I haven't kept any precise figures, but I find that long flights result in lower oil consumption per hour than short flights and/or touch and goes.
I average about a quart of oil/10 hours/engine but feel that much of the usage is vapor out the crankcase vent. I always end up with some drip on the pans under the vent pipe after the airplane has been in the hangar overnite. Do others have this, too?
A. H. Powers ICS 2978