The Secret Horsepower Race by Calum Douglas (and piston engine discussion)

[sgeorges4]

I mean using the picture and drawing for model ,per example a what if ta 152 with the DB 603N or L or a bf 109 HV1 base on both the picture of the me 409 and the drawing of the prototype

from http://fighters.forumactif.com/t3739-messerschmitt-bf-109-h-v1

Also I got further into the book and I do like the different character being use for the report

 

[Hobbes]

Page 409 briefly touches on the differences in Merlin production by Rolls-Royce vs. Packard.

This article talks about this difference in more detail. I'll also link to one of my favorite Youtube documentaries: the origins of precision. This is a history of how mass production became possible by introducing more accurate means of measurement, enabling parts to be made identical.

 

[steelpillow]

De Havilland Australia set up a production line for Mossies and for ease of supply used Canadian timber and Packard-built Merlins. Both caused much grief, as the Canadian timber had a different strength specification from the usual European birch, while the Packard Merlins were far from a drop-in replacement.
(When a modest level of production finally got going, the real problem with operating wooden aircraft in the tropics soon became apparent; it was said that by the time you had rolled it out of the hangar, fired it up and reached takeoff speed, the glue had rotted and the termites had eaten everything except the pilot's seat, the tyres and the Merlins.)

 

[Sherman Tank]

My copy arrived today (Merry Christmas to me!) and I didn't realize what a big beast it would be!

I skipped to the paragraph or two describing the "hyper engine" program and it very succinctly answered my question about the program's disappointing results. Can't wait to read the rest.

 

[Pasoleati]

Calum, how good performance would you estimate for 91 octane fuel + water injection vs. straight 100/130? Let's assume a B-series R-2800 as the engine.

 

[Sundog]

My copy showed up a couple of days ago (Yeah!) and I too was amazed at what a tome this book is; in the best way! Nice work, Calum.

 

[Ray]

My copy arrived today. Started reading immediately. Don't think I will finish it tonight. Damn, that's small type for old eyes.

 

[Nick Sumner]

Review posted on amazon.ca

I have a few questions raised by the text.

On page 142, a letter from the UK Air Ministry about the Thornton fuel manufacturing Plant in the US states "...the term 100 Octane as used in the USA corresponds to 90 Octane on our standards." This greatly surprised me, I thought that both the US and UK used the same Octane and PN number ratings.

At the top of page 424 in an answer given by Otto Cuno during an interrogation postwar he states (of the Jumo 213) "The engine power peaked at 4500 RPM." Is that a misprint? 4500 RPM on a stroke of 165mm gives a piston speed of nearly 25 m/s! That seems incredibly fast in an age before the widespread use of cermets and ceramics in engines. Most WW2 engines had piston speeds below 15 m/s which was (for the era) pretty fast.

 

[Nick Sumner]

One other question Calum, did you ever come across the bore and stroke measurements for the Porsche 72 19.7L inverted V16 of 1936? Or those of the Porsche 70 17.7L X32 engine of the same era?

 

[Hobbes]

At the top of page 424 in an answer given by Otto Cuno during an interrogation postwar he states (of the Jumo 213) "The engine power peaked at 4500 RPM." Is that a misprint? 4500 RPM on a stroke of 165mm gives a piston speed of nearly 25 m/s! That seems incredibly fast in an age before the widespread use of cermets and ceramics in engines. Most WW2 engines had piston speeds below 15 m/s which was (for the era) pretty fast.

4500 rpm is pretty high, but the book mentions 4000 rpm in several places for the 213. 4500 may have been a 'let's see how high we can get before it blows up' deal, while 4000 was the regular 'combat emergency' rpm.

 

[Calum Douglas]

Review posted on amazon.ca

I have a few questions raised by the text.

On page 142, a letter from the UK Air Ministry about the Thornton fuel manufacturing Plant in the US states "...the term 100 Octane as used in the USA corresponds to 90 Octane on our standards." This greatly surprised me, I thought that both the US and UK used the same Octane and PN number ratings.

At the top of page 424 in an answer given by Otto Cuno during an interrogation postwar he states (of the Jumo 213) "The engine power peaked at 4500 RPM." Is that a misprint? 4500 RPM on a stroke of 165mm gives a piston speed of nearly 25 m/s! That seems incredibly fast in an age before the widespread use of cermets and ceramics in engines. Most WW2 engines had piston speeds below 15 m/s which was (for the era) pretty fast.

The comments by Cuno are almost certainly regarding the Jumo213J, which was an advanced experimental engine. Service 213`s would certainly not reach that speed.

Britain and the USA had not yet aligned their fuel specifications at that stage (1940), US fuel ratings would be AN-F... etc and British specs would be to British designations DED..., when it was discovered that the US fuel was deficient in the rich mixture area, they all got their heads together, and realised that you had to measure octane at lean AND rich, and it was at that point that 100/130 was born (which was essentially just a new name for 100 octane, just that the 130 gave the required rating at rich mixture). The full story is more complicated but I dont have my files in front of me now so thats all just from memory. You might want to re-read the book as I suspect that is all in the book hidden in various places !

Basically 100/130 was a unified fuel spec for 100 octane. Thats over simplifying, but basically the story of it.

Anyway thanks for the positive review.

 

[steelpillow]

The overall sizes of the Merlin and Griffon were much the same, but the Griffon had greater capacity and power. Both underwent significant incremental development during their lives. What were the characteristics of the Merlin which prevented incremental changes to morph it into something similar to the operational Griffons?

 

[Hobbes]

They were similar; as far as I can see, developments that could be shared, were shared. Materials improvements, general design of the supercharger etc.
the big difference was displacement, and that's a difficult parameter to change. If you change the bore and stroke, you get a knock-on effect: bore is limited by the cylinder liners and block design. Increase the bore by too much and you'll have to redesign the block, redo the cooling system etc. Stroke also quickly impacts lots of parts.
Also, there was little point in increasing the Merlin's displacement. They already had the 37-l Griffon: why increase Merlin capacity when you can just swap in a Griffon instead ?

 

[Pasoleati]

Question: Did the Griffon suffer from not having rollers as cam followers on the rockers?

 

[sgeorges4]

calum what do you think about my recension for aéro journal?

"The Secret Horsepower Race: Second World War Fighter Aircraft Engine Development on the Western Front de Calum douglas

Ce livre récemment sorti concerne le développement des moteurs à pistons réalisés par l'angleterre ,les états unis ,l'allemagne et l'italie. Il faut 480 pages et celui-ci nous raconte de manière chronologique ces développements. Le livre est agrémenté de biographies des différents intervenants ,d'une grosse quantité de rapports d'époques sur lesquels l'auteur s'est basé pour écrire son ouvrage et des photos/plans des différents moteurs évoqués. Il y a également des nouveautés tels que le me 409 à moteur DB 628 découverts par l'auteur en fouillant dans les archives et de manière surprenante ,une petite partie est dévolu aux moteurs hispano suiza français. L'ensemble des sources sont cités à la fin de l'ouvrage."

 

[Calum Douglas]

calum what do you think about my recension for aéro journal?

"The Secret Horsepower Race: Second World War Fighter Aircraft Engine Development on the Western Front de Calum douglas

Ce livre récemment sorti concerne le développement des moteurs à pistons réalisés par l'angleterre ,les états unis ,l'allemagne et l'italie. Il faut 480 pages et celui-ci nous raconte de manière chronologique ces développements. Le livre est agrémenté de biographies des différents intervenants ,d'une grosse quantité de rapports d'époques sur lesquels l'auteur s'est basé pour écrire son ouvrage et des photos/plans des différents moteurs évoqués. Il y a également des nouveautés tels que le me 409 à moteur DB 628 découverts par l'auteur en fouillant dans les archives et de manière surprenante ,une petite partie est dévolu aux moteurs hispano suiza français. L'ensemble des sources sont cités à la fin de l'ouvrage."

It certainly looks like an accurate description of the book.

 

[sgeorges4]

can I send it to caraktère then?

 

[Calum Douglas]

can I send it to caraktère then?

Yes, sure.

 

[sgeorges4]

done! maybe it'll appear in the next number since my recension on dan sharp bookazine were in the 79 http://www.aero-journal.com/enkiosque.php

 

[steelpillow]

They were similar; as far as I can see, developments that could be shared, were shared. Materials improvements, general design of the supercharger etc.
the big difference was displacement, and that's a difficult parameter to change. If you change the bore and stroke, you get a knock-on effect: bore is limited by the cylinder liners and block design. Increase the bore by too much and you'll have to redesign the block, redo the cooling system etc. Stroke also quickly impacts lots of parts.
Also, there was little point in increasing the Merlin's displacement. They already had the 37-l Griffon: why increase Merlin capacity when you can just swap in a Griffon instead ?

Well, yes and no. The Merlin's block was notably redesigned from two-piece to one, it could have been redesigned again, had the will been there. The rest of the cooling system was also progressively upgraded; you don't use the same kit throughout a 750 hp to 1,240 hp with intercooler power growth. Increasing bore is done often enough, changing stroke is a bigger challenge, but has also been done.
The Griffon suffered endless teething troubles and keeping up with Merlin development proved perhaps its greatest challenge, delaying its introduction by perhaps two years. What was it about the Merlin that ran out of steam, could not be developed out, and so could no longer hold the Griffon at bay?

 

[steelpillow]

One thing I feel is missing from the book is more than a passing mention of Miss Shilling's orifice, the washer that was fitted quite literally as a stopgap to moderate the Merlin's inverted-flight carburettor problems. It is well enough documented elsewhere, but a brief account of the problems, how the washer did and did not fix them, its effect on the aircraft's battle capability, and how long it remained a standard fitting, would be a useful round-out to the tale.

 

[Hobbes]

The block redesign was done to minimize knock-on effects: the only parts involved were the block castings and the head gasket, IIRC.
Increasing the bore quickly leads to a new design for the heads, which leads to new valves etc.

Cooling upgrades were mostly the pump and radiators: components you can swap out without influencing much else. A big-bore block might change the coolant flow through the block, which takes time and effort to get right (no hotspots).

IIRC the limit for the Merlin was fuel detonation: this set a limit to the supercharger pressure.
Resolving that required one or more of these:
- improved cooling of the heads, so a head redesign
- better fuel
- switching to fuel injection

 

[steelpillow]

The block redesign was done to minimize knock-on effects: the only parts involved were the block castings and the head gasket, IIRC.
Increasing the bore quickly leads to a new design for the heads, which leads to new valves etc.

Cooling upgrades were mostly the pump and radiators: components you can swap out without influencing much else. A big-bore block might change the coolant flow through the block, which takes time and effort to get right (no hotspots).

IIRC the limit for the Merlin was fuel detonation: this set a limit to the supercharger pressure.
Resolving that required one or more of these:
- improved cooling of the heads, so a head redesign
- better fuel
- switching to fuel injection

And yet increasing the bore, redesigning the head, re-routing the coolant, revising the valves, all these have been done on many occasions; for example all (if you count cooling airflow) were applied by Halford to the DH Gipsy Six series at one time or another, why not the Merlin as well, and save reinventing every single detail of the engine? Then again, the Merlin was redesigned for thick crankshaft bearings, it could and should have also been given hollow-crankshaft lubrication similar to the Griffon.

But yes of course, your last point is on the right lines, supercharging was the real key to performance, which led to high compression ratios and hence high exhaust valve temperatures. The Merlin ran into the need for better knock-resistant fuel before the Griffon did. On the other hand a Merlin II was run with fuel injection in 1943, which would have helped. By this time all the well-researched technologies had been implemented and the Griffon was at last holding its own. Introducing a new generation of technologies such as fuel injection, valve overlap, knock-resistant fuels, and perhaps even the swirl throttle if somebody at the back had been awake enough, would have taken longer than converting to the Griffon.

But as Calum highlights so graphically, all these newer technologies were not new, they were more like missed opportunities. Had the resources put into the Griffon been devoted to them instead (and there were enough advocates floating around), the Merlin would have comfortably tided Rolls-Royce over the few short years until the jet revolution, and the whole postwar internal combustion industry would have greatly benefitted.

 

[Foo Fighter]

One thing I feel is missing from the book is more than a passing mention of Miss Shilling's orifice, the washer that was fitted quite literally as a stopgap to moderate the Merlin's inverted-flight carburettor problems. It is well enough documented elsewhere, but a brief account of the problems, how the washer did and did not fix them, its effect on the aircraft's battle capability, and how long it remained a standard fitting, would be a useful round-out to the tale.

Apparently they never fitted them to the Mosquito. I was watching a program and apparently this was the cause of a mosquito loss in 2012 I think, inverted on the airshow, engine out and stall. Two crew lost

ASN Wikibase Occurrence # 18913

Last updated: 3 January 2021

This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.



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Date:	21-JUL-1996
Time:	12:01
Type:	de Havilland DH.98 Mosquito T.Mk III
Owner/operator:	British Aerospace PLC
Registration:	G-ASKH
C/n / msn:	ex.RR299
Fatalities:	Fatalities: 2 / Occupants: 2
Other fatalities:	0
Aircraft damage:	Written off (damaged beyond repair)
Category:	Accident
Location:	1 mile west of Manchester Barton Airport (EGCB) England. - United Kingdom
Phase:	Manoeuvring (airshow, firefighting, ag.ops.)
Nature:	Demo/Airshow/Display
Departure airport:	Hawarden Airport (EGNR)
Destination airport:	Hawarden Airport (EGNR)
Investigating agency:	AAIB

Narrative:
The last airworthy de Havilland DH.98 T.Mk. III Mosquito (G-ASKH, ex-RAF serial RR299) crashed on 21-7-1996, 1 mile west of Manchester Barton Airport (EGCB) during an air display. Both occupants were killed (pilot Kevin Moorhouse and engineer Steve Watson). According to the following extract from the official AAIB report into the accident.
"The aircraft left Hawarden at 11:30 hrs on 21 July and flew to Barton Airfield where, after a short period holding off, the pilot started his display routine at 11:56 hours. The main display axis was along Runway 09/27. The routine consisted of a series of non-aerobatic manoeuvres such as climbs, descents, medium turns,level flight at 220 to 240 knots, along the display axis not below 100 feet agl and 'wing overs'; the latter is a manoeuvre which involves the aircraft reversing its course by climbing and rolling to the left or right.

The weather was fine, the surface wind was generally from the south at 9 knots and the temperature was 26 degrees C;the wind at 2,000 feet was 240 degrees and 10 knots. The display was nearing its conclusion with a fly past along the display axis from east to west followed by a steep climb into a 'wing over' to the right during which control of the aircraft was lost.

The aircraft was then observed to complete a number of uncontrolled manoeuvres before control appeared to have been regained, but at too low a height to prevent impact with the ground".

Damage sustained to airframe: Per the AAIB report "Aircraft destroyed". As a result, the registration G-ASKH was cancelled by the CAA on 16-12-1996 as "destroyed".

The inquest one year after the accident found that a historic problem with this aircraft (engine cutting out during negative g) is what caused the left engine to temporarily but fatally cut out during the wing over. It was an engineer from the second world war that provided us with this information. Both men are sadly missed.

Sources:

1.https://assets.publishing.service.gov.uk/media/542301dce5274a1317000b69/dft_avsafety_pdf_501355.pdf
2.CAA: https://siteapps.caa.co.uk/g-info/rk=ASKH
3.https://www.independent.co.uk/news/two-die-as-last-mosquito-crashes-1329886.html
4.https://forum.keypublishing.com/showthread.php?37977-Mosquito-RR299-crash
5.http://vintageaeroplanewriter.blogspot.com/2011/02/dh-mosquito-rr299.html
6.http://www.warbirdregistry.org/mossieregistry/mossie-rr299.html
7.Julie Moorhouse, Kevin Moorhouse's daughter who attended inquest.

 

[Foo Fighter]

If it's a simple fix, why are all these engines not so fitted?

 

[Calum Douglas]

One thing I feel is missing from the book is more than a passing mention of Miss Shilling's orifice, the washer that was fitted quite literally as a stopgap to moderate the Merlin's inverted-flight carburettor problems. It is well enough documented elsewhere, but a brief account of the problems, how the washer did and did not fix them, its effect on the aircraft's battle capability, and how long it remained a standard fitting, would be a useful round-out to the tale.

Well the difficulty is, that this book is basically 100% primary archival material only, and I`m not particularly interested in what other people have written other than using it as a crib-sheet for further archive finds (half of it is also usually wrong). I spent a HUGE amount of time and effort trying to locate records of what she did, and despite months at Kew in London, and directly having the researchers at Farnborough Air Sciences Trust look through all the surviving RAE records, virtually nothing remains. Even her (now out of print) biography has virtually nothing really solid on the restrictor (the whole book has about 4 pages on it), and I also spent a fair while talking to Dr Nina Baker who has been trying to get in touch with Shilling`s family for months.

One problem with limiting the book to things I can prove with original reports, is that many things which of course DID happen, may not be possible to write about in detail, as I would rather briefly mention something accurately, than write half a chapter on bits stolen from other books for which I have no evidence. This is certainly not ideal, but is the only way I have of making sure that the picture I present, whilst not "complete" is at least accurate.

Should I be able to obtain original paperwork to elaborate on it (the only diagram of it is copyrighted, as its a sketch printed in her biography), it will go into a future edition.

The only report I do not have from the appendix in her biography is this one, which is probably the most important one, and is likely in the possession of her family, or possibly in an archive inside a larger file, which nobody at Kew or Farnborough has a location for.

 

[steelpillow]

Hats off for the deep search, Calum (sorry, the one on my icon doesn't come off).

And Edgar Brooks, the one man who might have been ahead of you on all arcane Spitfire matters, is sadly no longer with us.

I would have expected the carburettor manufacturer to fit the things on the production line and have a drawing or two for that lying around, especially as it seems to have been accompanied by a mod to the needle valve. It seem unreasonable to expect the squadrons or R-R to modify every new carb they received. Drawings long gone, I suppose, and I have no doubt you will have covered that base anyway.

 

[Pasoleati]

the Merlin was redesigned for thick crankshaft bearings, it could and should have also been given hollow-crankshaft lubrication similar to the Griffon.

But the Merlin was provided with the end-oil feed in the 100 srs.

 

[Calum Douglas]

Hats off for the deep search, Calum (sorry, the one on my icon doesn't come off).

And Edgar Brooks, the one man who might have been ahead of you on all arcane Spitfire matters, is sadly no longer with us.

I would have expected the carburettor manufacturer to fit the things on the production line and have a drawing or two for that lying around, especially as it seems to have been accompanied by a mod to the needle valve. It seem unreasonable to expect the squadrons or R-R to modify every new carb they received. Drawings long gone, I suppose, and I have no doubt you will have covered that base anyway.

Sadly I just cant answer these points, but I have heard that Nina has had some progress with the family although I dont know how far she got with it. Every time something is about to happen another Lockdown happens and everything stops again... its a miracle I managed to get my book out in the nick of time. I`d never have been able to write it in the current situation... anyway...

 

[SeaslugMk2]

One thing I feel is missing from the book is more than a passing mention of Miss Shilling's orifice, the washer that was fitted quite literally as a stopgap to moderate the Merlin's inverted-flight carburettor problems. It is well enough documented elsewhere, but a brief account of the problems, how the washer did and did not fix them, its effect on the aircraft's battle capability, and how long it remained a standard fitting, would be a useful round-out to the tale.

IIRC the problem was fully solved by changing the carburettor for a side-jet unit which wasn't affected by the engine's orientation (or negative g).

SRJ.

 

[pathology_doc]

Got the book on Friday.

It might almost have been entitled "How not to run an aircraft engine procurement program." In my opinion the focus is primarily upon the German engine development saga, with the British content comparing and contrasting the mechanically-driven supercharger development pathway and the carby vs. fuel injection doctrines, the American content comparing and contrasting turbocharger progress, and the Italian content more or less for the record.

Calum's deep dive into the manner in which "rare element" resource deficits (nickel, cobalt etc.) impinged upon the German engine developers to make the task of matching the Allied achievements almost impossible was an eye-opener to me, and made for quite fascinating reading. Ditto the fuel issue. And then we get to the management problems (especially at the highest level). In retrospect the miracle is that the Germans lasted as long as they did.

I skimmed a lot of the transcripts, but that's alright; Calum summarizes the upshot of all of them very well, and going through them in detail will make for a good second read.

I came away thinking that in broad, the Germans had the best ideas and the worst execution (although he makes it clear that some of the reasons for that were beyond the engineers' control) while the British had it the other way around - they might have clung inappropriately to the mechanical supercharger and the carburettor until the very end, but they systematically raised both to the pinnacle of the art (ETA and more importantly, in the context of front-line service - the quantum leap which was the Merlin 60 series did not merely languish on the test bed but actually revolutionized the Spitfire, Mustang and Mosquito).

One thing I think the book could have covered in greater detail is the Vulture story. The issues the German engines were having were covered in great detail, and I was expecting a similar dissection of what brought the Vulture to grief and whether the problems might have been cured if there had been time and effort to spare (e.g. the time and effort that Napiers put into getting the Sabre to work).

For obvious reasons, the book does not go into jet engine development. Nevertheless, I got the feeling on reading some of the detail stuff on superchargers and turbochargers that it would not have been at all difficult to slide gently off into a side discussion of the impact of supercharger/turbocharger experience on early jet work (particularly the axial turbocharger the Germans were playing with).

I had no problem at all reading the type, and I felt that the switch to typewriter font for the quoted material did lend an air of period authenticity to the material.

All in all an outstanding effort. I walked away from it wanting to read more from the author on other engine development programmes (e.g. Merlins for bombers, the Hercules, dead-ends such as the Bristol Aquila and the Napier Dagger, Russian and Japanese perspectives), which is always a good sign.

Money well spent.

 

[Calum Douglas]

Got the book on Friday.

It might almost have been entitled "How not to run an aircraft engine procurement program." In my opinion the focus is primarily upon the German engine development saga, with the British content comparing and contrasting the mechanically-driven supercharger development pathway and the carby vs. fuel injection doctrines, the American content comparing and contrasting turbocharger progress, and the Italian content more or less for the record.

Calum's deep dive into the manner in which "rare element" resource deficits (nickel, cobalt etc.) impinged upon the German engine developers to make the task of matching the Allied achievements almost impossible was an eye-opener to me, and made for quite fascinating reading. Ditto the fuel issue. And then we get to the management problems (especially at the highest level). In retrospect the miracle is that the Germans lasted as long as they did.

I skimmed a lot of the transcripts, but that's alright; Calum summarizes the upshot of all of them very well, and going through them in detail will make for a good second read.

I came away thinking that in broad, the Germans had the best ideas and the worst execution (although he makes it clear that some of the reasons for that were beyond the engineers' control) while the British had it the other way around - they might have clung inappropriately to the mechanical supercharger and the carburettor until the very end, but they systematically raised both to the pinnacle of the art.

One thing I think the book could have covered in greater detail is the Vulture story. The issues the German engines were having were covered in great detail, and I was expecting a similar dissection of what brought the Vulture to grief and whether the problems might have been cured if there had been time and effort to spare (e.g. the time and effort that Napiers put into getting the Sabre to work).

For obvious reasons, the book does not go into jet engine development. Nevertheless, I got the feeling on reading some of the detail stuff on superchargers and turbochargers that it would not have been at all difficult to slide gently off into a side discussion of the impact of supercharger/turbocharger experience on early jet work (particularly the axial turbocharger the Germans were playing with).

I had no problem at all reading the type, and I felt that the switch to typewriter font for the quoted material did lend an air of period authenticity to the material.

All in all an outstanding effort. I walked away from it wanting to read more from the author on other engine development programmes (e.g. Merlins for bombers, the Hercules, dead-ends such as the Bristol Aquila and the Napier Dagger, Russian and Japanese perspectives), which is always a good sign.

Money well spent.

Thanks for that feedback, and I`m glad you feel it was a good buy. I have a few things to say which might help.

You`re quite right that a lot of the material concentrates on Germany, this was really just how it ended up by virtue of the level of novelty & importance of the archive material I was able to find. I think Germany (and I`m sure Japan, if I am ever able to) had the most interesting stories as they had unique difficulties. Without wanting to denigrate the Allied effort, in certain respects it could be said that it was their war to lose, and that victory was merely a matter of competently applying the resources they had. Thats an awful simplification because doing something sensible and competant turns out to require a lot of brilliance and superb management..haha.

I agree that the Vulture needs more coverage, my problem was that I had very little primary source material on it. I had to VERY carefully manage my time at Rolls-Royce because their main corporate archive site is only open (was.. only open.. now not at all... anyway) on Mondays between about 12:30 and 4:30pm, and you are not allowed to copy documents with your own camera. You can imagine how much time and money one would need to cover a lot of ground. Therefore, I had to decide to concentrate on the Merlin, and make that my focal point. By comparison, at the Imperial War Museum, where all the German stuff is, it was open 5 days a week from 10 to 5pm. I spent I would say... a month full time there with a camera and remote trigger, and managed to copy 55 thousand pages (comprising 1700 or so actual reports). So, I had to be incredibly careful what I tried to copy from RR, and this is why many individual stories like the Vulture are only briefly commented upon, in the end this also became important as the book became so big, that even if I had managed to get more material, I would never have been able to fit it into the book. So, the book became concentrated on the most operationally important types (with a few forays into the weird and wonderful).

I also agree that Jets would make an excellent side-topic, however, I`m not a gas turbine engineer, so I`d need to team up with a specialist to make a book of commensurate depth and accuracy on jets. I "might" be able in future to do that with the American gas turbine expert Dr S. Can Gülen, with whom I am about to have Professor Kollmann`s 1947 memoirs published through the American Society of Mechanical Engineers (ASME). In that book we cover Jet engines a little, but, I would warn you that it is an academic textbook with a few historical passages, its very maths heavy, and not bedtime reading unless you are a very dedicated enthusiast, or an engineer of some kind.

May main issue with making future books is working out how to fund it. At the time I was lucky and the market was buoyant, so I`d saved up a few years contract money to live off and pay for flying/driving about to various archives. Now things are tight, so I`d possibly have to look at crowdfunding in future, we`ll see. Thank you for your kind comments, they mean a lot.

 

[pathology_doc]

in the end this also became important as the book became so big, that even if I had managed to get more material, I would never have been able to fit it into the book.

You know, of course, that most of us here would have been quite happy for the book to be much, MUCH bigger.

Operational limitations noted. I know we can't have everything, and it's always fascinating to be able to talk to the author and find out why not.

I am that very dedicated enthusiast (or at least, one of them). Just how heavy does the maths get?

 

[Calum Douglas]

Nothing too intense but enough to put off most casual readers. The whole book isnt all like this, but perhaps 1/3 of it is. German engineers at the time didnt calculate supercharger output in the same way "we" did, plotting pressure ratio against flow (or corrected flow), instead they chose to use adiabatic work, (H_ad) so a fair bit of the book introduction is explaining for todays compressor engineer what thats all about. It has a couple of advantages, such as if you want to calculate the work of a multi-stage compressor, you just add together the adiabatic work of each stage. Up to a certain altitude, the "meters head" of this unit is "nearly" the same as the equivalent work to counter atmospheric, meters altitude rise - so if you want a supercharger to maintain sea level boost to 8000m, you can design one which produces an adiabatic work of 8000m. That starts not to quite hold true at very high altitudes, but its an interesting "guideline" for the aero engine designer to use.

About half the book is my translation of Dr Kollmanns original manuscript, and the other half is by Dr Gülen, who puts it all in modern context and expands upon it further. I have also added in a few "anecdotes of relevance" here and there. This snippet below is a direct translation from Kollmanns memoir which his son allowed me to copy. It had been sat in his family home since 1947.



1947 Original below (he started writing down his thoughts about 1943, but I suspect that the somewhat unfavourable passage of the war in 44/45 probably stopped his writing, until after returning from Turbomeca in France to Germany, he found the time to write the final manuscript).

 

[steelpillow]

"My main issue with making future books is working out how to fund it."

Indeed. And I can guarantee that if the author has a budget in mind, the book will cost twice that and add ten.

 

[fightingirish]

"Book of the month"
Congratulations, dear Calum, here a book review by Mr. Denis J. Calvert!
Source of the screenshot:
Aeroplane Monthly - January 2021 - page 98

 

[Pasoleati]

Pathology_doc raised the issue of German mismanagement. Is there any book comparing German war industry management (especially aircraft industry) WW1 vs. WW2?

 

[pathology_doc]

Pathology_doc raised the issue of German mismanagement. Is there any book comparing German war industry management (especially aircraft industry) WW1 vs. WW2?

It would make an interesting comparison and contrast. Among other things, some of the issues Calum brings up as affecting aero-engine and airframe development in World War 2 (particularly high-performance fuels and ultra-high-grade steels) would probably not have been relevant in the technical context of the First World War.

 

[Calum Douglas]

Pathology_doc raised the issue of German mismanagement. Is there any book comparing German war industry management (especially aircraft industry) WW1 vs. WW2?

It would make an interesting comparison and contrast. Among other things, some of the issues Calum brings up as affecting aero-engine and airframe development in World War 2 (particularly high-performance fuels and ultra-high-grade steels) would probably not have been relevant in the technical context of the First World War.

I wouldnt be so sure, I was seriously shocked by advances in WW2, WW1 might have equally large surprises in store... I only worry that insufficient documentation may survive to shed serious light on it... we`ll see. Right now I cant do anything as all the archives are still shut, its a perilous time for historians and serious researchers.

 

[edwest4]

I must say it's not that perilous. Just follow the precautions and plan for the future. A few months back a book was released in the German language about a tank built during World War One. It contained new photos and it corrected some old information. As a long-time follower of document releases, I've also seen references to private collections. A few German auction sites regularly feature original award documents and photos for the Luftwaffe. And German eBay has photos of crashed and captured French and British aircraft on a fairly regular basis. One picture can add to the historical record.