A light sport pilot reported an NMAC with a helicopter on short final to a non-towered airport.

Narrative

I took off from ZZZ1 direct to ZZZ in My RV-9A. My intent was to enter the pattern for Runway XY for a couple of touch and goes then proceed to ZZZ2.Weather was clear with calm winds. As I entered the right downwind there was a Cessna on final and a regional jet in the run up area next to XY. On ADS-B and the radio we were the ONLY aircraft in the area. Down wind; base and initial final were clear of traffic and all normal.As I was on short final a radio call from the regional jet on the ground was 'Do you see the Blackhawk'!!. Just as 'do you' was said a green H-60 from the left and behind me; at the same flight level filled my windscreen no more than half a rotor disk away. I immediately did an emergency descending right turn to the west and distance my self from the runway. The Regional jet pilot made a few comments that I can't recall at that time.The H-60 per the regional jet informed me the H-60 continued on two more times in a right pattern for runway XY; still no radio calls or nothing on ADS-B. I made a large circle south of the airport to enter the left downwind again for [Runway] XY. I then did notice on the ADS-B a unidentified aircraft departing the area at 114 knots to the NE. Info: I have at least 2000 hours as a crewman in both civil/ military helicopters including HH-60H's. My distance calls are pretty reliable.