Natick Letter with Changes_Redacted.pdf

This document is a memorandum from the U.S. Army Natick Soldier Center (NSC) Aerial Delivery Engineering Support Team (ADEST) detailing preliminary changes to Helicopter Sling Load (HSL) Training Blocks, specifically for the 4000 lb Training Block. The changes include modifying material specifications, adjusting design parameters, and standardizing construction requirements. Key modifications involve changing the lift eye material from 440C Stainless Steel to 1018 or 1020 Cold Rolled Carbon Steel, adding a surface finish for corrosion resistance, and reducing the block's length from 138.5 to 95.0 inches. Additional changes include reducing the number of reflectors from 22 to 16, reducing lateral vertical rebar loops from 23 to 15, and maintaining the concrete in its natural color without added dye.

The document provides technical specifications for the 4000 lb Training Block, including detailed design requirements such as marking the sides with 8-inch high black "4000" characters, specifying material standards (ANSI 1018 per AMS 5069), and outlining testing procedures. The training block is intended for proof load testing, with a block weight of 4000 lbs and a load factor of 3.5, requiring inspection of lifting provisions and concrete structural integrity. The modifications aim to standardize the training block's design and performance characteristics for military sling load training purposes.