Standing Well Back
1970-1980

Explosive Devices on the Moon.

It may seem bizarre, but Rocket Propelled Grenades were taken to the moon on a couple of the Apollo missions to the moon in the 1970s. Three were fired, and five were abandoned.  So there is an interesting EOD task outstanding on someone’s operational docket for a future mission.    This is the surprising story.

One of the ambitions of the Apollo project was to understand the geology of the Moon. Accordingly, a number of passive and active seismic experiments were planned.  The active seismic experiments were mounted during Apollo 14 , Apollo 16 and Apollo 17. The active component of the experiments on Apollo 14 and 16 had two parts. Both involved placing ground sensors and then using explosives to create a shock waves.  The first experiment was relatively small scale, using a hand-held “thumper” which fired small cartridges to impart a small shock wave to the surface of the moon, which were then detected by the sensors. It is the second experiment that I find more interesting however.  For this experiment a number of rocket propelled explosive devices containing varying amounts of explosives were used, and the launch initiation was radio-controlled, with the impact causing the detonation when they struck the moon. In much of the documentation the system is called a mortar but elsewhere the charges are referred to as rocket propelled charges or grenades. It’s semantics, and doesn’t really matter.  But what they were innovative and relatively complex explosive charges designed to be launched by radio signal from a baseplate, and impact the moon surface some distance away, detonating to send a distant shockwave back to the sensors.

It’s worth considering the fundamental differences that launching a rocket/mortar/grenade provides on the surface of the moon that don’t occur on the surface of the earth.  There is no atmosphere so there is no need to streamline the projectile. Also there is only a fraction of the gravity.  So trajectory calculations are very different and hence design parameters of the munition quite different. Calculating the range tables would have taken some interesting but not difficult calculations.

As far as I can make out the grenade launcher/mortar system was identical on both Apollo 14 and 16. The four explosive devices on each system were set to fly 150, 300 900 and 1500m but the explosive charge was not the same across the four projectiles – but rose with the range. The explosive charge weights of the grenades were 0.1, 0.3. 0.6 and 1.0 lbs of explosive consecutively. Unsurprisingly, there were multiple safety mechanisms in the systems and the experiment was designed to be initiated by earth-bound technicians and scientists after the astronauts had departed back to Earth. So the astronauts’ job was to set the ground sensors, put the launch system in place and level it appropriately and then “stand well back” by a few million miles.

For the Apollo 14 mission the launcher was placed in a sub-optimal position due to a crater, and the experiment was abandoned because of concerns that the dust from launch of the projectiles would cover other experiments.  This surprises me since  the lunar module itself contained a much bigger rocket and surely threw its own dust much more widely.  So there are four unarmed, unfired explosive projectiles sat in launch tubes near the Apollo 14 landing site waiting for some EOD operator to sort them out. Good luck with that.

For the Apollo 16 mission, although there were problems setting up the launcher, the system was fired, launching three of the four projectiles. On the launch of the third device, the base plate tipped over so the fourth remained unlaunched. Our intrepid Space Force EOD operator of the future should consider carefully the arming state of this abandoned device.  Not a place you want to have an ammunition incident.

The design of the mortars and associated system is particulate interesting technically. I have covered the varying charge weights above. Clearly it was important to know the velocity of the projectile after launch and this was calculated by a a 25ft stainless steel break-wire line with a copper electrical cables wrapped around that which was attached to the projectile and which broke after launch, one immediately and one at 25 ft allowing its velocity to be calculated. The angle and pitch of the launching platform was also recorded, and also on each projectile there was a radio device transmitting the time of flight.  So the angles, speed at launch and the time of flight of each missile were were all known. Quite a complicated little munition with interesting safety features. The calculated range was expected to be accurate with 5%. Each grenade was less than 3 inches across and the larger devices about 6 inches long, the smaller 4 inches long.  They were mounted on the base plate in a bank of 4.  Here’s a circuit diagram of the grenade, which shows some interesting design features – including a spring loaded blanking plate isolating the detonator from the main charge.  This steel plate is ejected by the action of the spring as the explosive device leaves the tube, allowing direct passage from the detonator to the main charge and also releasing a safety microswitch. Some of you will have seen bore-constrained spring-actuated safety measures on some earth bound systems.   There was an omni-directional impact sensor to cause the detonation and a thermal battery to power both the 30 Mhz transmitter and the initiation system.

The mortars were designed to be launched at 45 degrees.  The rocket motor is very short duration, and indeed is designed to have been fully burnt-out at less than 10 milliseconds, before the device has left the launch tube – another reason for the vagueness in terming this a rocket or a mortar, but note that this is fired basically from a tube that is open ended at both ends, making this in my mind a rocket propelled grenade, nonetheless. I think this was chosen (rather than a closed tube mortar) to make an overall lighter system.

I jumped up to the moon last week and managed to get this X-ray of the Apollo 14 system ;- )

 

 

All this is useful information for our imaginary space-suited EOD operator. I think the answer is “blow in place”.  :- ).   I understand that the 3 grenades that functioned provided useful results and the shockwaves of their detonation were detected.

Apollo 17 also used eight radio controlled explosive charges (these not intended to be launched but placed) to conduct seismic experiments. These were small 57 g charges that were detonated by radio control when the astronauts were halfway back to earth, and had been manually placed at distances away from the landing site and the sensors.

 

 

20th Century

WW2 Thermobarics?

If this story is true, (and it may not be), it changes what we have thought about the origins of thermobaric weapons. It also could have changed the course of WW2 in one instant. Bear with me as I explain.

Thermobaric explosive weapons came to the general attention of the defence community in the 1990s.  They are still widely misunderstood. The explanation is also not helped by slightly odd nomenclature and descriptions. “Thermobaric” is one such descriptor. Sometimes “Fuel Air Explosives (FAE)” is used, sometimes “Vacuum bombs” even if the words have somewhat different meanings.  Sometimes thermobaric weapons are infantry weapons, engineer demolition weapons and at other times artillery weapons. Sometimes they are deployed by Chemical units.  All these lead to confusion, as do amateurs who also comment that where terrorists add gas cylinders to IEDs they are creating thermobaric or fuel air explosives, when generally that is not the case.  If you need to, you should read up elsewhere on thermobarics but please go beyond the rather simplified wikipedia efforts.

Here’s a very simple summary.  The ability of a fuel when mixed with air and initiated in the right mixture can cause explosions. This is well known and accidental things such as coal dust explosions in mines, and even dust in agricultural or industrial situations has been known to cause significant destruction.   It is possible to artificially, rather than accidentally, cause such explosions to occur, although it is not necessarily easy. Chucking gas cylinders on top of an IED pretty much doesn’t work whatever people may tell you.  The oxidisation of the fuel in the explosion and the progress of a blast wave through the fuel and air is very complex and affected by a large number of variables.  What is important is the effect of such an explosion. Traditionally military weapons, at least in the West, have concentrated on attempting to reach as high a peak pressure for the blast wave as possible, on the assumption that the higher the peak pressure the higher the damage to the target.  Thermobaric weapons however don’t follow that logic. On a graph of pressure over time, the energy imparted by the explosion is represented by “the area under the curve”. Thermobaric explosions give a lower peak pressure but the duration of the pressure is much longer, so there is much more energy involved.  The long pressure pulse also has horribly strange effects in terms reflection, reinforcement and effects on targets, structures, and the human body.  Long pulses knock buildings over very effectively so thermobaric weapons were seen as useful against  structures  and some of the “peculiar effects” that themobarics have in some environments made them “good” at killing people and even against armoured vehicles. That’s about all I’m going to say on that aspect of subject for now, do your own research.  But they make dramatically different weapons with “new” destructive capabilities and should not be underestimated.

Some sweeping statements now, which I’m then going to hit with relatively new information:

Thermobaric weapons first came to my attention in the 1990s, like most people, I think.  The story was the Russia had invested in some new technology and weapons like the shoulder launched RPO-A were the first example. Translation often (in those days and still today) classed these as “flame weapons” which confused the issue but all of a sudden people seemed to realise their effect against targets and the West sat up.  More and more thermobaric/FAE weapons have been produced over the years, including RPG variants, and artillery variants. Perhaps the most dramatic variant is the TOS-1 “Buratino”, a Russian armoured multi rocket launcher that has the ability to attack a large area (such as towns, villages, armour start lines, forming up points etc) with a barrage of thermobaric weapons.  It has an apparently remarkable effect.  Google it. The weapons have been used in Chechnya and indeed the Middle East (probably) and now they are on everyone’s radar.  The technology was presumed to have been Russian, and relatively recent. But if you did some research you might have come across a passing reference to an unsuccessful attempt by Nazi Germany to use thermobaric weapons to attacks formations of Allied bombers, with a missile system called “Taifun” – Germany for Typhoon.

A few days ago an old colleague, Paul H., pointed me in the direction of two books. The books are interviews with German soldiers who were in France around the time of D-Day in 1944. As I understand it the interviews were conducted in the Mid 1950s by Dieter Eckhertz and the books have been edited by his grandson and finally published in the last couple of years.   WW2 history, like most war history, is written by the victors, and the books are fascinating because they give the perspective of the losing side, from apparent primary sources. The Germans, not surprisingly, often have a different take. On their own, the books are fascinating. There are two volumes, both available on Amazon :

“D Day Through German Eyes – by Holger Eckhertz.

Link https://www.amazon.co.uk/gp/product/B071NTXK2H/ref=series_rw_dp_sw

Kindle version are cheap.

One chapter in Book One has a fascinating chapter regarding the operational use of Goliath RCVs by the Germans against tanks on the beaches of Normandy, and links to my earlier blog post about these early RCVs here.

But it is at the end of the second book that really made me sit up. You really need to read the chapter yourself and I don’t wish to take away from the authors right to be rewarded for publishing it. So here only in startling outline is what is said.:

  • Germany had an apparently large effort developing thermobaric weapons in WW2.
  • The interviewee, K L Bergmann,was a specialist weapons officer with thermobaric weapons. He eventually died in the early 1980s.
  • The design evolved and was used at various stages of WW2 along the development line, that perhaps were very crude to start (not much more than “flame weapons”  and got increasingly sophisticated.)
  • A version of the Taifun weapon (Taifun A) was used very effectively, allegedly, against Russian Bunker structures in Sebastopol wit dramatic effect.
  • A Taifun system of some kind was allegedly used against the Warsaw Ghetto.
  • The interview clearly implies that the weapon was “tested” against captured Russian soldiers as human targets to examine the effect on the human body.
  • By the summer of 1944, the system had evolved in to Taifun B.  It was mounted as an MLRS system on a number of tracked vehicles (Stuka zu Fuss type vehicles) Interestingly (and very importantly) the interviewee who had taken a detailed part in the development program describes the contents of the Taifun B system as containing a burster charge with a fill of kersoene like liquid with the addition of carbon and aluminium particles. I think that’s a pretty credible thermobaric material, in outline. A second missile system fired after the main charge caused initiation of the dispersed cloud, but eventually the initiation was integral by the summer of 1944.
  • Taifun B was deployed to Northern France with the intent it be used against any port seized by the Allies as the focus of the invasion.  The intent was to simply destroy the port with a barrage from Taifun B and the officer in command appears to have had no doubt it would have that dramatic effect.
  • The fact the Allies didn’t land at a port such as Dieppe or Calais for the D-Day invasion and instead landed on beaches surprised the German command and meant the Taifun-B system wasn’t deployed quickly. There is some discussion by the interviewee about the effect the system would have had on the Mulberry harbours.
  • Eventually the Taifun B system was deployed to counter the expected US breakout from Normandy, under General Bradley, Operation Cobra. Taifun was deployed to the correct place, and the very densely packed tanks of General Bradle in its form up location was set up as the target. However just before the fire order was given the Taifun B vehicles were hit by counter-battery fire (maybe accidentaly as part of a rolling barage), and the launch of the missiles was prevented.
  • Bergmann believed that the use of his thermobaric wepaons would have destroyed Operation Cobra, and could have changed the course of the war. Also he believed that the effective operational use would have convinced the German command to use it again and again.

My assessments:

  • The word “Taifun” seems to have been used to describe a number of weapons systems that were part of the Thermobaric program. They evolved over the war.
  • I note that some commentators have dismissed some of the interviews in the books as fiction because they don’t match “established facts”. To me the interviews seem authentic but I’m no professional historian.  I again point that usually it is the victors who write the history and it doesn’t surprise me there are anomalies from these German interviews.  I find the description of the chemical content of the Taifun B system convincing as is the effect of artillery on a loaded Taifun B Stuka zu Fuss vehicle and its rockets. The description of a thermobaric effect is also convincing, as is the evolution of the system, which is logical. Elsewhere separate interviews such as the operator of the Goliath RCVs ring true to me.
  • I need to research more on possible Taifun usage against Russian bunkers in Sebastopol in the 1942 offensive. This is slightly hampered because the Germans used “Taifun” to describe a very wide strategic military operation in Russia.
  • Ditto Taifun use against the Warsaw Ghetto in 1943 needs more research.  There is an odd discussion here:  https://forum.axishistory.com/viewtopic.php?t=106078   which describes it as a demolition device using a fuel air explosive to destroy tunnel systems.
  • I think anti-aircraft Taifun systems may have been an entirely different system and may or may not have been thermobaric. https://en.wikipedia.org/wiki/Taifun_(rocket)  Again the use of the word Taifun may be confusing matters
  • Research is hampered by a number of things. a. Secrecy of the original project.  b. Confusion over the nature of “flame weapons” and thermobaric weapons, with historians and perhaps the military conflating the two, perhaps understandably. c. The  use of Taifun to describe a much broader German invasion of Russia and d. the fact that Taifun thermobaric weapons evolved over a period of time. e. A lot of amateurs on the web who while clearly understanding nothing about thermobarics feel able to offer detailed comment.
  • To me there is a striking similarity between the Taifun B concept allegedly deployed in France in 1944 and the TOS-1 system of todays’s Russia. I think earlier Taifun A, was possibly simply an engineer demolition tool using a fuel gas pumped into tunnels and defensive structures. Taifun B appears to have been much more advanced system delivered by rockets. Early version of this rocket delivered system required a second barrage to initiate the cloud, but by the summer of 1944 this had been integrated.

This is still somewhat of a mystery, and I’m not yet fully certain it is true – some have raised doubts about the veracity of the author. Let me know what you think.

 

Here’s a pic of a possible launch vehicle showing large calibre rockets (added Sep 2020)

Rockets

The First Metal Cased Rockets

Over the past few months I have been in conversation with a new Indian friend, Mr Nidhin Olikara.   He has done some tremendous work with archaeological colleagues on some ancient rockets recently discovered from the time of Tipu Sultan, in the late 1700s in India.  These metal cased rockets predate any European metal cased rockets, and were, I believe a source of technology for Congreve’s rockets, developed at Woolwich in England in the early 19th century.  Congreve gave little or no credit to the Indian technology which he exploited, and no credit at all to the Dublin rebels’ rockets, which I believe were also inspired by the Indian rocket technology.

This is a complex story of industrial history, archaeology, munitions exploitation, technical intelligence, metallurgy and ordnance design.   For context, I have written before about European rocket development here:

http://www.standingwellback.com/home/2018/5/2/the-history-of-metal-cased-military-rockets-an-investigation.html

and Robert Emmet’s rockets in Dublin in 1803 here:

http://www.standingwellback.com/home/2012/12/28/the-mystery-of-the-the-man-with-no-history-other-spies-and-e.html

Mr Olikara and his colleagues came across many rockets which appear to have been disposed of down a well. They have been able to recover these and examine them scientifically and the results are fascinating. They have written a paper recently published in the Journal of Arms and Armour Society, Volume 22, No 6, dated September 2018. It is not yet available on-line.

Rockets were developed in India by the forces of Haider Ali and then his son Tipu Sultan in the late 1700s. They were used extensively against their enemies, including the British. Amongst Tipu Sultan’s allies, were the French, which may be relevant for later parts of this story. It appears that the British recovered some of these metal cased rockets to Woolwich Arsenal.

Some of the 160 rockets that Mr Olikara recovered have now been analysed and the results are fascinating. A quick summary:

  • a. The rockets are largely of a similar dimension to the (later) first of Congreve’s rockets, varying in diameter between about 35mm and 65mm
  • b. They appear to be made of what we would call today “mild steel”. ie relatively low carbon content. This would make the metal relatively malleable.
  • c. The assessment is that the cylinder components of the rocket were hot or cold forged on a cylindrical die or anvil, with two end caps (one with a vent) forged onto the ends. To be clear, the base material is a rectangle of sheet mild steel, hammered on a cylindrical anvil into a tube shape and two flat circles then attached to the ends, by hammering. One of these ends has a central vent acting as a venturi choke.
  • d. Remarkably the contents of the rocket were still largely present and chemical analysis gives results consistent with gunpowder/blackpowder.  In some rockets there is still a clear suggestion of a formed central combustion chamber formed in the propellant.
  • e. Perhaps most interesting of all, from a munitions design perspective is that the rockets appear to have been lined with a refractory element such as clay, providing a layer between the explosive/propellant fill and the steel wall of the rocket. Most intriguing. I can find no reference of a similar fabrication in later Western rockets

What is still unclear is the filling process in relation to the fixing of the end caps. What came first?  Fixing the end caps first makes sense from a safety perspective but makes the filling process tricky. I expect it will depend on the nature of the filling and how easy it was to load it in the cylinder. I suspect that the front end cap was fixed first, and the rear closing cap fitted “snugly” then removed, the rocket then lined with clay, dried, and the powder fill put into place. The combustion chamber would then be bored, the rear cap affixed in some manner (carefully) so as to not ignite the charge, and a fuse made of some sort of cloth inserted in the nozzle/venturi.

What is also is unclear is how the longitudinal seam of the rockets metal cylinder body was formed. I suspect it was “folded” in a “finger lock seam”. To do this, (and speaking as a very amateur blacksmith), the two sides of the rectangle to be joined would be first turned and folded back a few mm on the edge of an anvil into a lip. When the sheet is then formed into a cylinder these folded turns would interlock.  I will experiment in my own forge in coming days and try to post pictures.

I think the implications of these findings might be as follows:

  1. The Armies of Haider Ali and Tipu Sultan had an industrial level production firstly of mild steel in sheet form.  I doubt this was “ rolled” steel but was probably very skillfully hammered. what is most significant,  I think, is that the steel was being produced for a “ disposable”, one-time-use system. That indicates that sheet mild steel which heretofore was perhaps an expensive luxury for body armour of the rich and wealthy was available in such quantities in its sheet condition to be economic to make into one-time-use discardable munitions. I think that’s quite significant.
  2. This was proper industrial scale production of steel components, albeit the rocket diameters seem to vary.  The skills in hot and cold forging mild steel are not dissimilar to the making of protective armour.   The history of technology of India in a broader sense has often been ignored or discounted by the West. India’s metallurgical developments of such things as pure wrought iron, mild steel, carbon steel and Wootz steel is fascinating and the technological processes associated with manufacture of items from these materials seems to have been often ignored in history.  This book  https://www.amazon.co.uk/Indian-Oriental-Military-History-Weapons/dp/0486422291 published originally in the middle of the 19th century gives some insights into the broad range of military metallurgy in India over a number of centuries.
  3. The technology is well in advance of European rocketry which did not use metal cases (apart from the Emmet rebellion in Dublin in 1803), until 1805. Congreve, a man of his time, was disinclined to give credit to India, Emmet the Irish Rebel or indeed others (a Scotsman also claimed to have sent him the idea of metal cased rockets.)  Congreve was driven of course by the opportunity to make a considerable fortune and reputation. Also, perhaps the role of technical intelligence from one’s enemies was, as it still is, always understated.

This development, like all good historical stories, prompts further questions:

  1. How did the French alliance with Tipu Sultan allow them to obtain metal cased rocket technology and pass such technology down to manufacturing instructions to Emmet in 1802/1803?
  2. Why did the French (at the time renowned for their scientific expertise in military matters) not develop rockets themselves until after Congreve had? French interest approved by Napoleon seems to have started in about 1809.
  3. What was the level of input into Congreve’s development from Irish rebel Pat Finnerty, Emmet’s rocket maker who ended up working for Congreve at Woolwich in 1804?
  4. What earlier (non-metal cased) rocket experiments at Woolwich by the British artillery general, General Desaguliers was Congreve able to draw on. He would have been aware of these experiments I’m sure, which had occurred some years earlier but were deemed a failure. But much would perhaps have been learned about propellant.
  5. Was there any technology transfer in the other direction?  Mr Olikara and his team found what I am certain is a rocket boring tool in their investigation, used to bore a combustion chamber in the packed rocket body – it is remarkably similar to tools used in European rocket making in the 1600s…also,   steel rolling mills were developed in Europe in the latter part of the 1700s… is it possible that this technology transferred to India, enabling the production of quantities of sheet steel for the rocket bodies? Or did Tipu Sultan simply reply on a large number of people involved in the manufacture, hammering out sheet steel with such skill?

Mr Olikara has also, interestingly and separately from the paper, found records of what I take to be a British military EOD operation in 1871. The operation involved the disposal (by an Ordnance officer) of cannon from the time of Tipu Sultan (70 years earlier) and mentions finding rockets that were still filled with propellant  from this time. One of the cannon exploded (still loaded from 70 years earlier) while it was being prepared for destruction, killing one man.  So in 1871, Ordnance EOD operations were dealing with dangerous munitions from earlier wars… Plus ca change!

The development of military rockets by Congreve and subsequently by quite a number of European and American nations continued throughout the 19th century, slowing when artillery systems improved, but there was certainly some sort of rocket arms race as Congreve, then Hale developed British rockets systems and the Europeans raced to get ahead.  Even today it is possible to see in very real terms the evolution from Mysorean rockets to Congreve, to Hale and all the way through to say a modern Russian 107mm rocket system – and such systems are being adapted for improvised systems in Syria  and Iraq today with much effect. Military metal-cased rockets are a staple of modern warfare, but now the nature of its origins in India is somewhat clearer. Those wishing more detail should obtain Mr Olikhara’s paper (I may be able to help), and also a book “The First Golden Age of Rocketry by F H Winter is a useful reference.

Rockets

The history of metal-cased military rockets – an investigation

A couple of years ago a wrote a few posts about the emergence of metal cased military rockets as a weapon system in the early 1800s. In retrospect I made some hurried assessments, and after a while digging I’d like to revisit. The links to my older posts are below but I’ll repeat some of the story here for coherence. This is a story of terrorism, weapons technical intelligence, politics, subterfuge, tall tales and obfuscation, leading to financial success for one individual (William Congreve) that perhaps wasn’t entirely deserved.  The traditional, commonly accepted wisdom was that Congreve “invented” rockets in about 1804, introducing “new” metal-bodied rockets, and also introducing larger calibre and longer range variants. He was supposedly “inspired” by the use rockets by Tipu Sultan in the Mysorean wars in India in the late 1700s.  I think that is a misrepresentation (mostly by Congreve himself), of a much more interesting story which I’ll try to make here.  I’ll also try to give credit for what I think Congreve deserved . I have been encouraged by a new colleague, a keen historian from India, Nidhin Olikara from Karnataka in India. Nidhin is involved in some exciting research in this area which I cannot reveal yet. Mr Olikara’s blog is here:

I’ll lay the story out chronologically as best I can:

  1. After being “invented” in China, rockets appeared first in Europe in the late 1300s and early 1400s. Rocketry was discussed in the book “Bellefortis” written in about 1405. However I think there is a red herring – the picture below, from Bellefortis, is quoted often as an image of a rocket. But I think it is not – to me it is simply a spear head, and the “rocket vent” is simply the socket for a spear. Some people quote the size of the man holding the rocket/spear but the other images within Bellefortis are massively inconsistent in scale too.  I do accept however that Bellefortis does apparently discuss rockets elsewhere in text.

   Rocket or spearhead with socket? I think the latter.

2. Throughout the 1500s and 1600s rockets were well known in Europe, mainly as a component of massively complex fireworks displays which became very popular in the late 1500s onwards. Leonardo da Vinci discussed rockets and a number of books about “pyrotechnics” were published. Some of the books clearly made the jump from rockets as a form of pyrotechnic entertainment, to rockets as a military weapon.  In the 1500s rockets were clearly being developed by Conrad Haas (1529 -1569) in Austria/Hungary. Haas’s technology was surprisingly advanced, and included bell shaped nozzles and multi-stage systems.

Note the venturis on the rockets and the engineer creating
a combustion chamber with a spike

3. Haas probably influenced a German, Johann Schmidlap who developed further the staged rockets in about 1561.

Double and triple stage rocket motors

4.  In the late 1500s and early 1600s there were a number of experts publishing instructions on rocketry, these include the aforementioned Haas and Schmidlap, and others referred to by later authors as “Brechteltus”, Diagus Ulfanus, Adrian Roman, James Valhouse, Furtenbach and Frontsbergue. Many of these authors/experts developed their own formulae for the best dimensions of rockets in terms of diameter and length. Many also describe a very specific number of taps with a mallet of a specific weight for driving a needle into the packed rocket for the purposes of optimising the rocket motor ignition surface/chamber. This may seem an obscure instruction but is important.  As far as I can tell these rockets were not metal cased but made from paper or card.   In these early years of rocketry I understand that the propellant was standard blackpowder (gunpowder). As firearms developed over this period improvements were made to gunpowder to speed up its reaction.  This made it rather too powerful for rockets with the pressure from the product gases being very high and the cardboard and paste cylinders could not contain the pressure so the tube ruptured.  So rocket gunpowder was made by adding additional carbon (charcoal) which reduced its burn rate.  This issue is fundamental to the development of rockets over the period – having a slow enough burn rate to not rupture the body of the rocket, but enough to project the rocket forward. Much trial and error went in to the development of effective geometry and hence design and production of the rocket motors.  I have found some vague references to the military use of rockets against cavalry in 1600 but so far I have no detail.

5.  A book was written by Jean Appier in about 1620, called La Pyrotechnie de Hanzelet Lorrain.  Here’s an image of a simple rocket design from that book. Note the “warhead” with a fuse that is initiated as the rocket motor finally competes burning. Still there is no sign as yet of metal cased rockets. Note the combustion surface in the rear, created by tapping a mallet into the packed propellant.

Note warhead initiation when motor finishes burn

6.  In 1635, and English book called Pyrotechnica by Robert Babington detailed rocket manufacture. These were not metal cased. Here’s a diagram of the mould used to create the rocket motor. Note the “needle” used to create the correct combustion geometry within the rocket’s gunpowder. Many of the documents and books discussed here recount how the needle is inserted into the packed gunpowder and gently knocked into place with a number of blows from a hammer. Basically the mould former on the left is lined with paper and card, filled with damp gunpowder, then the needle inserted and tapped into place and then dried. The needle is removed and the vent/nozzle formed (“choked”) with a twist of card held in place with string. This rocket is two and a half inches in diameter (which is a dimension that will be repeated in the future. Babington’s book is remarkably detailed. Babbington describes that the best paper to use for the body (“coffin”) of the rocket should be “old law books”!  He then describes a range of explosive compositions and how to make them. The thrust of Babington’s book is entertaining firework displays – but it is fascinating how some of his more exotic pieces presage the use of sub-munitions. He also describes a range of test apparatus to allow the testing of gunpowder.

Rocket mold, cross section and needle for making combustion chamber.

7.  Another book  “The Great Art of Artillery” by Kazimierz Siemienowicz published in 1650 also described a number of rocket systems.  Again I can see no detail referencing metal cased rockets but there is considerable discussion about the variants of propellant mixes needed for various sizes of rockets.   This document provides extremely detailed manufacturing instructions.  (I am using an English translation published in 1729.)  it is interesting to note that Siemienowicz comments about the habit of “pyrobolists” (those making rockets) to keep the methods of manufacturing very secret – but who let the secret out while drunk…  Siemienowics describes rocket cases made from paper, pasteboard in some cases reinforces with wound thread and in some cases made from wood, with conical noses.  The paper ones are described in some cases as being reinforced with iron wire, “for fear the powder would split it”.  He does describe however a range of quite large rockets.  Here’s a diagram of some of a range of Siemienowicz’s rockets.  Note the Multiple rocket using 7 smaller rockets (unlike Elon Musk’s 9). Note also the range of payloads and multi staging. Siemienowcz is extremely detailed on various aspects of quality control.


Siemienowicz’s advanced designs

Siemienowicz appears to be an admirable chemist, physicist and engineer. He spends pages decrying his predecessors who were closer to alchemists, who described their rocket making art in mystical forms hiding the secrets of their craft through pseudo-science. Siemienowicz developed some rules for rocket making and explains the science behind these rules:

First Rule: The larger the rocket the weaker and slower should the rocket propellant be (and vice versa, the smaller the rocket the faster burning propellant is required. This, he explains relates to the available surface area of the combusting propelllant’s hollow cone.

The second and third rules relate to the composition of the propellant in certain circumstances, adjusting the carbon, sulphur and saltpetre comparative quantities.

Siemienowicz describes rockets that are stabilised in flight with sticks and others stabilised by fins. He also describes a stabilisation method I have not come across before using a lead ball fastened to a piece of wire that trails to the rear of the rocket, which he says acts like a stick. Another technique he describes is to add lead filings at various points in the rocket motor – very sophisticated in concept, altering the movement of centres of gravity and thrust in a complex manner.

8. In 1696 Robert Anderson, and Englishman wrote a book with a clear rocket design, two and a half inches in diameter and about 18 inches long.  In my earlier blogs I had misinterpreted some of the instructions from this book, assuming them to describe a metal cased rocket. After careful research and examination of this book I now no longer believe this to be the case, and my earlier assessment was an error.  I think Anderson was using paper and pasteboard and not a metal cased body.

9.   In the late 1700s , in the Mysorean wars in India with the British, the Army of Tipu Sultan used rockets extensively. Some of these were metal cased rockets (I think the first) and some of these rockets were recovered to England for analysis, at Woolwich Arsenal laboratory.   The laboratory was under the control of William Congreve’s father. At the time William Congreve (junior) was not employed at Woolwich, he was busy as a publisher of a political magazine. So there were military metal-cased rockets in Woolwich some 20 years or so before Congreve is credited with their invention. I believe two of these metal cased Mysorean rockets are in a museum in the UK and I’ll be checking on this in coming weeks.  My Indian friend Nidhin is investigating his excellent sources in India. I suspect that the crucial key here is the advanced metalsmithing available in Mysore at the time – often underestimated by Western historians – able to create a closed end lightweight metal cylinder, strong enough to contain the pressures of a rocket motor but light enough to not interfere significantly with flight.

10.  In 1803 Robert Emmet’s uprising in Dublin used metal cased rockets (two and a half inches in diameter) against British forces, it is possible using the specific design and dimensions of Anderson’s rockets from 1696, or even Babbington’s from 1645. However rather than use paper or pasteboard, Emmet used a metal cased rocket.  I’m not sure yet where this idea came from but it is possible it came from Robert Fulton, the American inventor whom he met in Paris in 1802. There is also a French connection to Mysore, and the French could also have recovered metal cased rockets from Mysore to Paris, and hence to Emmet.  Certainly, reports suggest that Emmet came back from Paris with specific instructions on on how to construct rockets.   Another possibility is that one of his workmen, Johnstone, had previously worked in India for the East India Company and had encountered the earlier metal cased rockets.  There is a possibility that Emmet was using manufacturing instruction from one of a number of pyrotechnic books – many had similar instructions and statements suggest those instructions included tapping the rockets with needles to create combustion chambers.  I believe some of Emmet’s rockets were recovered to the Ordnance laboratory at Woolwich, still under the control of Congreve’s father, in 1803.  Again, this is just a few months before Congreve junior became employed by his father at Woolwich. So we know that there had been two sources of metal-cased rockets in Woolwich laboratory before William Congreve (Junior) even began his employment there, and it is very likely that Weapons technical intelligence activities and exploitation were undertaken by the laboratory..    There is also a very strong suggestion that one of Robert Emmet’s men, Pat Finerty, who had been employed by Emmet to make rockets for the Irish uprising was now taking the Kings shilling and was working in the laboratory at Woolwich, perhaps providing insight and experience. Perhaps he was a British spy in the first place.

11.  In 1804, Congreve junior was struggling. His political publishing venture had gone bust and he needed work. But his father was a senior administrator for Woolwich Arsenal,  and all of a sudden he had employment at Woolwich, and he also had potential access to political patronage – vitally important for raising money.   The next few years saw Congreve develop and deploy military rockets. As a former editor of a political publication, Congreve knew the power of media and in parallel campaigned vigorously for funding and patronage to further develop military rockets. He even got himself awarded a commission as a Colonel and took charge of the rocket attack on Copenhagen and elsewhere, distrusting the military to deploy “his” invention. (In return they distrusted him and his lack of military experience).  The development of Congreve’s rockets needs a whole different blog post (or book). But the point I am making here is this:

a. Congreve was a canny political operator, seeking patronage and funding.

b. Within the politics of the time, he understood that he would optimise his chances of patronage if he could take the entire credit for the development of militarily useful rockets.

c.  Diluting the credit for the development with tales of Haider Ali or Tipu Sultan did not fit the politics of the time.

d. Nor indeed would giving the credit in any way to Irish rebels.

I also note that Congreve was an ardent patent producer – except when it came to rockets. was he concerned he might have been challenged?

So, Congreve has gone down in history as the “inventor” of military metal-cased rockets. but we can see that this was incorrect.  We can also see that a wide variety of rocketry principles were developed by scientists and engineers in the two or three hundred years before 1804.  What Congreve did do was this:

a. Management of a secret technical intelligence exploitation operation which reverse engineered both the Mysorean rockets and rockets from the Irish uprising.

 b. Modern quality control and the development of robust and repeatable industrial processes- therefore enabling predictability of range etc.

 c. The development of larger rockets with greater ranges and payloads, utilising the scientific knowledge of propellant technology at Woolwich.

 d. The development (albeit by trial and error) of improved deployment and use operationally to improve effectiveness.

Congreve made much of the fact that an enemy capturing a Congreve rocket couldn’t reverse engineer it, and my assessment  is that this could only be because of the chemistry of the propellant, which by the technology of the day could have been tested but not analysed chemically very well. I think the technical knowledge of the Woolwich Laboratory with regard to propellant science was crucial to the development of Congreve’s rockets.

In the future I hope that the work of Nidhin Olikara and his colleagues will shed more light on Mysorean rocket technology, and the pre-eminent role they had in the development of metal cased rockets, well before 1804.

21st Century

Intriguingly Similar Designs of Improvised Munitions Over Decades

One of the most notable improvised weapons in the last 15 years has perhaps been the “IRAM”.  This “Improvised Rocket Assisted Munition” appeared in 2004 in Iraq, using the rocket motor of a 107mm rocket with a “bolted on” over-calibre warhead. This is a relatively short-range munition with more target effect than a standard 107mm, but quite difficult to range and target.  The IRAM munition came in various designs. Here’s one variant:


IRAMs 2004

Such munitions appear to be being used now by Syrian government forces and others in Syria. See this report from the excellent Brown Moses/Bellingcat website from 2013:   http://brown-moses.blogspot.co.uk/2013/11/is-syrian-military-using-another-type.html.  Sometimes the users seem to have not fired these from 107mm tubes (with the overcalibre warhead “left out the front”) but from tubes with a greater diameter. See: http://brown-moses.blogspot.co.uk/2013/11/the-syrian-national-defence-forces-most.html .  In this variant the rocket motor is “under-calibre”, in effect.

When the IRAM appeared in 2004 it was commonly thought to be a new type of improvised munition. But as readers of this blog might already suspect, it wasn’t new at all – the concept was used in the early part of the Vietnam war. Here’s the image of Viet Cong overcaliber warhead that was fitted to a 107mm rocket, just as they are today. The image provider suggests that the warhead was cast iron, but the welds in what is probably rolled mild steel are clearly present.  These early Viet Cong “IRAMs” were fitted with what were described as WW2 Japanese impact fuzes.

 


Viet Cong over-calibre warhead for 107mm rocket


Japanese WW2 impact fuze on Viet Cong warhead

Now here’s another interesting thing – probably coincidental. The design of the Viet Cong over-calibre warhead is remarkably similar to a Provisional IRA mortar bomb warhead. This image is from a de-fuzed Mk 12 mortar bomb taken in 1991.  The IRA warhead was of course not on a rocket but on a mortar, but the design structure of the mild steel welded warhead looks remarkably similar to the Viet Cong warhead, does it not and is of an almost identical construction. The Mk 12 mortar of course is a horizontally fired anti-armour weapon with a copper cone liner, but the outer form of the warhead is remarkably similar.

 


PIRA Mk 12 Mortar bomb with identical shaped warhead

Keen readers of this blog will recall too that Irish revolutionaries were firing rockets horizontally at the British Military as early as 1803, using a rocket designed in 1696. 

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