 The towing arm was fitted with a sprung force stem, contrived so that the tow arm 'floated' horizontally at zero relative weight.Each front corner of the chassis was fitted with a swing-out A-frame boom equipped with a screw jack and foot plate.The booms enlarged the Meillerwagen footprint to stabilise it during erection of the rocket, and provided a means of adjusting the Meillerwagen transverse level.