GoodGuy -> RE: Nebelwerfers? (9/14/2013 1:00:57 AM)
ORIGINAL: Joe D.
I know Nebels were considered anti-personnel, but were they also as effective against armor like the katushya (spelling?) rocket?
The answer would be yes and no.
But let me outline what I've read and researched a while back.
While the first incendiary Air-to-Air rocket seems to have been used by the French (against observation balloons) around 1916, the german fighter pilot Rudolf Nebel (as well as the rest of his unit, most likely) had deployed signal rockets against balloons and even enemy fighter planes the same year.
Adoption of rockets by Soviet air units:
In turn, the Russians had been experimenting with air-launched rockets since the early 1930s, which - according to some Russian sources - had been used by an experimental fighter group in the skies over Nomonhan during the soviet-japanese war/conflict in 1939, for the first time.
Even though many authors point out that there's no evidence that would back up the claims that 2 japanese aircraft were shot down using air-to-air rockets, japanese intelligence concluded that Russian planes must have been equipped with 76mm-guns (an idea that could be later found on german planes during WWII, as an early pre-form of today's tank-busters, planes that were equipped with an AT gun that had its own suspension - to reduce the recoil), leaving japanese aircraft designers puzzled, as mounting such huge weapons on fighter planes was deemed to be impracticable, indeed.
These russian rockets, designated RS-82 (82 mm) later on and then officially introduced in 1940, featured high-explosive warheads and were designed to be launched by planes or bombers (from rails attached to the wings or undercarriage), but were - according to some sources - already available since around 1937 and mounted on LaGG-3 planes, for example. Because many Russian planes were destroyed on the ground and in the air during the German onslought in 1941, and because the Russians did not want the Germans to capture the rocket technology, frontline air units were not equipped with rockets until either very late in 1941, or very early in 1942.
Around 1942, the RS-132 (132 mm) rocket was introduced, even though it had been around as experimental weapon since ~1932.
If i am not mistaken, it seems like the usage of rockets by Russian air units slowly shifted from a less practicable air-to-air role (which rather had a psychological effect only, as only firing salvos, which produced a tremendous and dangerous drag, appeared to improve the pretty low hit-ratios, to some extent) towards an air-to-ground role, where then - just like with the 82mm Katyusha rockets - it was concluded that the warheads of the 82mm-rockets were efficient against un-armored vehicles, troop concentrations and small fortifications, but ineffective against heavy fortifications and tanks, and that rockets with larger warheads were needed, which led to the Russians introducing the RS-132.
The RS-132-rockets were relatively heavy, so that light fighter planes could not carry them. They were eventually carried by the IL-2 Sturmovik, a plane powerful and stable enough to carry/mount them, as well as by bomber planes, where some bombers used them as defensive weapon mounted on their tails - notably against German fighter planes attacking from the rear.
After putting the RS-rockets in service, the Russians concluded that the rockets could be a useful weapon for area bombardments, if launched in salvos from the ground, so they developed frames/rails to launch 8 rockets from such fixed sites. Since such frames would be vulnerable to spotting and attacks from the air, and vulnerable due to their size and lack of armor protection, they tried to make them mobile by mounting them on trucks, later known as the BM-8 and BM-13 and BM-13-6 Katyusha launchers, adding another 4-8 rails eventually, where the BM-13-6 was based on Lend-Lease-trucks delivered by the US and Britain, namely the Studebaker US6, Ford/Marmon-Harrington, Chevrolet G-7117 and GMC CCKW, where the Studebaker - in accordance to the high numbers delivered to the Soviet Army, became one of the most widely used platform for the Katyusha systems at one point.
The Katyusha rocket launcher:
With the Katyushas, the Russians had similar fears regarding the possibility that the launchers and their 82mm-rockets could be captured by the Germans, but they were less reluctant to use those: In 1941, there were several instances where Katyusha units were endangered to get rolled/surrounded and where they then fired all of their remaining rockets, but where the commanders then ordered to destroy all vehicles before the Germans could close in.
While some sources I read state that the rockets M-8 and M-13 (launched by the BM-platforms) had derived from the RS-rocket family, I did not come across a proper source that would back up that these rockets were just derivates or successors of the RS-rockets.
Still, the Russian wikipedia section seems to state that the RS-82 and the RS-132 had been re-designated M-8 and M-13 in 1942, but there are quite some western sources (books, articles) outlining that the latter were improved and partially re-designed and then designated accordingly, because the ground-to-ground role of Katyusha system demanded a larger rocket "motor".
The Russian website www.airwar.ru states that the PC-82 and the PC-132 (western sources and the Russian wiki refer to them as RS-x) were "upgraded" and then re-designated M-8 and M-13; the author lists 2 sources for his article, the article "MiG jet weapons" by Yevgeny Arsenyev + Nicholas semirekov in "Aviation and Time", and "Wings of Russia. History and aircraft of Mikoyan design bureau".
Whatsoever, it seems that the most popular ground-to-ground rockets launched by the Katyusha launchers were the types ....
- Type ____ range: (acc. to Chris Bishop, "The encyclopedia of weapons of World War II", 2002)
M-8 ........ 5900 meters
M-13 ...... 8740 meters
M-30 ...... 2800 meters
M-31 ...... 4325 meters
- Type ___ range: (acc. to Peter Stache, "Sowjetische Raketen im Dienste von Wissenschaft und Verteidigung", 1987)
M-8 ........ 5500 meters ...... warhead contained 0.6 kg HE
M-13 ...... 8470 meters ...... warhead contained 4.9 kg HE
M-30 ...... n/a
M-31 ...... 4300 meters ...... warhead contained 28.8 kg HE
According to most sources, a salvo of 16 rockets could be fired within 7-10 seconds, each vehicle could be deployed within 2-3 minutes. The frame could be elevated from 4 to 45 degrees, and the (initially fixed) frame could be turned 10 degrees to each side in later versions. The M-30 was a 300mm-rocket based on the M-13, but which carried a bulbous 52kg-warhead carrying ~28.9 kg (~64 lbs) of high explosives.
Air-to-air and air-to-ground rockets used by Russian aircraft (infos derived from Russian websites):
- Type _____ features:
RS-82 ........ initial (frag- ?) version, entered service in 1937, warhead with 0.36 kg of HE
RBS-82 ...... AP-version adopted in 1942, could penetrate up to 50mm of armor. Operated by IL-2 "Sturmovik".
ROS-82 ...... "jet" fragmentation projectile
ROFS-82 ..... Version with HE-fragmentation warhead
AP-82 ........ Incendiary "MS"
TRS-82 ...... Turbojet missile, developed in 1943
- Type ______ features:
RS-132 ........ initial (frag- ?)version, entered service in 1938, warhead with 0.9 kg of HE
RBS-132 ...... AP-version, adopted in 1942, could penetrate up to 75mm of armor. Operated by IL-2 "Sturmovik".
ROFS-132 ..... Version with HE-fragmentation warhead
ROS-132 ...... Jet fragmentation projectile
AP-132 ........ Incendiary ("MS")
TRS-132 ...... Turbojet missile, developed in 1942.
Effectiveness of Russian air-borne rockets fired at enemy aircraft and armored ground targets:
According to some english websites (http://www.tarrif.net/wwii/guides/a2g_rockets_2.htm , for example), the Russians conducted a study that evaluated the effectiveness of air-to-ground rockets against enemy armor. In this field test, 182 RS-82 rockets were fired at a stationary tank from a distance of around 500 meters. 7 out of 182 rockets had scored hits, causing no damage.
The author on airwar.ru (http://www.airwar.ru/weapon/anur/rs82-132.html) seems to refer to the very same study, stating that the hit-ratio on the stationary tank was 1.1% and that the hit-ratio (when firing 186 rockets) on a column of tanks amounted to 3.7%.
The translation tool failed in the following section, so I gather that the tests involved firing single rockets, as well as firing salvos of 2, 4 and 8 rounds, but the author also seems to mention several angles of approach, respective 5-10 degrees and 30 degrees, where it's not quite clear whether the attacks were conducted at angles of say 10 degrees horizontal, or vertical (where the latter would involve a bold and almost vertical dive).
The author of the article on tarrif.net points out, that the shots on the column were made from a distance of 300 meters, and that the decrease in range had upped the hit-ratio and finally caused some damage (by direct hits) to light tanks and half-tracks, but he also states that near misses as close as 1 meter did not cause any damage, whereas Airwar.ru stresses, that even a miss of 0.5 meter did not appear to be harmful to a tank.
The study concluded that the RS-82 could only knock out PzII Ausf. F, Pz 38(t) Ausf. C, and Sd Kfz 250 halftracks, but only if it scored a direct hit.
The same study examined the efficiency of the RS-132 as well, but - as a result of its weight/design - the deviation was even higher, resulting in 0 hits at ~500 meters. The distance was decreased again, this time to 200 meters, where then 134 rockets had been fired at the vehicle column, scoring 2 direct hits on 2 medium tanks, where these 2 tanks were deemed out of action, but with near-misses causing no significant damage.
According to Russian authors mentioned on Russian websites, the Russians had more success when their planes would engage German fighters with their rockets, like during an early encounter in the war, where a couple of MiG-3 attacked a group of 6 Me 109 fighters, firing a "simultanous" salvo of six RS-82, taking out four 109's at once, and where the remaining 2 Messerschmitts then withdrew immediately. These rocket types were also used against German medium bombers.
The author on Airwar.ru points out that due to these two RS types' lack of accuracy/efficiency against enemy medium and even light armor, other rocket versions were added to the IL-2's arsenal, like the RBS-132, which featured an armor-piercing warhead, and the improved ROFS-132 with a HE-fragmentation warhead.
The ROFS-132 was an improvement - if compared to the RS-82 and the RBS-132 - regarding accuracy and flight stability. Also, due to its design (HE-fragmentation), its shrapnels could penetrate up to 15 mm of armor, at 30 degrees, and up to a distance of 1 meter. At a distance of 3 meters its fragments still had enough kinetic energy to penetrate 30 mm of armor at 60 degrees, where then the resulting holes in the armor would have average sizes of 20-25mm x 35-80 mm.
According to the author, a direct hit on a StuG IV assault gun (or on the side of a Jagdpanzer IV/70) would let fragments of the ROFS travel all through its roof or its side armor and either destroy equipment, or kill crew members (or even the entire crew). A hit on the engine compartment of a Pz.IV would have knocked it out (by either destroying the engine or causing a fire).
Despite the somewhat improved accuracy and the added "punch" caused by the fragmentation, hitting enemy tanks that were not moving in column formation, but in (spread out) combat formations, appeared to be a totally different story, with hit-ratios still being very unsatisfactory, in the main.
RBS-82 and 132:
While suffering of the same inaccuracy as the RS-82 and the RS-132, described by the author as "circular deviation", the RBS-rockets had hollow-charge warheads, afaik, making them the most potent rockets for use against tanks, in theory.
While the Russian PTAB (a cluster bomblet with a hollow-charge warhead) could penetrate 70mm of armor at 60°, and while the German SD 4HL (cluster bomb similar to the Russian PTAB, with 0.35 kg TNT, where its design also featured a level of outside fragmentation that was pretty effective against accompanying infantry) could penetrate 60mm of armor at 60°, it is probably safe to say that the RBS-132 could reach at least half of the penetration of the cluster bombs.
US AP rockets were able to penetrate 38mm (US 5 inch / 127mm HVAR) of armor and 1250mm of concrete, British AP rockets could penetrate up to 85mm (the british RP3 60 pound HE/GP) of armor.
But unlike the HC-cluster bombs, which would hit enemy tanks at angles of around 90 to say 70 degrees, AP rockets would often hit the targets at angles that had enough potential to just let them bounce on the target (a problem with all HEAT charges), or at angles where they just hit the tracks and penetrated at the side down to the bottom of the undercarriage without knocking out the tank, or where they would completely miss.
On top of that, it had the very same low accuracy as the RS-types.
Soviet High Command shifting the focus to the development of PTAB cluster bombs:
After the aforementioned field test, the Soviet High Command concluded that RS-rockets were ineffective against tanks. It seems that the Hollow-Charge versions (RBS), which were added to the arsenal, did not improve the effectiveness of rockets against tanks in general, because their design would feature the same inaccuracy and drag on the aircraft, that could not be improved until the end of the war.
Some Russian units deployed handcrafted suspensions for the rocket rails in the field, in an attempt to reduce the drag and recoil produced by the weight of the rocket and the actual launch, but these modifications were removed eventually, because the increased wind resistance, caused by the shape of the larger rail mounts, had reduced the maximum speed tremendously.
The US, the Germans and the British had similar problems, where the US tried to overcome the low accuracy by developing high-velocity rockets (HVAR, ~419 meters/second) with improved rocket motors, stabilizers and shape design, where, as far as I know, the 5-inch HVAR was relatively successful, but still anything than accurate. Still, it seems like only the US had managed to overcome the low inaccuracy partially, to some small extent.
The British RP3 25 pound rockets had sharp trajectory drops, which made it very hard to aim, and the British RP3 60 pound rocket had reported accuracies of 1%, with 25% of the rockets failing to detonate on impact. In theory, the 60 pound HEAT version could destroy Pz.III and Pz.IV from any direction, when the angle of impact was favourable.
Since the field test proved to the Soviet High Command that contemporary rockets were ineffective against tanks, it encouraged the promising development of the cluster bomb, eventually designated PTAB and put in service in 1943. The most widely used platform to drop these bombs was the IL-2, which could carry 4 cases, with 48 PTAB bomblets in each case.
Since the PTAB could penetrate 70mm at 60°, and since (roof) top armor parts of the tanks of the time had relatively thin armor, maybe except for the roof of the engine compartment, it could penetrate any contemporary tank.
The Panther Ausf. D built from January to September 1943, for example, featured a turret roof (2-7 degrees from horizontal) armor with a thickness of 15mm, only. While it seems that experiences of German tank crews being attacked by Russian attack aircraft and dive bombers had helped to trigger the upgrade of the turret roof's armor to 30mm in the "G" model (produced from March 1944 to April 1945), the model "A" turret roof did not receive any upgrade, even though IL-2 planes dropping PTAB bomblets had scored vital hits on German tanks and tank formations during the Battle at Kursk.
According to Robin Higham and John Greenwood, in "Russian Aviation and Air Power in the Twentieth Century" (1998), 8 IL-2 planes had destroyed 15 German tanks out of a formation of 70 tanks, in the very first combat deployment of these bomblets, 3 days before the Battle of Kursk started. In one of the following combat missions during the Battle of Kursk, 4 IL-2 attacked a group of 25 German tanks, knocking out 7 and damaging 4 in the process, on 15th of July 1943. The next day, 23 IL-2 destroyed 17 tanks and 40 vehicles.
A single IL-2 equipped with 4 PTAB-cases, could drop 192 PTAB bomblets and hit practically all vehicles residing or moving within an area (depending on speed and angle of approach) averaging to around 15 meters x 70 meters.
While a single PTAB had a weight of 1.5 kg, the German counterpart SD 4 HL (which was dropped from cases as well) had a weight of 4 kg, either mounted in AB 500 cases (74 bomblets) or AB 250 cases (40 bomblets).
Looking at the results of successful runs/missions, the cluster bomb appeared to be the most effective air-to-ground AT weapon in the Russian arsenal.
Did the Russian Katyusha systems use AP rockets?
This is a tough question. Due to the fact that the Soviet High Command even deemed 132mm-HE rockets to be ineffective against tanks, if launched from aircraft at distances from 500 or 600 meters to 200 meters, and due to the fact that the 2 AP-types delivered the same low levels of accuracy, I would say no.
There are some webpages claiming that the M-8 and M-13 Katyusha rockets were inter-changeable, which means that they could be launched by IL-2 planes, as well.
I did not come across any proper sources/citations for such claims, except for the bits on Russian webpages hinting towards a re-designation (upgrade) and such dual-purpose.
While AP-rockets that were launched by planes delivered a hit-ratio of up to 3% (depending on calibre, pilot skill, training, weather conditions, etc. etc.), at the most, Katyusha-based AP-rockets (if they were used like that at all) must have had an even lower hit ratio, let alone the fact that an AP-round needed to score a direct hit, whereas a near miss remained without any effect on the armor, because most of the explosion pressure in such AP-rounds was concentrated to create the armor piercing metal beam.
While some hollow-charge weapons were specifically designed to create an additional and - if compared to dedicated HE-rounds - relatively small blast on the outside, producing a number of shrapnels that would affect accompanying infantry to some extent, like the design of some of the German hollow-charges (SD 4 HL), the blast of even a very near miss would not be able to harm a tank, generally.
Also, while HE or HE-fragmentation salvos launched from Katyusha platforms appeared to be ideal tools to deliver a devastating area bombardment, salvos of widely spread AP-rounds with a very reduced blast radius would have appeared like a collection of firecrackers when missing, in comparison, imho.
That said, firing an AP-rocket from a ground-to-ground system at a group of tanks, say 5000 - 8500 meters away, would have been a real waste of rockets. Since air-to-ground rockets suffered of tremendous spread at short and medium distances already, long-range ground-to-ground launches created an even bigger spread.
Since I do not own books covering the Katyusha systems, I'd be thankful for any comments or additions from fellow forum users, though, especially if they cover the different types of rockets used by the Katyusha platforms. Some questionable sources claim that - next to the actually used smoke and signal rounds - Katyusha platforms also had AP-rounds at their disposal, but do not point to any source (book, military study, etc.) that would back up that claim.
Also, there are these russian sources indicating that the aviation HE-RS-182/132 rockets had to receive an upgrade (a stronger rocket motor) before they could be used as M-8 and M-13 on a Katyusha system. I could not find any source indicating that RBS-rounds (AP) had received such upgrades.
Armor-piercing rockets for German Nebelwerfer?
German sources state that there were no AP-rounds available for the Nebelwerfer. One reason may have been the fact, that the launchers were basically developed for a rocket developed for Fallschirmjäger units, under supervision of General Dornberger, who envisioned the rockets (40 kg) to be launched from a rather simple frame that looked like a metal grid (weight: 13 kg). The spread at ranges of 5500 meters appeared to be 230 meters, which was way to high. Since the Wehrmacht was convinced that the rocket itself would be effective, a launcher that offered a higher accuracy was developed. The 150mm-Nebelwerfer 41 then offered a lower spread, with 50% of the rockets hitting a rectangle of 130 meters x 80 meters, an acceptable spread, if looking at the calibre and effective amount of HE (2.4 kg) and the design (the HE-charge was put in the tail/rear part of the rocket, in order to maximize blast and amount of shrapnels. The Wehrmacht used HE and smoke-warheads, only.
Effectiveness of German Nebelwerfer HE-rounds against armored targets.
I have not come across any field tests or specs that would verify or outline the effectiveness of HE-Nebelwerfer rounds against armored targets.
Even though I could not find any info regarding the specific weight of the HE-fragmentation charge in a Russian ROFS-132 rocket, I could imagine that the 150mm-rockets of the Nebelwerfer had a similar - if not higher - effectiveness against tanks, and I assume that it had a somewhat larger HE-charge.
The 210mm-Nebelwerfer rocket, carrying almost the same amount of HE (28.6 kg) as the bulbous Russian M-31 (300mm) rocket, must have had an even greater effect on armored targets, as its large HE charge created a massive blast and shrapnels, where the shrapnels would travel up to 100 meters, epecially if you consider that a salvo of a Abteilung involved 90 rockets hitting the target area within 6-10 seconds. The Nebelwerfer could also perform the curling or rebound shots with timed fuzes, which I mentioned in my previous post, so (aimed) direct fire at armored targets using frozen ground/paved ways for rebounds was very well possible, and way more accurate, too.
These are my conclusions so far, though, so I'd be really interested to get my hands on sources covering possible events where Allied armor got knocked out or damaged by Nebelwerfer guns, or sources covering their effectiveness against armored targets in general.