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The Secret Horsepower Race: Western Front Fighter Engine Development
The piston engines that powered Second World War fighters, the men who designed them, and the secret intelligence work carried out by both Britain and Germany would determine the outcome of the first global air war. Advanced jet engines may have been in development but every militarily significant air battle was fought by piston-engined fighters.
Whoever designed the most powerful piston engines would win air superiority and with it the ability to dictate the course of the war as a whole. This is the neverbefore- told story of a high-tech race, hidden behind the closed doors of design offices and intelligence agencies, to create the war’s best fighter engine. Using the fruits of extensive research in archives around the world together with the previously unpublished memoirs of fighter engine designers, author Calum E. Douglas tells the story of a desperate contest between the world’s best engineers – the Secret Horsepower Race.
Whoever designed the most powerful piston engines would win air superiority and with it the ability to dictate the course of the war as a whole. This is the neverbefore- told story of a high-tech race, hidden behind the closed doors of design offices and intelligence agencies, to create the war’s best fighter engine. Using the fruits of extensive research in archives around the world together with the previously unpublished memoirs of fighter engine designers, author Calum E. Douglas tells the story of a desperate contest between the world’s best engineers – the Secret Horsepower Race.
480 pages, Hardcover
Published December 29, 2020
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Displaying 1 - 13 of 13 reviews
August 20, 2022
This is a highly detailed, rich study of the piston engines of the World War Two era, largely limited to the Western Front. That is to say, the focus is on British, American and German (single-seat day) fighter engines, with some small side-steps towards French, Italian, and Russian engines. Within that seemingly limited scope, the author found enough new material to fill about 450 pages with often surprising information and insights.
A word of warning: The author is an engine designer himself, and he doesn't always consider it necessary to provide technical background. Often enough he does, but when the does not, the result can be cryptic to many readers. Calum Douglas sort of expects you to know that the connecting rods of a Daimler-Benz DB601 inverted V-12 are in a fork-and-blade arrangement, and what that is. I think this book would have been more digestible for most aviation history fans if it had an introductory chapter on the structure and workings of high-performance piston aero-engines. Maybe that is something to consider for a future edition, but this book already weighs over two kilograms. So many people may want to read a background text on piston engines first. (I'm inclined to suggest Bill Gunston's Development of Piston Aero Engines, although the first print of that book was in 1993 and it may be a bit dated.)
That said, if you have enough technical knowledge to begin to understand the intricacies, this is fascinating stuff and it really changes our understanding of the technical competition between these air forces. Crucially, in this book a wealth of new information on the design of WWII engines is considered in relation to their fuels and the available raw materials and engineering resources. There is a a lot of technical detail in this book, but that is integral to the argument that the author builds: The most conspicuous successes in WWII piston engine design did not come from radical innovation, but from consistent step-wise improvement with great attention to detail.
And I have never seen such a detailed study of WWII aviation fuels, a surprisingly complicated subject and one that had very significant historical consequences. Crucially, the Germans found themselves in great difficulties by having to compromise on the composition of their 100 octane C3 fuel, which caused no end of trouble by its effect on the oil system and by its adverse reaction with self-sealing fuel tanks. German chemists were well enough aware that the high fraction of aromatics in this fuel blend had important disadvantages (as well as some advantages), but as it was much easier and cheaper to produce for their synthetic fuel industry than the alternatives, they had little choice. The C3 fuel was already very scarce as it was. Gradually, they increased its production and improved its behaviour.
It is well known that availability of rare metals was a limiting factor on German wartime engineering, but in this book we learn how this affected engines parts ranging from big-end bearings to exhaust valves and turbochargers. The desirable materials to have for high-performance engines, besides the obvious steel and aluminium, fill a surprising list that includes copper, silver, gold, nickel, chromium, cobalt, indium and platinum: Nearly all of them in short supply in wartime Germany. Problems did not stop there, as oil, rubber, cleaning fluids, even methanol ran out. German engine designers spent a lot of effort merely coping with the bad supply situation, effort that then could not be spent on improving performance. The consequences were dire, and if you have a passing knowledge of WWII fighter aircraft, the serious concerns about the initial reliability of the BMW 801 and DB 605 (both usually thought of as successful engines) are an eye-opener.
Substantial lengths of text are quoted directly from meetings at the German Air Ministry (the RLM) and the Luftwaffe, as stenographers were present for high-level meetings. The atmosphere of confusion, evasion and frustration is palpable, as well as the general ineffectiveness of the RLM's and Luftwaffe's technical leadership.
This book looks at engineering challenges as they were addressed in a highly competitive international context. For WWII aircraft that has often been done, but for their engines this may be unique because there have, to my knowledge, been no such in-depth competitive studies yet. For example, Daniel D. Whitney's Vee's For Victory! is excellent, but as it is primarily a detailed study of the V-1710, it doesn't give you the same feeling for how and why design choices were made, although it includes some comparison with the Merlin. Calum Douglas shows where British, American and German design practice diverged, in the case of German design practice by quite a lot, and how this was driven by purpose (i.e. tactical preference), circumstance (availability of fuels and raw materials), and quality of decision making.
And if all this sounds like too much technical geekery to you, then you can take some comfort in the author's interest in the organisation of the development teams, the personalities (with the briefest of biographies) and the relationship between them. This too had a major impact, and the Allies benefitted enormously from the very professional organisation of the British and American effort and their close collaboration. While the 3. Reich repeatedly neglected technical opportunities because of its scattered approach and a failure to exchange knowledge within the industry. Fortunately, they were often far from realising the full potential of their engines. Chapter 9 includes post-war intelligence summaries that contain scathing comments about the capabilities of the Reich's leadership.
The structure of this book is chronological and linear, with pieces of available information set in the order in which they fit. This can be confusing, as it causes abrupt jumps in the storyline, from Rolls-Royce to Daimler-Benz to BMW and back. But you get used to it. A bit more problematic is the rigorous focus on new material. This is understandable, especially as the book is already hefty, but it means that for the general reader, there are surprising gaps. For example, there are many hints at the causes of the failure of the Rolls-Royce Vulture, but never an explanation. The author tries to fill some of the gaps in short summaries at the end of each chapter, a solution that works reasonably well. And Chapter 10 is a short technical-historical summary to refresh your memory.
If you already have books on aircraft engines on your shelves, you may wonder whether this addition is worth it, and how it compares. The answer is that it is definitely worth it, being a treasure trove of new information. It is also a high quality print, with excellent rendering of photographs.
There are some layout issues: I am not that enthusiastic about the typewriter font used for quotations, the structure of the index is a bit weird, and I recommend to keep a magnifying glass handy for some of the pictures and graphics that are compressed in a single column. (But Calum Douglas put larger versions of the images on his website.) In the last chapters, probably because of time pressure, there are a few places where part of a sentence is missing, or another sentence is repeated. (Errors that were corrected in later editions.) But these are small details in an excellent work.
A word of warning: The author is an engine designer himself, and he doesn't always consider it necessary to provide technical background. Often enough he does, but when the does not, the result can be cryptic to many readers. Calum Douglas sort of expects you to know that the connecting rods of a Daimler-Benz DB601 inverted V-12 are in a fork-and-blade arrangement, and what that is. I think this book would have been more digestible for most aviation history fans if it had an introductory chapter on the structure and workings of high-performance piston aero-engines. Maybe that is something to consider for a future edition, but this book already weighs over two kilograms. So many people may want to read a background text on piston engines first. (I'm inclined to suggest Bill Gunston's Development of Piston Aero Engines, although the first print of that book was in 1993 and it may be a bit dated.)
That said, if you have enough technical knowledge to begin to understand the intricacies, this is fascinating stuff and it really changes our understanding of the technical competition between these air forces. Crucially, in this book a wealth of new information on the design of WWII engines is considered in relation to their fuels and the available raw materials and engineering resources. There is a a lot of technical detail in this book, but that is integral to the argument that the author builds: The most conspicuous successes in WWII piston engine design did not come from radical innovation, but from consistent step-wise improvement with great attention to detail.
And I have never seen such a detailed study of WWII aviation fuels, a surprisingly complicated subject and one that had very significant historical consequences. Crucially, the Germans found themselves in great difficulties by having to compromise on the composition of their 100 octane C3 fuel, which caused no end of trouble by its effect on the oil system and by its adverse reaction with self-sealing fuel tanks. German chemists were well enough aware that the high fraction of aromatics in this fuel blend had important disadvantages (as well as some advantages), but as it was much easier and cheaper to produce for their synthetic fuel industry than the alternatives, they had little choice. The C3 fuel was already very scarce as it was. Gradually, they increased its production and improved its behaviour.
It is well known that availability of rare metals was a limiting factor on German wartime engineering, but in this book we learn how this affected engines parts ranging from big-end bearings to exhaust valves and turbochargers. The desirable materials to have for high-performance engines, besides the obvious steel and aluminium, fill a surprising list that includes copper, silver, gold, nickel, chromium, cobalt, indium and platinum: Nearly all of them in short supply in wartime Germany. Problems did not stop there, as oil, rubber, cleaning fluids, even methanol ran out. German engine designers spent a lot of effort merely coping with the bad supply situation, effort that then could not be spent on improving performance. The consequences were dire, and if you have a passing knowledge of WWII fighter aircraft, the serious concerns about the initial reliability of the BMW 801 and DB 605 (both usually thought of as successful engines) are an eye-opener.
Substantial lengths of text are quoted directly from meetings at the German Air Ministry (the RLM) and the Luftwaffe, as stenographers were present for high-level meetings. The atmosphere of confusion, evasion and frustration is palpable, as well as the general ineffectiveness of the RLM's and Luftwaffe's technical leadership.
This book looks at engineering challenges as they were addressed in a highly competitive international context. For WWII aircraft that has often been done, but for their engines this may be unique because there have, to my knowledge, been no such in-depth competitive studies yet. For example, Daniel D. Whitney's Vee's For Victory! is excellent, but as it is primarily a detailed study of the V-1710, it doesn't give you the same feeling for how and why design choices were made, although it includes some comparison with the Merlin. Calum Douglas shows where British, American and German design practice diverged, in the case of German design practice by quite a lot, and how this was driven by purpose (i.e. tactical preference), circumstance (availability of fuels and raw materials), and quality of decision making.
And if all this sounds like too much technical geekery to you, then you can take some comfort in the author's interest in the organisation of the development teams, the personalities (with the briefest of biographies) and the relationship between them. This too had a major impact, and the Allies benefitted enormously from the very professional organisation of the British and American effort and their close collaboration. While the 3. Reich repeatedly neglected technical opportunities because of its scattered approach and a failure to exchange knowledge within the industry. Fortunately, they were often far from realising the full potential of their engines. Chapter 9 includes post-war intelligence summaries that contain scathing comments about the capabilities of the Reich's leadership.
The structure of this book is chronological and linear, with pieces of available information set in the order in which they fit. This can be confusing, as it causes abrupt jumps in the storyline, from Rolls-Royce to Daimler-Benz to BMW and back. But you get used to it. A bit more problematic is the rigorous focus on new material. This is understandable, especially as the book is already hefty, but it means that for the general reader, there are surprising gaps. For example, there are many hints at the causes of the failure of the Rolls-Royce Vulture, but never an explanation. The author tries to fill some of the gaps in short summaries at the end of each chapter, a solution that works reasonably well. And Chapter 10 is a short technical-historical summary to refresh your memory.
If you already have books on aircraft engines on your shelves, you may wonder whether this addition is worth it, and how it compares. The answer is that it is definitely worth it, being a treasure trove of new information. It is also a high quality print, with excellent rendering of photographs.
There are some layout issues: I am not that enthusiastic about the typewriter font used for quotations, the structure of the index is a bit weird, and I recommend to keep a magnifying glass handy for some of the pictures and graphics that are compressed in a single column. (But Calum Douglas put larger versions of the images on his website.) In the last chapters, probably because of time pressure, there are a few places where part of a sentence is missing, or another sentence is repeated. (Errors that were corrected in later editions.) But these are small details in an excellent work.
April 30, 2021
Such a comprehensive reading about aircraft engines! It has taken me a while to read. I am not going to lie, it is a tough read sometimes, nevertheless it is a really impressive work, which makes you realize the effort back in the design offices in Germany, UK and USA. A good following part for this book will be to learn about the scenes behind the USSR at the time.
October 26, 2022
The Author has done exemplary work in combining authentic and official accounts of the development of engine technologies during this period. I don't think there is any other book like this. A must read for all machine enthusiasts. Being a high school student myself and interested in aviation technology and history, I found this book to be very useful chronological account of how the technology developed and how external factors such as the treaty of Versailles led the Germans to pursue development of technology that proved vital during the war. Another interesting fact to note is how incredibly hard it is to develop an engine and how long it really takes from the initial concept to a working and functioning prototype that can be put into frontline fighters.
January 31, 2021
Erks, fitters, riggers, and ‘Blackmen’, Reno racers, A&Ps, aerodynamicists, warbird operators, pilots and restorers, historians, engineers and gearheads of all flavors... Rejoice! Finally, the fascinating story of aero engine development of WW II has arrived. Very technical, yet very readable, an unparalleled work.
January 24, 2021
Absolutely fantastic.
September 4, 2022
Excellent balance between historical accuracy and technical content. If you like engines and history, do not miss this book!
February 8, 2021
Note that I received a review copy of this book.
I should start by saying, I've enjoyed reading a number of books on jet engine development, but I've never read a book on piston engines before. While WW2 aircraft were my first obsession as a kid, I moved onto jets at a relatively young age, and am only now beginning to re-discover this era.
The Secret Horsepower Race is a very readable account of piston engine development on the Western Front in World War II. It's very well written, and proceeds broadly in chronological and narrative form through the pre-war period and the years of World War II identifying key people, events and technologies that influenced the technological development of piston engines in the various nations. It is impeccably researched and referenced, and includes detailed quotes, drawings and charts from source documents to back up Callum's narrative, while most of the major figures in the book are given a small biographical sketch for context.
The book consists of 480 pages, split into 10 main chapters in chronological order. There are copious drawings, photos and charts included, and endnotes give detailed references. There's a list of the archives consulted, and reading through the endnotes shows the immense breadth of research Calum put into the book. This book will be a standard reference for aviation writers engaging with World War II subjects in future, I am sure.
The coverage of engine types is most detailed on German and British engine designs. As Calum notes, some other nations (e.g. Italy) have less archival material available, and he also notes he intentionally covered American developments in less detail as there are already excellent published accounts of their major engine programs available. I also suspect the inclusion of more detailed US engine development history would have increased the page count beyond even the most tolerant publishers' limits.
The cover design is excellent, very dynamic and attractive, it makes you want to pick the book up from the shelves. The page layout is generally attractive, and the text well edited and proofread. Kudos to the Tempest Books team.
The text is laid out with two typefaces used to clearly differentiate between Calum's words and quotes from original documents. For me, as noted by a small number of other readers, the "distressed typewriter" typeface used for the quotes is a little harder to read than is ideal for a book of this length. It didn't affect my enjoyment of the book, and I get the design intention, but given the quantity and length of the quotations included in the book, I think the balance between design for "authentic period feel" and readability was a little off. Your mileage may vary.
In addition, I think that better use could have been made of the captions. Chris Gibson gave me some advice for my book regarding captions - that they should contain something interesting about the picture or drawing that you won't find from the main text. In many cases, the captions in this book simply tell you what the photo, drawing or chart presented is, but not why it should be interesting to a lay reader. Sometimes you can infer from the nearby text, but not always. So rather than simply say "Fuel evaporation curves from a DB 601 Engine", include a few words on what this chart illustrates for the non-engineer reader. This is especially important for those charts which are reproduced in German - as I often couldn't understand what the labels on the axes were, let alone what conclusion I could draw from the chart.
These are however very minor quibbles on an authoritative and deeply interesting book. I look forward to Calum's next book with great anticipation, and also to future publications from Tempest Books.
I should start by saying, I've enjoyed reading a number of books on jet engine development, but I've never read a book on piston engines before. While WW2 aircraft were my first obsession as a kid, I moved onto jets at a relatively young age, and am only now beginning to re-discover this era.
The Secret Horsepower Race is a very readable account of piston engine development on the Western Front in World War II. It's very well written, and proceeds broadly in chronological and narrative form through the pre-war period and the years of World War II identifying key people, events and technologies that influenced the technological development of piston engines in the various nations. It is impeccably researched and referenced, and includes detailed quotes, drawings and charts from source documents to back up Callum's narrative, while most of the major figures in the book are given a small biographical sketch for context.
The book consists of 480 pages, split into 10 main chapters in chronological order. There are copious drawings, photos and charts included, and endnotes give detailed references. There's a list of the archives consulted, and reading through the endnotes shows the immense breadth of research Calum put into the book. This book will be a standard reference for aviation writers engaging with World War II subjects in future, I am sure.
The coverage of engine types is most detailed on German and British engine designs. As Calum notes, some other nations (e.g. Italy) have less archival material available, and he also notes he intentionally covered American developments in less detail as there are already excellent published accounts of their major engine programs available. I also suspect the inclusion of more detailed US engine development history would have increased the page count beyond even the most tolerant publishers' limits.
The cover design is excellent, very dynamic and attractive, it makes you want to pick the book up from the shelves. The page layout is generally attractive, and the text well edited and proofread. Kudos to the Tempest Books team.
The text is laid out with two typefaces used to clearly differentiate between Calum's words and quotes from original documents. For me, as noted by a small number of other readers, the "distressed typewriter" typeface used for the quotes is a little harder to read than is ideal for a book of this length. It didn't affect my enjoyment of the book, and I get the design intention, but given the quantity and length of the quotations included in the book, I think the balance between design for "authentic period feel" and readability was a little off. Your mileage may vary.
In addition, I think that better use could have been made of the captions. Chris Gibson gave me some advice for my book regarding captions - that they should contain something interesting about the picture or drawing that you won't find from the main text. In many cases, the captions in this book simply tell you what the photo, drawing or chart presented is, but not why it should be interesting to a lay reader. Sometimes you can infer from the nearby text, but not always. So rather than simply say "Fuel evaporation curves from a DB 601 Engine", include a few words on what this chart illustrates for the non-engineer reader. This is especially important for those charts which are reproduced in German - as I often couldn't understand what the labels on the axes were, let alone what conclusion I could draw from the chart.
These are however very minor quibbles on an authoritative and deeply interesting book. I look forward to Calum's next book with great anticipation, and also to future publications from Tempest Books.
March 11, 2023
There are a number of aspects to the battle for aerial supremacy over Western Europe in WW2 - quantity of aircraft, quality of aircraft, munitions, effectiveness of bombing, pilot training - in this book, Douglas is focused on engine development and how it impacted the battle for aerial supremacy. He is also limiting the scope of this book to Western Europe, with a focus on the UK, US, Germany, and some space for Italy.
There is a lot of great insight in this book - it looks at design and development challenges and process for piston driven aircraft engines. The comparisons between the US, UK, and Germany broadly, and engine manufacturers such as Rolls Royce, Allison, and Daimler-Benz (and many more) offer insights into the common challenges, unique challenges, and different approaches that were taken.
I had some sense for the basics of this aspect of the contest - e.g. the quest for more horsepower, how material deficiencies impacted engine quality - but Douglas offers a look in significantly greater depth. In this book there is much to learn - the different engineering approaches of incremental improvement vs search for breakthroughs; how shortages of key materials impacted Germen engine design - and quality and reliability; and how Allied superiority was partly driven by superior industrial policy.
This book opened up a greater understanding of the role of engine development in shaping WW2 - I think one of the challenges is that Douglas is thorough and goes tremendously in depth - I lack enough knowledge of engines to be able to fully appreciate all of his discussion - I learned a lot, but there is a part of this book that I was not fully able to grasp due to my limited knowledge. This represents one of the potential challenges of this book. It would be interesting to get some other perspectives on this from other readers.
There is a lot of great insight in this book - it looks at design and development challenges and process for piston driven aircraft engines. The comparisons between the US, UK, and Germany broadly, and engine manufacturers such as Rolls Royce, Allison, and Daimler-Benz (and many more) offer insights into the common challenges, unique challenges, and different approaches that were taken.
I had some sense for the basics of this aspect of the contest - e.g. the quest for more horsepower, how material deficiencies impacted engine quality - but Douglas offers a look in significantly greater depth. In this book there is much to learn - the different engineering approaches of incremental improvement vs search for breakthroughs; how shortages of key materials impacted Germen engine design - and quality and reliability; and how Allied superiority was partly driven by superior industrial policy.
This book opened up a greater understanding of the role of engine development in shaping WW2 - I think one of the challenges is that Douglas is thorough and goes tremendously in depth - I lack enough knowledge of engines to be able to fully appreciate all of his discussion - I learned a lot, but there is a part of this book that I was not fully able to grasp due to my limited knowledge. This represents one of the potential challenges of this book. It would be interesting to get some other perspectives on this from other readers.
February 22, 2021
If you have an interest in WWII history and technology, the 480 pages of The Secret Horsepower Race by Calum E. Douglas are a treasure trove of original source documents and artful storytelling. The book chronicles the life and death duel for piston aircraft propulsion superiority between Britain and Germany during WWII. Perhaps one third of the book is verbatim transcripts of documents and personal discussion between the respective military organizations/personalities and the manufacturers/personalities responsible for the design and production of piston aircraft engines. It is precision history right from the original sources. There are hundreds of photographs, tables, charts, and diagrams of the engines, engine parts, and performance characteristics. This technical information is expertly blended with geopolitical, energy, metallurgical, and managerial issues in logical, chronological fashion. There are welcome summaries at the end of each significant time period to refresh the memory of the intermittent reader. Some will opine that some of the images are small or difficult to read, but this is more than balanced by having all this original information in one place. I read a lot of WWII books, but I learned dozens of new things from this book as well as a wider perspective on the competitive knife-edge that is war.
October 15, 2023
If you've ever been interested in the finer points of the air war over Europe in World War II, such as why it was so important to install a Rolls-Royce Merlin engine in the North American Mustang, or why the Germans could not make use of really high-test gasoline, this is the book for you. A lot of these issues are not unknown in the existing literature, but the author brings the experience and knowledge of a one-time race-car power-plant engineer to the conversation, and a bit of the competitive passion of Formula 1 too. This is not to mention that this book is a tribute to modern archival research techniques, as Douglas apparently digitized all the available stenographic minutes from the conferences of the German Air Ministry so that they were in machine-readable form, and turned lose the computer to zero in on more relevant portions. As someone who had a career as an archivist at the U.S. National Archives I'm a little bit in awe at the effort this took. There is very little that I can mark down this book for, apart from some choices in book lay-out that don't contribute to readability; Douglas himself writes well, and makes a very complicated topic pretty comprehensible.
February 15, 2024
Best performance engine focused book I have ever read. If you like horsepower and engines, you will love this book. You don't even have to be a fan of history to enjoy the heck out of it. I would not consider myself a history buff at all. I have been fascinated by engines since my earliest memory. Not to toot my own horn, but I consider myself a darn good "non-professional shade tree mechanic" and have done it all. Full engine rebuilds, full car restorations, performance engine builds, ect.....what I learned the Germans were doing (from this book) back in the 30s and 40s blew my mind. I read the whole thing in less than 10 days. I was obsessed. It's not bogged down by too many personal details of the involved characters - just enough. What you do get is the fascinating technical details that keep the pages turning if you have a love for performance engines and the chase for horsepower. I HATE when a book about a technical subject such as the nuclear bomb, flight, aerospace, ect gets bogged down by far too many personal details and stories. This book did not disappoint me, it enthralled me and has me searching for books of similar character and detail.
April 29, 2022
I am not an engineer, but an avid reader about WW2 aviation. This magnificent volume taught me a tremendous amount about the interplay of thermodynamics, metallurgy and chemistry--factors that heretofore I barely considered.
More than anything Douglas shows how the crucible of competition--from air racing to warfare-- provided the spur for creative genius. The minds and spirits of the engineers who developed the engines discussed in this book, and the mad circumstances that tested their mettle, lurk within the technical drawings and graphs that amply illustrate their accomplishments.
Thank goodness the good guys won that now distant conflict; that said, Douglas points to a victory shared by all who engaged in that deadly race; namely, the victory of the human mind's ability to imagine, envision, and problem solve.
More than anything Douglas shows how the crucible of competition--from air racing to warfare-- provided the spur for creative genius. The minds and spirits of the engineers who developed the engines discussed in this book, and the mad circumstances that tested their mettle, lurk within the technical drawings and graphs that amply illustrate their accomplishments.
Thank goodness the good guys won that now distant conflict; that said, Douglas points to a victory shared by all who engaged in that deadly race; namely, the victory of the human mind's ability to imagine, envision, and problem solve.
March 4, 2024
The lessons for this book for how to organize something and how to have a working product are really hard to beat, coming out of an actual war :)
Displaying 1 - 13 of 13 reviews