Effect of the R4M rocket being invented pre-war?

[wiking85]

What would the effect on the air war in Europe have been if the Luftwaffe had the R4M rocket by 1939?
https://en.wikipedia.org/wiki/R4M
I mean the air-to-air, air-to-ground anti-armor, and air-to-ground anti-personnel versions. What does it mean for ground support/interdiction and bomber killing? Would it halt the USAAF strategic bombing campaign in 1943 if a single engine fighter could shotgun a bomber box, effectively making the Bf110/Me210/410 unnecessary for bomber killing? How does it affect cannon development and 'Zerstörer' usage? Would the Me109 have been (more) useful as a fighter-bomber in 1939 and onward? How does it change the usage of the Fw190F ground attack fighter? AFAIK historically the R4M was only used in 1945 briefly, so didn't get a chance to affect the war whatsoever:
https://de.wikipedia.org/wiki/R4M#Erprobung_und_Einsatz
Thoughts?

 

[wiking85]

Okay, I guess I'll start and you all can critique my opinion.
Having such a cheap and effective rocket at the beginning of the war would make ground attack pretty effective, even more so than it historically was, as the fast Me109 that did strafing could now contribute accurate rocket attacks on tanks with a good chance to knock them out. Stukas too could use them, though the Bf110 probably would have some trouble due to the wings being taken up by engines; its probably just easier to use the cannons and center line mounted bombs. FW190F and Gs become a lot more effective starting in 1942 when they are introduced, as they have a weapon that can accurately be used as high speeds. Probably bad news for the Soviets. In terms of bomber killing in 1942-43 it makes the Destroyer concept obsolete, letting the Bf110 and Me210/410 more useful as nightfighters, long range escorts (in the Med.), and as bombers/recon. Me109s can be used effectively to bust up bomber boxes on their own without much if any escort, while the FW190 can focus on lower altitude operations, rather than having German fighters struggle for high altitude performance with bomber killing cannons that made them sitting ducks for allied fighters. No need for big wing form ups that got them smashed up by Allied fighters in 1943-44 as they were assembling, rather they could attack in small groups with shotgun hit and runs from higher altitude dives and speed away before escorts could get involved. Rinse and repeat until the boxes are broken up and bombers can be picked off by small groups of fighters. Its much harder to counter than big formations, which can be dealt with by fighter sweeps. It would lower Luftwaffe losses significantly, especially with the two engine fighters, and may cause cost prohibitive losses to USAAF bombers, while delaying the end of the LW due to the P-51D not having easier targets en masse. No need for things like the Sturmböcke, so most LW fighters could focus on anti-fighter armament and staying light and maneuverable.

This probably also eases the transition to fighter-bombers and fighter production over standard bombers and Stukas. Perhaps the Ju87G doesn't make an appearance?

 

[davebender]

FF rockets and armored Fw-190F attack aircraft were a perfect match. If Luftwaffe mass produce R4M FF rocket during 1939 there will be a matching armored fighter-bomber to carry it. All sorts of aircraft are possible but I doubt it would be based on Me-109.

 

[GrauGeist]

There were a few different methods for firing 210mm rockets from the Me410, and this could have easily been done on the Bf110 with the 55mm rockets...

They tried a "revolver" system built into the nose of the Me410 as seen here:

And they also had wing-mounted launch-tubes as seen here:

So a 55mm launch system wouldn't have been that difficult. It would have certainly been interesting to see how much of a boost to ground attack effectiveness it would have given the Ju87 or the Hs129.

 

[davebender]

Don't need anything that complex. Historical R4M under wing racks worked just fine and rocket pods were in the development pipeline.

I have my doubts as to whether the relatively expensive Me-110C-4 (includes CAS armor package) would be produced in large numbers. More likely Hs.123 production gets extended through 1940 with under wing racks for FF rockets. Then replaced by Hs.129 during 1941 whose design would be modified to have R4M rocket pods as primary weapon system.

 

[GrauGeist]

But the "revolver" bay proved two things:

1) That rockets could be deployed from the centerline.

2) Maximization of available space. For example, instead of having one or two 210mm tubes on the centerline, they had 6. Just imagine how many 55mm tubes you could have in that same space.

 

[davebender]

FF rockets are relatively accurate but they still don't come close to accuracy of high velocity cannon. So you don't gain much by placing FF rockets on centerline. Otherwise that's where FF rocket pods would be mounted on modern CAS aircraft such as AH-64 and A-10.

 

[GrauGeist]

Disagree...

Modern aircraft simply don't have the room for a "revolver" system like the Me410 did, with the exception of the A-10, of course.

As far as mounting rockets on the fuselage, look at the F4 Phantom, which had 4 fuselage hard-points (semi-embedded) in addition to the traditional wing pylons.

I don't think that being centerline mounted is a case of improved accuracy, unless it's MG or cannon, but it's more of a case of taking advantage of available room.

 

[wiking85]

Would the Ju87R have been able to use the AP rockets with fragmentation sleeves for night harassment? How would it have made an impact on various ground campaigns or even in airstrikes on naval targets?

 

[GrauGeist]

There's certainly no reason why the Stuka couldn't have used the R4Ms...the advantage of the R4M over the 37mm or groups of bombs, was the wider pattern of contact against targets. Especially at night, where a Ju87's accuracy at bombing would be impaired by low-light.

The downside to that, would be the tell-tale rocket ignition giving the AA gunners a point of reference.

 

[davebender]

RM 85,970. Me-109.
RM 131,175. Ju-87.
RM 210,140. Me-110.
.....All of these prices were declining as factories gained experience. However price spread between these aircraft types would remain about the same.

Me-109 is cheap but aircraft with wing mounted radiators are inherently vulnerable to ground fire.

Ju-87 is relatively low cost. CAS armor package available for Ju-87B and standard equipment for Ju-87D. Ju-87 already has plenty of hard points and is proven gunnery platform for ground attack.

Me-110 is fast and has plenty of range/payload. CAS armor package available for Me-110C and becomes standard equipment on Me-110E. Stable gunnery platform too. However relatively high price makes it an unlikely candidate for mass production CAS aircraft. Ju-88 has essentially the same strengths plus relatively high cost.

.....Ground attack variant of Ju-87 is certainly a viable 1939 option. Germany would need to double Ju-87 production. Which might be a good thing anyway as production cost of all Ju-87s (including dive bombers) would decline due to economy of scale. This option eliminates need for Hs.129 program. I suppose Henschel would get contract to produce the additional Ju-87s.

 

[davebender]

R4M rocket used diglykol propellent which was relatively smokeless. CAS aircraft would be much easier to spot then rocket exhaust.

 

[KiwiBiggles]

I think the point about the rocket exhaust was about its visibility at night, when the previously invisible aircraft would become highlighted by the glare of the rockets

 

[davebender]

Conducting CAS at night without the aid of terrain following radar isn't such a good idea...

 

[GrauGeist]

Which might be a good thing anyway as production cost of all Ju-87s (including dive bombers) would decline due to economy of scale. This option eliminates need for Hs.129 program. I suppose Henschel would get contract to produce the additional Ju-87s.

That's all the Stuka was at the beginning of the war, a dive bomber.

The Hs129 was a pure Ground Attack aircraft, different mission objective than the Stuka, there would be no need to discontinue the Hs129.

R4M rocket used diglykol propellent which was relatively smokeless. CAS aircraft would be much easier to spot then rocket exhaust.

Relatively smokeless, yet still left tell-tale signs of it's passage, as seen in photos and footage.

On a moonless night, a salvo being launched from the wing-racks of an aircraft would have lit the aircraft up like a ghetto church for a few moments...

Conducting CAS at night without the aid of terrain following radar isn't such a good idea...

You say this as if there were no night ops flown at all...

You had night time harassment missions flown by the Night Witches in their U-2 aircraft and the Luftwaffe had fighters loitering in the area to intercept.

Same goes for the Western front where the Allies were trying to intercept the night time harassment flights by the Luftwaffe.

 

[gjs238]

Night Witch

 

[Shortround6]

Not sure where the idea of the R4M being a 'wonder weapon' comes from.

The air to air version was a rather small rocket that while effective if it hit an airplane was a bit lacking for ground attack. The entire rocket weight close to what an 81mm mortar round did and once you take away the propellant weight and weight of the motor tube and fins you wind up with a decent amount of HE but not much metal for fragmentation.

Comparing it's 55mm diameter to modern 2.75in (70mm) or 68mm rockets and NOT comparing the weights gives a rather distorted view of it's capabilities. The 1950s Mighty Mouse rocket weighed over double what the R4M did and the warhead alone weighed 3kg compared to the total weight of the R4M of 3.85kg (the Mighty Mouse weighed 8.4KG but had a much longer/heavier motor). By the time of Veitnam and Helicopter useage the 2.75 rocket kept little but the caliber having both new warheads and new motors. By the end of the Viet Nam war a new generation of rocket motors was being introduced, granted this mostly increased the range but even the the 1960s motors could be fitted with a variety of warheads including both 3.95kg HE/fragmentation and a 7.3 HE/fragmentation warheads. Obviously the modern rockets have much more target effect than the R4M would have had. 1950s/60s European 2in/51mm rockets with anti-personnel heads went about 4.54-4.8kg.

As far as shaped charge warheads go you are now changing TWO things, the development of the rocket itself and the development history of the shaped charge warhead. Germany went through about 4 different designs of shaped charges for the 10.5cm howitzer before hitting a decent one. The British were the first army to introduce a hollow charge service weapon. The No 68 rifle grenade and for a 2.5in overall diameter it offered about 38mm of penetration in early versions which increased to about 50mm in later versions.

At any given point in time or development of the hollow charge it's penetration was usually a ratio of it's diameter. during WW II some pretty good advances were made and things got a even better during the the 1950's let alone today but expecting 1944 penetration from a 1940-41 warhead of the same diameter wasn't going to happen. And considering that even the Germans were planning on going to a 210mm warhead on the last anti-armor rockets being worked on that should tell us something. Granted 1940s tanks didn't have as thick armor.

The R4M was an ingenuous design that helped lead the way to many post war rocket systems but it took a number of years of post war work to get it to the levels of performance it achieved even in the 1960s. Even for air to air use in the 1950s it didn't quite turn out as hoped and that was with planes equipped with radar, radar ranging and collision course fire control computers.

 

[gjs238]

This guy strapped bazookas onto his L-4 Grasshopper!
https://en.wikipedia.org/wiki/Charles_Carpenter_(lieutenant_colonel)

 

[Shortround6]

There is also a world of difference between night harassment and actual close air support missions.

Night harassment, while having a number of it's own dangers, was about denying the troops under attack sleep, affecting their morale, and perhaps interfering with resupply. It had little or nothing to do with performing strikes on troops engaged in close combat in a land battle, attacking tanks or gun positions engaged in combat (unless previously located and targeted).

Before you worry about terrain following radar you had better worry about a better targeting sensor than the Eyeball, MK I, for locating the targets at night and aiming whatever weapons you have.

Swanning about the battlefield at night and tossing bombs over the side isn't going to produce any better tactical results than Bomber Command got for strategic results swanning around Europe in 1940 dropping bombs on what they thought were cities. Kept people up at night though

 

[Koopernic]

The R4M "Orakan" (Hurricane) was a revolutionary air launched missile. Initial German research on air to air missiles had concentrated on spin stabilised rockets that lacked fins and could thus be tube launched from 'revolver' or Gatling like systems. The obvious advantage was that without stabilising fins they were compact, low drag and might even be hidden inside the aircraft.

Unfortunately the dispersal rate was high, I believe the slightest variation in the rocket motor and its spin deflectors effected accuracy. I suspect another was the magnus effect, as the rockt spun it aerodynamically pulled to one side. The WGr 21 21cm tube launched rockets that were derived from the German Amy's 'nebelwerfer' artillery was used to attack USAAF bombers as well as ships during the Normandy landing. The Magnus effect was such that the pilots were told to aim 80m to one side for every 1000m of range.

By introducing folding fins excellent low dispersal and high accuracy was obtained that matched the Mk 108 canon fairly well. The R4M was only 5.5cm but this was enough. An infrared proximity fuse was also to be introduced.

These method used, with some success., was a side on attack on the big US bombers, using a gyro sight known as the EZ-42. This was a very accurate sight, somewhat more elaborate than the allied K-14 as it compensated for air density. A ranging device called Oberon combined with a range only radar the FuG 248 was to relive the pilot from the task of setting range with the stedometric range finder. There was a better sight, the EZ45, easier to install.

Ground attack versions of the R4M (they had their own designation numbers) was known as the Panzerblitz-II and simply received the 88mm warhead of the Panzerschrek (German bazooka). In its ground launched form a penetration of 220mm was achieved at 30 degrees but the air launched version is often listed as only 130mm, presumably due to higher spin and impact speed. This is enough to penetrate the tanks sides, back, top and front of all tanks bar the IS-2. Even here a 45 degree dive on the frontal armour of an IS-2 gets the frontal armour at its thinnest since it is sloped back 45-60 degrees and penetration should occur.

The advantage of this weapon was that compared to the larger more powerful allied rockets three times as many could be carried thereby greatly increasing chances of a direct hit, and this with reduced drag.

A similar weapon was the larger 70mm "Fohn" rocket. A larger 20cm folding find rocket was the R-100 of which about 25 were test fired. It carried a proximity warhead and was expected to be useful against night bombers at ranges of 1.2km. A shaped charge warhead that fired incendiary pellets forward into the target aircraft was also developed, fuse triggered by a radar set timer.

As to how effective they would have been? I would say they would have proven quite effective, the Fw 190D9 carried out a few missions with 16 as opposed to the Me 262's 24. In my view they required a gyro site to be truly effective and of course they would have slowed a fighter aircraft down, though not as much as the WGr 21.