D38999 Specials: Flexible Design for Reliable Performance

D38999 specials are available in several options, but two types standout. The first type is aluminum nickel bronze MIL-DTL-38999 connector. The aluminum nickel bronze special is popular in aerospace and defense applications, such as military ground vehicles and some shipboard applications. Unlike conventional 38999s, which are manufactured in aluminum with various plating options and include a plastic composite material and stainless-steel elements to resist high temperatures, the aluminum nickel bronze 38999 specials are made of highly corrosion-resistant materials that are equal to, if not better than, stainless steel, meaning that these are engineered to provide significantly better anti-corrosion protection than aluminum.

The second type is the hybrid 38999 series 1.5, an option that has evolved over the years. There is no such specification for 38999 series 1.5, but it is a nickname of a commercial 38999 connector family that uses the scoop-proof coupling interface lengths of 38999 series I, and the diameters and mounting sizes of 38999 series II. DEUTSCH 38999 connectors Series I, III, and IV are standard connectors.

Our D38999s are built for reliability in technology that must operate without unexpected failure. All TE 38999 product derivatives are designed to mil-spec standards and validated through TE-controlled processes and field-proven reliability from years in use. These products are often used as commercial options, but they are still used in harsh environments.  

This group of 38999 specials is rapidly evolving at TE. Unlike the first group of 38999 specials, these product derivatives are not part of a product line. These connectors offer several modifications to the standard product and are designed to help engineers resolve unique connection challenges. For example, one of the newest 38999 specials is a high vibration plug connector that is rated higher than standard qualified D38999/26 plug connectors.

This group of 38999 connectors are crucial when trying to design a system that requires fitting many components – microprocessors, diodes, resistors, thermal management system, and capacitors – into a single box. In such cases, it is not uncommon for engineers to simply run out of the space needed for the input/output connector. And what they find is that the standard 38999 connector will not solve the issue. What they need is an application-specific connector, one that improves upon what exists, allows, or meets the 38999 standard connector.

When building a box, the standard approach is to mount receptacles onto the box. We typically supply crimp contacts with our D38999s. This enables installers to terminate the wires to the contacts, to the back of the connector and onto the back of the box, where there is usually a plug with a cable harness attached to it. The cable connects to the core application – aircraft, ground vehicle, radar system, or others.

For these types of applications, it is often critical to build smaller and lighter boxes to save on size and weight, which enables the aircraft to save on fuel and fly at increasingly faster speeds or soldiers to carry advanced technology over long distances. To enable this, instead of using the crimp contacts that come with our standard D38999 connectors, engineers remove connectors extended from the back of the box and solder the printed circuit board directly on the back of the connector inside the box. Our portfolio of D38999 specials includes three types of product derivatives: PC Tail connectors, 38999 Mounting Flange, and Integral Rear Banded Platform.

When the engineering challenge is unique, TE engineers can develop a fully custom 38999 connector to address a range of requirements. This includes designs new to the market and unique to the application yet fully using mil-spec standards in a 38999 connector that requires more than a simple or mid-level change. Customer requests for fully custom 38999 connectors are infrequent, mostly because of the longevity of this product in the marketplace, and because most previous iterations of customs have been adopted into product line derivatives.

One example of a fully custom 38999 connector is one that was developed 20 years ago. It is primarily used in applications to launch munitions from aircrafts. This connector uses the mil-spec principles of standard 38999 connectors – as well as other circular connectors – to deliver high reliability when used in harsh environments.

Because a fully customized connector does take time to develop and manufacture, customers typically engage with us early on in their design process, giving us enough time to meet their product requirements. Development timelines can range from four months to a few years, depending on the complexity of the designing and the machining required to produce it.