The Arpin A-1 was a low-wing monoplane of wooden construction and plywood covered. The empennage was carried on a pair of diamond cross section booms mounted on the rear wing spar at the edge of the centre section. The fins were tall, with a slight extension below the boom and carrying unbalanced rudders. The booms were at wing height but the side by side two seat enclosed cabin sat on the wing with the uncowled 68 hp (51 kW) British Salmson AD.9R radial immediately behind, with its centre line well above the booms and tailplane. The pusher arrangement and a short nose provided good visibility from the cabin.