Design Selection Tests for TRAC Retraction Mechanism.
Abstract
An investigation was conducted to select appropriate materials for and to demonstrate the satisfactory operation of a fullscale jackscrew and nut assembly for a TRAC variable-diameter helicopter rotor blade. The investigation successfully demonstrated the operation of a suitable material combination in the jackscrew/nut configuration, with more than 300 full retraction-extension cycles under full design load and rotational speed conditions. The operation of the system improved significantly as the test progressed, with the coefficient of friction, the temperature rise, and the wear rate all decreasing with time. This result confirms that successful full-scale development of the TRAC rotor concept is achievable. It was concluded that a wear life on the order of 1000 retraction-extension cycles can be achieved in a production design. A materials evaluation phase of the investigation utilized rings of selected material combinations to simulate a single thread contact. The preferred material/lubricant combination that emerged from these tests was a high-strength maraging-steel screw, coated with vitrolube dry-film lubricant, and a carbon-graphite nut. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1977
- Accession Number
- ADA037307
Entities
People
- Harold K. Frint
Organizations
- United Technologies Corporation