Pinecone wrote:The skis on the polished 180 with green accents, N32050, in the 2018 pictures caught my eye. The hydraulic cylinders are exposed, not like Flyidynes/Wiplines that I’ve seen in pictures. Can anyone comment on them?
Those are Federal AWB skis, not sure but maybe AWB 2500A.
The more visible cylinder is a “Rigger”, which establishes and controls the attitude of the skis. It permits the skis to ride over irregularities on snow, but keeps the skis level in flight. That rigger replaces the bungee equipped primary cable on front of ski. Still a “limit” cable up front, to prevent ski from going over in the event the rigger failed.
The other cylinder barely visible is the retract/extend hydraulic cylinder. There is an arm that attaches the skis to an inside stub axle. The skis rotate on this stub axle.
Unlike with the Fluidyne/Wipaire C series retractable skis, the AWB skis place the entire weight of the plane on that arm when skis are down. With the Fluidyne, the weight of the plane rests on the tires, which rest on the ski tops.
The AWBs have different length arms, depending on model. The “A” models have longer arms, and will accomodate 8.50 tires. Some of our Cubs wore these skis, with modified arms (lengthened) Which let us run 25 inch Goodyear Airwheels with these skis. Which is how you spell “heavy”.
MTV