Designed & Manufactured Solenoid Valve for a 737 Cargo Door Lift Conversion

Many of the projects that are brought to our team at Westfield Hydraulics come to us from customer referrals, as was the case in the project highlighted here. We were asked to design and manufacture a prototype for a cargo door lift conversion kit for the Boeing 737 aircraft. The lift kit is a 4 way, 3 position, 3,000 PSI system that uses Skydrol hydraulic fluid. The design is based on a derivative of an early military design and features a precision manufactured steel and copper solenoid valve that is machined using milling, turning, honing, and lapping equipment. The assembled valve has a height of 3.500”, a width of 2.710”, and a height of 2.500”. To operate reliably and in the tight space allowed, the spool and sleeve clearance was held to ±0.000070”. Quality testing for this product includes testing at an operating pressure of 3,000 PSI with a differential pressure of 40 PSID and a flow rate of 0.1 GPM.

In many respects, designing retrofits or conversion kits is more challenging than designing new products as there are additional constraints placed on the design. In this case, the lift kit had to fit within a very compact space to prevent interference with other structures and components on the aircraft. We managed the qualification of the unit and provided the complete prototype in the short time frame specified by the customer. Since the project was approved, we have produced over 300 of these cargo door lift conversion kits for our customer. For additional details about this custom aircraft retrofit project, contact us directly.