Have you ever seen a powered parachute touch down on the runway a little too hard and witnessed the flexing of the main rails?  Have you ever taxied your powered parachute down a less-than-perfect airstrip and found yourself doing a little more bouncing than you appreciated?  Most PPC pilots can relate to these circumstances.

It is typical for the main rails of a powered parachute to distort at their critical load point approximately midway along their length.  In most cases this distortion is temporary as the rails respond to normal loading and rebound in accordance to the properties of the material used in manufacturing.  Any unsupported beam-type of construction is subject to these characteristics regardless of the type of material used.  In circumstances of over loading, the beam will not return to its original position and, hence, you will develop bent rails.  Such action is cumulative.  That is, even the most rigid materials slowly give way with repeated overloading and will eventually indicate a downward sag.  We have all seen machines in this condition.

The triangulated structure of the Blue Heron Undercarriage Truss System provides the needed support for the critical load point of the rails.  The truss system, optional equipment on Marathon, Express Convertible, and XC-912 models, is easily installed beneath each rail running from the axle to the nose section, and can be accomplished in about 15 minutes.  The ability to adjust the tension of the truss and to therefore pre-load a counter-arc to the rail tubes themselves, further prevents rail flexing and material failure.  This is similar to the arc that can be seen on a typical flatbed trailer before it is loaded.

Many of the advantages of this system are obvious, especially the additional support given to handle the harder than normal landing.  One of the greatest benefits of this system, however, went unperceived.  Side-by-side testing showed that the Blue Heron with the Undercarriage Truss System plants the aircraft firmly on to the runway upon touchdown and maintains a more stable taxi roll.  There are  two reasons for this.  First, the rigidity of the supported rail components prevents the more typical spring action on the rail materials.  Secondly, due to the rigidity of the rial support system, adverse landing and taxi forces are transmitted to the rear axle of the aircraft where the spring rods and shock absorbers properly handle these forces.

The Undercarriage Truss System has been awarded PATENT PENDING status by the US Patent and Trademark Office.  It is optional equipment on the Marathon, Express Convertible, and XC-912 model aircraft, and is available as a bolt-on kit for previous-generation aircraft.  The cost is $90.00 for the complete set.  The truss system is also available for all other major manufacturers 2-place aircraft.  Contact us for more information.