A Navion A landed hard on RWY 01 after an attempted go-around. The pilot indicated that he was landing to the north with full flaps and discovered he had a gusting tailwind. He initiated a go-around and at 50 ft AGL he brought the flaps up halfway. The aircraft settled and landed hard on the runway. The winds were reported from 150 deg at 10 kts 24 nm west of the airport. The Flight Training Handbook, Advisory Circular 61-21A, cautions pilots about the premature retraction of flaps during a go-around. It states, 'Caution must be used in retracting the flaps. Depending on the airplane's altitude and air speed, it may be wise to retract the flaps intermittently in small increments to allow time for the airplane to accelerate progressively as they are being raised. A sudden and complete retraction of the flaps at a very low airspeed could cause a loss of lift resulting in the airplane settling into the ground.'