Germans had not abandoned Cavity Magnetron

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Deleted member 1487

Is 1935 early enough to have radar proximity fuses in service for 1940? AFAIK the Luftwaffe's flak arm was so large even then that it might be possible to get the cost reductions that the Americans achieved later in the war.
No and the cavity magnetron had nothing to do with the VT fuse. A big problem there was Hitler ordered halt of defensive weaponry not ready in 6 months in 1940 to get ready for Barbarossa and didn't restart proximity fuse research until 1942 sometime. So they lost about 2 year and had a ridiculous number of versions with all sorts of triggers (acoustic, infrared, etc.). By the end of the war they were getting one ready for production based on an electro-static principle, but the war situation, conscription of scientists since 1940 and on all delayed the project so it never was ready. Likely best case scenario it could have been ready in 1942-43 without the 1940 halt order to research and no conscription of scientists and fewer projects and concentration of resources.

But the Proximity Fuse was a minor component to high altitude bomber killing. Accurate radar and gunnery computers, servo-motors slaved to the radar and gunnery computer, and auto-fuse setter were much more important when working as a system. As I said both the Germans and US were getting ~300 rounds average per bomber kill in 1944-45 with 9-10cm radar without proximity fuses. The US did get down to about 100 rounds per V-1 kill with proximity fuse, but the other components were more important to improving shoot down rates. The Germans averaging 300 rounds per bomber kill would be 10x more effective on average than they were in their best year of bomber killing in 1942. Window reduced accuracy to abysmal rates in 1943-45, but 9cm radar was able to penetrate cloud of aluminum foil.

I wasn't thinking in terms of the Germans having more surface warships, but it might give the ones they had an advantage over the Royal Navy before they caught up. For example in night actions such as the destroyer attack on the Bismarck, Hipper's encounter with a British troop convoy and some of the Russian Convoy battles.

Would better AA gunnery radar either with or without proximity fuses have helped the Bismarck when she was attacked by torpedo bombers from Victorious and Ark Royal? IIRC a combination of the Mk 37 director and VT fuses helped the South Dakota shoot down 20 Japanese aircraft at the Battle of Santa Cruz.
Perhaps it would increase KM gunnery accuracy; certainly in night actions it would be very helpful. Yes naval and regular AAA would be very much improved with 10cm wave length or less radar guidance. The 1941-1942 attacks on German warships would suffer very badly as a result.
 
No and the cavity magnetron had nothing to do with the VT fuse. A big problem there was Hitler ordered halt of defensive weaponry not ready in 6 months in 1940 to get ready for Barbarossa and didn't restart proximity fuse research until 1942 sometime. So they lost about 2 year and had a ridiculous number of versions with all sorts of triggers (acoustic, infrared, etc.). By the end of the war they were getting one ready for production based on an electro-static principle, but the war situation, conscription of scientists since 1940 and on all delayed the project so it never was ready. Likely best case scenario it could have been ready in 1942-43 without the 1940 halt order to research and no conscription of scientists and fewer projects and concentration of resources.

But the Proximity Fuse was a minor component to high altitude bomber killing. Accurate radar and gunnery computers, servo-motors slaved to the radar and gunnery computer, and auto-fuse setter were much more important when working as a system. As I said both the Germans and US were getting ~300 rounds average per bomber kill in 1944-45 with 9-10cm radar without proximity fuses. The US did get down to about 100 rounds per V-1 kill with proximity fuse, but the other components were more important to improving shoot down rates. The Germans averaging 300 rounds per bomber kill would be 10x more effective on average than they were in their best year of bomber killing in 1942. Window reduced accuracy to abysmal rates in 1943-45, but 9cm radar was able to penetrate cloud of aluminum foil.


Perhaps it would increase KM gunnery accuracy; certainly in night actions it would be very helpful. Yes naval and regular AAA would be very much improved with 10cm wave length or less radar guidance. The 1941-1942 attacks on German warships would suffer very badly as a result.
As was discussed on this forum several years ago the Germans also reportedly experimented (I believe with some success ?) with simply using impact fusing for their heavy AA shells. More accurate gun laying with cavity magnetron based radars would help in this context as well.
 

Deleted member 1487

As was discussed on this forum several years ago the Germans also reportedly experimented (I believe with some success ?) with simply using impact fusing for their heavy AA shells. More accurate gun laying with cavity magnetron based radars would help in this context as well.
Indeed. They can rapid fire without needing to worry about setting fuses and wasting time with that.
 
IIRC, the cavity magnetron drove the pre-war German techs to despair. It was so neat, so efficient, but it frequency hopped so much they could not integrate it into their wonderfully precise systems.

Yes, the UK's 'strapped' magnetron was 'less hoppity', but the trick was to tie the receiver to the transmitter. Analogy with a circus' dancing horses-- They don't dance to the music, they prance in their own time and the band plays along...

The RAF's magnetrons had a demolition charge, but the assemblies were such solid things that putting their pieces back together was not difficult. What astonished the German techs was that the RAF had accepted the remaining frequency instability and worked around it. This was totally, totally against their 'technik' ethos...

==
FWIW, proximity fuses were built around hardened 'micro-valves' derived from the 'hearing aid' industry. And there-by lurks a bunch of potential butterflies...
 

Deleted member 1487

IIRC, the cavity magnetron drove the pre-war German techs to despair. It was so neat, so efficient, but it frequency hopped so much they could not integrate it into their wonderfully precise systems.

Yes, the UK's 'strapped' magnetron was 'less hoppity', but the trick was to tie the receiver to the transmitter. Analogy with a circus' dancing horses-- They don't dance to the music, they prance in their own time and the band plays along...

The RAF's magnetrons had a demolition charge, but the assemblies were such solid things that putting their pieces back together was not difficult. What astonished the German techs was that the RAF had accepted the remaining frequency instability and worked around it. This was totally, totally against their 'technik' ethos...

==
FWIW, proximity fuses were built around hardened 'micro-valves' derived from the 'hearing aid' industry. And there-by lurks a bunch of potential butterflies...
Do you have any info about the microtubes and whether Germany had a similar industry?
 
What astonished the German techs was that the RAF had accepted the remaining frequency instability and worked around it. This was totally, totally against their 'technik' ethos...
Ja. Why the Nazis lost WWII, reason 463... "The best is enemy of good enough"
 
Google, google, google... Aha !!

https://en.wikipedia.org/wiki/Proximity_fuze
As usual, the Germans invented a zoo of variants, but were told to stop because such were distracting from winning the war. IMHO, by the time they needed them, the Germans simply didn't have the industry or skilled labour to turn out millions and millions of these...

And I didn't know about the anti-personnel artillery applications that 'sliced & diced' that fog-bound 'Battle of the Bulge' attack...

http://articles.baltimoresun.com/1993-01-11/news/1993011049_1_fuse-proximity-smart-weapons
Against dive bombers, took ~2500 'traditional' rounds per hit. Prox-fused, 50~60 killed two !!
But note article lacks wiki's timeline, so doesn't mention this style of prox-fusing using sub-miniature valves was invented in UK...

https://sites.google.com/site/8thafhsmn/pictures/proximity-fuses
Neat explanation of safety & arming systems, plus the self-destruct should it miss.

https://ww2aircraft.net/forum/threa...mber-offensive-against-germany-in-1944.37723/
Lots of USAF links. Also a persistent doubter that such could be done without transistors 'handed his ass'...

And, ooh, an old AH thread with onward links...
https://www.alternatehistory.com/forum/threads/early-german-proximity-fuse.211720/
Due care, please ?? Stuart is *very* learned, but not omniscient...
 

Deleted member 1487

With the proximity fuse we are well beyond the scope of the cavity magnetron, IIRC the Germans were developing two useful paths, a radio fuse like the US one and an electrostatic trigger fuse. The latter apparently was more advanced and didn't rely on micro-tubes.
 
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The other problem is batteries. Tubes need power.

US worked out to make batteries that could be stored in European winters to Pacific summers, and survive the G-Loads of being fired from cannons.
 

hipper

Banned
I wasn't thinking in terms of the Germans having more surface warships, but it might give the ones they had an advantage over the Royal Navy before they caught up. For example in night actions such as the destroyer attack on the Bismarck, Hipper's encounter with a British troop convoy and some of the Russian Convoy battles.

Would better AA gunnery radar either with or without proximity fuses have helped the Bismarck when she was attacked by torpedo bombers from Victorious and Ark Royal? IIRC a combination of the Mk 37 director and VT fuses helped the South Dakota shoot down 20 Japanese aircraft at the Battle of Santa Cruz.

That's a bit of a myth,
The Showboat claimed 20 kills but Professor Lundstoms research suggests that the whole us fleet at Santa Cruz shot down 25 Japanese aircraft with AA fire their best performance of the war so far. Read the first team and Guadalcanal. For a truly excellent history. Which uses Japanese loss records notUS AA claims.

Cheers Hipper.
 
If the Germans had pursued cavity magnetron development, they could have put gigahertz-frequency radar on a aerodynamic radar dome by early 1942 on the Junkers Ju 88C model. The result would be an excellent night fighter that would have sent RAF night bomber raid losses soaring--and as a result we would have seen a lot more Mosquito NF models built just to counter the Ju 88C.
 

BlondieBC

Banned
You asked about the impacts, so I will just assume the technical details are correct.

Round 1: Flak is 10 times to 30 times more effective. And it is roughly equally effect in day and nigh fire. First pass, we assume same resources devoted to flak as OTL. Flak zone are simply impassible kill zone for the Allies since losses will be well above the sustainable rate. And they night losses will be the same as daytime losses since using radar not vision. So you need to look up the unsustainable bomber loss rate, seems like it was 3%. Then take some sample major raids from OTL, both day in night. Split out flak from other causes of lost planes. Sit in a spreadsheet with a 10X, 20X, and 30X columns for flak only. I bet you that the raids are not sustainable, even in March, April 1944. So impacts here.

  • No D-day since allies never control the skies.
  • But Axis still lose in Russia.

Round 2: In reality, the axis shift resources east. First thing is the fighters say to the east to much greater extent. And we have way, way too much flak in the west. So the Axis will make more artillery shells and more artillery. I can't model this well for you, but lets assume that 50% of OTL fighters in the West are in the east from 1942 onward, and maybe much higher % in 1944. The Axis pilot losses are much better, so we don't bleed out the quality pilots. You use 50% of flak production OTL to make artillery for the east. Axis then break up big artillery parks Russians use for offensives. The axis use artillery much more lavishly than OTL.

It kind of looks like a war winner, even before I deal better night fighters in the west. I am not so sure the Russians can get a head of steam going in 1943. And would these changes help control the skies around Stalingrad? I just lack the details.

And go to north Africa which has a lot of flak. Are the guns there too? Does Flak claim 10X OTL kills?
 

BlondieBC

Banned
Surface warfare. Trying to think of way of quantifying it. One post has it 10X more effective. Seems hard to believe, but I will run with it.

CLAA Atlanta class has 16 X 5", 16 X 1.1", 6 X 20 mm

Bismark 16 X 4.5", 16 x 1.5", 12 X 20 mm

Both are about the same. If the Bismark AAA is 10 X as effective, that means it has the effective protection of 9 CLAA escorting it. Or put another way, the flak of a early 1944 US carrier group minus the planes. There is not way dozen or so Swordfish make it thru the AAA alone of a US carrier group. The Bismark it untouchable. It is late at night, but I think I misread your post. 10 effectiveness means allied planes can't operate of Axis Flak areas, be it land or ships. If one can shoot a B-17 at 10K feet down with 300 shots, It will be under 20 shots for a torpedo bomber flying low and level. Basically, every volley by the Bismark shoots down 2-3 planes.

BTW, the USA burned their PT boats right after the war since with gun controlled by radar, the PT boats would be sunk before you get to torpedo range on bigger ships. So something like the U-flak boats would have worked in 1943.
 

Deleted member 1487

You asked about the impacts, so I will just assume the technical details are correct.

Round 1: Flak is 10 times to 30 times more effective. And it is roughly equally effect in day and nigh fire. First pass, we assume same resources devoted to flak as OTL. Flak zone are simply impassible kill zone for the Allies since losses will be well above the sustainable rate. And they night losses will be the same as daytime losses since using radar not vision. So you need to look up the unsustainable bomber loss rate, seems like it was 3%. Then take some sample major raids from OTL, both day in night. Split out flak from other causes of lost planes. Sit in a spreadsheet with a 10X, 20X, and 30X columns for flak only. I bet you that the raids are not sustainable, even in March, April 1944. So impacts here.

  • No D-day since allies never control the skies.
  • But Axis still lose in Russia.

Round 2: In reality, the axis shift resources east. First thing is the fighters say to the east to much greater extent. And we have way, way too much flak in the west. So the Axis will make more artillery shells and more artillery. I can't model this well for you, but lets assume that 50% of OTL fighters in the West are in the east from 1942 onward, and maybe much higher % in 1944. The Axis pilot losses are much better, so we don't bleed out the quality pilots. You use 50% of flak production OTL to make artillery for the east. Axis then break up big artillery parks Russians use for offensives. The axis use artillery much more lavishly than OTL.

It kind of looks like a war winner, even before I deal better night fighters in the west. I am not so sure the Russians can get a head of steam going in 1943. And would these changes help control the skies around Stalingrad? I just lack the details.

And go to north Africa which has a lot of flak. Are the guns there too? Does Flak claim 10X OTL kills?
I'm sure the Allies would work on countermeasures. Still in terms of night fighters and improved spotting, including probably being able to develop the first AWACS, the Germans would have a serious night fighting force. Daylight raids would be pretty devastated, though they can fly higher at low accuracy. Then the issue is developing FLAK in sufficient quantities that can reach that high, the FLAK 41 version of the 88mm gun was problematic, so never had the numbers of the regular 88. Perhaps more resources are used for the 105mm FLAK?
https://en.wikipedia.org/wiki/FuG_240_Berlin#Berlin
The N-4 was a further development of the N-3; it rotated the antenna in the horizontal plane under an FuG 350 Naxos-antenna style teardrop housing atop the aircraft fuselage. The result was a 360-degree image of the sky around the aircraft that was presented on a plan position indicator (PPI). This version was later renamed the FuG 244 "Bremen", but was not approved for production. The Bremen was one of the first airborne early warning (AEW) systems to be developed, although no production units were produced.

In terms of the units in Africa the historical radar unit I posted a picture of was a fixed unit that wasn't mobile like the SCR-584 the US developed, but with a long enough development time perhaps the Germans would make a mobile unit that could be deployed abroad.

The thing is the Brits would probably capture one and develop countermeasures:
https://en.wikipedia.org/wiki/Operation_Biting

Then the question is do the Germans continue to hone their designs to get around countermeasures, like 3cm radar like H2S instead of the 9cm radar I posted a picture of, developed in 1944 IOTL. Still if the Germans do develop an AWACS then they could actually fly over the jamming and chaff and direct airborne interceptions independent of ground control if necessary, plus see incoming raids and figure out what is a spoof or not even if Mandrel barrage jammers are used.
 

Deleted member 1487

Surface warfare. Trying to think of way of quantifying it. One post has it 10X more effective. Seems hard to believe, but I will run with it.

CLAA Atlanta class has 16 X 5", 16 X 1.1", 6 X 20 mm

Bismark 16 X 4.5", 16 x 1.5", 12 X 20 mm

Both are about the same. If the Bismark AAA is 10 X as effective, that means it has the effective protection of 9 CLAA escorting it. Or put another way, the flak of a early 1944 US carrier group minus the planes. There is not way dozen or so Swordfish make it thru the AAA alone of a US carrier group. The Bismark it untouchable. It is late at night, but I think I misread your post. 10 effectiveness means allied planes can't operate of Axis Flak areas, be it land or ships. If one can shoot a B-17 at 10K feet down with 300 shots, It will be under 20 shots for a torpedo bomber flying low and level. Basically, every volley by the Bismark shoots down 2-3 planes.

BTW, the USA burned their PT boats right after the war since with gun controlled by radar, the PT boats would be sunk before you get to torpedo range on bigger ships. So something like the U-flak boats would have worked in 1943.

Here is the historical US 10cm naval gunnery radar:
http://www.navweaps.com/Weapons/WNUS_Radar_WWII.php
Mark 8
War Status Used by US Battleships, introduced in 1942-43
Installed Mounted on Main Battery Directors
Purpose Fire Control
Power 15-20 KW, later 20-30 KW
Wavelength 10 cm
PRF N/A
Transmitter Dimensions 10.2 x 3.3 feet (3.1 x 1 m)
Tracking Range 40,000 yards (37,000 m) on Battleship sized target
Range Accuracy 15 yards (5 m)
Bearing Accuracy 2 mils
Resolution 400 yards (370 m) and 10 degrees

Scanned via pulse-switching. Mark 8 mod 0 could spot 16-inch (40.6 cm) splashes out to about 20,000 yards (18,300 m) and the improved Mark 8 mod 3 could reliably spot 14-inch (35.5 cm) and 16-inch (40.6 cm) fire out to at least 35,000 yards (32,000 m).


Accuracy of a 3cm version:
Mark 13
War Status Used by US Battleships and Cruisers
Installed Mounted on Main Battery Directors
Purpose Fire Control
Power 50 KW
Wavelength 3 cm
PRF 1,800
Transmitter Dimensions 8 x 2 feet (2.44 x 0.61 m)
Tracking Range 40,000 yards (37,000 m) on Battleship sized target
Range Accuracy 15 yards (5 m)
Bearing Accuracy 2 mils
Resolution 400 yards (370 m) and 10 degrees

This radar could discern individual shell splashes from 16-inch (40.6 cm) projectiles out to over 42,000 yards (38,400 m).

Not sure if the AAA gunnery radar of 1941 would be the deciding factor, proximity fuses were pretty crucial for stopping low flying torpedo bombers.
 
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That's a bit of a myth,
The Showboat claimed 20 kills but Professor Lundstoms research suggests that the whole us fleet at Santa Cruz shot down 25 Japanese aircraft with AA fire their best performance of the war so far. Read the first team and Guadalcanal. For a truly excellent history. Which uses Japanese loss records notUS AA claims.

Cheers Hipper.
Fair enough. Does that mean Bismarck is still likely to be torpedoed in 1941 even if its sixteen 4.1" HAA guns were firing proximity fused shells? Improved AA gunnery might make Brest a safer place for The Twins. Improved AA radar might mean that the aircraft that dropped the bombs that hit Gneisenau in 1942 was shot down before it could drop them.

Will the longer term effect be that the WAllies would put more effort into jet aircraft and guided missiles?
 

BlondieBC

Banned
I'm sure the Allies would work on countermeasures. Still in terms of night fighters and improved spotting, including probably being able to develop the first AWACS, the Germans would have a serious night fighting force. Daylight raids would be pretty devastated, though they can fly higher at low accuracy. Then the issue is developing FLAK in sufficient quantities that can reach that high, the FLAK 41 version of the 88mm gun was problematic, so never had the numbers of the regular 88. Perhaps more resources are used for the 105mm FLAK?
https://en.wikipedia.org/wiki/FuG_240_Berlin#Berlin


In terms of the units in Africa the historical radar unit I posted a picture of was a fixed unit that wasn't mobile like the SCR-584 the US developed, but with a long enough development time perhaps the Germans would make a mobile unit that could be deployed abroad.

The thing is the Brits would probably capture one and develop countermeasures:
https://en.wikipedia.org/wiki/Operation_Biting

Then the question is do the Germans continue to hone their designs to get around countermeasures, like 3cm radar like H2S instead of the 9cm radar I posted a picture of, developed in 1944 IOTL. Still if the Germans do develop an AWACS then they could actually fly over the jamming and chaff and direct airborne interceptions independent of ground control if necessary, plus see incoming raids and figure out what is a spoof or not even if Mandrel barrage jammers are used.

If the bombers go higher, then the Germans will switch to 105 production since they have too many 88mm. Can I move the excess 88mm to the east and be effective? Say in Stalingrad? Or around Kursk? Or staging areas for major attacks? Or is it really only heavy bomber effective?

It looks like to me, that bomber command never really gets going. Either US or UK. We broke the Luftwaffe in March 1944, ITTL, it will not happen to 1945 at the earliest. A lot changes. Also, we have really wanked German industrial production since there will be many fewer bomber raids. Lot more tanks, trucks, etc. Maybe that first big attack on Hamburg that worked so well fails, and causes a bomber halt?
 
Does the Cavity Magnetron have other applications? If it can be used to improve radar can it be used to make sonar more accurate? Can it be used to make homing torpedoes?
 
It's a bit of a misconception that German radar was more advanced than British in 1940. Naturally, German sets that were just entering service were more sophisticated than the CH system that had been up-and-running for several years, but that's hardly surprising. If you compare like-for-like the Germans were never ahead.

I also think people wildly exaggerate the US role in producing the proximity fuse. The important part was coming up with the idea and designing the circuit: hardening the components to withstand g-forces was just 'cookbook' engineering that could be done by any moderately-skilled person: try something - if it fails modify it and try again. It might take time and resources but did not require any great genius to do.
 
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