A light sport aircraft pilot reported instances of a flight school's helicopters not complying with non towered airport procedures one of which resulted in a NMAC.

Narrative

I experienced the following unsafe aircraft operation at the ZZZ airport. I and a private pilot (Person A) taxied Aircraft X from the hangar out to the runway at the ZZZ airport. I was in the front cockpit and Person A was in the aft cockpit. Upon reaching the runway; there was a helicopter Aircraft Y; sitting in the middle of the runway on the west end of runway X. The R-22 had two occupants; one of which was a CFI and the other a student. This was later confirmed by a CFI at the flight school. Before entering the runway; I made a radio call (the ZZZ CTAF is XXX.XX) announcing our intentions to back taxi runway X and that we would taxi past the R-22 sitting in the middle of the runway on the south side. The R-22 did not acknowledge our radio call.After completing the before takeoff checks; I made another radio call announcing our intentions to take off from runway X and make left traffic and then make a full stop landing on runway X. The R-22 took off ahead of us without making a radio call. We waited until the R-22 had made its crosswind to downwind turn to ensure adequate spacing. Just as we were lifting off of runway X; we heard the R-22 make a radio call that they were on the downwind for runway X. I did see the R-22 on the ADSB in as displayed on the Garmin Aera 660 GPS. It was shown as being on the downwind leg of the traffic pattern as we just began our crosswind turn. Due to the low sun angle of the setting sun in the west and since we were flying west into the setting sun; I asked Person A to keep a good look out for the R22. When we were abeam the mid-point of the downwind for runway X; we saw the R-22 on final for runway X. Knowing that the R-22 would need to slow down and come to a hover to land; we extended our downwind an extra mile to give the R-22 time to complete its touch down and to complete its next take off. Person A commented that we were pretty far out and asked me if the engine quit; could we make it back to the runway. I made two additional radio calls stating that we were making a base turn and then a final turn and we were going to make a full stop landing runway X. The R-22 did not acknowledge any of my radio calls. The R-22 had been on the runway for about 30 seconds by the time I was on a 0.5 mile final. The R-22 was positioned in the middle of the runway on the west end of runway X and effectively blocked any ability to land on the runway. Person A suggested I make a go around and I immediately initiating a go around on runway X and made a radio call that we were going to go around; with the hope the R-22 would not take off under us and possibly collide with us. Again; the low sun angle from the west made seeing the R-22 a bit difficult; but we side stepped to the right side of the runway climbed out and passed over the R-22 on runway heading. It should be noted that the north side of the runway is bordered by a tree line; so side stepping to the left side of the R-22 on the runway would have put us close to the tree line. On the south side there are hangars and additional trees; but there are less obstacles. At no time during my down wind; base or final turn; or even after initiating the go around did the R-22 make any radio calls to acknowledge our presence. On the ground; Person B; was at his hangar; which faces the runway and watched the entire episode. Additionally; Person B has a radio on that monitors the CTAF XXX.XX. Later; after we were able to land; Person B told us that he heard every radio call we had made and that they were loud and clear. Person B also concurred that the R-22 had not responded to any of our radio calls. After making the go around; we decide to leave the traffic pattern and fly to the southeast to go look at Person A's house. Person A and I discussed what had just happened and that maybe the R-22 was having some sort of avionics issues. Approximately 10 minutes later we decided to return to the ZZZ airport since it was getting dark and the aircraft is not approved for night VFR operations. During our flight to the southeast; I was monitoring XXX.XX and heard the R-22 making radio calls that it was operating in the traffic pattern for runway X at the ZZZ airport. I made a radio call on XXX.XX; at 10 miles from the ZZZ airport and again at 5 miles; announcing that we would enter the traffic pattern on the mid field down wind for runway X and we would be a full stop landing. The R-22 did not respond to any of my radio calls. I made a normal pattern entry and upon reaching the mid field point on downwind; I could clearly see the R-22 on the runway flying back and forth on runway X / XX. I made two additional radio calls announcing that we needing to land on runway X; as well as the standard base and final turn call outs. Upon turning base; I did not see the R22 on the runway; upon turning final; I saw the R-22 fly back onto the runway. On final I made an additional radio call and I had lost sight of the R-22 in the glare of the sun. Once we descended down behind hills to the west of the ZZZ airport; the sun glare was reduced; and I saw the R-22 on the runway and then pick up to a hover and fly west on runway.At this point; I was unsure what exactly the R-22 pilot was thinking; I had made multiple radio calls announcing our intentions to land on runway; the pilot is not communicating and now the R-22 is facing me. My concerns were that if I did a go around that the R-22 might take off on runway XX and fly into me. Any evasive turns to the north of south would put near obstacles of rising terrain. Additionally; the sun was setting fast at this point and I was concerned about having to make a night landing. I am not night current; the aircraft is not approved for VFR night operations. Landing on runway XX would have put us landing directly into the setting sun to the west. I made five additional radio calls of 'Aircraft landing on runway X; helicopter please clear the runway'. Finally; the R-22 turned off the runway and I was able to land safely. After securing the aircraft; Person B came up to the hangar and asked what happened. He had watched the entire episode from his hangar. Person B again stated that he had heard all of my radio calls; the 10; 5 mile; down wind; base; final and the five calls for the helicopter to clear the runway; loud and clear. Person B also confirmed that the R-22 made no radio calls during this episode. 15 minutes after securing the aircraft in its hangar; I called the President of the ZZZ Airport Board of Directors. Additionally he is a CFI who operates R-22 / numerous helicopters with the flight school. I summarized the entire episode with Person C and Person A provided his concurrence as to what he had seen regarding the actions of the pilots operating the R-22. I expressed that as a CFI; what the CFI / pilot of the R-22 was a safety issue and could have resulted in an accident. Person C said he would try to address the issue. Additionally; Person C acknowledged that he has told the CFIs at the flight school that IAW (In accordance with) the FAR 91.113(g) aircraft landing aircraft have the right of way.Being that I made numerous radio calls announcing our intentions to land; the pilot of the R-22 had well over 5 minutes to understand that we were landing and that they could plan to exit the runway in a timely manner. The CFI / pilot of the R-22 created a safety hazard by not communicating their actions; which could have resulted in a midair collision of our aircraft. Executing another go around was an option; however the setting sun and not knowing if the R-22 was ever going to acknowledge our radio calls; I decided to continue the landing approach and would have landed off to one side the runway to avoid the R-22. The other option could have been to go around and fly to the closest airport; land; and hope that we didn't violate the FAR for operations and equipment at night. It is unclear if the CFI / pilots had the radio volume turned down so they could not hear any radio calls or they were ignoring them; both should be considered safety issues.This is not the first time that I have experienced safety issues with aircraft operated by that flight school. On one occasion; while on short final to runway XX at the ZZZ airport; one of the R-22 helicopters flew out on to the runway and attempted to take off on runway X with no radio calls; directly at me on short final for runway XX. I made multiple radio calls that I was landing on [runway] XX and to please clear the runway. At the last minute the R-22 cleared the runway. I was able to land; but the #2 aircraft in my formation had to do a go around. Later I asked the CFI what had happened; he stated 'it was no big deal; we heard you; we simply didn't turn the volume up on the radio so you could hear us'. This statement made no sense whatsoever. In another episode; one of the R-22s acknowledged my radio call that I was landing on runway XX at ZZZ but stated that they were going to take on runway X and 'stay below you'. I asked them to hold in place until I land; however they took off any way and I lost sight of them. I saw a blur of the R-22 as it passed about 100 feet below my right wing on final approach.