Case studies

Omniseal® Rotary Lip Seals
Reading time: 3 min

Helicopter Main Gearbox

    Mark Scoular
Aviation High Speed Low Coefficient of Friction


How would a helicopter main gearbox (MGB) successfully function without the proper sealing solution? Rotary lip seals are widely used to seal the oil lubricant within the gearbox and protect it from leaking out at where the shaft enters and exits the gearbox.


A number of significant helicopter accidents are caused by a loss of lubrication as friction is increased between components, leading to a mechanical failure of gearbox components. 

Helicopter Main Gearbox

The main gearbox, also known as a transmission, is a critical part in a helicopter’s airworthiness and safety because it is responsible for reducing high input speed generated from engines and providing appropriate torque to main rotors and other accessory systems. 


Our customer trusts our polymer lip seals due to their low coefficient of friction, low wear rate at high rotary speed, high thermal resistance, and ability to run dry if loss of lubrication should occur. 

Along with these mechanical properties, our customer finds that the lightness and compactness of our lip seals and their ability to prevent dust and pollutants to enter the gearbox and ruin the gears are also major advantages for using our rotary lip seals. 

Omniseal® Rotary Lip Seal Group

Protecting the skies!


  • Acts as a rotary seal between gearbox and exterior to retain oil in contact with a high speed rotating shaft

  • Wiper design prevents dust and particles from coming inside the gearbox 

  • Adjusts for hardware misalignment, wearing on sealing material is minimal



  • OmniSeal® Polymer Rotary Lip Seal, Series 31


  • Helicopter Main Gearbox (MGB)


  • High-Performance Polymer Material A27

Precision Part

  • Custom Lip Seal

Technical Details

  • Media: Jet Oil

  • Temperature: -55°C to 210°C (-67°F to 410°F)

  • Speed: up to 25 m/s

  • Pressure difference: Up to 14 psi (1 bar)

  • Counter face: Chromium hardened shaft


Tags: Aviation High Speed Low Coefficient of Friction