Outboard, the wing panels tapered to rounded tips, carrying both the balanced and slotted differential ailerons and hand-operated camber-changing split flaps.

[1][2] The fuselage was a rectangular box formed from spruce longerons, with a ply roof behind the cabin, where a long, multipart canopy enclosed the pilot and passenger's seats.

In front of them the 90 hp (67 kW) Blackburn Cirrus four cylinder in-line, inverted engine was mounted on steel bearers, driving a wooden propeller.

[5] Its tour ended the following July, and it was flown back to Riga by P. Avery in a record nine hours, non-stop from London.

[6] The I-12 was enthusiastically reviewed by the British aeronautical press[2] and Rollasons were designated as distributors after the I-12 had been adjusted to meet UK certification requirements.