Cotta Tech Talk – High-Speed Gearboxes Used in Major Aerospace Manufacturer’s Grid Lab

A major customer of Cotta is using our high-speed gearboxes in conjunction with a device called a dynamometer to spin generators used in jet aircraft. The goal is to bring hybrid electric propulsion to aircraft.  The Grid is an advanced electric power systems lab. The lab will allow our customer to develop electric motors, controllers, generators and distribution systems to achieve electrified propulsion on jet aircraft. As with automobiles, the effort to electrify propulsion is part of an industrywide goal to reduce carbon emissions. Testing helps improve the energy efficiency of jet aircraft to reduce the plane’s operating costs and meet regulatory requirements of a low-carbon economy. For over 50 years Cotta has been offering a broad range of high-speed gearboxes that can be used in a wide range of applications.

Today our gearboxes are being used by major aerospace commercial, business and military jet aircraft manufacturers such as Boeing, Bombardier and Lockheed Martin along with engine and component manufacturers such as Pratt & Whitney, General Electric, Collins, and Honeywell to name a few. Whether it is for R&D or a production test stand Cotta can customize a high-speed gearbox to meet your exact needs.  Contact Cotta today to learn more about our extensive line of high-speed gearboxes.

Cotta Tech Talk – Gearbox Repair Services

In the heart of industrial operations, Cotta gearboxes play a crucial role in ensuring smooth and efficient production. However, with the increasing demand for continuous operation, critical components of the gearbox can often malfunction or break down. This is where Cotta steps in, offering comprehensive and specialized gearbox repair services designed to get your operations back on track quickly and reliably. Cotta has a clear understanding of these causes and employs a meticulous repair process that ensures that gearboxes are restored to optimal performance.

Common Causes of Gear Failure

1. Wear-Related Issues:
   • Moderate Wear: Caused by inadequate lubrication or contamination, leading to surface damage in the addendum and dedendum areas1.
   • Excessive Wear: Progression of moderate wear results in significant material loss, often accompanied by pitting.
   • Abrasive Wear: Radial scratches or grooves caused by foreign particles like metal debris or sand in the lubricant.
   • Corrosive Wear: Chemical reactions from moisture or additives in lubricants leading to fine pitting on gear surfaces.
2. Surface Damage:
   • Frosting: Micro pits on the surface due to heat breaking down the lubrication film.
   • Spalling: Shallow, large-diameter pits caused by high contact stress.
   • Pitting: Initial pitting results from improper gear fit, while destructive pitting occurs due to surface overload.
3. Mechanical Failures:
   • Breakage: Teeth break off due to high stress or excessive loads, leaving evidence of fatigue at the failure point.
   • Misalignment: Poor alignment causes uneven wear and premature failure.
   • Overloading: Excessive loads on gear teeth or shafts result in stress beyond design limits.
4. Lubrication Issues:
   • Insufficient or improper lubrication leads to overheating and friction between metal surfaces, causing gear and bearing damage.
5. Contamination:
   • Dirt, sand, or metal particles in the lubricant cause abrasive wear and seal failures, leading to leaks and reduced efficiency.

Gearbox Repair Process

Cotta employs a systematic approach to repair gearboxes, ensuring that all issues are addressed effectively:

1. Initial Inspection

• Perform a visual and functional assessment of the gearbox to identify external damages, leaks, or misalignments.
• Assign a unique job number and document the gearbox condition with photographs for reference.

2. Disassembly

• Carefully disassemble the gearbox to avoid further damage.
• Catalog each component for inspection and future reassembly.

3. Cleaning

• Remove all grease, debris, and contaminants from components to allow accurate inspection.
• Clean internal lubrication systems to prevent future contamination issues.

4. Failure Analysis

• Inspect gears, shafts, bearings, and seals for wear patterns, cracks, or other signs of damage.
• Conduct non-destructive testing on reusable parts to ensure safety and performance standards are met.

5. Repair or Replacement

• Repair damaged components through machining or welding.
• Replace worn-out parts such as bearings, seals, and gaskets.
• Reverse engineer and manufacture new parts if original components are unavailable or beyond repair.

6. Reassembly

• Reassemble the gearbox with precision, ensuring proper alignment of gears and shafts.
• Apply fresh lubrication tailored to the specific gearbox requirements.

7. Testing

• Conduct thorough performance tests such as no-load spin tests to verify functionality.
• Check parameters like backlash, tooth contact patterns, and shaft end play for compliance with original specifications.

8. Final Quality Assurance

• Repaint external casings for corrosion resistance.
• Package the repaired gearbox securely for transport back to the client’s facility.

By combining expert diagnostics with precise repair techniques, Cotta ensures that repaired gearboxes meet or exceed their original performance standards.
This comprehensive process minimizes downtime while extending the operational life of your equipment.

Powered by Custom-Engineering Expertise: Did you know?

For more than a century, Cotta has been a driving force in the design of heavy-duty transmissions. Charles Cotta engineered his breakthrough constant-mesh shifting transmissions in 1906 and soon supplied the emerging automobile and truck industries with main transmissions. Cotta shifted to industrial products and the off-highway vehicle market in the 1940’s and then, two decades later, we added a line of high-speed gearboxes. Today, Cotta is the premier leading manufacturer of top-quality, precision-engineered gearboxes for many specialized mobile and stationary applications such as: vocational trucks, defense, off -highway, aerospace, heavy industry, well-drilling, mining, marine and much more.

Cotta designs in accordance with SAE, AGMA, ISO, and API standards to ensure product quality and to support our zero-defect policy. We have over 5,000 existing product designs available, plus our experienced engineers and craftsmen can take any new transmission application from concept to delivery at our production facility here in Beloit, WI. You don’t have to be a gearbox expert with Cotta as your source. Whether you need a standard, modified standard, or a completely new design, our engineering team will work with you to meet your specific requirements, effectively and efficiently. Cotta’s engineers and designers work with our customers to develop solutions and then deliver drawings in virtually any CAD format to drop into the customer’s own design.

High-performance products. Collaborative team of experts. Solving problems and exceeding expectations. We are Cotta.

WWETT 25: Did you know?

Reggie Williams from Cotta, LLC will be WWETT 2025 on February 19-20 in Indianapolis, IN to network with team members from Wastewater OEMs, Environmental OEMs, and MROs – as well as learn about new products and emerging trends in the industry. If you’d like to setup a meeting at the show, please email sales@cotta.com.

Our State-of-the-Art Testing Facility: Did you know?

Cotta has earned our reputation as a preferred high-performance gearbox supplier by consistently improving our current products while developing new innovative ones. We comprehensively monitor the quality of all internal processes. First-piece inspection is conducted on every machining sequence, starting at the source to support our zero-defect policy, and then we assemble and test every product shipped from our plant.

To further enhance these capabilities, we invested in a state-of-the-art gearbox test facility that includes three programmable cells for High-Speed, Low-Speed, and Special Purpose Testing. Our onsite test lab is just one more reason why customers choose to work with us. Schedule a visit to Cotta and see it!