Guided anti-aircraft missiles - possible?

[fastmongrel]

Hi Tomo no I wasnt an AA man I was Royal tank Regiment a loader in Chieftains. The AAA batteries were Royal Artillery that would be attached to our unit. The Bofors L70 whenever I saw it in practice was pretty damn impressive and I wouldnt have liked to fly into a barrage they could throw up. The Rapier became better but early on it was a bloody good job the Warsaw Pact didnt roll in because for all the good they were when introduced we might as well have used the GPMG on the turret roof.

 

[delcyros]

The initial guidance system would only have been viable in daytime without cloud cover. An operator tried to align the missile and target with a joystick, also called MCLOS. The more sophisticated intended guidance system was Beamriding and required a Würzburg Riese radar to track the target and a Mannheim Radar to track the missile. Both were tried with the Wasserfall and Schmetterling. This beamriding technology would have been more effective than optical steering, and would also allow usage in nighttime or poor weather. The reason why the Wasserfall project didn´t received the same priority as the V2 SSM project was that the western allies didn´t deploy high altitude bombers, such as the B29 over Europe. A massive deployment was anticipated and triggered various attempts to reach higher effective AA ceiling. The capacity limit for large AAA was already reached and higher cruising altitude would be more effectively countered by SAM than Flak.
SAM missiles developed by Germany typically relied on a large high explosive burster (blast effect), rather than shrapnel. Initially, western allied SAM missiles did the same.
The RIM-67 initial pure blast warhead was 137lbs HE compared to the 463lbs of high explosive in the early C2W warhead, which subsequently was replaced to 661lbs in the final version. Compared to Taifun or Schmetterling, the C2W didn´t exactly required to come physically very close t it´s target to destroy it.
The Red Dean attained a lethal blast radius of 50ft with 100lbs (50% probability kill category A-immediate). The soviet S25 with 485lbs conventional TNT blast warhead attained 164ft lethal radius and is probably a close prallele to the C2W.
Two or three C2W detonating high order in a combat box of B17´s with an individual lethal sphere of roughly 300ft across is a very intimidating prospect.
Tight combat boxes, which were good against fighter opposition and improved hitting rates during the bombing run would find themselves at an elevated risk against these weapons.

 

[bobbysocks]

they would have to have some sort of guidance system to be effective. bomber crews would be able to see the launch if there was no cloud cover and take evasive action. it wasnt uncommon for bombers and fighters to witness the quick launch of V1s and V2s that were in their path. the rocket crews were afraid they where the intended targets and got everything they could into the air (and to the uk ) so it would not be destroyed. in doing so many gave their positions away for future missions.

 

[delcyros]

Hitting a maneuvering target is certainly more difficult than hitting a plane flying straight and level.
There certainly was still a lot of developmental work required to bring the C2W into operational status.
However, keep in mind that this rocket moves with max. 2600fps (after acceleration), and in within 30sec. after launch (incl. acceleration) it reaches a position 10 st.mls slant distance from the launching site. A loaden B17/24 cruises at alt straight line approx. 1.5 st. mls in this period and the probable error after initiating a break up of formation and maneuvering off from straight line is +-0.25mls for 30sec maneuvering time over a 45/45 deg cone in flight direction. Even a 90 deg turn would end up in this half minute within the 45 deg cone fan shaped area. Probability of inflicting lethal damage with the given blast radius against a single bomber would be 28% for an unguided Wasserfall using just the data processed by Flakzielgerät 42 without manual controll and time fuse. MCLOS and Radar beam aided MCLRA were developed to attain 50% theoretical lethality but the technology didn´t yet existed to expect much more (and even these theoretical figures was often cut by 1/2 to 3/4 when exposed to operational combat conditions). Altough both, IR heatseeking and active radar homing were under investigation in 44 45, the projects weren´t yet matured enough, so MCLOS and radar assisted MCLRS are the only viable options. Raising the altitude and distance to A/C greatly improved the chances to miss the target.

But using the rather primitive MCLOS and MCLRA guidance, I guess it would have been possible to field SAM with the given level of technology. Even using the modified Flakzielgerät 42 may be sufficient to establish 5% operational success rate without guidiance thanks to the huge high explosive warhead.

 

[parsifal]

I think it is absolutely day dreaming to think the Germans were capable of producing effective guided SAM defences with the technology availble to them

The nearest equivalent shown in the following article, and which I can think of were the Soviet SA2 defences deployed to defend North Vietnam during the Linebacker II offensives. Despite deployments well in excess of anything likley to have been achieved over the Reich in WWII, firing against B-52s ( a similar, tartget to a WWII bomber) the SA2 defences achieved exactly 15 kills against 729 sorties. thats a kill ratio of less than 2% per sortie. And im willing to bet the farm the Soviets achieved a far reliable system with their SA2 defences than anything the germans could have cobbled together in the dying days of the Reich.



Surface to Air Missile Effectiveness in Past Conflicts

 

[delcyros]

While the SA-2 was more advanced than the C2W in any imaginable way, I disagree with the conclusion that either the SA-2 nor the C2W was / would be ineffective.
A direct comparison is hard to make. The C2W was designed with intruding aircraft in the high and medium altitude band in mind, like to the SA-2. They may have a similarity here. However, the C2W was designed with intercept charackteristics based on a bomber cruise speed below 900km/h, while the SA2 could cope with >1000km/h intruder speed. Just the differences in speed involved means it would be far more difficult to got to the target in time and as calculated due to the rapid increase in error bars associated with higher cruise speed. The SA-2 was 15% faster than the C2W but it´s targets were [A] more diffciult to damage (absolutely because jet engined A/C were indeed less suspect to damage and stronger structurally to cope with the higher speeds and relatively because it had a warhead of less than half the size of the C2W, corresponding to a 1/3 smaller lethal blast radius) and faster by a factor of 2.5 to 3. A B52 moves in a 30sec time the SA-2 requires to go there 5 st. mls rather than only 1.5 the B17 is able to cover against the C2W. The interceptor problem is significantly more difficult for an SA-2 to damage a B52 than for an C2W to damage a B17, ignoring jammers and other effects.
And while a 2% loss rate doesn´t appear very appealing, the pure number alone disregards that the SA-2 effectively denied the use of the high altitude and medium altitude band, changing aerial combat and forcing attackers to use the low altitude band, where Flak was much more effective than would otherwise be the case. Operation against SAM protected areas was possible using specialised wings of SAM supression WW and massive deployment of ECM jammers in the bombers. Neither the RAF nor the USAAF were prepared for this in ww2 and the relative electronic technology disparity between the 60´s USAF and Vietnam is more in favour of the USAF than it was 1944 against Germany, respectively. One has to factor in the number of missiles expanded to attain a kill in order to extract conclusions about the efficiency of a weapon system. Against F105 low terrain following high speed interdiction fighter bombers, about 150 SA-2 were expanded to attain a kill, during Linebacker 2, only about 50 SA-2 were required for each B52, despite all jammers, SAM supression, loose approach formation, high cruise speed and very high altitude mission profiles.
It may also be helpful to remember that 2.2% loss rate was the mean for the BC during ww2 to both, LW nightfighters and Flak. In effect, having SAM instead of balltistic V2 would have added bomber losses to the allied cause by two reasons: First due to direct damage and 2nd due to forcing responsive measures which increase the effectiveness of low altitude FLAK. To put in in prospect, the 15 B52 downed by SAM were out of only roughly seven-houndred well supported B52 sorties.
The SA-2 was found to be deployed in a low target environment with high speed jet propelled targets (>500mph) in loose formations and correspondingly with high degree of SAM surpression and jamming efforts to keep B52 operating. The C2W however would find itselfe in a high target environment with slow, big piston A/C targets (<200mph) in unflexible, tight combat box formations at medium altitude without ECM jammers. Denying the high and med altitude band -or alternatively, forcing to adopt loose bomber formations to reduce the exposure risk level would be a very significant asset to the german war effort.

I have no doubt that the C2W would have close to 0% success rate in Vietnam. However, ww2 isn´t Vietnam with regards to capabilities of A/C and electronic warfare. I also have no doubts that the C2W could have been fielded operationally, had the intent been to priorize the SAM rather than the SSM in mass production, as expressed by Speer. The effective guidance was there and in service. MCLOS (day) and Manual controll link by radar guidance (night) with radar controll link, heat seekers and active radarseekers in development.

 

[davebender]

I agree that V2 missiles did little for the German war effort except consume resources. However a large scale German SAM program might have also done little except consume resources.

12.8cm Flak 40 production.
Production Stats on German Tube-fired Weapons 1939-1945
367 weapons produced prior to 1944.
664 weapons produced during 1944.
98 weapons produced during 1945.

Why not increase production of the highly effective 12.8cm Flak40 early on? If obvious targets such as Ruhr, Hamburg and Berlin were ringed by a hundred or more such weapons they would be a lot more dangerous to enemy bombers. No need to wait for development of new technology. Just hand Rheinmetall a purchase order for 1,000 weapons during September 1939 after Britain declares war on Germany.

 

[parsifal]

There is no evidence of any nation postwar copying, or putting into production the German SAMs that you mention. The Russians in particular had access to a lot of german techs, but their first SAM, the SA1 did not enter limted service until 1955. The first US SAMs were not cleared for production until 1954, and still had problems (as i recall this was the Nike, which didnt become efective until Nike Hercules...and needed a nuclear warhead to be considered effective, due to its innaccuracy) . The British introduced their first generation SAM, the Bloodhound in 1958, and this was not very effective at low level and still suffered guidance problems.

If the germans were so close to finding a solution to the basic interception problem, why didnt someone hit on a solution sooner than they did.

Also this business that jet techs are somewhat more durable than prop driven aircraft has no basis that i know of.

Also, whilst the the SA-2 was designed to combat supersonic aircraft, and the German not (appar3ently, and allegedly...i dont think it was designed or able to much at all in reality), the example i quoted from the article is of the 729 sorties by B-52s in 1971. These were not supersonic aircraft, they were faster than the B-24s/B-17s, but only to the tune of a loaded speed of 520mph, compared to a b-17 of around 250mph . against a loaded B-29, the likley opponent of a projected German SAM system, the B-29 had a loaded speed of 350 mph, or a B-36 with a speed of just over 400mph, the difeference is not that great.

Nobody saw fit to copy the c2W, which begs the question "why not?" The answer should be obvious. It didnt exist as an effective air defence weapon

The other furphy about the size of the warhead. Specifically, the belief or suggestion that a warhead of double size might make a significant difference to lethal radius. Ive seen a number of tests that show this otherwise. its because lethal blast radius is actually related to the volume of a sphere in non targetted ballistics. The volume of a sphere is

V = 4/3 pi r3

Maximum blast radius against a high altitude target such as a U-2 is around 244 m due to the rarefied atmosphere. At medium to low levels against fighter sized targets the kill radius is about 65 m and the blast radius for severe damage is 100-120 m. The weapon has a CEP figure of 75 m with the large blast radius compensating for any system inaccuracies.

Assuming the SA2 and the C2W both have untargetted ballistic characteristics, and the SA2 warhead is half that of the C2W. That means its lethal volume is 60721957m3 at ultra high altitudes, and more realistically 11472532m3 at medium to high altiudes.

Now if the c2W is twice the warhead size, it wont have a lethal radius twice as big, in fact its lethal radius only increases to 305m at ultra high altitudes, and about 80m at more normal altitudes. You need targettedballistics to get much difference to lethal radius, and that wasnt developed until the 60s., and not by the germans, who by then were back in the business of weapoins development.

 

[delcyros]

The Russians in particular had access to a lot of german techs, but their first SAM, the SA1 did not enter limted service until 1955.

I disagree. The russians decided to copy the Wasserfall in 1946 but after 1 and a half year of intensive research in their occupational zone, they didn´t found an intact specimen of the C2W, just a couple of destroyed frames and the single authetic object among them was part of an actuator. They also barely were able to reconstruct the technical documentation until 1947 and failed to get the key engeneerers for flight controll for them.
When they finally set up the R101 SAM project in 1948 following discovery of an intact but experimental C2W8 in Poland (a design approach discontinued by the german Wasserfall project in 1944) they buildt it up with so many modifications, that You barely can call it a genuine Wasserfall anymore. It took to the end of 1947 to finnish the drawings of the R101 and to 1949 for the first soviet R101 to be launched which continued through 1951.
However, as You note the Wasserfall was developed with 1944 threat environment in mind. Slow medium to high altitude bombers. The rapid process in aeronautic engeneering caused by the genral advent of the jet engine meant an unanticipated rapid progress in bomber performance in just a few years. The soviet R101 was already obsolete by 1950. The B-47 made its first flight in 1947 and had performance outside the interception envelope of the R101. The advent of nuclear bombs meant that all interception attempts had to be effective to be worth keeping. The B47 was able to deploy nuclear bombs with near impunity of R101. Thus, the soviets decided correctly to uprate performance by enlarging the R101 to the new R108 standart (with an interim R109 stage for testing). The project started in 1949 but it was found to be more easy to start from scratch as much had been learnt in the meantime about transsonic and supersonic aerodynamics. This was triggering the entirely new S-25 project, which inherited a lot of lessons learnt by the R101 project but as a new start.
It is entirely incorrect to blame the C2W as a failure based on performance matches against bombers, which were a good two generations beyond those of the designers scope.

If the germans were so close to finding a solution to the basic interception problem, why didnt someone hit on a solution sooner than they did.

They would, had the bombers continued to cruise with 200mph and had the nuke not been added to the weapon arsenal. The advent of jet engined bombers and nukes required much higher intercept solutions.

Also this business that jet techs are somewhat more durable than prop driven aircraft has no basis that i know of.

It is correct. The USAAF after statistical analysis of jet encounters found that it too significantly more hits for .50cal to down Me-262 than other twin engined prop A/C and developed a special jet killer ammunition 0.50cal API as a response. The USAAF did a fair study with their own jet engines and vulnerabilities against impact, shrapnel and blast effect and concluded that jet engines are less sensible to damage by these factors than where piston props. Later, when the P80 became aviable, it was stressed that the airframe was laid out for higher stress caused by higher speeds, which also was a benefit compared to piston A/C.

These were not supersonic aircraft, they were faster than the B-24s/B-17s, but only to the tune of a loaded speed of 520mph, compared to a b-17 of around 250mph .

If You use the enroute loaded cruising speed for the B52 then please alos use it for B17/24. The B24´s enroute loaded speed is certified with 180mph for the B17 it is often given with 160mph, which makes the B52 beeing 3 times as fast enroute. Both planes are capable to cruise faster but not sustained and only with low payload/low range profiles. This is a enormous difference in performance.
The B29 had more of performance but is still within the intercept enevlope of the C2W. The B29 is actually what triggered the whole C2W project.

The other furphy about the size of the warhead. Specifically, the belief or suggestion that a warhead of double size might make a significant difference to lethal radius. Ive seen a number of tests that show this otherwise. its because lethal blast radius is actually related to the volume of a sphere in non targetted ballistics. The volume of a sphere is
(...)
Now if the c2W is twice the warhead size, it wont have a lethal radius twice as big, in fact its lethal radius only increases to 305m at ultra high altitudes, and about 80m at more normal altitudes. You need targetedballistics to get much difference to lethal radius, and that wasnt developed until the 60s., and not by the germans, who by then were back in the business of weapoins development.

I stated previously:

... it had a warhead of less than half the size of the C2W, corresponding to a 1/3 smaller lethal blast radius

This is correct. Indeed I never claimed it to have 2 times the blast radius, the data I gave are suggesting a radius of~1.3 times that of the SA-2 at reference altitude. If you follow my data given above, I assumed spherical spreading, not linear scaling. The HE warhead of the C2W in the final version was 305kg, which is 2.24 times that of the SA-2, which is credited with a lethal blast radius (1 sigma 66.2% probability cat A) of 100m with this warhead in medium altitude. SQR[3] of 2.24 =1.30 and 1.3*100 is 130m for the C2W where the SA-2 attains 100m (66.2% probability). Or 78.5m for the C2W where the SA-2 attains 60m (2 sigma 95.4% probability). Using the 1 sigma probability range, a 130m radius to impact means that the burst can be 260m across (=850ft diameter). Placed in the middle of a tight combat box formation, such a burst has enough size to infict damage on more than one bomber A/C, though not all may be killed in this event. In any way, the burst is MORE dangerous than the smaller one of the SA-2 (or for that matter the large SA-1) by detailing blast effects only. However, by the mid 50´s, it became apparent that blast isn´t suitable anymore as previosuly in trials conducted against high flying jet propelled A/C due to their more rugged airframe design and less numerous sensible engine parts causing a return to shrapnel warheads, so a direct comparison is difficult to make.
As a note I distinctly believe that the blast effect drops with altitude caused by the fact that less particles in less dense higher altitude atmosspheres are involved in the formation of the pressure wave. I remember to have read it in a paper detailing blast effect at various altitudes conducted in 1952 by the US ARMY. But I can check.