[1] The P 5 had an approximately rectangular plan wing apart from blunted tips and was built in one piece around twin spars with plywood covering.

The wing was braced to the fuselage on each side with a parallel pair of steel tube struts from the lower longeron to each spar.

[1] The P 5 was powered by a 22 kW (30 hp) air-cooled flat twin Haacke HFM-2 driving a propeller designed by the brothers and mounted within a metal cowling with its cylinder heads exposed for cooling.

Behind the engine and its fuel tank the fuselage structure was rectangular in section and was ply covered, flat-sided apart from rounded decking.

[1] Its fixed landing gear had large mainwheels on a single axle, supported via rubber cord shock absorbers by steel V-struts at either end.

[1] The P 5 was completed in June 1921 and moved to the local flying school's airfield where Jan Gabriel took it on its first flight early in September.

Access to the cockpit was improved by replacing the trailing edge flap with a semi-circular cut-out which reduced the wing area by 0.3 m2 (3.2 sq ft).