One of the tractor biplanes had an airfoil of flat section, a stabilizer and no rudder, 2 wheels and a single skid, and an Anzani motor - perhaps the same one as in the helicopters. The other had wide fixed flat spars in each wing, with wide trailing sections like sails attached for the full length of the wings. The tractor propeller was mounted far forward with the engine amidships; the fuselage was a long box uncovered except for the top surface. A curved rudder and broad tailplane brought up the rear; the whole machine ran on 2 wheels and a double tailwheel.