Impact of the R4M if it was ready earlier?

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Politician01
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Impact of the R4M if it was ready earlier?

Post by Politician01 » 17 Aug 2021 08:28

OTL during the last 2-3 months of the war the R4M AA rocket proved to be a higly effective and cost efficent Bomber Killer. Reports are sporadic and sometimes contradictory but it would seem that when just 20-30 German fighters armed with the R4M attacked a bomber formation of several hundred bombers, the Germans would lose a handfull of aircraft compared to several dozen Allied Bombers.

The rockets needed just a few seconds to hit their target - so it was nearly impossible for Allied Bombers to conduct evasive maneuvers - especially in tight bomber formations. Just one hit was reported to be fatal and the rockets were fired in salvos of 24 pieces.

Now what would have happened if the development of this weapon was accelerated from 1942 onwards and it was ready for mass production by the beginning of 1944? IMO this weapon could really have stopped the Allied Bomber Offensive because the ratio was just to unfavorable for the Allies. It would have enabled the Germans to conduct highly effective and cost efficent hit and run attacks - some 50 German fighters could fire 1200 rockets - and then scramble, before Allied Fighters would have intercepted them. Not even the Allies could stomach a ratio of 80-100 bombers lost during each bombing raid - for the price of 10 or 15 German fighters.

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Re: Impact of the R4M if it was ready earlier?

Post by glenn239 » 17 Aug 2021 17:16

Politician01 wrote:
17 Aug 2021 08:28
OTL during the last 2-3 months of the war the R4M AA rocket proved to be a higly effective and cost efficent Bomber Killer. Reports are sporadic and sometimes contradictory but it would seem that when just 20-30 German fighters armed with the R4M attacked a bomber formation of several hundred bombers, the Germans would lose a handfull of aircraft compared to several dozen Allied Bombers.
B-29's were relegated to night missions early in the Korean War, which suggests that if the R4M had been introduced earlier the USAAF might have switched to night bombing.

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T. A. Gardner
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Re: Impact of the R4M if it was ready earlier?

Post by T. A. Gardner » 17 Aug 2021 20:34

Glenn239 suggests one of several changes in tactics the USAAF might have adopted. But his point is correct, the USAAF would adapt to this change in weapons by the Germans and very likely still prevail. I doubt the R4M would prove so devastating that it would shut down the bomber offensive.

I give you one postwar example of the effectiveness of the FFAR against aircraft...

https://en.wikipedia.org/wiki/Battle_of_Palmdale

Other tactics the US might employ is putting escorts out further from the bombers to make earlier intercepts of incoming fighters. They might up using fighter aircraft to attack Luftwaffe fields ahead of the bomber's arrival in the area meaning the enemy planes never get off the ground.
Another would be to allow escorts that have an enemy engaged to be chased to a shootdown. That is, the fighters don't stay with the bombers once they have an enemy fighter in their sights. They hound them all the way back to their airfields and shoot them down if they attempt to land. Given that the Allied fighters generally have more range--eg., flight time--they can outlast the German planes who run out of gas first.

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Re: Impact of the R4M if it was ready earlier?

Post by Peter89 » 18 Aug 2021 09:34

The average German fighter pilot in 1944 had a career expectancy of about 15 sorties, of which in the first 5 they had zero effectiveness. A new weapon applied on the same aircrafts will not solve the LW's problems.
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Re: Impact of the R4M if it was ready earlier?

Post by glenn239 » 18 Aug 2021 18:01

Peter89 wrote:
18 Aug 2021 09:34
The average German fighter pilot in 1944 had a career expectancy of about 15 sorties, of which in the first 5 they had zero effectiveness. A new weapon applied on the same aircrafts will not solve the LW's problems.
The R4M was probably more lethal throughout the learning cycle, whatever the pilot's skill level. That is to say, whether a green newbie or a veteran ace, hitting a target with R4M's was probably more likely for that individual than with a cannon firing pass. (So a green pilot could easily miss any given time with either R4M's or cannons, but overall green pilots would still cause more kills with R4M's than with cannons).

WRT to night operations, the R4M would probably have been quite effective in conjunction with radar to set up the shot.

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Re: Impact of the R4M if it was ready earlier?

Post by Takao » 18 Aug 2021 21:21

glenn239 wrote:
18 Aug 2021 18:01
Peter89 wrote:
18 Aug 2021 09:34
The average German fighter pilot in 1944 had a career expectancy of about 15 sorties, of which in the first 5 they had zero effectiveness. A new weapon applied on the same aircrafts will not solve the LW's problems.
The R4M was probably more lethal throughout the learning cycle, whatever the pilot's skill level. That is to say, whether a green newbie or a veteran ace, hitting a target with R4M's was probably more likely for that individual than with a cannon firing pass. (So a green pilot could easily miss any given time with either R4M's or cannons, but overall green pilots would still cause more kills with R4M's than with cannons).

WRT to night operations, the R4M would probably have been quite effective in conjunction with radar to set up the shot.
WRT night operations...Probably not.

Bombers flew in a stream, not a box - so, you actually have to hit your target, not pray and spray at a bomber box.

Radar was to get the pilot within visual range and acquire and shoot down the target visually, not act as radar guided gunfire control from a distance.

Then, what will happen to our German pilot when he launches a Salvo, and is blinded for several seconds or minutes by the flames from the rocket engines.

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Re: Impact of the R4M if it was ready earlier?

Post by T. A. Gardner » 19 Aug 2021 04:19

glenn239 wrote:
18 Aug 2021 18:01
Peter89 wrote:
18 Aug 2021 09:34
The average German fighter pilot in 1944 had a career expectancy of about 15 sorties, of which in the first 5 they had zero effectiveness. A new weapon applied on the same aircrafts will not solve the LW's problems.
The R4M was probably more lethal throughout the learning cycle, whatever the pilot's skill level. That is to say, whether a green newbie or a veteran ace, hitting a target with R4M's was probably more likely for that individual than with a cannon firing pass. (So a green pilot could easily miss any given time with either R4M's or cannons, but overall green pilots would still cause more kills with R4M's than with cannons).

WRT to night operations, the R4M would probably have been quite effective in conjunction with radar to set up the shot.
The typical loadout was 24 R4M rippled on the target from anywhere around 500 to 1000 yards. I don't know what the dispersion pattern for those is at those ranges, but it better be pretty low. At 1000 yards, a B-17 is not a very big target...

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Re: Impact of the R4M if it was ready earlier?

Post by T. A. Gardner » 19 Aug 2021 04:22

Takao wrote:
18 Aug 2021 21:21
glenn239 wrote:
18 Aug 2021 18:01
Peter89 wrote:
18 Aug 2021 09:34
The average German fighter pilot in 1944 had a career expectancy of about 15 sorties, of which in the first 5 they had zero effectiveness. A new weapon applied on the same aircrafts will not solve the LW's problems.
The R4M was probably more lethal throughout the learning cycle, whatever the pilot's skill level. That is to say, whether a green newbie or a veteran ace, hitting a target with R4M's was probably more likely for that individual than with a cannon firing pass. (So a green pilot could easily miss any given time with either R4M's or cannons, but overall green pilots would still cause more kills with R4M's than with cannons).

WRT to night operations, the R4M would probably have been quite effective in conjunction with radar to set up the shot.
WRT night operations...Probably not.

Bombers flew in a stream, not a box - so, you actually have to hit your target, not pray and spray at a bomber box.

Radar was to get the pilot within visual range and acquire and shoot down the target visually, not act as radar guided gunfire control from a distance.

Then, what will happen to our German pilot when he launches a Salvo, and is blinded for several seconds or minutes by the flames from the rocket engines.
The problem at night is you have to get close enough to see the target, and if you can do that, shooting R4M at it is likely to see you taken down in the resulting debris field. This is why the Schrage Musik upward firing 20 or 30mm guns were adopted. Even cannon at close range could result in debris that threatened the firing plane trailing the target.

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Re: Impact of the R4M if it was ready earlier?

Post by Peter89 » 19 Aug 2021 07:31

glenn239 wrote:
18 Aug 2021 18:01
Peter89 wrote:
18 Aug 2021 09:34
The average German fighter pilot in 1944 had a career expectancy of about 15 sorties, of which in the first 5 they had zero effectiveness. A new weapon applied on the same aircrafts will not solve the LW's problems.
The R4M was probably more lethal throughout the learning cycle, whatever the pilot's skill level. That is to say, whether a green newbie or a veteran ace, hitting a target with R4M's was probably more likely for that individual than with a cannon firing pass. (So a green pilot could easily miss any given time with either R4M's or cannons, but overall green pilots would still cause more kills with R4M's than with cannons).

WRT to night operations, the R4M would probably have been quite effective in conjunction with radar to set up the shot.
By 1944, the LW pilots had trouble with landing their planes without damage. A lot of them bailed out rather than facing the enemy formations. Or reported mechanical problems. It also happened that they were not even aware that they have been in aerial combat... etc.

The "effective Luftwaffe" by 1944 was a core of pilots who could actually hit targets and do aerobatics, but the majority couldn't do any effective combat.
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Re: Impact of the R4M if it was ready earlier?

Post by Carl Schwamberger » 19 Aug 2021 16:48

My guess is a earlier deployment of this weapon further discourages sending bomber raids past escourt range. Might even waive away the Ball Bearing Raids of latter 1943. Perhaps then less attrition of the US heavy bomber & higher attrion of interceptors for either side.

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Re: Impact of the R4M if it was ready earlier?

Post by TheMarcksPlan » 20 Aug 2021 04:34

Politician01 wrote:some 50 German fighters could fire 1200 rockets - and then scramble, before Allied Fighters would have intercepted them.
Getting to the bombers without being intercepted is kind of the whole ballgame; carrying racks of rockets underwing doesn't help there.

R4M would definitely have helped but we're talking on the margins. By early '44 even a doubling of aerial attrition ratio in LW's favor probably doesn't stop 8th AF, only blunts it.

What most commentators miss is the LW's defensive campaign was already highly efficient and remained so until LW's collapse around mid-44. The supposedly climactic Big Week battles, for example, cost AAF ~5x more than LW. By that stage of the war, however, Allies could wage war with massive inefficiency and still overwhelm Germany because SU was doing most of the work.
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Re: Impact of the R4M if it was ready earlier?

Post by glenn239 » 21 Aug 2021 14:21

T. A. Gardner wrote:
19 Aug 2021 04:22
The problem at night is you have to get close enough to see the target, and if you can do that, shooting R4M at it is likely to see you taken down in the resulting debris field. This is why the Schrage Musik upward firing 20 or 30mm guns were adopted. Even cannon at close range could result in debris that threatened the firing plane trailing the target.
R4M coupled with the airborne radars later in the war might have been a really nasty combination.

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Re: Impact of the R4M if it was ready earlier?

Post by Richard Anderson » 21 Aug 2021 18:26

More nonsense. "Big Week" was 20-25 February 1944. During that period the USAAF launched 3,280 sorties against Germany and lost 154 heavy bombers. In response, the Germans launched 3,078 fighter sorties in reply and lost 240 (159 confirmed lost and 81 missing). So a loss per sortie of 4.7% for the USAAF versus a loss per sortie of 7.8% for the Jagdwaffe. I am unsure how those simple figures can be tortured into "cost AAF ~5x more than LW".

And before the responses begin, the source for the Germans is the Luftwaffe, the postwar report found in AIR 77/18, as "German Fighter Reaction to Anglo-American Bombing Attacks", compiled from "German Air Force files belonging either to the German Air Force Historical Branch or the German Air Force Quartermaster Branch". The source for the USAAF is Bombing the Axis.
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Re: Impact of the R4M if it was ready earlier?

Post by T. A. Gardner » 22 Aug 2021 02:37

glenn239 wrote:
21 Aug 2021 14:21
R4M coupled with the airborne radars later in the war might have been a really nasty combination.
For the R4M to be effective at night with radar, the Germans would need 3 cm radar systems they didn't have. Yes they had some 10 cm ones based on British magnetrons--often ones recovered from wreckage. Going to 3 cm would have been difficult given the state of the German electronics industry. They would never be able to turn out the sets in really large numbers. That would require new tubes, and more raw materials that were in critically short supply.

Then you'd need a lead computing gunsight system that went with those radars, something in its infancy in Germany in 1945. Hughes in the US got this sort of system to work shortly after WW 2 ended but the requisite systems already existed. The US had gyro gunsights in service in large numbers. They had lead computing fire control systems that fit in aircraft like the B-29, and they had the necessary radar sets.

The radar has to be accurate enough to pinpoint the target with precision, something Lichtenstein sets, particularly the longer wave SN-2 set couldn't manage to do.

So, I'd say the Germans might theoretically manage this by 1946 in a less precise system and be working towards a solution, but there'd be few sets available and their accuracy would be questionable.

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Re: Impact of the R4M if it was ready earlier?

Post by TheMarcksPlan » 22 Aug 2021 07:38

Politician01 wrote:
17 Aug 2021 08:28
Now what would have happened if the development of this weapon was accelerated from 1942 onwards and it was ready for mass production by the beginning of 1944?
What are your thoughts on the feasibility of such development by early '44? We have online an archived source that summarizes some primary documents but the documents themselves have disappeared from the web archive. Other than that, I can't find much on the specific development timeline.

One might construct a thought experiment in which Germany makes most/all the right moves towards putting a roof on Fortress Europe in 42-43. R4M would seem to be part of that; lazily using the Granatenwerfer 21cm, with its poor ballistics, seems to reflect Germany's fundamental strategic errors in this field. I don't know if that's true but could see it being so - more research required.

I still doubt it's enough, however. While R4M had little effect on the Me-262's performance, an equal number of rockets on Me-109 or Fw190 would have created a larger proportional share of drag. That leaves your bomber interceptors very vulnerable to escorts, though less vulnerable than fighters with underwing gun pods. Rather than analyzing this issue as if all German fighters were carrying R4M's, perhaps it would be best to look at subbing rockets for gun pods on the "heavy" groups only.
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