By John Keller
Environmental demands for military and aerospace electrical and electro-optic connectors are becoming ever more pressing as defense systems enter the network-centric age, and as defense planners rely ever more heavily on unmanned vehicles.
The emerging era of network-centric warfare–in which every soldier, weapon, and vehicle becomes a node on a massive tactical information network–means that everything on the battlefield eventually will require connectors, from the soldier in the foxhole to tactical aircraft and orbiting satellites.
All this means that military systems designers are demanding electrical and electro-optical connectors that are lighter, smaller, tougher, and more affordable than ever before.
“One big trend we see in ground forces is they are all linked via communications,” explains John Binder, industry manager for the military and aerospace business at rugged connector supplier Hypertronics Corp. in Hudson, Mass. “This is just another area where we need connectors that cannot fail–in sand, dust, water, changes in thermal conditions, and the constant vibration of somebody walking, or in a tank that is bounding around for days.”
Hypertronics offers the Hypertac system, which uses pin sockets with wire baskets that hug the contact pin as the pin is inserted in the socket. “It is always in continuous connection with all these wires to the pin,” Binder explains. The wire basket inside the connector is ruggedized in a barrel construction to withstand extremes in shock and vibration.
The Hypertronics Hypertac connector system is used in the U.S. Army Non Line Of Sight (NLOS) cannon system, which must withstand the explosive force of the cannon firing as often as 10 times per minute.
Ruggedizing connectors also is a primary goal of Winchester Electronics Corp. in Wallingford, Conn. “We are developing a product that is anti-rotational after it is torqued, so it stays in place,” says John P. Murphy, strategic customer manager at Winchester Electronics.
Aircraft systems designers are particularly sensitive to connectors that use nuts and screws that can come loose after exposure to long-term shock and vibration–even to the extent of using nuts with holes in them that are used to wire the nut to the aircraft bulkhead.
The problem with nuts and screws that come loose is known as foreign object debris (FOD) damage, which can happen when small bits of debris like nuts and screws gets sucked into jet engines while on the tarmac. This can cause costly damage and take aircraft out of service.
Murphy says the major trends he sees in the rugged connector business are light weight, composite construction, rugged-ization, and nuts and screws that cannot inadvertently come loose.
Unmanned vehicles–in the air, on land, and at sea–also are placing big demands on connector designers. “The number-one law of a connector is it must mate; things fail because they lose their connectivity,” says Hypertronics’s Binder.
Unmanned vehicles are different from manned vehicles in that they often can withstand much more severe levels of shock, vibration, and G forces. “In unmanned vehicles you don’t care about shock and vibration because there’s no person in there to take the impact,” he says. “If it’s unmanned, you can go sub-stantially higher than 10 Gs–providing your vehicle can take it.”
Unfortunately, many connectors available today cannot operate reliably through forces as strong as 10 Gs. “If your connector fails, you will lose signal, or you will lose power, and your system will fail,” Binder says.