Lockheed Martin delivered F-35s without the new fire control radar due to delays. Instead, ballast is being installed in it's place under the nose cones to maintain the flight characteristics perfectly.

As development and testing of the APG-85 are delayed by cooling and power-consumption challenges, new fighters are rolling off the assembly line with empty nose pods.

To maintain aerodynamic balance and flight characteristics, ballast is installed in the aircraft’s nose. 

 The AN/APG-85 is designed by Northrop Grumman for the Lockheed Martin F-35 with a 50% improved range (via higher power Xmission compared to its predecessor, the AN/APG-81

https://militarnyi.com/en/news/lockheed-martin-delivers-f-35-without-an-apg-85-due-to-delays/

As of February 13, 2026, the U.S. Air Force has officially denied reports that it received F-35 fighters with “empty radomes.”

-Instead, the USAF clarified that Lot 17 aircraft are currently delivering with the older AN/APG-81 radar sets

However, I read online that those do NOT fit in the F35 radome

-These setbacks contribute to the F-35’s ballooning lifecycle cost, now estimated at a staggering $2.1 trillion through the 2070s.

https://www.19fortyfive.com/2026/02/why-the-f-35s-new-super-radar-is-forcing-the-air-force-to-use-20-year-old-tech/

Holy shit, I still understand radar. I was a radar tech in the Navy (and a machinist mate (mechanic) and a quartermaster (charts and navigation) and an MP) and fixed radars at Raytheon