Experienced a slow loss of oil pressure over a 15-20 minute period during cruise testing. Low cruise alert occurred at 55 psi and by time I landed, the pressure was down to 25 psi. Inspection of the aircraft reveals oil all the way down the bottom of the fuselage and on the top of the nose gear leg. It is here at the gear leg that the breather tube is secured. Oil droplets were present on the tube. No other oil was seen anywhere elseon the engine.
