Some thoughts on major oil leaks in big radials....
While there will be some oil coming from the cowl flaps, gravity is not in suspension and the bulk will work its way down.
I once lost a jug on an R-2800, literally lifting an inch up off the crankcase. There was some oil on the top of the wing, but the vast majority flowed down and completely bathed the underside of the nacelle and wing. Over the years flying C-118s and C-131s, I lost at least 3 engines, all of which pumped out an amazing volume of oil. It always looks far worse than it is due to the hysteresis of oil and being blown at high speed.
In the image Guppy posted, the oil comes out around the front of the cowling ring and over the top. Oil will not flow forward. There will be aerated oil mist from the cowl flaps with some minor leakage around the seams and Dzus fasteners. The bulk will leak out through the oil cooler door underneath the F6F. The oil would be nearly jet black too, with nary a hit of brown. This is due to the oil carrying a great deal of microscopic carbon (from combustion). Fresh oil is amber, used oil would be very black. The oil tank is topped off during every refueling, but the tank and sump isn't drained except during specific scheduled servicing increments. The volume of carbon in the oil strainers is impressive, but generally unimportant. What you are looking for is metal... That's important.
Anyway, the resulting leakage would look more like this:
Rather than like this:
My regards,
Widewing
