Hi-Endurance Switching, Sensing
& Linear Position Sensors

Thermal Switches for Military and Commercial Jets

In a past life I was privileged to work on the very first fly-by-wire system used on the F16. This was the first system of its type used in an operational jet fighter utilizing a quad redundant custom designed CPU and optical fiber to relay cockpit commands to control surfaces in a matter of milliseconds. The project was a joint development between General Dynamics (Now Lockeed Martin) and the now defunct Bendix Flight Systems Division and development took several years. I watched our computer go up during first flight back around 1986 and the test pilots were universally complementary about the responsiveness of the system and especially the fail-safe digital backup unit which was way more functional and flyable than the analog DBU’s that they were used to.

The F16 and its digital upgrades continue to this day. Since then there have been thousands if not millions of improvements large and small to the F16 which remains a staple of NATO, US, and allied air forces around the world. It was at one time the most deployed fixed-wing aircraft in the world serving over 25 nations. And while the F16 is no longer being procured for the US Military, they are still being built and sold to friendly air-forces around the world. The F16 was a great design and had quite a run.

One aircraft in our inventory however, hasn’t had a major upgrade in over 5 decades. It’s the T38 Talon, used to train almost all our jet pilots for the last 50 years. Production of this aircraft actually stopped in 1972 and it lacks capability for upgrade to much of the current generation avionics and display technology. Finally however, after a tough competitive bid process between the Lockeed Martin T50A and Boeing, the Air Force is finally going to do something about it. In 2018 the Air Force awarded Boeing — along with partner Saab — a $9.2 billion contract to procure 351 advanced pilot training aircraft and 46 ground-based training systems.

The new trainer is called the T7A “Red Hawk” trainer, and represents an all new airframe design that is considered 5th generation. As such it will have capabilities that allow it to be the training bed for modern F22 and F35 pilots.

The Red Hawk — which features a single General Electric F404-GE-402 engine and can reach supersonic speeds — is also the service’s flagship “e-Series” aircraft, a designation given to systems designed, built and tested using digital engineering techniques. Service officials hope the process will allow companies to catch problems faster and develop systems more affordably.

The T-7A completed its critical design review in August 2020, which marked the end of the design phase and the beginning of the build and test segment of the program, according to the Department of the Air Force’s Acquisition biennial report for 2019 and 2020.

Ultra-Modern Jets, yes, but with the same ageless challenges.

While many applications for thermal controls have gone the way of remote switches and local sensors, there is still a place for the hardened, standalone, autonomous thermal switch. One of those places, may well be the avionics bay of the Air Force’s next generation of fighters like the T-50A and the Red Hawk.  With concerns around fail-safe operation, and various “golden bullet” scenarios, a locally active thermal switch is still the best solution for monitoring temperature in many avionics applications.

CPI has supplied reliable thermal switching solutions to various major aircraft manufacturers worldwide for applications in the avionics bay ECS, APUs, compressors, galley equipment, for hydraulic fluid temperature monitoring, and many more. Our most common aerospace designs have been qualified per RTCA DO-160C and MIL-STD-810.

General Product Features of CPI Thermal Switches

temperature_switchesAll CPI thermal switches are designed and manufactured in the USA at our East Hanover NJ facility. Most commonly used is our M series thermal switches referred to as our “Plug-Stat” series. Contact movement is achieved via the different expansion rates of two metals fused together. This is a slow-make-and-break device, which provides very close tolerance temperature sensing, with a small differential and a set point range: 0°F-650°F (-17.8°C-343°C). For those requiring even higher temperature operation, our Rod & Tube series can operate reliably at set points up to 1750F.

In general CPI’s line of thermal switches have the following characteristics and options:

  • Capable of setpoints from 0 to 1750F
  • Hermetically sealed designs available
  • Glass-sealed MIL connectors
  • Thread and surface mount designs
  • Various probe lengths
  • Meet the requirements of RTCA DO-160C, and MIL-STD-810

Call CPI today for more information about proven thermal switching solutions for commercial and military avionics.

Make The "Switch" to CPI

If your momentary switch application demands high performance, we think you should demand CPI. Please call us today to speak with our engineering team about your needs.

(973) 887-9400