UK has advanced solid motors in the 1940's

[PMN1]

Possibly ASB....probably by accident but what would be the implications of the UK being able to reliably mass produce solid rocket motors equivalent to those on the OTL Trident II missile.

Firstly by end of 1940

Secondly by end 1945

Edit: No-one else has been able to do the same at this time.......

 

[Workable Goblin]

Well, as an isolated PoD producing solid rocket propellant equivalent to that on the Trident II (the Trident II motor itself would not be that useful) is definitely ASB--that was the result of decades of research and development of new propellant combinations and methods of manufacture following the discovery of modern composite propellants at JPL in the early 1940s. It's like asking what would happen if Goddard could build an SSME in 1925.

That being said...looking at ways to advance solid rocket technology faster is definitely viable. There's no particular reason that composite propellants couldn't have been developed earlier, except that no one seems to have been looking; the actual first composite solid rocket propellant, GALCIT-53, mixed asphalt with potassium perchlorate, neither of which were particularly exotic. Meanwhile, Britain shot itself in the foot in this regard by banning experimentation with rocketry in the islands, leaving the British Interplanetary Society to simply theorizing unlike their counterparts elsewhere. It's not implausible that you could have some experimenter discover and publicize composite propellants several decades earlier, say before World War I, and then have Britain not restrict rocket experimentation so much in the interwar years.

The BIS was always a little more interested in solid rockets that other societies, AFAIK, so they might be able to figure out tips and tricks to get propellants comparable to what existed IOTL in the 1950s or maybe even 1960s IOTL by 1939 or 1940. Still not the equivalent of the Trident II, but good enough for a Polaris or Minuteman, if only they had a nuclear warhead to put on it. More realistically, they could build better JATO units and missiles or rockets for various purposes, having a safer and more stable yet higher-performance propellant mixture for them than black powder or early composite propellants.

 

[PMN1]

Well, as an isolated PoD producing solid rocket propellant equivalent to that on the Trident II (the Trident II motor itself would not be that useful) is definitely ASB--that was the result of decades of research and development of new propellant combinations and methods of manufacture following the discovery of modern composite propellants at JPL in the early 1940s. It's like asking what would happen if Goddard could build an SSME in 1925.

That being said...looking at ways to advance solid rocket technology faster is definitely viable. There's no particular reason that composite propellants couldn't have been developed earlier, except that no one seems to have been looking; the actual first composite solid rocket propellant, GALCIT-53, mixed asphalt with potassium perchlorate, neither of which were particularly exotic. Meanwhile, Britain shot itself in the foot in this regard by banning experimentation with rocketry in the islands, leaving the British Interplanetary Society to simply theorizing unlike their counterparts elsewhere. It's not implausible that you could have some experimenter discover and publicize composite propellants several decades earlier, say before World War I, and then have Britain not restrict rocket experimentation so much in the interwar years.

The BIS was always a little more interested in solid rockets that other societies, AFAIK, so they might be able to figure out tips and tricks to get propellants comparable to what existed IOTL in the 1950s or maybe even 1960s IOTL by 1939 or 1940. Still not the equivalent of the Trident II, but good enough for a Polaris or Minuteman, if only they had a nuclear warhead to put on it. More realistically, they could build better JATO units and missiles or rockets for various purposes, having a safer and more stable yet higher-performance propellant mixture for them than black powder or early composite propellants.

What diameter SRM's would you be talking about, still enough for a Minuteman or Polaris size and performance missile?

 

[marathag]

Ammonium Perchlorate and Polysulfide synthetic Rubber was around in the 1920s, just need someone to mix together and do some minor tweaking of the curing catalyst to get 1950s level ISP from them

 

[Peg Leg Pom]

The motors are relatively easy, it's just chemistry after all. The real problem is guidance systems, there's no point having a rocket that hits Malta when you're shooting at Munich.

 

[Workable Goblin]

What diameter SRM's would you be talking about, still enough for a Minuteman or Polaris size and performance missile?

I mean, what diameter you get is determined by military needs and requirements over technical limitations (that being said, casting large rocket motors is not trivial...but it's a technology that could be developed if you wanted). As Peg Leg Pom points out, the real limitation on missile size is more likely going to be accuracy and lack of nuclear payloads for them (which are connected, of course, since nuclear and thermonuclear warheads don't need to reach the same degree of accuracy for a given level of damage). Large rockets like the Minuteman and Polaris are for strategic purposes, where with conventional warheads they are less effective than bombers or other methods of deploying weapons with the technologies of the 1940s. Thus, rockets (on the Allied side) aren't likely to be much bigger than OTL, they'll just be a bit better.

That being said, having rockets that are more practical for military needs than IOTL may increase interest in attaching guidance systems of some sort to them earlier than IOTL, though both sides were experimenting with guided rockets of various types by 1943-1944. One particularly interesting possibility is that the Allies focus on developing proximity fuses for rockets instead of gun shells, given that rockets experience much less shock during firing and this reduces the technical difficulty of developing a working proximity fuse. This might lead to higher usage of rocket artillery by the Allies, or possibly less effective artillery overall.

 

[AJE]

I mean, what diameter you get is determined by military needs and requirements over technical limitations (that being said, casting large rocket motors is not trivial...but it's a technology that could be developed if you wanted). As Peg Leg Pom points out, the real limitation on missile size is more likely going to be accuracy and lack of nuclear payloads for them (which are connected, of course, since nuclear and thermonuclear warheads don't need to reach the same degree of accuracy for a given level of damage). Large rockets like the Minuteman and Polaris are for strategic purposes, where with conventional warheads they are less effective than bombers or other methods of deploying weapons with the technologies of the 1940s. Thus, rockets (on the Allied side) aren't likely to be much bigger than OTL, they'll just be a bit better.

That being said, having rockets that are more practical for military needs than IOTL may increase interest in attaching guidance systems of some sort to them earlier than IOTL, though both sides were experimenting with guided rockets of various types by 1943-1944. One particularly interesting possibility is that the Allies focus on developing proximity fuses for rockets instead of gun shells, given that rockets experience much less shock during firing and this reduces the technical difficulty of developing a working proximity fuse. This might lead to higher usage of rocket artillery by the Allies, or possibly less effective artillery overall.

Technical limits wouldn't limit the diameter of the missile, but depending on development level it would mean a missile had to be liquid rather than solid fueled. There were 2 main phases of development in solid rocket size after asphalt solid motors were developed, when extruding motors larger than JATO rockets was impractical (it might still be impractical). The first was to develop cast motors large enough for SAMs, which was done for the Talos missile booster OTL (adapted for the Nike Ajax, Terrier, and Tartar), and its technical development is covered here. Before this large SAMs had liquid-fuel sustainers with clusters of solid-fuel boosters (hence the Nike Ajax and many Soviet SAMs in the 1950's being liquid-fueled). The second phase was to develop solid motors large enough to power ICBMs, which was apparently done by Edward N. Hall and Thiokol for the Minuteman missile, also used for the Polaris missile. Before this large ICBMs were liquid-fueled (Soviet ICBMs were all liquid-fueled until 1976). So depending on which of these phases the UK would be at, their solid rocket motors would be used in anything up to small missiles, large SAMs and IRBMs, or ICBMs, with anything too big for the existing technology being liquid fueled.

That being said, the British did develop proximity fuses for the Unrotated Projectile rocket OTL- that was the original intent for the fuses before they were adapted for guns.

 

[James Ricker]

The real trick would be the guidance system highly inaccurate ballistic missiles would exist but the real benefit would be in a 1940s version of the MLRS
It would be highly mobile and could hit the D-Day beaches from England
Long range rocket artillery would have major effects on the war in Europe
The British being rather nice and having a rather healthy dislike of the Nazis would show The Americans how to make solid rocket fuel in the Americans would make a lot of rockets

 

[Workable Goblin]

Technical limits wouldn't limit the diameter of the missile, but depending on development level it would mean a missile had to be liquid rather than solid fueled.

I took it as a given that we were discussing the maximum size of solid-fueled rockets. That being said, a significantly earlier development of composite solid propellants may have indirect knock-on effects that you're not taking into consideration. Building larger liquid engines capable of use in a vehicle like an ICBM was itself a significant technical challenge, it's just that a lot of the work was done by the Nazis before most people started thinking about them. If composite solids are discovered earlier, that work may not be done and so the technical challenges of building large liquid-fueled missiles may seem to be greater at any stage than developing larger solid motors.

That being said, the British did develop proximity fuses for the Unrotated Projectile rocket OTL- that was the original intent for the fuses before they were adapted for guns.

I should clarify that I meant that they might not bother undertaking the challenge of adapting the proximity fuse for gun projectiles if they have cheaper, safer, and better rocket projectiles than IOTL.

 

[marathag]

should clarify that I meant that they might not bother undertaking the challenge of adapting the proximity fuse for gun projectiles if they have cheaper, safer, and better rocket projectiles than IOTL.

Until you make guided missiles able to track aircraft, AAA would be a major goal.

 

[phx1138]

several decades earlier, say before World War I

Given the Brits had Congreve rockets in the 1810s, and were using them in the Crimean War, how big a stretch would it be for somebody to think improving the stability and range might be a good idea? Go from that to realizing black powder isn't enough, and just stumble on asphalt and perchlorate.

Given that happens, how big a stretch is it for somebody to stumble on the idea of the motor having a cavity down the middle (which, AIUI, produces more thrust and a better burn)? And burning from the top, instead of the bottom (which, AIUI, produces a more stable flight)?

Getting to something akin to an SRB doesn't seem likely, because there's really no point to such a big lifter without nukes or man in space goals, but it does mean anything from Hedgehog Mousetrap (or Weapon Alpha, or ASROC) to Panzerfaust to MLRS (all the way up to LCT{R}) might be on the cards...

Edit:
IMO, most of the uses I imagine for solid rockets don't really need guidance systems, just decent stability (either fins or nozzles). They don't need to be steered, in general, to serve as artillery, ATW, or mine clearance systems (& arguably not as barrage AA, either). If they develop early enough to be practical AAMs, OTOH, they might--& that could be handled by radio command guidance, couldn't it? (Improving electronics enough for beam-riding, CW homing, or IR seems to want a POD of its own, unless we posit having better rockets has led to a desire, or need, for AAMs a lot sooner than OTL.)

 

[Workable Goblin]

Given the Brits had Congreve rockets in the 1810s, and were using them in the Crimean War, how big a stretch would it be for somebody to think improving the stability and range might be a good idea? Go from that to realizing black powder isn't enough, and just stumble on asphalt and perchlorate.

The problem is that while asphalt is available in the early 19th century (and, indeed, much earlier), perchlorates are not; they require a considerably more advanced chemical industry than existed at the time. I'm not sure off the top of my head precisely when ammonium perchlorate became available commercially, but that would be the earliest reasonable date where you could get the development of composite propellants to occur.

 

[phx1138]

The problem is that while asphalt is available in the early 19th century (and, indeed, much earlier), perchlorates are not; they require a considerably more advanced chemical industry than existed at the time. I'm not sure off the top of my head precisely when ammonium perchlorate became available commercially, but that would be the earliest reasonable date where you could get the development of composite propellants to occur.

I'd happily wait for that. IMO, the other problems, including core cavity and top-burning, could easily occupy research until composite propellants become possible (or practical).

 

[yulzari]

Right at the end of the black powder rifle cartridge days (i.e. pre 1886) there was intense research and use in service of solid black powder rifle cartridge charges with variations on hollow cores, annular spaces and open slots. All to modify the pressures and duration of inflagration of the charge on ignition. So the influence of shape upon combustion was understood long before the 20th century.

Had smokeless powder not been developed there can be little doubt that black powder development would have been researching superior oxidizing agents and fuels to potassium nitrate and charcoal (which latter was already the subject of much experimentation and huge variations in materials and processing).