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.

 

 

19th Century

Book Review – “Killing Strangers” by T K Wilson

The author of this book kindly referenced me in this important work, so I feel happily obliged to give it a review.  Tim Wilson is the professor at CSTPV in St Andrews University, an organisation I had some interaction with a couple of decades ago, and it remains a leading academic organisation looking at terrorism. The book examines how terrorism or political violence has become commonplace in the modern world and I think is an important contribution.  It helps that it is very readable and of course I’m flattered to be referenced so I hope this doesn’t come across as too biased a review.   I think the book is a well structured analysis, providing the context for terrorism but also examining what makes it so prevalent in the modern age.  My review below is less well structured – I’m going to highlight certain concepts that the author brings out which intrigue me.

 

Of course I should make clear that I don’t regard myself as a historian at all – I’m simply interested really in the technical evolution of some of the things terrorists use, and that gives me a slanted perception, but also perhaps a valid one.

  • Early on in the book, the “disarming of society” as it occurred some centuries ago in Europe is discussed. I think this is interesting and highlights some tricky issues, relating to firearms in particular and the associated culture of these weapons. In Europe the advent of firearms in the 16th, 17th and 18th century as the primary weapon of violence really only affected armies. Other than a small number of hunting firearms, the most powerful weapon was in the hands of the military.  Society was not given access to firearms in any sense that enabled them politically.  This began , I think, early in the 1500’s with the development off the wheellock which I have written about recently. Early on in that century wheellocks were banned from use in a number of countries, and a real threat was seen from the fact that they could be concealed. Emperor Maximilian I banned them from use in Austria and then throughout the Holy Roman Empire. As the author points out, there was also a cultural move against weapons in general, with their use either not favoured from custom or banned in law.   It fascinates me that now in the 20th century many parts of the world deadly weapons are, in some places, now de rigueur in some societies. And there’s the whole American firearms can of worms that I’m not going to dive into here – other than point out its curious anomaly.
  • The 18th century brought a political motivation to upend order from populations, or parts of populations, rather than being solely driven perhaps the cruder aspirations of powerful individuals as was seen before. The French and the American revolutions seem to be the genesis, and indeed from my own narrow perspective the use of explosive weapons was not unknown even at this time.  These revolutionary fervours seem to have been re-ignited in the 1840s albeit with limited success, and they gained pace throughout the latter part of the 19th century, when various revolutionary themes, such as social revolution, anarchy, Irish nationalism, and other febrile politics all provided an environment for political violence to proliferate. Of course at the same time, significant scientific strides were also occurring in regards to the development of explosives.  The use of explosive weapons for political violence was not new in the late 19th century but certainly became much more commonplace.  In my view, a number of things converged to make this happen
    • Revolutionary or political fervor
    • Scientific advances making explosive devices more effective
    • Knowledge of the science
    • Availability of components (linked naturally to the preceding two factors)
  •  In terms of the scientific advances, the author refers to Walter Laqueur’s concept, first really put out in his 1977 book “Terrorism”, of what he calls the “minaturization” of explosive devices and to be honest I struggle to see this as a valid concept. What Laqueur sees as “miniaturisation” of IEDs , I think is better understood as the arrival on the scene of more “energy-dense” devices. Devices didn’t get smaller in the late 19th century as Laqueur suggests, they got more powerful.  There were plenty of small devices seen in the decades and centuries before when gunpowder was the explosive charge. They got no smaller (in any particular way) in the anarchist, revolutionary and fenian bombs of the 1880s which contained dynamite or other high explosives. But the increased energy density made them more powerful, and therefore more effective. I certainly can see nothing “miniature” about these devices technically that makes them smaller than earlier low-explosive devices.  Tim Wilson, to be fair, mostly identifies this flaw in Laqueur’s concept. I think  there are quite a few examples of some pretty small devices prior to the 19th century – have a trawl through the 18th century devices in the link in the column to the right and you’ll see plenty of “small devices” that preceded the high explosive small devices of the late 19th century. To be blunt, Laqueur didn’t look hard enough when he said the first postal device was in 1895 – they had been around for decades or even centuries. Laqueur falls for the common failing of many in assuming that such things as explosive devices are always recent – something that is the purpose of this blog to counter. Laqueur is simply weak when it comes to technical matters. As an aside (and I apologise if this is turning into an anti- Laqueur diatribe), his assessment of the use and impact of devices in the Second World War is way off the mark. Perhaps I’ll post a more thought-through critique on Laqueur in the future. Tim Wilson too recognises here Laqueur’s weakness with regard to the Second World War,  I think.  
  • In terms of the spread of knowledge of the science of explosives and their application I think there are some interesting factors occurring in the late 19th century that deserve some scrutiny. The US Civil War certainly saw extensive use of explosive devices in innovative ways, and there may well have been a “transfer of knowledge” to those Irish Americans who served on one or other of the sides in the war and who may have subsequently become members of the Irish Fenian Brotherhood or Clan na Gael.  Other conflicts too threw up opportunities for ordinary men to learn the art and science of bomb making.  Intriguingly there was also a strange American theme of “Bomb making schools” in the 1880s, a classic example of which I wrote about on this blog some years ago which was a bomb school sponsored by O’Donovan Rossa. That particular proponent, the pseudonymous “Professor Mezzeroff” had this to say about the spread of IED knowledge, when writing a letter in an anarchist pamphlet “The Alarm” stating:

    “and I won’t stop until every workingman in Europe knows how to use explosives against autocratic government and grasping monopolies.”  He claimed to always carry an IED:“I take it through the street  in my pocket; I carry it about in horse cars – if you carry two or three pounds (of nitro-glycerine) with you people will respect you much more than if you carried a pistol.”

    Other anarchist pamphlets and books of the time, such as Johann Most’s “Revolutionare Kreigswissenshaft” were self-proclaimed (if somewhat flawed) attempts to spread the knowledge of IEDs. The spread of revolutionary pamphlets certainly spread the technical details of bomb-making as well as igniting revolutionary fervour.   Finally, I have a suspicion that the industrial revolution itself spread a broader knowledge of engineering that could be applied to the manufacture of IEDs, and the related spread of quarrying and mining to support the astral revolution provided a cadre of individuals able to comfortably utilise explosives for destructive effect.  After all, an explosive charge used to cause a rock fall in a quarry, or in a mine is nothing other than a command wire IED.

  • Tim Wilson points out that the use of powerful devices, as effective devices and as propaganda of the deed (exacerbated by the global communications of today)  enable tiny groups to have an impact.  I may be stretching a point but perhaps too in the modern day of social media even more destructive effect can be waged with scarily simple concepts such as anti-vax conspiracy stories. I may be being  little febrile myself but compare the number of deaths caused by anti-vaxers with say, the Red Army Faction of the late 20th century – I know which one I’m more terrified of.  And it ain’t some weird German revolutionaries, it’s the even weirder, and much more widespread anti-vax conspiracists. Sometimes they too seem to be pushing anarchic arguments.
  • The author’s description of the fearful populations worried about terrorist explosions in London, Paris, Barcelona and Chicago in the 1880s is interesting and not something I had considered before in any depth. He points out the the legacy today continues in terms of the security apparatus present today responding to sustained terrorist threats. I am reminded too of my own time in Northern Ireland in the 1980s and 1990s and of the effect of Belfast “Disruption Days”, which often needed no explosives at all to gridlock a city. Indeed the author describes how the seriousness of revolutionary inspired gun-battles in Berlin in 1919 were measured on a scale of how much disruption was caused to the tram network and its schedule.
  • I was fascinated to read of the tactic, employed by Italian fascists, other fascists and even the Belfast IRA of the forced consumption of castor oil (and its inevitable gastric and intestinal consequences) to publicly humiliate their targets. How strange. The public view of such events, along with lynching and along with more formal public execution is of course designed literally to terrify a wider public.
  • The author discusses how anarchist terrorist attacks have declined since the 1930s something I hadn’t really considered. I do note that in some senses that motivation did continue in later decades – the classic “anarchist cookbook” of the 1970s after all continued the proliferation of knowledge, even if the anarchism was nothing really very detailed. But I did sense in the attacks of the Unabomber, and I dare I say it in some of the more peculiar extreme right wing linked attacks in recent decades a continuation of the focus on the destruction of authority for its own sake. Is it fair to view for instance the Oklahoma bombing as nothing other than an anarchistic attack on authority?  (Remember I’m a techie not a political historian….). Is the anarchy of the right any different than the anarchy of the left?
  • I think perhaps that in the section of the book on the Second World War and the use and effect of “terrorist attacks” focuses a little too much on the relatively few attacks in Western Europe without (like most histories, I’m sad to say) any mention of the tens of thousands of partisan attacks in Eastern Europe that really did impact the war by complete disruption of the vital cog in the German war machine, namely the railway network. So this is a criticism not of this book, but of “western history” in general – the huge partisan efforts to blow up railways in Eastern Europe preceding and enabling the advances of the Soviet forces deserves much more study, even allowing for a little Soviet exaggeration, and Nazi cover-up.
  • There’s an interesting assessment of the street protests of 1968, compared to earlier street protests as far back as 1948, and the author rightly suggests that although they seemed threatening at the time, history shows they came nowhere near to the societal overthrow predicted. The same too in 2020 with “BLM, antifa and proud boys” I think. In broader sense too, I think that the bogeyman of terrorism in the early 21st Century is nowhere near as dangerous as governments and terrorists alike would have us believe. It suits both governments and terrorists to suggest that these acts are an existential threat. They are not.
  • I’m amused by the story of members of the Weather Underground studiously keeping to road speed limits when driving, lest a casual speeding offence bring them to the attention of the authorities. By such mundane actions, the “free spirits” of a revolutionary movement are constrained directly by a carefully managed society/police effort. The mundane power of governments from speed limit enforcement of the 1960s to the remarkably powerful but dually mundane ANPR and cell phone monitoring and associated data analysis today making it a real challenge to mount any sort of terrorist attack (and get away with it) today. Similarly the mundane (in some senses) potential of forensics and data analysis is now so powerful as to make life for the everyday run of the mill terrorist virtually impossible, and along with that the GRU operatives of the Salisbury type attack so easy to identify, as well as what they had for breakfast and what car their spouse drives.
  • There’s a passing reference to the supposed technological expertise of the Provisional IRA, citing Oppenheimer’s “IRA, The Bombs and the Bullets”. Frankly compared to modern terrorism the technology of past IRA devices isn’t anything to write home about, and was overblown (with the exception of the odd one or two devices).  It sometimes suits governments countering terrorism to exaggerate the technical or operational expertise of their terrorist opponents and the technological competency of the Provisional IRA is one such area. Another good example is the concept of the “Evil Genius terrorist bombing mastermind” such as  Ramzi Yousef, now spending the rest of his life in a prison cell. A cursory look at his track record shows he was no genius. The secret truth is that the most effective terrorist bombs are the most simple.
  • I was intrigued by the reference to police databases and the struggles that police have had and maybe still continue to have with regards to recording of useful data. I once wrote a couple of  blogs in “another place” about card indexing systems – first used (literally using seized playing cards during the French Revolution) and then by Napoleon’s Chief of Police to record his intelligence. Tim Wilson recounts here how a Scotland Yard Flying squad detective investigating IRA bombs in the 1970s, sought out the records from the Met Police investigation of the 1939 IRA “S” Plan campaign – to find … nothing had been recorded. Indeed as I wrote about here – the repeat bombings which show how often people are surprised by short memories.
  • It is interesting that the author points out the remarkable number of heads of state who were attacked with explosive devices “while on their way to the opera” and even more while on display in a carriage or transportation that was entirely predictable to the aspiring terrorist – I’ll certainly have to write a piece about that in a future blog.
  • There is interesting discussion about the relative lack of frequency of IED use in the 17th and 18th Centuries. The technology existed at this point in history – but was there really a reduction of the actual use of IEDs? Some of this is based on what I think (and which the author recognises) as Lacqueur’s erroneous perceptions. My view is actually there were plenty of occasions where explosive devices were used in the 250 year period between 1580 and 1830.
    • Many examples are on this blog – seek the links in the right hand column. Ship-borne IEDs, letter bombs, casket bombs, VBIEDs – there are probably more there than is commonly appreciated.
    • There was wide adoption during this period of hand held “grenades”. It’s no coincidence that Regiments of “Grenadiers” using hand held thrown grenades (explosive devices after all) were to the fore in their period, They may have been used in battle rather than in street violence but they were there.
    • There were some very significant use of innovative devices – not least during the US War of Independence.
    • Indeed, “war” saw widespread use of explosive devices and sometimes they become lost in history as “mines or torpedoes” or just categorised so that they don’t appear in histories of political violence – in that sense Laqueur may have a small point.  But there’s an issue over definition here – I would view Bushnells Barrel IEDs, and the “turtle attack” used to attack the British fleet in 1776 as the use of innovative IEDs – but others may regard the as a simple mine warfare. I don’t doubt that there was a “slump” perhaps of political assassinations between 1650 and 1790 but I don’t see them disappearing.  Again Laqueur is simply wrong to suggest that industrial manufacture techniques in the late 19th C enabled small devices to be produced. Some devices of the 16th C are of equivalent size and function – the issue is the energy density of high explosives, not the size of the mechanical components.  The author of this book recognises that it is the ubiquity of high explosives that made the difference, not the associated miniature componentry.
  • There are numerous mentions of interesting incidents which I was unaware of, and thus they provide flag posts for me to head down the burrows of IED history in coming blog posts – – I’m particularly  grateful for that and one of the first will be the demolitions expert and apparent “pervert” Sylvestre Matushka who used IEDs to attack two trains in 1931. A very weird story.
  • The author discusses convincingly the ebb and flow of terrorist attacks in the 20th century, and the reasons for the dynamic frequency of these attacks. I was also struck by the discussion – the first I have ever come across – of the emotional satisfaction the bombings provide to some. The language of playfulness is certainly there, as the author describes, but until now I had not considered its reasons.  The “magical secrecy” of the bomb attack reflects the “skill’ of the perpetrator and the ingenuity of the device (again a refection on the “master bomber” trope). This is in contrast to my own feelings as a retired EOD type – I see bombs as nasty , dirty things to be “disposed of” and got rid off – things that are hurtful and lack consideration, likely to harm innocents. I think there’s some interesting psychology on both sides of the fence here. Someone once asked me if I would be prepared to meet a former terrorist bomber, but the thought literally disgusts me. Hence, too, my contempt for raising a theme of the “evil master bomber” as something remarkable. I just see plain nastiness and not always competent nastiness but rather contemptible. But I also recognise the anomalies and exceptions in my disgust which is not particularly coherent. I’d love to meet Garland and Lawrence, who used the IED so successfully in the desert in the First World War, and one or two others who I’ve written about in these pages. One man’s terrorist, etc.

Overall this is a good analytical book, highlighting aspects of terrorism in useful context and bringing out aspects I wasn’t aware of, or from a different perspective. I think most EOD types who consist of the majority of the audience of this blog would find it useful and it would add to the broader understanding of the phenomena of terrorism for them. Recommended.

Finally a quote that Tim Wilson picks out which I agree is a statement of great clarity. This is by Michael Henning, a survivor of the 7 July 2005 bombings in London. He says the following:

“The terrorists think they are getting back at the State., but they’re not, there have ripped apart the people – the state is unscathed”.

16th Century

Development of Mechanical Explosive Initiators in the early 16th Century

A few days of enforced idleness has given me a little space to think. Inspired by my (off topic) recent post, a book review on the evolution of piston engines in the Second World War I’ve been thinking again about key technological developments in history with regard to explosives and related issues.

To put this blog into context, let me try to make things really simple.  An explosion, (whether that be of high explosives or gunpowder) is a chemical reaction, typically a change from a solid to a lot of gas. For about 500 years from about 1000 AD to 1500AD, there was only gunpowder, a low explosive, and this mix of chemical solids could be brought to change to gaseous products with the application of a naked flame which starts essentially a combustion process.  So by introducing a naked flame, or equivalent amount of heat, it starts the reaction, and causes the explosion of hot gases. Until about 1500 the only way of igniting gunpowder was by heat or flame. You can see my earlier post about other related technologies here.

But having to have an already burning flame or equivalent is tricky. You can’t disguise it easily. If your “match” is unlit you have too start a fire somehow and that takes time, even more so before the age of boxes of matches and cigarette lighters.  All this led to practical challenges in the use of firearms and explosives.  The most efficient method until 1500 (and indeed for many years later) was to have ready a slow match burning well in advance,

The time was ripe then in 1500 for a more flexible way of initiating gunpowder, either in a firearm or for an explosive device or indeed nay kind of munition that used gunpowder.  There then appears to have been a key turning point enabled by a number of disparate technologies. These include:

  • Engineering skill in terms of precision craftsmanship from clock makers. This included the development of skill which creation of relatively fine metal components that could be shaped into a fair amount of detail.
  • Advances in metallurgy and associated engineering that led to effective steel springs.  The springs become a “store” of energy which can be released to cause sparks with a little ingenuity. To be effective, springs needs to be relatively high in carbon so they don’t lose their “springiness”.   In the century running up to 1500, the manufacture of springs became optimised.
  • To me  (as an amateur blacksmith) there appears to be some clear links and cross over between “door lock” mechanisms that use springs to release levers, and these gun lock systems. As I understand it these engineering developments were also occurring at about this time in history.  And of course the word “lock” crosses the gap – in German where these may have been invented the word used for both firearm locks and gun locks is “Schloss”.

Around 1500 the wheel lock was developed, perhaps in Germany or perhaps by Leonardo Da Vinci.  The mechanism of the wheel lock is that potential energy is stored in a spring.  When the spring (carbon steel enabled by metallurgy) is released, this spring (a coil)  typically causes a steel wheel to turn around a spindle as in clock technology. The wheel , with a jagged edge turns against a quantity of pyrites, causing sparks to occur. The sparks drop into a container of ignitable material, typically gunpowder in our case.  In preparation to ignition a key is used to tension the spring, which is held on a latch.  That spring can be held indefinitely, with only the release of a latch needed to initiate the mechanism and whatever combustible is placed next to it. When the latch is released by a trigger, the wheel spins and another spring loaded lever pushes the pyrites into contact with it. Interestingly the “wheel” also needs to ideally be carbon steel to get the best sparks, so the development of these two key components were driven by clock makers developing springs for their mechanisms using carbon steel, and understanding how energy could be released from a spring and applied usefully. After all, engineering is often about how energy is turned from one form to another.

I’ve written before about a lovely diagram from the 1580s of an IED initiated by a wheel lock , with a fantastic picture I found in a book in the British Library. That post is here, but I’ll repeat this diagram below for convenience – it’s one of my favourite historical IEDs. One doesn’t need to understand the writing to work out what’s going on – note the string attached to the trigger, the wheelock mechanism and the fuze leading to a barrel of gunpowder.

So this image was a wheel lock initiated IED from 1582, and I wanted to find an earlier example.  Some sources suggest that Leonardo Da Vinci was the “inventor”, so I’ve been hunting for Da Vinci diagrams.  Here, below, is one from the “Madrid Codex” . Whether Da Vinci actually designed this or was simply copying a design made by a German inventor is an issue for the academics. If I’m honest I can’t quite understand the diagram (and also the accompanying text!)  but I have picked out some key points.  Let me at least point these out to you:

  1. The Trigger, is at the lower right hand side.  Compare this with the trigger above at the top, tied to a piece of string which runs round a pulley.
  2. There are two Serpentines in the diagram below. A serpentine is best thought of as a lever which acts under the effect of a spring. If I’m honest I’m not certain of the purpose of the left hand one – it could be as a release-latch on the spring loaded steel spinning wheel.  The right hand serpentine I think holds the pyrites, and a spring action pushes that down when triggered. “Serpentines” were of course used before wheel locks to hold the burning fuze of a match lock, then press it into the gunpowder when a trigger was pulled releasing it. the second serpentine could though, be a failsafe, duplicate to the first.
  3. The spinning wheel is shown vertical and isolated but I suspect it was horizontal, but it’s not clear to me how this was held. I’m also not sure what the circular object in the middle is.

 

In doing some more digging I found a couple more interesting diagrams that are worth showing in the context that I think they may not be to ignite explosives, but rather to light tinder, which in effect meets the same requirement.  Perhaps these “mechanical tinder igniters” were precursors to the wheel lock. They date from the first decade of the 1500s, right in the early days of match locks and I have lifted them from the “Loffelholz Kodex”. Here’s the first:

This is really a beautiful diagram, from 1505, and I think shows a pocket-sized igniter. A portable “everyday carry” from 500 years ago.  The box container contains tinder” or , if you like, gunpowder. The brass slide holds the tinder in a box. A cord is fitted to a spindle, and wound round and round. Also attached to the spindle is a steel wheel, and the serpentine holds the pyrites. The user, with a ring on his finger to which is tied the cord, pulls, the wheel spins, the pyrites is engaged , sparks fly and light the tinder. Replace the tinder with gunpowder, and run the cord as a trip wire and you have a booby trap IED.  You can see that with the addition of a clock spring ,  a release catch to allow the spring to act on the wheel and another spring to engage the pyrites, it is the same idea.

The second diagram is more complicated, and I confess I can’t quite work it out. But it is clearly a wheel lock device for some purpose or other. If you can interpret the action here, please let me know your thoughts. I can see the “wheel”, the tinder box, the serpentine holding the pyrites and one , if not two triggers, but I can’t quite work out the springs.  Clearly this is meant to be screwed onto the side of something.

What these inventions do, that previously wasn’t very easy to achieve, are:

  1. Reliable ignition of gunpowder without the need for a pre-lit burning fuze, allowing concealment in advance. This is a key IED capability. Previously any emplaced device would have been spotted by the smoke emitting from a match, and could not have been left for any length of time.
  2. Booby trap initiation – using the “string” to release a spring, or pull a spindle, both causing sparks and thence initiation of a charge.
  3. Command initiation from a distance, again using the string.
  4. Timed initiation – because a clock could be used to to cause the trigger to be pulled – and it was clock engineers who were developing the mechanisms anyway.

So these are startling new offensive capabilities for explosive devices. As such, the development of the wheel lock had perhaps more of an impact on explosive device design than on firearms. where , in battle at least, the need to conceal a burning match was not an issue.  Perhaps there was an impact though on the use of firearms in ambushes and for highway robbers, when firearms could be concealed under a cloak. Such mechanisms in firearms were quickly banned in some countries – again showing the potential for the illicit use of a mechanism such as this for nefarious effect.

As such I think that historically speaking the development of the wheel lock is one of the most significant engineering developments in the history of explosives as it provided several distance new IED capabilities.     Wheel locks were expensive to produce so the use of match locks continued for some time – flintlocks which came some time later were simpler and therefore cheaper to produce, eventually phasing out the wheel lock.  That development is in itself interesting because it was a “simpler” technology replacing a complex engineered device.

Before I finish, there’s two interesting aside. Most wheel locks used a concentric spiral spring to turn a spindle that ran through its middle. But there’s two other initiating systems , one a variant of the spring construction. This is it below, another Da Vinci Drawng, this from the Codex Alantic and you can see that the spring is a longitudinal coil rather than a spiral, but it still acts on a “wheel” that is perpendicular to the length of the spring.

Finally another approach to the same problems this not using a wheel at all but a longitudinal bar of steel pulled so that it scrapes along the pyrites. This is the Monk’s Gun, held in the Dresden Armoury. This dates from somewhere between 1480 and 1550.

Although it has no “wheel” it has the advantage (?) of being somewhat simpler. You can see the “serpentine” holing the pyrites, and the ring on the bottom is pulled to the right, causing the teeth on a steel slide to act on the pyrites producing a spark – hidden behind would have been a touch hole leading to the chamber of this simple gun.

 

19th Century

“Not in the Habit of Buying Bat Guano”

A false alarm from 1881, dealt with by Lt Col Majendie, the lead British EOD agent at the time. Goes to show that press reporting can be febrile and not conducive to sensible response.  The efforts of the press to spin up terrorism hysteria then as now could be a bit batsh!t crazy.

 

20th Century

Book Review – The Secret Horsepower Race

The subject of this book review is perhaps a little outside my usual scope, being a history of largely mechanical engineering developments. The book is ” The Secret Horsepower Race: Western Front Fighter Engine Development” by Calum Douglas.

Is there a more complex piece of machinery in history than a WW2 fighter engine combining dozens of technologies- with demands on it from 0, to 35,000 feet, and when life or death is the outcome?

This book has sparked significant interest from me for a number of reasons:

  • I’m originally a metallurgist and there’s a fair bit of that in there.
  • I have some background in Technical Intelligence matters in a previous life, decades ago, and there was plenty of that going on in the 1930’s and 1940s in this field. Techniques were largely the same!
  • Although I’m not a mechanical engineer I have a modicum of knowledge and recently have been refurbishing a 1914 stationary engine – this gives me just enough understanding to get through most of the technical elements of the book. When I say “refurbishing” I mean “tinkering and occasionally get it to spring in to life”.
  • My father was a mech engineer and had a connection with Ricardo, a British engineering research company which played a key role, and also with Vickers who bought Supermarine in 1928.
  • This blog is essentially about the technical development of certain weapon technology – and this parallel weapon technology development to the matters I discuss on this site was pretty important.
  • I “get” the importance of piston engine development at this period and had previously dipped into the subject a few years ago
  • I know many of the readers of this blog have a broader technical interest in military history

Mr Douglas has written a tour de force here. The research from various sources in various languages has clearly been thorough and detailed. The book hangs together well, is well structured, laid out and with significant effort on technical images, which genuinely add to understanding.  I admit that sometimes the replicated graphs of WW2 engine performance under tests sometimes become hard for me to decipher – a reflection on my patience rather than the author’s work. But they are there if you need to interpret them.   He has bridged the highly technical subject matter to most readers with a modicum of knowledge like myself in a clear and unambiguous way. I confess at points I went off to do some side research in occasional subjects (like getting a better understanding of sleeve valves and disc valves, as an example, about which I was ignorant) to give me a better understanding of some of the issues he discusses but I don’t see this as a negative – I’m now a more knowledgeable reader. A book that encourages one to read more around a subject can only be a good thing. If the author had felt the need to explain such matters, it would be several volumes long and I think he chose the right path, by and large.  Another example of this – I had to read up on the differences between “pre-ignition” and “detonation” (in terms of internal combustion engines) which I didn’t grasp the reasons for and the differences, but more importantly I was keen to understand the chemistry of detonation in the context my own separate understanding of explosive science. It surprised me that post-combustion products or remnants could explode “again” at the pressures present in the cylinder. Again, no huge negative and a detailed technical analysis like this would normally demand some contextual reading for the average consumer.  I also like the way he gives detailed technical excerpts from his sources as part of the main narrative – it helps the book hang together rather than having to refer to appendices or footnotes. The verbatim arguments recorded diligently by stenographers between the various German protagonists is astounding and, separately, pithy letters within other nations equally surprises, and it’s a positive to detail these directly.  On occasion a throw away line intrigues me and sets me off on a tangent – like the mention of 146 Merlin engines sat in France in June 1940 ahead of the Nazi invasion and an oblique mention of attempts’ to re-patriate them – there’s a story there, I suspect, that I’ll dig in to – readers may recall that I’ve written in the past about the efforts of The Earl of Suffolk who was getting machine tools, diamonds , scientists and heavy water out of France at this very time.

I think the book is important for a number of reasons:

  • The development of aero engines in the 1930s shows how nation states can influence strategic technology development in both useful and negative ways.  It is clear that the governments of UK, USA and Germany were all talking with commercial companies to develop key technologies, set priorities, targets, directions and aspirations, and providing money too. Sometimes that guidance failed or pushed matters in the wrong direction but at other times it led to remarkably fast technology development.   Like many I had heard of the importance of the UK ‘s efforts to win the Schneider trophy in the early 1930s, and I had the false (schoolboy) impression that it was simply a precursor to the Spitfire, but only now do I see the the importance that this government funded effort to support the Supermarine company in the competition and the benefits in terms of engine development capability.  But beyond that, the “R” engine in the Schneider trophy winning aircraft was hand-built and had an expected life of 4 hours operating only at sea level. In 1940, the RAF needed thousands of Merlin engines, with hundreds of hours possible on each, operating higher than 30,000ft.
  • The pace of technology development was remarkable. We think that technology development is fast today in the early 21st century. But take this as an example – In 1914 many aircraft engines used a wick to deliver fuel to the combustion chamber.  Just 17 years later, the “R” engine in the Supermarine S6 was as if from another planet, generating 2000bhp.  But the “R” in the float plane only operated at sea-level. 12 years later Spitfire IXs were operating at 38,000 ft, an entirely different proposition
  • It may seem that “piston engine development” is a single subject – but as Mr Douglas lays out, it’s much more interesting than that. To develop an aircraft piston engine the following technologies need to be improved, each of which impacts on and complicates the other:
    • Engine layout and construction
    • Metallurgy, as applied to every component
    • Valve technology
    • Fuel technology to prevent “knocking” or pre-detonation.  Germany was hampered by the logistics of its synthetic fuel production.
    • Carburation- how to get the fuel to the right place in the right form and with the right energy output – using carburettors, pressurised carburettors and eventually fuel injection.  Hugely complex engineering challenges in this alone.
    • Cooling technology and the associated challenges with pressurising cooling systems, applied to engines and components such as turbo chargers and even valves.  I had no idea that liquid sodium was used as a coolant inside valves.
    • Superchargers and Turbochargers.
    • Lubrication technology
    • Bearing technology
    • Spark plug technology
    • Logistics – the Luftwaffe were clearly hampered by poorly thought through logistics for their fuel production, by circumstance already a difficult challenge but one they made worse by poor decisions on storage and production logistics.  This is in marked contrast to the British effort to secure a robust logistics system for 100 octane fuel.
    • In some German engines the whole engine had to allow a gun barrel to be slid down the middle

The development of one technology often impacts on others – creating complexity. To give a simple example, adding lead to a fuel to improve its performance, has a knock-on effect (pun) causing more corrosion. So then a designer has to balance more performance with less engine life, along with a host of other implications from maintenance engineering resources, raw material supply, pilot training, production engineering, etc. At speed, in war and with life and death to consider too. It’s interesting that it often appeared that German research efforts were focused on “getting around” material constraints, while UK and US efforts largely focused on simple engine improvement. One wonders what the excellent German engineers could have done if resources were not a problem. Perhaps the Saturn 5 in the US space program indicates the potential of what might have been.

So the book is essentially a description of how nations pull together widely divergent technologies into a single strategic direction, with varying degrees of success. (Spoiler, the Allies win, although they were losing for some time).  The author’s efforts to address the parallel tracks of technology development in a coherent way are commendable.   I find it fascinating that each nation had its strengths within the above subsets of expertise but the overall successful engine required a fusion of many and, as often as not, that fusion was administrative rather than technical. In the early part of the war the German fuel injection system was streets ahead of problematic British carburettors. The Americans were better at fuel technology and turbochargers and the British had their strengths too, radiators being one example. Running successful engineering projects requires excellent communication systems and administrative skills as well as engineering knowledge. The question is, do those communication and administrative skills lie best in government or in engineering companies?  In the German system at one stage there was a clear gap between a central ministry and the development labs in terms of setting technical priorities. It was a fault at this interface that caused the Me 109G , intended to be a replacement for the Me 1o9 F, to be no better than the aircraft it replaced – a true disaster from the German perspective.  One particularly interesting example of  British government-company integration was the installation of “moles” who were “embedded” with engine manufactures with a specific, openly acknowledged role of reporting to Beaverbrook’s Ministry of Aircraft Production (MAP), providing eyes and ears and direct up-to-date communications between Ministry and manufacturer.  These liaison positions were titled “Resident Officers”. I think that’s an interesting concept.  High tech development of multiple systems becomes a communications problem as much as anything else.

Government competence is an issue in terms of technical development. While there were some remarkably capable engineers within Nazi Germany, when the Nazis placed political appointees in the engineering system, or gave authority to people because they were famous pilots, things fell down. Fascists and competent government don’t go hand in hand.  A good example is the appointment of Ernst Udet, a WW1 fighter pilot and protege of Goering to head a technical research department, for which he was eminently unsuitable.  Running research departments demands an unusual fusion of technical brilliance and administrative skills – a mix that political extremists rarely provide.  But in Germany it wasn’t just personal inadequacies that flawed their strategic engineering development response – it was also the structure and attitude of its fascist government that seemed to think that metaphorically barking orders equates to authoritative competence. Italy was even worse.  That’s an interesting lesson for today’s governments too.  Running trains on time might be within the capability of a fascist government, but not making a 2000bhp Merlin operate at 35,000 ft and shoe-horn it in to a Mustang.   The point is really knocked home in reports in the book detailing how so many of the best Luftwaffe pilots were killed not by enemy action but by engine failure.

The book does highlight for me the strategic importance of any nation holding its engineers in high regard. The engineering talent that was applied to the development of piston engines in the 1930s and in subsequent war years is simply stunning. We celebrate the contribution soldiers and airmen make but the contribution to a national goal in war of engineers was never more apparent then. There were many more British aircraft engineers than Barnes Wallis, and dare I say some of them at least of equal stature, but today largely forgotten.   For what it is worth the Germans provide a fine example still to this day – “Dr-Ing” is still an honourable title in Germany – but in the UK engineers seem to be held in less high regard.  The occasional inserts provided by the author on key engineers emphasise the human aspect of this technological battle.

The amount of Technical Intelligence going on in the 1930s and 1940s was a surprise to me. British and American engineers visited Nazi engine development sites until the late 1930s and vice versa. Indeed in some areas technology was exchanged – the FW-190’s superior performance was at least due in part to above-board transfer of technology in the 1930s. Regular engineers working for civilian companies were clearly reporting back to government authorities about what they saw and heard on foreign visits. There was also covert activity with , for example, two German spies visiting the US Government facility at Wright Field in such a manner that they were able to draw extensive diagrams of equipment and tooling. The different approaches to analysis of captured enemy equipment is also fascinating – do you bang out a quick report, or do you spend a year or two doing detailed analysis? If you classify it as “Secret” , is it usable information?  If you are 3/4 of the way through the development of your own fuel injection system is it helpful; or a distraction, to have a report on the enemy’s system thrust under your nose, by an analyst who perhaps hasn’t seen your work?  Age-old problems seen in stark outline here with the US, UK and Germany all taking different approaches to Tech Intelligence analysis.

One area that particularly caught my attention, perhaps unsurprisingly, was a specific Technical Intelligence effort to examine fuel systems from captured or shot-down German aircraft. At every such opportunity, samples were taken, analysed and correlated over time. This provide a remarkable database for Air Intelligence to examine. Furthermore they clearly and specifically engaged with the top fuel scientists in the country to draw inferences from changing fuel specifications – and whether these were driven by technology demands or forced by fuel supply and synthesis problems. A great example of how collecting mundane data consistently can allow very valuable insights into enemy technical and strategic capabilities. The author, quite rightly, describes the analysis provided as a result as “astounding” – a great lesson for modern military technical intelligence.  On the flip side however, the British took an age to work out that the additional gas injection system they found on captured German aircraft was using Nitrous Oxide, despite knowing that the Germans referred to it as the “Ha-Ha” system. It never occurred to the Tech Int analysts or indeed the British combustion experts until much later.

One final Technical Intelligence matter – Open source – there is repeated reference to the important technical information on newly developed German engines by reading articles in magazines – the German seemed quite comfortable even as late as 1942 to announce aspects of their engineering developments in openly published magazines for enthusiasts. Similarly, in November 1941 American articles about new fighter aircraft engines were being openly published, and German Tech Int copied a diagram of a twin supercharged Merlin from “Flight” magazine. Who needs spies when the opposition makes public their secrets? That is, assuming people to bother to read the published material, which was not always the case.

As I read the book, I encountered several fascinating engineering problems and learned how different nations addressed them – fuel dissolving in lubricating oil on cylinder walls was one such issue for the Germans who ran their engines cooler, but not so for the Merlin which had a deliberately hotter running coolant system but  that meant the fuel evaporated off from the hot lubricating oil. Thus the German lubricating oil became dilute and less effective, even though, in principle, a cooler engine was a better thing.  Another interesting technical issues for Messerschmidt 109s was an engine malfunction caused by high performance synthetic fuel being stored in a flexible canvas rubber bag, which the fuel reacted with, reducing the fuel’s performance, polluting it, and damaging engines, reducing their life.

As someone with a modicum of metallurgical knowledge I was still surprised at the criticality of the lack of nickel for the German war machine. I hadn’t come across that before and the author’s explanation of the implications of essentially the German nation having no nickel in any of its components are stark. There’s probably an interesting story somewhere about how they obtained what nickel they had, mainly from Finland.  High performance engines operate in and produce inside themselves demanding environments for steel, and nickel is crucial in making steel less reactive -and this lack of nickel leads, as the author makes clear, to a direct consequence of lower performance engines. Their aircraft had less performance because of a lack of nickel – a mundane alloy component in today’s world. Imagine being the Daimler Benz house metallurgist and being told to come up with a nickel steel alloy, but not use any nickel.  At a crucial part of the war (1942) the conflicting demands on metallurgical resources means that key alloys were being taken away from aircraft production for use in flak guns.  Again, a fascist diktat-run government couldn’t manage the implications of that.

In one interesting area the German were well head and that was in developing control systems. The multiple subsystems in advanced piston engines create real challenges in terms of an operator managing them – and the Germans put great thought into automating these control systems where possible – allowing the pilots to concentrate on “being pilots” and not monitoring and adjusting sub-systems as a “flight engineer”. Today these would all be electronic but creating mechanical systems for this was quite something. Here’s an image below of the BMW engine management system from an Fw-190. Scarily complex, a mechanical analogue computer, automating engine controls.  Also… imagine being the engineering intelligence analyst presented with a captured engine trying to work out what every component actually did – intelligence analysts need to be very competent engineers too, and that crosses over into my own field of expertise too:

In a time of current “National Crisis”, it’s interesting to sense the concern across the Allies in June 1942, as they examined a captured FW-190 and it became apparent they were “losing” the air battles with it, and why. The reports seem to reflect depression and deep concern that Allied aircraft improvements were some way off. Intriguing, especially since the Mk9 Spitfire was only a month away, and the P51 Mustang , also Merlin powered, arrived very soon after.  It is also of interest that efforts to develop aircraft engines were in a sense similar to today’s efforts to make a Covid vaccine. You didn’t put all you eggs in one basket and in parallel with the continual (and amazing) development of the Merlin, several other horses/engines were backed, some of which proved fruitless, but in time of war made sense to reduce risk.

I also find it fascinating that piston engines of the time struggled to have a used duty cycle of hours flown – struggling often to get 100 hours without major refurbishment. I don’t know what they cycle is modern passenger jet aircraft power units is (fundamentally simpler, in a sense I guess), but the engine life must be in the ten thousands of hours. Another area that intrigued me was the development of turbine blade technology for turbochargers, and a very clever rim mounted turbine used in a Russian swirl throttle – I wonder if the science used in developing these was later applied to jet turbine blade design.  Until now I had sort of assumed that turbine blade design for jets started from scratch.

It’s not my habit to pick out errors so hopefully the author will forgive my wry smile when Eric “Winkle” Brown is described as an RAF test pilot. He was of course, a naval officer, posted to the Royal Aircraft Establishment (RAE) as Chief Naval Test Pilot. Probably a simple transposition of an F for an E.  My only other criticism , (I hope constructive) is that it would perhaps benefit from an Annex discussing the aircraft these engines provided power for – and their roles, as context for the engine development. It would have helped to understands that the Typhoon for instance originally was intended as a straight replacement for the Hurricane as an interceptor, and not as the “FGA” aircraft it became. Similarly the impact of the various models/roles versus engine variants of the Mosquito and Spitfire perhaps could have been pulled through a little more in an Annex.

Mr Douglas’s book brings a huge range of history and technical issues together in a readable and fascinating book. I’ve not some across a more enthralling book on an engineering subject. I’d recommend it to anyone with at least a little engineering knowledge.  It’s well researched history, telling an important tale. You can get it online, but best of all use a local independent bookshop if you can.  If you have a little engineering background and an interest in history, you’ll find this book fascinating.

Lastly an aside, which again brings about the human nature of war.  On of the key Luftwaffe technical administrators was Field Marshall Erhard Milch – a fundamental protagonist in the competitive development of fighter engines.  At the end of the war he tried to flee Germany but was caught on the Baltic Coast on 4th May 1945. On surrendering, he grandly attempted to surrender to British Brigadier Derek Mills-Roberts, a commando, while offering champagne, in an attempt to be treated kindly, according to his rank. Mills-Roberts was unimpressed with Milch’s attempted self-grandeur and attitude.  In previous weeks he had been appalled by Nazi atrocities when he liberated Bergen-Belsen. He lost his temper, seized Milch’s Field-Marshall’s baton and broke it on Milch’s head and then beat him further with the champagne bottle, fracturing Milch’s skull. He kept the baton as a souvenir. Milch kept his skull, just.

 

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