Gene,

 

My first three flights (back in 2000) resulted in flapless landings as a result of a jammed flap motor.  The reed/magnetic switches were just a fraction out and allowed the motor to run to a point where it jammed mechanically.   There was no issue with wiring or relays and a simple 1/4" adjustment of the sliding magnetic switches did the trick.  I think what happens is that adjustment on the ground does not take in to account the extra loading or airflow/drag and the movement of the flaps whilst flying is slightly greater than on the ground.  Thus if your setup is perfect on the ground it can lead to the motor being forced to move a fraction more as a result of airflow in the air.  The result, in my case, was that the motor arm extended to at a point where it jammed.  I have the outback style flap installation.

 

I hope this and the other contributions helps,