Seeking better airdrops

Inside the Roller Load Test Facility

By Jeffrey Sisto on September 12, 2013

Among the many testing capabilities housed at the Natick Soldier Systems Center, the Roller Load Test Facility offers the unique ability to simulate the roller and rail systems used in aircraft to deliver cargo airdrops - all while still on the ground.

Recently, engineers at the U.S. Army's Natick Soldier Research Development and Engineering Center used this facility to collect data samples taken during simulated roller load testing in an effort to develop the airdrop requirements of the Caterpillar 924H Wheel Loader - a multifunctional, front-end bucket loader used in the construction of airfields, roads, defensive berms, and demolition on the battlefield.

The facility allows engineers to see the force exerted on the rollers that move a cargo payload out of an aircraft during delivery. By recording and analyzing this force, engineers can identify the stressors placed on the rollers and determine if they meet the requirements to perform an airdrop of certain equipment payloads from various aircraft models.

Ultimately, the goal is to mitigate the force applied to aircraft rollers and airframe by the heavy equipment airdropped into combat theaters of operation.

Sensors along the roller track send readings about the weight and force of the cargo load to the control room computer, which records them in a database. The computer screen shows rows of numbers corresponding to the rows of rollers on the roller bed. The numbers are in constant flux, displaying minute changes as the weight exerted on the rollers slightly moves. A row highlighted in green indicates it is currently within its weight capacity.

If the weight limit for a roller is exceeded, the row is highlighted in red to show the engineers exactly which roller(s) are over the limit. When this happens, engineers must recalculate the weight dispersal, which often means they must adjust the honeycomb structures they have placed at key contact points throughout the load to absorb the impact of the drop.

Once the roller simulation testing is completed, the next step is to go through "tie-down" restraint development. This involves checking and rechecking all the restraint forces used in the trying, strapping, and taping of the equipment to the platform, which often can interfere with the suspension slings.

Securely strapped and tied down to the platform, rigged load data for the cargo load must be collected, having its height, width, and weight sampled, and center of gravity calculated. Only after the data is collected and validated, is the cargo load is ready for the next step - a Simulated Airdrop Impact Test - a new title coined by Moorachian to replace the old, inaccurate one of "Static Drop Test."

When it ultimately arrives in the hands of soldiers fighting in austere locations around the world, it will have been the work of the NSRDEC's Airdrop and Helicopter Sling Load Certification Team at Natick's Roller Load Test Facility that got it there.

Jeffrey Sisto is a journalist with the Natick Soldier Systems Center in Natick, Mass.