Standing Well Back
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.

 

1910-1920

Rediscovering the hand-howitzer

Some time last year I encountered this strange photo, which I assumed was a peculiar weapon of some sort developed in WW1.

At first I thought it was some form of captive bolt  “humane-killer” for horses, with the hook in front of the trigger designed to hook onto the bridle of a horse, perhaps for use under bombardment – the hand-guard protecting the veterinarians hand from snapping teeth. But I couldn’t explain other aspects of the complex system on the “top” of the weapon.  I put out a plea for help last summer on social media but got no useful answers at the time.  A couple of days ago I thought I’d try again and this time with success. So here is the story of this exotic weapon, named by the inventor as a “hand howitzer. I’d like to thank a number of folk who helped me find this – much appreciated.

The inventor was a Northern Irish engineer, by the name of Samuel Cleland Davidson. He did not have any great education, leaving school at the age of 15, but he clearly had an aptitude for engineering and he was an avid experimenter.  After some time in the tea trade, he invented a range of machinery to help with the processing of tea leaves. One of his inventions was particularly successful, a system using a centrifugal fan to blow hot air over drying tea leaves, and his engineering factory in Belfast was called Sirocco, presumably a reference to a “hot wind”. His company “Davidson and Co” went on to make a wide variety of fans and other related mechanical engineering equipment. His company made fans for the Titanic, built at the adjacent shipyard in Belfast, as well as for other ships around the world. Indeed during WWI it would appear that the entire German naval fleet were equipped with Sirocco fans.

Davidson was already 68 years old at the start of WW1, but his son James was an officer, who was killed on the Somme.

Now as readers of the blog will know, there was a lot of innovation encouraged in WW1 to address the particular challenges of trench warfare. Quite a number of grenade and trench mortar systems were developed with varying degrees of success and sophistication and I’ve covered some of these such as the Garland trench mortar in earlier blog posts.  The British Army and the Australian army set up “Munitions Inventions Departments” and these developed and tested such innovations. At some stage, perhaps driven by his son’s experiences. Davidson designed a grenade launcher. Unlike some of the cruder systems that abounded, the “hand howitzer” was somewhat more sophisticated, giving the ability to adjust the rage of the grenade mechanically.  He achieved this by having a system that vented the breech to a lesser of greater degree. If the vent was fully closed the range of the grande would consequently be maximised and the range was shortened incrementally by adjusting the vent.  By implication the system,  had some sort of mechanism to check the level or the angle of launch.  The full US patent for the system is here and open can see some sort of inclinometer on the side not shown in the photo above. The hook allows the system to be held firm while checking the inclinometer.  There were two versions, one hand held, and one fired from a tripod.

Here’s an extract from one of the diagrams in the patent. Note that there diligent engineer that Davidson was, has included a built in oil bottle into the bottom of the system (“u”).

Davidson’s son, James, was serving with 36 (Ulster) Division and was killed on 1 July 1916, the first day of the Somme. He was a Captain in the Machine Gun Corps. Some personal details of James Davidson are here.  Other details are here.  Although it has perhaps little bearing on his father’s invention, which brought me to this subject, one cannot but be moved by the story of his death. After eight o’clock on the morning of 1 July 1916, in response to a request for a Vickers Gun, the official battalion War Diary for the 13th Royal Irish Rifles reported that “Captain Davidson whose guns were in reserve was then sent out.”   At 10.20 am, the War Diary notes, Davidson reported:

“Am in B line & have got up two Vickers Guns, am consolidating both. Cannot say how many infantry are in line … We cannot possible advance & reinforcements, ammn [sic] & bombs most urgently needed.”

At 12.40 pm he sent a further message:

“I am holding the end of a communication trench in A Line with a few bombers & a Lewis gun. We cannot hold much longer. We are being pressed on all sides and ammunition almost finished.”

His family received a number of letters from his fellow soldiers. One was from Lieutenant WW Ashcroft written on July 3rd, 1916. He too was a member of the Machine Gun Company of the 108th Brigade, and noted of James Davidson that “It was through him that I came to the 13th [Royal Irish Rifles]…” He went on to describe to Davidson’s father the events around his son’s death:

“When things went badly, and he no doubt felt his obvious duty was to take up reinforcements, off he went, and for a long time he held up more or less single handed a dangerous position; although shot through the knee, he refused to be carried back; alternately he fired his Gun, and threw bombs until he had to retire to bind up his wound; he returned, and did what he could, and finally he started back to try and find reinforcements. He was shortly after shot through the head.”

Another, Gunner Thomas Pinkerton wrote in August 1916 to Samuel Davidson that he had been with his son when, having held out in the trenches despite being shot through the knee, Davidson had decided to try to get back to the British lines:

“We got to the German front line trench and went down the trench about 200 yards to get as much dead ground as possible. I topped the parapet, and helped the Captain up, and had just got through the wire when I noticed about a dozen men on my left, a few yards up, retiring. Just then the Germans opened a deadly Machine Gun and Rifle fire on us – we just got 20 yards from the wire when the Captain got shot through the head – he just fell, and never spoke nor moved. He died instantly – there was no hope.”

James Davidson’s body was lost in the confusion of the Somme. Twelve years later his body was found on the south side of the Ancre Valley, and identified from an engraved compass found in his pocket. He is now buried in the Serre Road Cemetery, No2, but his name also appears on the Theipval Memorial to the missing.

Samuel Davidson’s invention was registered and patented in 1917, the following year.  It is said he was negotiating a significant order for the hand howitzer with the US army but the end of the war came first and the design was shelved.  He was knighted in 1921.

I will have more on WW1 Munitions Inventions Departments activity in future posts.

 

 

 

 

Radio Controlled IED

German WW2 use of ROVs to deliver explosives

In recent years various terrorist groups and others have used land, sea or air ROVs to deliver explosive payloads to targets.  As usual, people view these things as new and innovative threats. But as readers of this blog site will know,  that usually isn’t the case and I have more details here of some interesting early use of such devices from WW2, although they go much further back.  Some of these may be classed as “improvised” but others are clearly formally developed systems – but let’s not get hung up on definitions, because the concept is what is interesting   There are several aspects to this – one is the technology that is used, and another is the tactical employment. Many of the implementations of this concept were unsuccessful but the reasons for this are also interesting and indeed are being repeated in modern terrorist use of ROV technology.  I won’t go into that aspect in too much detail for obvious reasons.   So here goes with a few interesting  German “land based” example ROVs from WW2.

I’ve written before about the WW2 German “Goliath” remote controlled mine, a small tracked vehicle not too different in scale from modern EOD ROVs.   Following the fall of France in WW2, the Germans captured  a prototype French ROVs used for explosive charge delivery which seemed to inspire the development of the Goliath. This vehicle had been “hidden” in the River Seine, but the Germans got to hear of it and salvaged it for technical exploitation and reverse engineering. (Readers may recall a similar reverse engineering operation from a “purchased” French speed boat just before WW1, that I discussed in an earlier post).

 

Captured German Goliath ROVs after D-Day

While there has been some attention on the Goliath tracked vehicle, used to deliver demolition charges to targets, perhaps just as significant for us looking at history was the German Borgward B remote tracked vehicle. A contract was let by the Wehrmacht to the Carl Borgward engineering company in Bremen for 50 tracked vehicles in 1939. It’s not quite clear if the Borgward B was developed originally to deliver demolition charges or for other purposes such as towing mine clearance tools or as an ammunition carriers.  One suggestion is that during the German invasion of France, German engineers found an operational need and had been converting, in an improvised way, standard German tanks to operate remotely for certain tasks. The theory goes that as a result of after-action reports from this campaign the Borgward B was converted to fulfil this role. But it’s war and it’s a little confusing as to which came first, the chicken or the egg.    In any event,  Blaupunkt, the radio manufacturer developed a radio controlled system for the vehicle. These vehicles and their sub-systems were gradually improved in following years resulting in several “versions” as both their use and requirements changed.  A variety of vehicles were used as “control” vehicles as the war progressed. The radio control unit was very “modern” in appearance, using a joystick control and shared many of the features of the Linsen boats control systems.  The key features of the Borgward B was firstly that it could deliver a large charge, (typically 45o – 550kg), and secondly it could drop off the charge and retreat, thus in principle being a re-usable vehicle, unlike the smaller and disposable Goliath.

Here’s a pic of the Borgward B. The driver would drive the vehicle “normally” until it was a “tactical bound” away from the target, then he would get out and the vehicle would then be controlled by radio remotely. It looks like a fun  drive, (unless you are told to drive it to the Eastern Front).

 

The Borgward B wasn’t a huge success. it was unreliable and quite vulnerable to enemy fire.  Some reports suggest that some versions were equipped with smoke units to lay smoke screens or just to hide its own approach, but I’m not sure how it would then be controlled if surrounded by its own smoke screen. Perhaps this version was simply used to lay smoke screen and move laterally across the battlefield.  I have found a report that a single Borgward B was fitted with a TV camera as an observation vehicle during the fall of Berlin, perhaps a prototype but in the main the later use of these vehicles, in theory was to deliver and drop demolition charges.  The explosive charge, when dropped, had a timer initiation system that after a short period caused the charge to detonate.   The charge was released with the help of gravity after explosive retaining bolts were fired by the operator. I’m cautious about this and think it could have been a lever actuator.   It appears that there was an adjustable safety mechanism that armed the charge only after a certain distance (not time) had been covered, so for instance an operator would set the safety distance to 100m as he exited the vehicle, and the charge would only become “armed” after the vehicle had covered that distance. That’s logical, but I’m not sure how it was achieved.  These vehicles were less suited, of course, to defensive operations than offensive, where their utilisation against defended structures was optimised. I’m led to believe that over a thousand Borgward Bs were produced (compared to many thousand Goliath vehicles).

Here’s a great pic of the explosive charge after being “dropped off” by the vehicle. You can see it slides off the front plate where it is held in a “shoe”.

I think it’s worth thinking about the relative strengths and weaknesses of the Borgward B and the Goliath.  The Borgward B could be moved into its tactical launch position by one man, but the Goliath needed a small team of men.  Perhaps that’s why the Goliath was used in defensive positions like the beaches of Normandy, where it was prepositioned in shrapnel proof hides, (but it wasn’t particularly effective). The Borgward B was larger and therefore more vulnerable, but delivered a much bigger charge than the Goliath more suitable to taking on defensive positions. The Borgward B was more expensive but in theory was reusable. In the main the Borgward B was radio controlled and this offered some flexibility but also posed some reliability problems with the technology of the day. The cable system principally used by the Goliath was more reliable but vulnerable to shrapnel damage.

There was an attempt at a “middle ground” the NSU “Springer” ROV developed in 1943/1944. This was smaller than the Borgward B, bigger than the Goliath, but was driven into launch position by a driver. About 50 were made, I think. Here’s a picture showing its scale and size. They seem to have limited operational use. I don’t have a handle on their control system.

 

I think it’s fascinating that the Germans also used vehicles captured  from the British and French and convert to ROVs. It seems that the German engineers saw potential in particular from the British Bren Gun carrier and the Belgian “utility tractor” (a British built tracked vehicle made by Vickers, who also made a proportion of the British Bren carriers).

Here’s a pic of both in “normal use”

A Belgian Vickers Utility tractor

Bren Carrier

A number of both these vehicles were converted to be cable-controlled demolition vehicles, each with a 1.2 km cable.  That’s quite a distance, and one imagines that control of vehicle at such range was tricky, based on distant observation.  A total of 60 were sent to the Crimea in 1941.  The German Crimean campaign of 1941 is interesting because I think it was used as a testing ground for range of innovative German technologies.  I’m currently exploring the use of an advanced prototype German fuel air explosive weapon in this campaign, to clear bunkers and defence structures, and it appears that these converted Belgian and British ROVs were used against the same targets to deliver relatively large explosive charges. I have also seen reports of Borgward B vehicles used in the Crimea at this time.  It appears that the majority of the 60 vehicles were deployed with mixed results – some destroyed by mines before they reached the targets, some destroyed by enemy fire, some failed and some functioned as intended destroying Russian defensive positions.  I can find no specifics over the amount of explosives carried by either vehicle, nor any specifics on the control mechanisms fitted.   It appears that the ROVs were “controlled” from a “mother” command tank.  The Germans complained that there were no spare parts for the captured ROVs and recommended development of indigenous vehicles accordingly.  Other feedback included the suggestion that they would be better employed in flatter, desert conditions, such as North Africa, rather than the complex urban defence environments of Sebastopol, and indeed at least one Bren carrier, captured at El Alamein was so converted.   While this effort to convert enemy tracked vehicles to wire guided demolition use wasn’t really repeated , it’s clear it had some success and more importantly allowed the Germans to develop tactics and concepts of operation. . I think too, given the large amounts of “enemy” vehicles abandoned in Europe at Dunkirk and elsewhere, it made economic sense to utilise them, and the Germans had no qualms about recovering, and using, where possible, quite a range of enemy equipment.

This picture is, it is claimed, a captured Bren carrier (complete with German Cross) fitted with explosives being deployed on the Eastern front. The vehicle in the distance is Borgward B, I think, so it seems very likely.

I think it’s fair to say that the Goliath and the Borgward B ROVs were less effective than the Germans had hoped in normal operations on the Eastern and Western fronts. But it’s worth looking more closely at their deployment in the tight urban environments of cities. There are notable reports of Goliaths being deployed into the Warsaw Ghetto in responding to the Warsaw uprising in 1943.  If ever there was a historic precedent to the urban destruction seen in modern day Syria, the destruction of the ghetto by the German in 1943 is it.    Goliath were used to target buildings, and of course with only small arms the defenders had little defence against these ROVs, unlike formal military units.  I also see parallels with modern anti-tank missiles being used against defensive positions in Syria, of which we are seeing many. Yes these aren’t as fast as those missiles but the targets and tactics are quite similar.

Here’s the remains of a burnt out Borgward B vehicle, I think destroyed by fire after it had dropped off its charge in Kilińskiego Street in Warsaw in August 1944. The explosion reportedly killed 200 residents. The story of this attack is dramatic and a desperately sad tragedy. Essentially the vehicle had been captured by Polish troops as the Germans attempted to deploy it towards a road block and was being paraded around Warsaw by cheering locals. Someone pulled a lever which caused the deployable explosive charge to slide off, and as we know there was a timer started by this activation which the crowds did not understand.  The charge detonated shortly after.  There is more detail here if you are interested. It is possible of course that this was a “Trojan horse” attack, and a number of sources claim this but I suspect that it was just accidental.

Here’s some pics of the Goliath systems being deployed in Warsaw.

This is the effect of a Goliath on a building in Warsaw

I think the German forces of WW2 had, in their ROVs, some interesting tools for offensive operations, and for the built up environments of  Warsaw and heavily prepared defensive environments off Sebastopol they were of some use.  But for German defensive operations, they were less suited. Fundamental unreliability was a major issue, it seems, with all the systems they used, and that’s both in terms of motive power and in terms of the control systems. Modern technology perhaps allows for more reliance on the systems used by terrorists and others. In a battle there is perhaps more of an issue of unit cost – whereas modern ROVs are cheaper, and not being deployed, in general, in battle conditions are doubly attractive. Modern ROVs have more precise controls including reliable and usable video components that makes control easier and more attractive. More accurate control also leads to the potential to reduce charge size and so allow the vehicle to be smaller. I think this aspect of modern ROV weapons is not yet widely understood.  Improved batteries for electric vehicles also increases range.  The issue of logistic support is somewhat useful in understanding use of ROVs for delivering explosives and again modern terrorist use changes the impact of that logistic support and is maybe less crucial in terms of systems.  What is inescapable now and in the past is that ROVs offer an aggressor a safe way of delivering explosives, with the size of the explosive charge required having, of course, an impact on the vehicles that might be suitable.  The key difference today is that technology has improved reliability of control systems, and also that technology is broadly available.  However it is susceptible to technical counter-measures.  In particular radio control systems are now consumer items and not limited to government enterprises.  There are also some other parallels in terms of utilisation of captured weapons systems – and here I’m thinking of the way some Syrian jihadists have adapted captured armoured vehicles for suicide VBIEDS.

I recommend thinking in terms of tactical design – the systems outlined above all approached the target to a “control” point. From there the mode of control switches – and remote control takes over.  It’s worth, as with any attack system, particularly terrorist attack using radio or other command systems, having a hard think about what defines that “control point”.  What are the characteristics of that change over point that are needed, are chosen and utilised? Understanding those will help you develop some counter-measures. Modern day control points are perhaps less clearly defined than these WW2 examples, but the principle remains. Another thought that comes to mind is the importance of Technical Intelligence to the EOD operator. Put yourself on the shoes of an EOD tech 75 years ago – what would you want to know about the command and initiation system before you dealt with such an object? It may have no relevance today but as a “process” it’s useful to think through how you, a modern EOD operator, would deal with such things in a variety of situations – it’ll get your brain thinking, and that’s the best use for a brain.

Most of you will be aware of the command driven vehicles used by modern terrorist groups – various Jihadi ones, ETA, FARC and the IRA have all use such systems and others too are in the back pages of this blog site. But most importantly don’t be then thinking remotely driven vehicles delivering explosives are anything new – they are more than a century old and there are lessons to be learned still. From a historical perspective I’m intrigued by the German campaign in Crimea and the manner in which they used innovative weapons systems there – I’ll be digging further as it’s not a part of WW2 that I’m all that familiar with and instinct is telling there’s some interesting history. I have one wild reference to an ROV being used underground there which I’m trying to track down, and of course Russian defence of Sebastopol in the century before has been a subject of previous blogs. It’s strange how the patterns of explosive use over the centuries return to the same places. Sebastopol, Antwerp, London…

 

16th Century

Chinese 16th Century Ship-Borne IED

An interesting pic below.

 

This is from a book written in the mid-1500s by a Chinese Imperial official and shows a sophisticated vessel containing large amounts of explosives.  This and other vessels of a similar nature were made at the Dragon River Shipyard near Nanking.  There are some interesting features to this:

 

  1. Note the bow of the vessel – these protuberances are described as “wolf’s teeth nails”. When the vessel is rammed against the target these steel teeth engage and fasten the bow of the IED vessel to the target.
  2. Note the “hook and eye connections” amidships. This is pretty clever. After the vessel is rammed into the target the entire “bow” containing the explosives and rockets, is detached by detaching the hooks from the eyes and the attackers row away the foreshortened vessel. Other vessels from the Dragon River Shipyard utilised other designs for leaving behind explosive or combustible material and rowing a smaller boat away  – and disguise was a key design consideration.  This vessel may have looked like an ordinary commercial vessel with plenty of crew aboard and therefore not like an expected explosive ship, which were usually towed.
  3. The skipper is protected from enemy weapons in a cabin, and the rowers are equipped with long poles to defend themselves and presumably light the charge.
  4. The official describes this vessel as being 14m long, with the forward detachable section being about 1/3rd of the length, (so roughly 5m long).

Europeans (specifically the Portuguese) would have encountered these sort of attacks in their war against the Chinese in the first part of the 16th century.  So these vessels just preceded the first real European use of this sort of weapon, namely the “Hoop” at Antwerp in 1584.  In the early 17th Century the Dutch too faced such weapons in their Chinese adventures. In 1637 a small fleet of English vessels arrived in China to trade and were attacked by a small fleet of fire ships and explosive vessels.  The attack was described by a man aboard one of the ships and adventurer called “Peter Mundy”. (That name will make some of you older British EOD types smile).  Mundy writes:

“The fire was vehement. Balls of wild fire, rockets and fire arrows flew thick as they passed us, But God be praised, not one of us all was touched.”

Mundy then learned that the attack was actually inspired by the Portuguese in Macao to deter British trade competition.  This concept precedes then the development of “spar torpedoes” used frequently in the US Civil war, where an explosive charge was on the end off a spar on the front of an attacking boat, designed to attach to the target.

20th Century

German Explosive Remote-Control speedboats of WW1 and WW2

Apologies, it has been some time since my last blog – I have been distracted on other projects.
This blog is an interesting addition, I think, and opened my eyes once again to matters of historical technology that have been forgotten by many. It concerns German remote-controlled, explosively-laden boats in WW1 and WW2 used in the English Channel and the north European coastline. Given current interest in drone technology it is tempting to start by putting it in that context, but I think I’m going to start by putting it in the context of the boat and ship-borne IEDs that have been something of a theme of this blog in recent years.  To remind you the North European coast from the Netherlands, through Belgium, the English Channel and round the French coast beyond St Nazaire have seen repeated use of the concept of a ship or boat loaded with explosives and sent to or placed next to a target for many centuries.  You can see my blogs on these by following the “ship-Borne IED” tag on the right hands column,   In rough historical order, these are:
  • The Hoop, Antwerp, 1584
  • A floating IED designed by Fulton, use against the French in 1620s by the British Royal Navy
  • Benbow’s Vesuvius of 1693, St Malo
  • Captain Dundas’s “machine vessel”, used against Dieppe and others used against Dunkirk, 1694
  • Meister’s ship IEDs of 1695
  • A catamaran IED used against the French by the Royal Navy in 1804
  • Cochrane’s Infernals of 1809 used at the Aix Roads, and a  larger vessel built in 1812
  • The Zebrugge raid of 1918
  • Operation Lucid, 1940
  • Operation chariot , St Nazaire, 1942
So all of these attacks used boats or ships loaded with explosives to attack ports and shipping.  In that context the use by the Germans of the same concept in WW1 and WW2 shouldn’t be a surprise but I have only just become aware of them.

WW1.

 Below is a picture of a WW1 weapons used by the Germans in the English channel in WW1. It’s called the “Fernlenkboot” (“remote control boat”), sometimes abbreviated to FL-boot.  The vessel was 17m long, and carried 700kg (1,500lbs) of explosive.   The concept was to use these against British Royal Naval vessels operating off the coast of Flanders – right in the traditional area for such attacks over the centuries. The control concept was quite complicated. Each boat had a spool of wire 20km long to provide control signals.  Observation was by aircraft which flew above and sent radio messages to a control station about steering directions.  The boat had a powerful petrol engine and could achieve speeds of 30 knots.  I have found some inconsistent but intruiging suggestions that as well as the cable controlled versions, radio control systems may also have been developed. Certainly some seem to have been equipped with antennae.
The commands available included
  • System test
  • Engine start, engine stop
  • Set Rudder position
  • Turn on a light, to enable the boat to be tracked at night
  • Detonate the warhead, to prevent capture of the boat if it missed its target
In later systems there was an auto destruct mechanism added that functioned after a time period.
The vessels were not used that often but one did hit HMS Erebus in October 1917 which was damaged but not sunk.
The provenance of this weapon is worthy of exploring. The system was built by “Siemens-Shuckert” and seems to have had its genesis in an idea that Werner Siemens the late 19th century engineer developed in 1871. I have blogged about Werner Siemens and his port defence command initiated IEDs before here.  In 1905 his son Wilhelm resurrected his father’s ideas for remote controlled boat weapon. It appears that Siemens developed the idea of an remote controlled , explosively laden boat some time before Tesla, who had a similar idea some 20 or 30 years later. Siemens really does play an important part in the history of explosive systems. The development of such technology of course parallels the development of modern torpedo technology. The advantage of a surface system is that it can be actively seen and steered by the user – the disadvantage is that the system can also be seen by the target, (stating the obvious here).    By 1914 the Siemens-Shuckert firm had continued to develop its technology and an interesting event occurred. There was a “power boat competition” in Monaco and a hi-tech French powerboat with an innovative engine was expected to be the winner. Just before the race, the boat was withdrawn by the French competitor and the boat disappeared – to turn up later in the Siemens- Shuckert research facility in Berlin, being reverse engineered. There was a French government investigation into the acquisition by the Germans of this technology. It appears that a man called Schmidt, who “pretended to be Russian” had bought the speedboat for hard cash. He was working with the German company Bosch, who were in return working for Siemens. This is the motor that appeared in the FL-boot in the war.  So some very interesting German technical espionage and industrial technology acquisition was going on before WW1.

WW2

In WW2, the Germans develop a similar concept called “Linsen” – high speed boats filled with explosives.  The concept was somewhat simpler – the boats had a crew (eventually of one person) who got the system within a distance of a target and then they “bailed out” jumping overboard. Then a control boat with an operator steered the Linsen craft to its target at high speed. this control boat in theory then picked up the original crew.  Like other systems, there were quite a few variants. Maximum speed from its Ford petrol engine was 31 knots. The boats carried a charge of 300kg.  A contact fuse in the bow caused the bow to blow off but the main charge (and engine) in the stern then sank, and detonated at a depth under the target, thus increasing the explosive effect. Clever.  Radio control from the support vessel was by ultra-short wave radio on the 7m band, a Blaupunkt, using various transmitted “tones” decoded into commands.  The receiver filtered the tones into relays and actuators.   The controls possible were:
  • Actuate starboard rudder
  • Actuate port rudder
  • Stop engine
  • Start engine
  • Slow ahead
  • Go faster
  • Detonate  the boat, if the attack was a failure.
  There is a suggestion that the control mechanism was also used in some of the Goliath tracked vehicles that I have blogged about here.
The control units, incorporating a very modern looking chest rig and joy stick look remarkably modern.
The Linsen boats were small, fast and worked in pairs.
The Linsen were used with very  limited success against Allied vessels off the coast of Normandy in the summer of 1944.   In one of those neat historical coincidences , later in 1944, Linsen explosive boats were used against Allied vessels trying to use the port of Antwerp in Belgium – some 360  years after the Hoop explosive vessel had been used near Antwerp to attack the Spanish invaders. Some things are never new…    Of course, other nations produced similar concepts in WW2, including the Italians, the Japanese (who used “swarm tactics” in high speed craft not unlike that envisaged by Iranian craft in the Gulf).  I may write about these in the future.    Small fast moving vessels containing explosives is a concept still very much in vogue, but largely the tactics remain similar, and the technology has advanced a little – but there’s really not much new, as ever!
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