with the turning bar at a location downstream from the slit whereat the air cushion is moving substantially the same direction as the web if web w were to approach the slit too closely it would be subjected to undesirable suction forces that would tend to pull the web downwardly if desired suitable adjustment mechanism not shown may be associated with the turning bar to enable an operator to 34 fine tune 34 positioning of the bar slit relative to the web to optimize results lateral air loss from the cushion supporting web w is prevented by employing two sidewalls 46 and 48 along the edges of the generally curved fluid flow attachment surface additional control over the characteristics of the air cushion may be provided by employing a suitable means of varying the width of the slit along its length to establish a desired air flow profile it has for example been found that by making the slit wider in the center than at the edges more air cushioning in the middle of the web is obtained which creates cross machine spreading and improved guiding of the web in essence this provides for a crowning effect in the web whereby wrinkles will be removed the turning bar may thus be used to accomplish the objectives of a far more expensive mount hope roll without contact with the web slit thickness variations may be accomplished through the use of any suitable expedient such as the employment of shims 50 or a screw adjustment mechanism of the type.