B-52 ECM

[Zipper730]

From what I remember, the B-52's jammers were aimed in such a way that they could project forward (off the nose) or rearward (off the tail), with almost all the radiated energy projected within around 15-degrees or so of the centerline downwards.

I'm curious why so many they wouldn't design the jammers to project out more to the side, as the aircraft seemed able to routinely execute 60-degree bank-angles (I'm not just referring to the post-target turn, but it seemed to be able to use these maneuvers in combat), or use more antennae?

Also for dealing with fighters -- wouldn't you want jammers that could deflect up?

 

[Brooke]

It might depend on the year. Prior to 1957 when the SA-2 became operational would be very different than after that where jamming it would work best off the nose or tail.
S-75 Dvina - Wikipedia
Radar Warning Receivers

 

[Zipper730]

It might depend on the year.

Mostly, I was thinking of 1966-1972 (B-52D).

When it comes to missiles you would presumably be dealing with jamming aimed below you because of the fact that they would be launched on the ground and would come up at you. On the way in, they'd be off the nose, and on the way out, they'd be off the tail. The limit of 15-degrees to either side seems rather minor because of the fact that even a 2g turn would require a 60-degree bank.

 

[MIflyer]

Making a turn tended to point the jammer antennas away from the threat and decreased the effectiveness of the jamming. This was a problem during the Linebacker II raids, because of the position of the turns relative to the target. This apparently was an attempt to keep the B-52 stream within corridors that were salted with chaff by the fighters.

Pointing jamming "up" was not considered to be a requirement because look down shoot down capabilities for fighters did not come along for another decade or so.

 

[XBe02Drvr]

Pointing jamming "up" was not considered to be a requirement because look down shoot down capabilities for fighters did not come along for another decade or so

The Navy F4 radars I was familiar with in the early 70s had a look down but not shoot down capability. They could track and lock a low flying A4 or Firebee from 30+ thousand feet and 40-50 miles OVER WATER, but not so good over land. They were, of course, fleet defense interceptors. If they wanted to engage, they had to come down from their perch, as their Sparrows couldn't get a discernible return in the surface clutter.
In the later 70s the Rome Air Development Center outside Utica NY had a B52 sitting on a compass rose on a hilltop surrounded by a forest of antennas, and often had a couple of light twins flying grid patterns over it. Sometimes we would fly past and it would be mounted on a stand upside down, other times right side up. Always wondered how they shifted it. Our VOR/ILS receivers would sometimes act squirrelly when we were near it.
Cheers,
Wes

 

[MIflyer]

A friend of mine was flying over southern Maryland and noted that his magnetic compass was going back and forth through about 90 degrees. That was curious, to say the least; he figured he had flown into some kind of an ECM test. He called the FAA and the guy he spoke to said, "Those people again! We told them to cut that out!"

Back in the mid-70's at Tinker AFB we got word that a B-52D tail gunner had passed out due to a loss of cabin pressure. It seemed that the cabin outflow valve's sensing port had gotten clogged with dust. We were asked to figure out if there was a modification that would correct that problem.

A senior engineer took me, the new guy, in tow and we went down to the B-52 IRAN area and started looking for the tail gun position. I looked at the airplane in the hanger, which was missing it vertical tail, and noted that it sure did look different from that 1/72 Monogram B-52D model I had built several years back. I asked where the radar for the tail gun was and the gunner's ejection seat and was told by the senior guy, "They take all that stuff out." Looking at the open top hatch, it did not appear that me that anyone could fit in there. So I went to the next position up the fuselage and found nothing there, flat medal. Then I moved up to the next bay and found nothing there, either. Then I went up to the next one. Still nothing but flat metal there, but there was a sticker labeling the mounting position for an ALT-"something." I recognized that an ALT was a radar jammer and there was no reason that a tail gunner would have one of those. I got out of the airplane and went looking for my senior guy. He looked at me and said, "The foreman says this is a G." I replied, "Yes, I just figured that out."

Of course, the B-52G has the tail gunner position up front with the rest of the crew, not back behind the vertical fin.

Sometimes the kid with the model kit experience knows more than the experienced guy.

 

[Zipper730]

Making a turn tended to point the jammer antennas away from the threat and decreased the effectiveness of the jamming.

Yes, I already understood that part...

This apparently was an attempt to keep the B-52 stream within corridors that were salted with chaff by the fighters.

Actually the tactics were selected because of the following reasons

• The B-52's were out of production, effectively irreplaceable, and had a nuclear commitment
• They were concerned about losing them to mid-air collisions

The tactics used for the Cold-War (1958-1962) seemed to indicate formations that didn't seem to be particularly long in terms of aircraft, but consisted of a huge number of aircraft executing dog-legs every certain number of seconds or minutes which involved criss-crossing flight-paths, as well as laying down chaff. They would carry decoys as well.

Pointing jamming "up" was not considered to be a requirement because look down shoot down capabilities for fighters did not come along for another decade or so.

I was writing several things, defense against fighters as well as missiles. The missiles would be coming from below and one would think the jammers would have more ability to aim off center since bank angles of 60-degrees were routinely pulled.

As for radar, as I understand it, the term "look-down/shoot-down" had to do with engaging targets at low altitudes not a target slightly below you.

 

[XBe02Drvr]

A friend of mine was flying over southern Maryland and noted that his magnetic compass was going back and forth through about 90 degrees.

When I was flying for the airline back in the 1980s, one always had to remember to turn off the flux gate correction on the gyrocompass when no. 1 or 2 for departure on Rwy 13 at LaGuardia. The power lines that fed most of western Long Island went under the Sound and surfaced right next to the approach end of 13. If you taxied into "position and hold" with your magnetic correction on, your gyro would start rapidly drifting off runway heading. In the 30 to 45 seconds you would typically wait for landing traffic to clear the intersection, your compass would be anywhere from 30 to 60 degrees off. If you were going to go IMC right after liftoff this was a bad idea, as the departure procedure was a climbing right turn to squirt you out through a narrow corridor between the Kennedy and Newark traffic. Pilot Flying would always remind Pilot Not Flying to turn the flux gate back on as soon as the gear hit the wells.
Cheers,
Wes

 

[GreenKnight121]

The tactics used for the Cold-War (1958-1962) seemed to indicate formations that didn't seem to be particularly long in terms of aircraft, but consisted of a huge number of aircraft executing dog-legs every certain number of seconds or minutes which involved criss-crossing flight-paths, as well as laying down chaff. They would carry decoys as well.

I was writing several things, defense against fighters as well as missiles. The missiles would be coming from below and one would think the jammers would have more ability to aim off center since bank angles of 60-degrees were routinely pulled.

Your first paragraph indicates that, over the whole formation, there would be jammers covering virtually the entire lower hemisphere, as the aircraft changed course etc. The same would go for the chaff and decoys.

Thus, no single aircraft would need to provide more than a part of the jamming coverage.

 

[Zipper730]

Your first paragraph indicates that, over the whole formation

Well formation might be a loose term here: Think of several hundred aircraft arranged into several dozen corridors (the closest formation would be line abreast) that would start changing heading every 60-90 seconds and would periodically criss cross back and forth.

Some of these corridors might very well split up as each bomber has it's own target (though the plan was to strike some targets 2-4 times so...)

there would be jammers covering virtually the entire lower hemisphere, as the aircraft changed course etc. The same would go for the chaff and decoys.

The decoys would have to follow the same pathways as the at least some of the aircraft.

Thus, no single aircraft would need to provide more than a part of the jamming coverage.

Depending on the width of the formation. I suppose it'd be possible to structure turns so that you could aim the jammer at the target (if you bank 60-degrees, you'd have the jammer covering 45-75 degrees out to one side either in front of you or behind)

 

[tyrodtom]

Well formation might be a loose term here: Think of several hundred aircraft arranged into several dozen corridors (the closest formation would be line abreast) that would start changing heading every 60-90 seconds and would periodically criss cross back and forth.

Some of these corridors might very well split up as each bomber has it's own target (though the plan was to strike some targets 2-4 times so...)
The decoys would have to follow the same pathways as the at least some of the aircraft.
Depending on the width of the formation. I suppose it'd be possible to structure turns so that you could aim the jammer at the target (if you bank 60-degrees, you'd have the jammer covering 45-75 degrees out to one side either in front of you or behind)

Just what scenario are you suggesting that would use several hundred aircraft in the cold war era ?

Certainly not a nuclear mission.

During the Vietnam War when B-52s were used for conventional bombing, but even the individual Linebacker missions never involved a hundred aircraft, Bombers, escorts, ECM aircraft, and tankers.

 

[XBe02Drvr]

even the individual Linebacker missions never involved a hundred aircraft, Bombers, escorts, ECM aircraft, and tankers.

Really, even the nights they "went downtown" to deliver the Christmas presents, and almost the entire Thai based USAF and Yankee Station Navy were involved in SAM suppression, MIGCAP, ECM, chaff sowing, recon, SAR, tanking, AWACS, and ELINT? That's got to be close to a hundred aircraft all told, including the SAC tankers. (They were one-on-one with the bombers, weren't they?)
Cheers,
Wes

 

[tyrodtom]

Really, even the nights they "went downtown" to deliver the Christmas presents, and almost the entire Thai based USAF and Yankee Station Navy were involved in SAM suppression, MIGCAP, ECM, chaff sowing, recon, SAR, tanking, AWACS, and ELINT? That's got to be close to a hundred aircraft all told, including the SAC tankers. (They were one-on-one with the bombers, weren't they?)
Cheers,
Wes

That's true, close to a hundred. But never several hundred.

 

[Zipper730]

Just what scenario are you suggesting that would use several hundred aircraft in the cold war era ?

To bomb the USSR int the stone age...

 

[tyrodtom]

A B-52 uses far too much fuel to do a assembly like the big formations of the WW2 era.
They have to take off, usually top off at a tanker, and go. Small, easily formed formations, for conventional bombing.
Each bomber could carry around 60-70 thousand tons of bombs. Just how much could you want ?

Large formations under a nuclear scenario would just invite a large airborne nuclear explosion that would disable the whole formation.

 

[XBe02Drvr]

Large formations under a nuclear scenario would just invite a large airborne nuclear explosion that would disable the whole formation.

Let's hear it for Genie and BOMARC!

 

[tyrodtom]

I meant 60-70 thousand lbs of bombs per aircraft, not tons.

 

[Zipper730]

A B-52 uses far too much fuel to do a assembly like the big formations of the WW2 era.

I don't think we are understanding each other...

They weren't exactly formations as line astern in the loosest sense with 600 aircraft arranged in a couple dozen strings which would criss-cross past each other and probably break up and merge with others until they reach their targets. They would bomb alone. As I understand it, it was called a basket weave because of all the criss crossing flight-paths: The idea was to simply overwhelm the air defenses with so many aircraft constantly changing direction and chaffing/jamming all at once along with specialized jammers.

That said, I'm probably not describing it right.

 

[tyrodtom]

There were only about 750 B-52s made from start of production to the end.
I wonder if 400 were operational at any one time, world wide.

I know you're talking about all aircraft, not just B-52s.

But now 600 ???

Sounds too dingy even for Curtis Lemay.

 

[Zipper730]

There were only about 750 B-52s made from start of production to the end.
I wonder if 400 were operational at any one time, world wide.

I just remember somebody making a comment about 600 B-52's needed to kill the Soviet Union. I figured they were talking about the SIOP.

That said if 400 was the correct number, I then stand corrected.