Like several of
Lawrence Brown's early designs, this parasol wing,
Curtiss OX-5-engined version of the wartime
Thomas-Morse S-4 biplane received no type name of its own. Both engine and airframe were available cheaply in the early post-war years. Its wing had a similar area to those of the S-4 and was rectangular in plan. Its structure was largely
spruce, with two box-beam
spars and an
airfoil of Brown's own design. The pilot's cockpit was under the
trailing edge, which had a deep, curved cut-out to assist upward vision. The wing was attached to the fuselage by pairs of near-parallel steel struts, encased in wooden
fairings overlain with
fabric, between the spars and the lower
longerons on each side. Its fuselage was an internally wire braced,
ash and spruce structure with a rectangular cross-section. The OX-5 engine, on a mounting intended to accommodate a variety of types, had its cylinders exposed and a ventilated metal cowling. Behind it, the passengers' cockpit was below the wing and between the spars. Behind the pilot's cockpit there was a curved upper decking that tapered to a tail which differed from that of the S-4, with a blunted triangular
fin and rounded rectangular
rudder. Its ground-adjustable
tailplane was also rounded rectangular in plan, as were the
elevators. The monoplane had conventional, fixed
landing gear. Its wheels were on a single axle, mounted on steel tube legs with rubber shock absorbers and trailing drag struts, both enclosed in wooden streamlining. Its tailskid was made from ash. ==Operational history==