With the banjo fittings done, I was able to proceed with the mounting of the propane manifold. This combines a solenoid valve with outlets for both the normal propane feed of the gas gennie and a takeoff feed for the pressure switch used to turn on the oil pump.
|The first step was to decide where to put the darned thing! Space is at a premium in and around the intake area of the turbine. I decided to set the body of the solenoid valve parallel to the turbine case outer. The output was then routed to the propane port on the face via a brass tube. You can see clearly here one of the completed banjo fittings to the right side of the manifold.|
|To route pressure to the pressure switch, I needed to "tap" the manifold. The pressure switch is located below and to the left of the turboprop when viewed from the rear. I could have simply cross-drilled and soldered a tube in place, but decided a more elegant solution was to have a rotating sleeve, sealed by o-rings. This setup will become clear as we proceed. The first step was to turn 2 o-ring grooves in the manifold body, as well as cross-drill the manifold.|
|The area around the cross-drilling was relieved a
bit, and a brass sleeve was turned to seal this area.
Here, the sleeve is slid a ways up the manifold to show
the o-rings. A hole as drilled in the sleeve, and a
correct tube was soldered in place.
Why such a torturous method? The sleeve can slide a bit longitudinally, as well as rotate, making final fitting very easy.
|This is what it looks like mounted on the gas gennie! At the bottom of the picture is the connection to the pressure switch on the oil pump pack.|
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