Oil Pressure Reading Idle Drop

De Havilland DH89A Dragon Rapide

By taildragger standards the Rapide is a sizeable twin which simply exudes elegance and style, a veritable gentleman’s aerial conveyance. Indeed ’DL started its civilian life as precisely that, its first owner being Eric Leslie Gander Dower MP. Now, recently certified, fitted with ‘new’ engines and given a new paint scheme, Delta Lima looks stunning.
The filler cap is on top the engine nacelle. Port and starboard tanks each hold 38 imperial gallons and are located just aft of the engines. A ‘gotcha’ here is to drop the cap, which is normally, but not always, secured with a chain, down into the cavernous nacelle. Jon informs me he hasn’t done it yet but it’s only a matter of time.
While in this area we check the condition of the small flaps, the underside of the wings, what can be seen of the closely faired-in undercarriage and the inboard struts and bracing wires. Apparently there is an F sharp when you twang a wire somewhere in the birdcage. Moving along the trailing edge we check the lower aileron, which is linked to the control column by the usual wires and pulleys and to the upper aileron by a push rod.
We carry on around the wingtip and leading edge to the port engine, all the while twanging bracing wires and checking the integrity of the surfaces and struts. The props on the Rapide are always pulled through two revolutions for the first flight of the day. This is essential on inverted engines, as any oil accumulated in the cylinders has to be purged prior to start to prevent a hydraulic lock damaging the con rods.
We check the wind generator still has its propeller. This 150amp generator is all we have to charge the chunky 42amp battery in the baggage hold. Starboard checks are the same except for also checking the security of the baggage door. Continuing around the tail we check the castoring tailwheel, twang more wires check EASA-required strobe light and arrive back at the cabin door, ready to climb aboard.
The seat, although comfortable, is non-adjustable and reminds me of the ‘sit up and beg’ seats in my father’s 1940-something Morris 8. Perhaps because I am rather short, the cockpit fits me nicely and I feel at home. The cockpit is the opposite of ergonomic, almost as if the various wires and cables were fed willy-nilly into the cockpit and only then was it decided how to connect them all up.

Oil pressure guage reading - TheMalibuCrew.com

I am not sure on your set up but I think you have a sender down around the oil filter. I have seen them get gummed up and show bad readings. You could pull it and flush it in gas or carb cleaner. I have seen that fix it. Its not a big buck item to replace. I have also seen gummed up engines with poor flow from cylinder heads back to pan and the oil get trapped in the heads and drop what is in the pan causing what you are seeing but this is extrema gumming. You could pull a valve cover and have a look.

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