• Combat helicopters are vulnerable to sudden loss of transmission
lubrication due to enemy fire
• Increasing the transmission life after sudden lubrication loss increases the probability of finding a suitable emergency landing site and directly saves lives
• The performance of standard bearings and Dicronite dry lubricated standard
bearings was compared under sudden lubrication loss conditions
• Bearings: M-50 steel roller bearings
• Load: 114Kgf (250lbf) radial load
• Speed: 10,000 rpm, inner race
• Lubricant: MIL-PRF-7808 lubricant at 65°C (175°F)
• Under normal lubricated conditions, the outer race temperature measured
• Under lubrication loss conditions, standard bearings failed at a maximum time of 6 minutes, minimum time of 3 minutes. An outer race temperature of 154°C (335°F) was measured at failure time.
• A Dicronite dry lubricated bearing ran for the duration of the test (38 minutes), under lubrication loss conditions, a six fold increase. An outer race temperature of 204°C (425°F) was measured.
• Dicronite dry lubrication increased bearing life sufficiently to enable an emergency landing per the military’s test conditions.Download as PDF