27 June 2008

History of the Navy's EW mission part 1

With the arrival of the EF-18G, I started to think about the history of the EW mission in the Navy and its possible future.

To start with we actually need to go all the way back to the World War Two. Right around 1943 the Navy through its Naval Research Laboratories started to work on smaller and lighter radar sets to be mounted on fighter aircraft such as the F4U and the F6F. That way these aircraft could be used to defend the fleet from night time snoopers. Along with that the NRL's were also working hard on radars so the torpedo, scouting, and bombing squadron could hunt for the enemy fleet at longer ranges and in worst weather then what the good ol'mark one human eye ball could find. As a side project a couple of the Naval Research Labs realized that if they were doing this then there might also be a way to create a way to an active way to disable enemy radars. At the time the only way to defeat a radar was through the use of something called Chaff or as the Brits called it "Window". Basically it was aluminum foil cut to certain lengths and dropped in huge bundles. This created a large blossom of reflected energy on the radar scope. Think of your classic radar scope and where there should be clear area there is a huge blot on it. That is what Chaff can do. The downside of Chaff is that it is pretty static, in that once you drop the stuff it just hangs there till it falls to the ground. On top of that you need to cut this stuff to the specific radio frequency that the bad guys are using. So if you guess wrong, well then it again isn't as effective. So that is where what is called active electronic counter measures comes in. This idea is that instead of using something passive like chaff, one uses electronic energy to "attack" the enemy radar sites. The scientists fiddled around and discovered that if you are able to "look" at the radar signal then mess with the return signal then hiding from the radar sites for longer were possible. One of the first aircraft to be converted to an electronic countermeasures aircraft was a Grumman aircraft.
The venerable TBF/TBM Avenger was modified into numerous different versions and types both during World War 2 and after the war. One of these variants was the early version of the Carrier On board Delievery (or COD) called the TBM-3R. Another version using the TBM-3R airframe was something called TBM-3Q. This aircraft started to see its development in 1945 and wasn't accepted to service until 1946. The basic differences between the TBM-3Q and the regular bomber version was that it replaced the after powered turret with faired over hole where an operator sat at looking at a radar scope, a pulse scope, and finally had the controls to operate the basic jamming system. The aircraft had installed the Yagi direction finding system installed in it as well as the APS-4 surface search radar system. On top of that it was still able to carry bombs and rockets under its wings. The Navy bought enough of these to try and issue about five to six of them out to the torpedo bombing groups in the post war carrier air wings. These aircraft only served with the Navy for two years from 1946 until 1948. Where they were replaced by the new Navy attack aircraft from the Douglas company and the design mind of Ed Heinemann

When the AD-1 Skyraider was accepted into the fleet it was realized that the old TBM-3Q couldn't keep up with the new hot rod attack aircraft being built by Douglas. So they asked the Douglas Aircraft Company to modify 35 of the AD-1's that were being produced to include space in the fuselage of the aircraft for an ECM operator along with all his gear. It was a tight fit, but they were able to install a little door on the port side of the aircraft and make room for a single man in the fuselage right behind the cockpit tub. Douglas also added a blister on the underside of the aircraft where the radiating antenna and air scoop for the electronics were located. Also permanently installed on the starboard wing was the same APS-4 radar set that the TBM-3Q had.
As structural difficulties lead to the replacement of the AD-1 with the AD-2 so to the AD-1Q was replaced by the AD-2Q. Same set up as before with the AD-1Q. They also installed a pod on the port side to hold chaff as well. So the AD-2Q could go and mess with the enemy radar signal or it could drop chaff along an approach path to hid the air group from enemy air defense systems.
As improvements came with the introduction of the AD-3 into fleet service AD-3Q was accepted into service as well. The AD-3Q's were in used in Korea where they used the ECM skills to jam the radar control anti-aircraft artillery the North Korean and People's Republic of China armies used to defend such things as rail depots, bridges, and other high value targets.

Most of the Q-birds were assigned to a fleet composite squadron where they were mixed with other specialized mission aircraft such as the AD-3N, F2H-2N's, AD-3W's, and those aircraft configured as special weapons delivery aircraft. Some of these squadrons were units such as VC-33, VC-11, VC-12, VC-35, VMC-1. Something else while I am taking the quick break. I realize that I might need to explain how to decipher the cryptic aircraft designation system that the Navy Department used up until 1962. Basically the alpha numeric code used to describe an airplane told you what the primary mission of the aircraft was, who the manufacture was, and what production variant it was. Any other codes following that described any additional missions that were added on to the airframe.

So for example TBM-3Q actually equals out like this:

  • T=Torpedo
  • B=Bomber
  • M=General Motors manufacture
  • 3= Third production variant
  • Q=Special Electronic mission

Or as in the example AD-1Q it would read like this:

  • A=Attack
  • D=Douglas Aircraft Company
  • 1=First version produced
  • Q=Special electronic mission

Any questions? Ah yes you in the back, what you don't completely understand it? Okay see if this crib sheet might help you out. Okay schools out. When we come back we will pick this up from the AD-4Q and work our way on up to the possible future of the Navy/Marine Corps EW birds.

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