Thanks for all the comments. I found them very helpful. I certainly agree with Michael and the need for instruction. I learned this after "endo" #3 going downhill when a car pulled out in front of me. I must have been unconcious for a second or two as I don't remember any from seeing the car and coming to on the ground. Anyway, I realize that in all the riding I was doing, I had never even practiced an "emergency stop." How stupid of me? After that I did them over and over until my muscles reacted before my brain.
"Endo #4" was also going downhill when my rear tire went flat (I didn't realize it...my first flat.) The front tire became very slightly unstable and almost imediately I was over the top. I do not have a good explanation as a rear flat should not cause this.
I have discovered the broken bones were probably caused by the onset of osteoprois.
So I have an explanation of the broken bones, but not the falls.
Thanks again for your advice.
Ron
PS: After all the reading I have done on recumbents, I think I have decided to get one regardless. They sound like a lot of fun.