coolant recovery type pressure cap. I am still trying to figure out

why

:-)

When that tank pukes coolant it pukes it overboard never to
be recovered. They also pay a huge weight penalty for this system
as the tank is heavy wall to withstand the pressure and it holds
about a gallon and a half of coolant or about 12 pounds right
there.


Paul Lamar

Hi Paul
I changed my coolant recovery system to a small pressurised overflow

tank

instead of the unpressurised original because the system had no

elasticity.

With short, very firm water pipes and small aluminium header tank the
pressure went quickly to cap pressure on start up and overflowed to the
recovery bottle. The overflow continued all the way to 10,000 ft. On the

way

down the pressure dropped to zero. This meant that I could not use my

low

coolant pressure alarm, and also suffered some water loss.

With the pressurised system there is no water loss and the pressure

remains

above 10psi until long after shut down. Only a small plastic bottle half
full is required. The bottle is off a GM Camaro car.
The gauge reads about 11psi at 1,000feet. At 9,000feet it usually reads
17psi. The cap, which is on the overflow bottle is labelled 10psi.
 I have a schreader valve to pump the system for cold testing, the cap
releases at 11psi. cold.

Happy flying, Ian Rotary RV6A. Australia.

Oops that should have read Camira not Camaro. The clue is that the

pressure relief valve is almost  as small as a needle valve, so external
pressure has very little effect.
Ian Australia.

 
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