FACTORS AFFECTING THE ICING RESISTANCE OF LUBRICANTS FOR AIRCRAFT ORDNANCE
Abstract
Recent samples of the all-weather semifluid lubricant for aircraft ordnance, both from manufacturers and from Navy stocks, have failed to meet the cold-sweat-cold gun firing test required by Military Specification MIL-L-19701 (NOrd). These failures were due to ice adhesion attendant on the poor water resistance of the lubricants. The probable cause of the loss in water resistance was the presence in the lithium stearate thickener of surface-active impurities such as sodium soaps and soaps of myristic and oleic acids. These impurities can be detected by measurements of surface tension lowering. It is probable that the water resistance of other lithium stearate thickened greases are also affected by these impurities. The investigation established that variations in raw materials other than the soap were not major contributors to the difficulties encountered. A lubricant of altered formulation has been developed and shown to be superior to the original lubricant. Variations in the consistency of the improved lubricant over a wide temperature range were found to be much less than those of the original lubricant. Resistance to water and to ice adhesion are increased. This material has successfully lubricated the Mk 12 machine gun equipped with the Mk 7 pneumatic feeder under ambient temperature and cold-sweat-cold conditions. This formulation retains all of the useful properties of the original lubricant, such as compatibility with MIL-P-5516 oil- resistant rubber, resistance to evaporation loss, corrosion inhibition, and antiwear protection.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 21, 1965
- Accession Number
- AD0624594
Entities
People
- H. R. Baker
- R. N. Bolster
Organizations
- United States Naval Research Laboratory