastic parts but I don't see how
it affects plastic parts buried inside a car door upholstery for one
example.
First gen RX7 nylon door pulls fail after being completely covered up.
Also the plastic rad tanks are under the hood 99.9% of the time where
they cannot see the ultraviolet light. Cracking is a common problem.
Paul Lamar ...No rotor no motor.
That's true, and another thing is that most of what we generically call
plastics are long chain polymer thermoplastics that are melted and injection
molded. There are many different types in use with different properties.
With the push for recycling, the exact composition may be questionable. In
any case, the point is that for an aircraft, use aluminum tanks.
Steve
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