Analysis

With the consideration of the success of this project, all attributes will be tested in the most extreme cases. For example, the lateral arms of the trailer must extend a certain distance away from the trailer to ensure stability. This can be done via a simple summation of moments.

Two other critical assessment areas concern the strength of the cable needed to draw up the vertical mounting legs, as well as the surface mounting hardware. The strength of the cable need to keep the trailer leveled was derived from a static stress analysis, taking into account how much weight each of the leveling arms will carry. In this scenario, two lateral trailer arms on the same side of the platform are carrying half of the weight of the trailer, 2500 lbs. each. Using an outside reference, it is determined that if using a half inch diameter steel cable, a safe load of 4,280 lbs. and a minimum breaking force of 21,400 lbs. can be incorporated into the design.

To determine the size of the bolts needed to hold down the pulley that re-directs the steel cable from a horizontal fashion into the vertical extending arms, a reference table in ‘Mechanical Elements in Machine Design’ is used. After determining that a grade 5 bolt is a suitable choice, a relation between the proof strength and tensile area is created to determine the diameter needed of a chosen number of bolts required to ensure that the pulley will remain stationary..

Square tubing is chosen for the lateral arms so that there is no unwanted rotation. The beam geometry is decided by taking into account the length of the inside beam, outside beam, and how much each overlap when at full extension. A shear and moment diagram are drawn up when considering propeller thrust and trailer weight. Using a bending equation to find an ‘S’ value, a suitable beam can be chosen from ‘Mechanical Elements in Machine Design