What's the story on the different chin pods?

[Nealius]

Was digging around on Tomcat history and noticed there were so many variations of the chin pods:

 

First just the ALQ-100, then an IR sensor, then IR was replaced by TV, then TV removed and covered with an aerodynamic cover, then both TV and IR sensors were added, then the TV sensor was removed and replaced with an aerodynamic cover again.

 

But I can't find any deeper explanation. Why was the TV sensor removed? Twice?

[near_blind]

I'm assuming you're referencing this or something similar:

 

http://www.anft.net/f-14/f14-detail-chinpods.jpg

 

Broadly speaking the evolution goes as thus: The F-14 was originally planned to have an IRST like the F-4, F-8 and other aircraft that proceeded it. Generally the rationale of the time is less because airedales were overcome with fantasies of becoming air ninjas like you see in today MP, and more ECM was rapidly becoming much more powerful and capable and there was real concern that strategic bombers using powerful jammers would be able to negate the radar. A passive means independent of radar capable of detection and potentially cueing the radar was considered appealing if not necessary. Problem is that IRSTs of the time were largely ineffective in actually finding or tracking targets except under the most optimal conditions. They weren't used, and if you're not using it there's no point paying to maintain them, so they were ultimately removed from the aircraft in the late 70s/early 80s.

 

Eventually someone had the idea to mount a variant of the ASX-1 TISEO system used on USAF F-4Es in the spot formerly occupied by the IRST for similar ends: passive, independent search and track. This ended up being the AAX-1 TCS we all know and love, and was fitted on most (if not all) F-14As and by extension A+/Bs starting in the mid-80s.

 

By this time the technology to create an IRST sensor sensitive enough to track potential targets and the computers powerful enough to filter out shenanigans had been developed to make that type of sensor practical in a fighter. Development of the F-14D was ongoing at this time, and it was decided to keep the existing, functional TCS system, but pair it with a new IRST to give the aircraft greater flexibility and redundancy when passively tracking targets.

 

Lastly the sketches/images of aerodynamic covers are not meant to imply the entire Navy woke up one day and decided they needed to rip all the TCS's out of their jets for a few years, twice. Things on aircraft break periodically, especially in a deployed state. The TCS isn't a system critical to the basic operation of an F-14 so the aircraft will still be flown without one present, however you don't want to leave a gaping hole flapping in the slip stream. Hence the aerodynamic cover over the hole until that TCS unit (or another) can be put back in the jet.

Edited December 7, 2019 by near_blind

[Nealius]

Ah, that makes sense. While building model kits, the instructions say to use one of those covered "broken" TCS pods for certain squadron choices, and it had me confused.