Date: 201809
Local time of day: 1201-1800
Location: AWO.Airport, WA
Flight conditions: VMC
Weather elements / visibility: Rain; 10
Light: Daylight
Aircraft: RV-4
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Landing
Airspace: Class E AWO
ATC / advisory: CTAF AWO
Second aircraft: Cessna Single Piston Undifferentiated or Other Model
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Private
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Conflict NMAC
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I entered the right traffic pattern for 16 at AWO from the south. I intended to enter the downwind on a 45; but ended up at a shallower angle due to avoiding rain showers in the area with an aircraft that has a wooden propeller. About the time I called entering the 45 for the downwind I head a single call of a Cessna on crosswind. I did not get a visual on the Cessna and assumed they were behind me. I called downwind on the radio and proceeded.I continued on downwind and didn't see any traffic or hear any further radio calls from the Cessna.I then called turning right base for 16 and looked in the direction of the turn. As I was turning base; the Cessna emerged from below my right wing crossing my path at about a 45 degree angle. I immediately increased my bank angle and G load on the airplane (~2G; 60+ degrees of bank) with a rapid evasive maneuver to pass behind and below the Cessna as it continued its downwind. The time from seeing the conflict to passing behind the Cessna was probably a maximum of 1-2 seconds.I did not pass through the wake of the Cessna so it may have had a greater margin of separation than my perception.I continued on base and final and landed uneventfully. I heard no further radio calls from the Cessna and saw them again on final about a half mile behind me while exiting the runway.When I departed AWO to return home the Cessna was still in the pattern doing touch and goes. Another aircraft asked if the Cessna had a radio as they continued to perform touch and goes with no calls. The Cessna answered and commenced making standard position reports.In retrospect; we must have been nearly parallel on the downwind with me just slightly higher and farther out from the airport so that the Cessna was hidden below my right wing.I don't think the Cessna ever saw me or was aware of the near miss.Corrective actions:-I should have ignored the rain and flown parallel to the pattern and entered the downwind at a 45 instead of joining the downwind nearly abeam the departure end of the runway. That would have provided better visibility of traffic already in the pattern.-Radio use is not required but another call to indicate they were on downwind from the Cessna would have alerted us that we were in the same area.-Do not depend solely on radio position reports; keep your eyes open-Do not depend on ADS-B in; I saw no targets on my portable EFB and was lulled into a false sense there wasn't anyone there.




Synopsis: RV-4 pilot reported a NMAC with traffic in the pattern at a non-towered field.