Taildragger,
I had the exact results you had with my h9 p-51. The gear sux. It collapsed just siting on the ground idling. Same line from horizon. Nothing we can do. So I said fine. I have bought 3 funtanas. I will never buy another plane from them if it has retracts. The P-51 as well as the AT-6 are very good looking and flying airplanes. You just have to either modify or buy new retracts end of story.
Al Renkel