Static and Dynamic Evaluation of A-37 Cast and Cast Carcass/Integral Tread Tires

摘要

This report describes work undertaken during Phases II and III of a three Phase program initiated with Zedron Inc., to establish the potential of cast tires for application to Air Force aircraft. Phases II and III involved static, quasi-static, and dynamic laboratory test and evaluation of 30 cast 7.00-8 Type III aircraft tire designs. These designs included tire carcasses which were rotationally cast/molded from thermoplastic polyester elastomer materials (Hytrels) of various hardness with and without reinforcements. Three basic cast tire designs were developed and evaluated during Phase II efforts; the one-piece cast tire, the cast carcass/replaceable tread tire, and the cast carcass/integral tread tire. The development of the one-piece cast tire was terminated after three design iterations (15 tires) were evaluated due to its shortened dynamic life caused by tread groove failures (areas of high stress concentration). The development of the two-pieces cast carcass/replaceable tread tire was terminated after two design iterations (10 tires) were evaluated primarily due to tread derailment problems. These designs, however, represented a considerable improvement over the one-piece cast tire designs as the tread groove failures (areas of high stress concentration) were eliminated by replacing the thermoplastic material with conventional tire materials in the tire tread. Twenty-five integral tire design iterations (105 tires), some of which included glass reinforcement, were tested and evaluated to the A-37 aircraft main gear tire specifications.