1944: Flak Alone Blasts the Allies out of the Sky

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ChristopherPerrien
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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#166

Post by ChristopherPerrien » 04 Nov 2016, 20:26

Note: there was also the Proximity fuze at the time. Eliminating the need for a "fuse setter" and also that time spent in the action of the gun. The prox fuse was the one thing the Germans did not have, that they really needed for their heavy flak. And they would have needed it before the Normandy invasion to make any difference.

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T. A. Gardner
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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#167

Post by T. A. Gardner » 04 Nov 2016, 21:22

ChristopherPerrien wrote:Note: there was also the Proximity fuze at the time. Eliminating the need for a "fuse setter" and also that time spent in the action of the gun. The prox fuse was the one thing the Germans did not have, that they really needed for their heavy flak. And they would have needed it before the Normandy invasion to make any difference.
Having power fuze setting and ramming makes a big difference. This change does two things:

First, it shortens the time between setting the fuze and firing the round. For non-VT rounds this means the fuze setting is increased in accuracy. Every second between setting the fuze and firing the round increases the error rate.

Second, it increases the rate of fire. In the US 90mm the ROF went from 20 rpm to 24 using a power rammer. That's nearly a 20% increase in firepower alone.

It also means the crew is doing less work so they tire slower, or you can pull crew off the mount for some other useful job.


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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#168

Post by stg 44 » 04 Nov 2016, 22:12

Sure the SCR-584 was better, but the point was that despite having a more complex system that didn't have the servo-motor system the US did there was a German built radar that increased FLAK efficiency 8-10 fold. Even if not as good as the US system it would dramatically increase the success of FLAK and make it immune to 1944 style Window jamming. Just because it wasn't the best system in the world at the time doesn't mean it wouldn't have fulfilled this thread's premise.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#169

Post by T. A. Gardner » 05 Nov 2016, 01:54

stg 44 wrote:Sure the SCR-584 was better, but the point was that despite having a more complex system that didn't have the servo-motor system the US did there was a German built radar that increased FLAK efficiency 8-10 fold. Even if not as good as the US system it would dramatically increase the success of FLAK and make it immune to 1944 style Window jamming. Just because it wasn't the best system in the world at the time doesn't mean it wouldn't have fulfilled this thread's premise.
All two prototypes made in the waning days of the war... It wouldn't have increased flak efficiency 8 to 10 fold either, any more than the US or British systems did for their guns. In the US case the gain was clearly about 30 to 40% with a radar, guns slaved to the fire control, an increased ROF, and VT fuses in use. That would mean that the previous 600 to 1000 rounds to bring a bomber down was reduced to say, 400 to 600.

So, the Egerland system would have helped. I'd say maybe a 10% increase on its own, maybe a little more. That hardly is going to make German flak suddenly super vicious. Even today we don't see what remaining heavy flak weapons there are being 8 to 10 times more effective than they were in WW 2. That alone argues that everybody has figured out that missiles are better than heavy flak at shooting down aircraft. Egerland might have made flak go from the same 600 to 1000 down to 500 to 800, say. That's improvement, but hardly massive improvement.
As for immunity from jamming: Hardly. The Germans already had existing systems in place like Wurtzlaus and K-laus that used pulse Doppler techniques to overcome chaff. These were only partially effective, in large part because electronics technology and tubes available couldn't make sufficiently fine discrimination between chaff and moving targets.
They also had pulse to pulse matching (Taunus), a demodulator to try and detect propeller modulation (Nürenberg). These were not entirely effective either and against heavy jamming only of limited use. There are others too. The Germans really did try to negate jamming, but only with limited success.

Neither Marbach (the round antenna in the foreground above) nor Kulmbach ( the bar antenna in the rear right of the picture) employed track-while-scan technology like say, the USN Mk 8 fire control radar did. That they operated in the 3 to 10 cm range doesn't mean much. The Allies were well aware of radar that ran in that bandwidth. So, they would have detected these fire control signals and could have easily modified equipment or made new equipment to jam them. They could also produce chaff that worked against those wavelengths since chaff was effective against Allied radars in those wavelengths. What initially made them immune to jamming was the German ignorance of radar operating at those wave lengths.

So, Egerland wouldn't have fulfilled this thread's proposed premise.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#170

Post by stg 44 » 05 Nov 2016, 02:04

T. A. Gardner wrote:
stg 44 wrote:Sure the SCR-584 was better, but the point was that despite having a more complex system that didn't have the servo-motor system the US did there was a German built radar that increased FLAK efficiency 8-10 fold. Even if not as good as the US system it would dramatically increase the success of FLAK and make it immune to 1944 style Window jamming. Just because it wasn't the best system in the world at the time doesn't mean it wouldn't have fulfilled this thread's premise.
All two prototypes made in the waning days of the war... It wouldn't have increased flak efficiency 8 to 10 fold either, any more than the US or British systems did for their guns. In the US case the gain was clearly about 30 to 40% with a radar, guns slaved to the fire control, an increased ROF, and VT fuses in use. That would mean that the previous 600 to 1000 rounds to bring a bomber down was reduced to say, 400 to 600.
Ah no, according to the combat results that were seen in France in 1944 after the breakout from Normandy they got shootdowns with an average of 350 shells WITHOUT VT fuses. With VT it was 100 or so shells per shoot down like with the V-1s. Considering that the initial shell requirement was 2500 shells per V-1 the improvement to 100 shells per V-1 with VT fuse and the SCR-584 meant it increased effectiveness 25 fold.
https://en.wikipedia.org/wiki/V-1_flyin ... craft_guns
The development of the proximity fuze and of centimetric, 3 gigahertz frequency gun-laying radars based on the cavity magnetron helped to counter the V-1's high speed and small size. In 1944, Bell Labs started delivery of an anti-aircraft predictor fire-control system based on an analogue computer, just in time for the Allied invasion of Europe.

These electronic aids arrived in quantity from June 1944, just as the guns reached their firing positions on the coast. Seventeen per cent of all flying bombs entering the coastal "gun belt" were destroyed by guns in their first week on the coast. This rose to 60 per cent by 23 August and 74 per cent in the last week of the month, when on one day 82 per cent were shot down. The rate improved from one V-1 destroyed for every 2,500 shells fired initially, to one for every 100. This still did not end the threat, and V-1 attacks continued until all launch sites were captured by ground forces.
T. A. Gardner wrote: So, the Egerland system would have helped. I'd say maybe a 10% increase on its own, maybe a little more. That hardly is going to make German flak suddenly super vicious. Even today we don't see what remaining heavy flak weapons there are being 8 to 10 times more effective than they were in WW 2. That alone argues that everybody has figured out that missiles are better than heavy flak at shooting down aircraft. Egerland might have made flak go from the same 600 to 1000 down to 500 to 800, say. That's improvement, but hardly massive improvement.
As for immunity from jamming: Hardly. The Germans already had existing systems in place like Wurtzlaus and K-laus that used pulse Doppler techniques to overcome chaff. These were only partially effective, in large part because electronics technology and tubes available couldn't make sufficiently fine discrimination between chaff and moving targets.
They also had pulse to pulse matching (Taunus), a demodulator to try and detect propeller modulation (Nürenberg). These were not entirely effective either and against heavy jamming only of limited use. There are others too. The Germans really did try to negate jamming, but only with limited success.

Neither Marbach (the round antenna in the foreground above) nor Kulmbach ( the bar antenna in the rear right of the picture) employed track-while-scan technology like say, the USN Mk 8 fire control radar did. That they operated in the 3 to 10 cm range doesn't mean much. The Allies were well aware of radar that ran in that bandwidth. So, they would have detected these fire control signals and could have easily modified equipment or made new equipment to jam them. They could also produce chaff that worked against those wavelengths since chaff was effective against Allied radars in those wavelengths. What initially made them immune to jamming was the German ignorance of radar operating at those wave lengths.

So, Egerland wouldn't have fulfilled this thread's proposed premise.
You're not understanding why the Brits then decided to introduce Window and why Egerland was effectively immune (which was proved with actually war experience): it used centimetric waves, not metric like the German systems with jamming aids. Window was cut to 1.5-.5 meters length, which worked great for blinding Wurzburg and Mannheim radar that at best were at 50cm wavelength due to not being cavity magnetron based. The cavity magnetron based Egerland system had 9cm wavelength, which was shorter than the Window chaff strips, so could tell the different between chaff and aircraft due to the greater accuracy of the microwaves used. At 9cm individual artillery shells could even be spotted, as the US did with the SCR-584 at Anzio.

The point of mentioning the Egerland system is suggesting that it is developed sooner so that it is ready by early 1944 and able to be introduced in increasing numbers and offering a dramatic decrease in shells fired down from the 16000 that were needed in 1944 due to the blinding effect of Window to perhaps 5-600 or even potentially less. If they need only 600 instead of the 16000 of the historical 1944 that is better than a 25 fold improvement. Even compared to the 1942 best of 3000 shells per shoot down that is still a 5-fold improvement.

The Allies did clearly know about X-band radar, but how long would it take them to realize the Germans were using it and cut down chaff to 9cm strips? How much faster would they fly apart and be rendered useless at that range? Jamming via barrage methods didn't put German radar down so much as chaff did. Plus barrage jamming could be homed in on and fired at.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#171

Post by T. A. Gardner » 05 Nov 2016, 02:15

Apples to baseballs. The V-1 was low flying non-maneuvering target that was usually, visible to the gun crews. Against high flying bombers, the success rate goes down as their altitude increases. The V-1 was a relatively easy target by comparison. For example, the 8.8 cm is really marginal versus US B-17 and 24 bombers flying at 25,000 feet. It is all but useless against a B-29 at 30,000. When you hit 35,000 it is worthless as that's above the gun's ceiling entirely.

It also won't account for heavy jamming the Germans encountered. They often had to resort to blind fire using predicted box barrages that ate literally tens of thousands of shells for maybe a few shoot downs at most. A switch in radar alone isn't going to make that big difference. Your own source ignores that the M2 / M3 90mm and integration into the fire control system played a role. The skill of the operators and gun crews could also have an effect here. When they first arrived, they would be trained but never had fired on a live target. With practice they get better.

What the Germans really needed was a good SAM. But, that wasn't going to happen.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#172

Post by Paul Lakowski » 05 Nov 2016, 03:57

IF the radar can be neutralized through jamming, SAM will be useless. A better option would be Wire guided AAM launched from a super fast interceptor.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#173

Post by T. A. Gardner » 05 Nov 2016, 05:43

Paul Lakowski wrote:IF the radar can be neutralized through jamming, SAM will be useless. A better option would be Wire guided AAM launched from a super fast interceptor.
Wire guidance of an AAM is very problematic. Without even considering anything else but the wire...

How do you keep tension on the wire or support it? If it becomes slack it could foul the firing aircraft.
The weight of the wire alone is going to cause an immense amount of sag in it.
How do you make a wire strong enough to cover literally several miles of air space and not break?

The X-4 Ruhrstal missile was literally a joke.

The British tried a different option with the Fireflash missile. This was a beam rider that was fired from relatively short range at the target. The terminal guidance was on a CW beam that would be difficult or impossible to jam.

Of course, if it were me, I'd have gone for something simpler. Use a V-1 re-equipped with a small turbojet engine that offers about 1,000 lbs of thrust or so. Fire it into the bomber box with the firing aircraft using command detonation from several miles out. A 2000 lbs. fragmentation warhead would likely take down or damage every plane in the box. Launch it from a twin at a distance and use a secondary plane to command detonate it.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#174

Post by Paul Lakowski » 05 Nov 2016, 06:57

LW tested it at the end of the war and seemed to be able to make it work in trails, provided there was two pilots ...one to fly the plane & one to steer the missile. Reportedly 1000 missiles were started before the factory was destroyed by American bombing. and of course it was used as the basis of some post war missile programs.

https://en.wikipedia.org/wiki/Ruhrstahl_X-4

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#175

Post by thaddeus_c » 05 Nov 2016, 18:41

T. A. Gardner wrote:Of course, if it were me, I'd have gone for something simpler. Use a V-1 re-equipped with a small turbojet engine that offers about 1,000 lbs of thrust or so. Fire it into the bomber box with the firing aircraft using command detonation from several miles out. A 2000 lbs. fragmentation warhead would likely take down or damage every plane in the box. Launch it from a twin at a distance and use a secondary plane to command detonate it.
they used small rockets to launch ground attack pulse jet aircraft Junkers was toying around with, until pulse jet got "up to speed" (pardon my non-tech term) but as you said they had small turbojets, wonder which the cheaper, more readily available choice?

from layman's viewpoint the failure to pursue high altitude aircraft seems a mistake? of course JU-86 reaching 42,000 ft. is not carrying a 2000 lb. bomb, not sure the practical limits of their programs? JU-388 might be most plausible "bomber killer"

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#176

Post by T. A. Gardner » 06 Nov 2016, 02:31

The alternate is a rocket / ramjet combination. Low velocity ramjets are simple technology. You build a V-1 sized AAM that can launch from say 15 to 20 KM out on a general radar heading towards a bomber group. The rocket drives it up to say 300 - 400 mph when the ramjet takes over raising the speed to say 500 to 600 mph.
At 2 to 3 miles from the target another aircraft takes over and command detonates the missile that is homing on the center of a radar picture of the box. The missile doesn't have to be highly accurate. It enters the box and the one ton warhead is detonated with heavy fragmentation.

Image

Given a total vertical and horizontal separation of less than 1000 feet between all the aircraft, virtually every plane in the box will take some sort of damage from that blast and fragmentation. The command detonation system would make the missile largely immune to jamming in that respect as well as alleviate the need for a proximity fuze. The radar needs only be sufficiently accurate to home on the box as a whole centering the missile on the box. It could even be engineered to home on noise jamming the box might be using on it. Likewise, chaff would only improve the targeting picture for the guidance system.

Of course, the Allies would respond by trying to take down the launch aircraft, and possibly the command plane(s) sending the detonation signal.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#177

Post by stg 44 » 06 Nov 2016, 02:50

Against daylight aircraft the R4M is much more effective all things considered. The bigger issue is how to deal with Bomber Streams

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#178

Post by T. A. Gardner » 06 Nov 2016, 03:09

Paul Lakowski wrote:LW tested it at the end of the war and seemed to be able to make it work in trails, provided there was two pilots ...one to fly the plane & one to steer the missile. Reportedly 1000 missiles were started before the factory was destroyed by American bombing. and of course it was used as the basis of some post war missile programs.

https://en.wikipedia.org/wiki/Ruhrstahl_X-4
Here's one example of how impractical the X-4 really is. Let's say the flight distance is 1.5 miles. That's about half the maximum range of the missile. There are two guidance wires, I'm assuming they're 20 gage copper wire. At the end of the flight the spooled out wires weigh a total of right at 50 lbs. They sag in the middle about 250 feet due to gravity.
The flight time is 9 seconds (at an average speed of 600 mph to take into account acceleration, etc.)
That alone means that the probability of one of those wires snapping or coming loose from the firing aircraft (in particular) is pretty high.

The operator (assuming a twin with a dedicated missile operator) is trying to guide it with the joystick and eyesight. This means for much of the flight he's trying to track a tiny star-like dot in the sky. The missile, at least from the video of firings available doesn't leave a really obvious smoke trail, but it might. That would help but it would also be an arrow pointing at the firing aircraft for escort fighters.
Given the low probability of hitting a tank with a similarly guided ATGM, like the Sagger, the likelihood of hitting a bomber moving several hundred miles per hour, from a guidance operator with no optical magnification and only limited actual launch guidances, is pretty much nil.

Even beam riding missiles developed in the late 40's and early 50's didn't do very good against even non-maneuvering targets. The Pk of missiles like the JB-3 Tiamat or Fireflash was pretty low, and they are way ahead of the X-4 in design.

Basically, the X-4 was a bust.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#179

Post by T. A. Gardner » 06 Nov 2016, 03:17

stg 44 wrote:Against daylight aircraft the R4M is much more effective all things considered. The bigger issue is how to deal with Bomber Streams
Maybe when coupled with jet fighters, but using prop planes the escort is going to chew them up in most cases before they get into range. Against the bomber stream at night the R4M would be the best choice. A twin engine nightfighter could easily have carried 50 to 100 R4M and used them in salvos against a particular bomber. The accuracy of radar necessary for a successful intercept would be less and the firing range could even be out of visual by a couple hundred yards.
One missile hits the bomber solidly, and it goes down.

Against bomber boxes you salvo and might get one bomber. But, their close proximity, and being in daylight allows the escorts more opportunity to take on the attackers prior to firing, and the bombers can shoot back too. Jets make the probability of that much lower and that would make them work with the R4M.
On the other hand a 2,000 lbs. (say one metric ton) warhead with fragmentation against a box of six bombers detonating somewhere within the box would damage or destroy all six planes. This is substituting mass destruction for accuracy. Even if it only worked a few times on the first few uses, it would have forced the USAAF to re-think their whole formation and daylight bombing concept. A new formation that prevented mass loss to this weapon would be necessary, or tactics would have to evolve to deal with the launch platforms that are often up to 20 + miles away when they fire.

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Re: 1944: Flak Alone Blasts the Allies out of the Sky

#180

Post by Paul Lakowski » 06 Nov 2016, 03:54

T. A. Gardner wrote:
Paul Lakowski wrote:LW tested it at the end of the war and seemed to be able to make it work in trails, provided there was two pilots ...one to fly the plane & one to steer the missile. Reportedly 1000 missiles were started before the factory was destroyed by American bombing. and of course it was used as the basis of some post war missile programs.

https://en.wikipedia.org/wiki/Ruhrstahl_X-4
Here's one example of how impractical the X-4 really is.......

Even beam riding missiles developed in the late 40's and early 50's didn't do very good against even non-maneuvering targets. The Pk of missiles like the JB-3 Tiamat or Fireflash was pretty low, and they are way ahead of the X-4 in design.

Basically, the X-4 was a bust.

REALLY WHAT WAS THE PK OF ME-109 VS B-17?


LW 20 sortie to shoot down each bomber and 8:1 for jets vs bombers....5% per fighter sortie & 12% for each Me-262 sortie.

Hit chance of early AAM VS jet fighters was 10% per missile in actual battle. What were the hit rates of fireflash?

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