In order to test the propulsion concept, EWR produced a test rig, called the "Wippe" (seesaw), during early 1960. The simple device incorporated a rudimentary cockpit fixed upon a horizontal beam, which had a "lift" engine mounted vertically at the centre, for the purpose of performing preliminary single-axis tests of the control system. A later "hover rig" was assembled, which had the skeletal fuselage of the VJ 101C along with a total of three Rolls-Royce RB108 engines installed in the approximate positions that they would occupy in the final flight-capable version. The small engines each could generate a maximum of thrust, enough to lift the test rig. Starting in May 1961, initial testing was conducted from a telescopic column, in March 1962, the new rig conducted its first "free flight" successfully. Additional tests performed with a cloth "skin" to simulate the fuselage and wings proved to be successful as well, having demonstrated satisfactory control throughout all seasons and weather conditions.