Imperial Airways: now with extra airmail

Daily Telegraph

An advertisement for Imperial Airways from the Daily Telegraph, 30 January 1935, emphasising its role in delivering airmail to the Empire: twice weekly to 'the East' (presumably India, Singapore, Hong Kong), once a week to Australia (a service which had only just begun the previous month), and twice weekly to Cape Town. A lot of effort went into selling the idea of air mail to the public, as this post at The British Postal Museum & Archive shows. Here, the modern lines of the Imperial A.W. 15 Atalanta is contrasted with the traditional garb of the imperial subjects in the background. The message is that technology will modernise the running of the Empire and help bind it together.

CC BY-NC-ND 4.0 This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. Permissions beyond the scope of this license may be available at

36 thoughts on “Imperial Airways: now with extra airmail

  1. jane fleming

    Flight to South Africa called in at KISUMU, Kenya. British staff lived there. Passengers also stopped off there.

  2. Erik Lund

    Was that the airfield where army ants built anthills in the middle of the runways? I know that it was an airfield further south that had to be abandoned because it turned out to be too expensive to hire porters to carry in avgas. In fact, by this time Imperial was well on its way to replacing the Atalanta with the Short boats, because it is cheaper to get gas at a port than up on the spine of the African highlands.
    Simpler times.....

  3. Urban Garlic

    No mention of Canada, I notice, presumably because transatlantic air-mail already worked pretty well.
    I'm also curious to know whether government-provided mail subsidies were as crucial to the development of British civil aviation as they were for the US. It occurs to me that the British might have been less embarrassed by a direct subsidy.

  4. Post author

    Transatlantic airmail was still in its infancy too (the first was in 1933, and that was a stunt). There were no regularly scheduled flights across the North Atlantic yet: the only established routes were to South America via Africa, by French and German aircraft (including Zeppelins). So no Canada because no airmail to Canada yet.

    My understanding is that airmail subsidies were seen as a way to spur the development of air routes to the Empire and to prop up civil aviation, though I don't know how important they were in financial terms. (Probably not enough, even though it had the airmail monopoly Imperial had to merge with British Airways to form BOAC in 1939.) I don't think this was particularly controversial, but the idea of direct subsidies to airlines (i.e. just for flying at all, not for carrying airmail) was highly problematic in the early 1920s in the era of the Geddes ax. Subsidies were paid but only temporarily, on an emergency basis. The hope was that civil aviation would soon be able to 'fly by itself'.

  5. Interesting. Let's not overlook the Dutch (embarrassingly for Britain & the Empire) coming second in 'the world's greatest air race' in October 1934 - only a few months earlier.

    While the winner was using a dedicated race 'plane, KLM flew a new, but standard, DC-2 and stopped at all their route stops. Rather like a bus coming second in the 24 Hr Le Mans, while making regular request stops.

    The British - and therefore the Australians - were not keen on the Dutch being allowed to extend their route from Holland to Java the last bit to Darwin, so they had to fill the gap themselves.

    I'll send Brett a link to my article on the ABC site on the DC-2's importance. (The anniversary is this weekend, by the way.)


  6. With a regular steamship service crossing the Atlantic in a couple of days, the value-added of an airmail route to Canada wasn't (presumably) very compelling yet in the Thirties.

  7. Erik Lund

    I don't think airmail should be underestimated. _All_ first class overseas mail was supposed to go by air starting with the Christmas 1938 rush. A week's difference in delivery of business mail can make a huge difference, and that is why the Civil Air Directorate focussed on it.
    Now, the 1938 rush was a bit of a fiasco, with flying boat problems (stranded in a lake in the Congo jungle? Oy!) and the failure of the Ensign, or, more accurately, Tiger, but that just reflects its boldness.
    And the North Atlantic airmail race mattered on another level. It was an outlet for national rivalry on par with the great days of the Blue Riband, and a technological freakshow. Really, if a historian can't be bothered to work on this, a science fiction writer should.
    There's been some secondary work (Higham and Clark) on the subject, but Burchall's annual reviews of developments in the late 30s' _Brasseys Annuals_ cover the highlights as well or better.
    As for the MacRobertson Race, _all_ contestants were required to make regular stops. The winning DH88 Comet didn't just beat the Boeing and Douglas contestants, it destroyed them. Scott and Campbell Black made 71 hours versus 90 hours for the DC-2 in spite of engine troubles, and the Mollisons were making even better time before Jim screwed it up.
    Remember that this was not supposed to happen. According to published cruising speeds, the DC-2 and Boeing 247 were going to beat the De Havilland racing planes. There were those who thought that the American firms' published performance statistics had more to do with sales than aeronautical engineering. The outcome confirmed this dramatically.
    But don't tell Correlli Barnett.
    _Flight_'s coverage is pretty good and online. I don't know how searchable it is, and it is probably under a pay wall these days, but if anyone's interested, _Flight_ is part of the standard periodical microfilm package at many libraries.

  8. Last I checked, Flight was online almost in its entirety, but the search facility is more than a little erratic, no doubt due to OCR artifacts. Browsing it's not the quickest way to go through a run, but it beats the stack service at most places...

  9. Sorry, Erik,
    You missed my point - the KLM DC-2 flew the KLM route, made the KLM stops as well as the required five race stops.

    Indeed the Comet racer beat them by a margin; of course it should, it was a dedicated, brand-new design racing aircraft built to do just this job. The DC-2 was a standard airliner, just entering service (the Boeing 247 was effectively rendered obsolete by the Douglas). Manufacturer de Havilland's best airliner equivalent, the de Havilland Dragon entered by the New Zealanders came in days later on November 3rd. The Dragon was even beaten by the Airspeed Courier - a light airliner.

    The difference of 70 to 90 hours isn't 'destroying' when you consider the Comets carried two crew and no/negligible payload. The Douglas was lightly loaded, but carried mail, three passengers and four crew in airline standard comfort. The Comet's engines were pushed to the performance limit by the crews at full, 'race' power - The Mollinsons blowing theirs on car fuel, but G-ACSS' losing power over the Timor sea. Meanwhile KLM flew at normal cruise, flew several hundred km further by staying on the KLM route as well, and made thirteen stops to the Comet's four before reaching Australia. The bus - race car comparison stands, and I'd expect the race car to do a lot better than 1/5th time of a bus in those conditions.

    As has been pointed out already, Britain had problems getting airmail working, while American aircraft successfully carried mail - including in the Great air Race, while the fact remains that British airliners, de Havilland particularly (ergo mailplanes) were not in the same game as the American types.

    American manufacturers brochure figures are a red herring, regularly misunderstood in Britain, the Americans understanding mrketing rather than understatement - what matters is that the American aircraft delivered what the airlines needed. The American engineering was simply better. The Douglas and Boeing had adjustable pitch propellers, the Comets having a bizarre French arrangement (the Ratier prop) because there wasn't anything in Britain suitable - the best being, wait for it, American, and a suitable type not yet in licence production in England.

    The DC-3, developed from the -2, was the first airliner to turn a genuine unsubsidised profit only carrying passengers - something no British pre-war international airliner could do. After the de Havilland DH-86 Express debacle in Australia with Hollymans, decent American types (DC-2, -3 and Lockheed 10s and 12s) were at last allowed in to replace the inadequate (and in the 86s case unairworthy) British types.

    Britain's Saturday Review stated: "No British liner, no British service machine in regular use in any Royal Air Force squadron at the present time is fast enough to have finished the race within a thousand miles of the American machine. It is almost incredible, but it is true."
    (From Terry Gwynn-Jones - Further & Faster, Allan & Unwin)

    As Jakob says, Flight's back issues is available to all as PDF pages as the Flightglobal archive.

    I could go on, I think I will when we get to the anniversary, but on my own blog, and link back here, if that's OK with Brett? Anyway, you read it here first.


  10. Erik Lund

    As we know from the JEH debate of two generations ago, the DC-2/3 is the _most important thing ever_. The fact that it was better than all British interwar planes demonstrates that Britain, despite massive support for research and development and all-out official encouragement of airmindedness, could not match the achievements of American private enterprise. Later, historians like Barnett and Wiener deployed this argument to revive the old Nonconformist argument that being British was bad for science.
    I know that digging up a minor forty-year-old controversy seems little more than antiquarianism, but this discussion heavily influenced an obscure British policy maker of the 1980s (Roofer? Hatcher?), and had some small consequences on the way science, academics and even financial regulation is done the world round. So it does behoove us to get our facts right.
    Those facts are: i) the DC-2 was entered into the MacRobertson Race with a claimed 75% power (1400hp max) cruising speed of 196mph, 62% power cruising speed of 183mph, disposable load of 6,125lb (34% all up weight), landing speed 61mph (_Flight_, 1 March 1934, 189--91)
    At a very conservative consumption rating of .5 lb/hp hr, it should have had a range of 429 miles per 1000lb gasoline carried. Indeed, it was originally intended to install long-range gas tanks in the KLM DC-2 and enter the new Fokker 36 in the race to compete for the handicap prize. (_Flight_, 1 Nov 1934: this is a PDF lift, so I'll suggest searching for "Albury").
    The figures cited above are part of a gruesome battle for sales in the early months of 1934. _Flight_ offers them in comparison with figures for the DH-86B, a biplane with cruising speed of 145mph at a consumption rate of 36 gall/hour, a total disposable weight of 3675lb (40% auw), and, most saliently, a landing speed of 66mph. The implication of a monoplane with a higher speed range than a monoplane led _Flight_ to very gently editorialise the possiblity of noses growing. This was repeatedly denied by Douglas, KLM, and the media. Now, the DH86 was not the most successful of aircraft, but the DH89 has a far better claim than the DC-2 to be fhe first airliner to flly commercially without subsidy. Note the statistic for %disposable lift, not spurious claims to speed. Unless your business model incorporates US Post airmail subsidiies that will be paid even if you send the mail by train, so long as you operate a passenger service --an excellent Congressional initiave for _American_ conditions--, it is going to be disposable lift that determines your profitability. In turn, efficiency of structural design that is decisive, not aluminum skinning, of, as we shall see in a moment, dubious merit.
    The MacRobertson Race was announced months in advance. Plenty of firms announced that they would enter experimental types, notably Lockheed. Only DeHavilland made the cut off, leveraging its developmental effort into an attack on the airscrew market. (The story of the adjustable>variable>constant speed airscrew is a complex one. Perhaps it will be written one day. The Ratier was certainly a peculiar design. It was more aerodynamically efficient and more useful than the two-pitch on the Douglas.)
    When the planes reached the finish line, the tale of the tape was this: Scott and Campbell Black took 71 hours to fly London--Melbourne. Thanks to small engines on a small plane, they stopped only 5 times, spending only 9% of transit time on the ground, reaching an average cruising speed of 190mph. Carrying 2 crew, 3 passengers and 420lb air mail (about 1/6th of the claimed disposable lift at which the aircraft was supposed to achieve the figures cited above), the Douglas was on the ground 15.6% of elapsed time, turning in an actual cruising speed of 173mph, and for most of the race only barely ahead of the Boeing 247D.
    This is does not prove what Correlli Barnett thinks it does.

  11. Dear Eric,
    I'm not sure what you are trying to say before 'getting our facts right', so I'll pick up there. I'm also not Corelli Barnett, not trying to prove political or national theories, just to clarify some facts of aviation history and performance.

    You misquote the crew of the DC-2. There were four, not two.

    Your sentence on the DH86 repeats 'monoplane', and as a result perhaps, I'm not sure of your point. It doesn't matter, because you'd never get me in one, it was, of the aircraft listed, the main one to avoid.

    (I've examined examples of all the types we list apart from the 86, which is thankfully extinct, and I've flown in the DH89 Dragon Rapide, and the Lockheed 10, as well as the Junkers Ju52/3m. DC-2 and Boeing 247 flights are a bit harder to catch, but I've crawled all over examples and talked to operators as well as having a go running the engines on a Lockheed 12. I've also talked to the men and women who fly these aircraft today, and use their understanding and explanations for my writing. The development of the propeller isn't a 'complex one' you just need to look for the explanation around vintage aircraft and operators, and their manuals, not in academic libraries.)

    You persist in missing the point of the race. The DC-2 placed first in the handicap - that is the transport rather than the pure race category - but they chose to take second in the pure speed category. An achievement of some note done in a standard airliner flying an extended version of the KLM route.

    Sir Macpherson Robertson, sponsor of the race, as well as wanting to boost Melbourne (and himself), said: " This is just the result I wanted - to show that a transport plane could reach Australia in four days."

    The Comet racer crews were exhausted on arrival, the KLM crews hardly fresh as daises, but certainly not worn out by the pressures and tough environment the Comet crews had flown in. The soundproofing and comfort of the DC-2 was a world away from the British airliners, let alone a dedicated race aircraft.

    "DeHavilland ... leveraging its developmental effort into an attack on the airscrew market." Not true in any aspect. They didn't have a propeller to do the job, there was not a British design that could, and so they chose what can politely called an 'interim' design from Ratier.

    "The Ratier was certainly a peculiar design. It was more aerodynamically efficient and more useful than the two-pitch on the Douglas." I would be interested in where you get the data to suggest the Ratier was a better propeller than the DC-2's Hamilton Standard. Not only was the Ratier inferior to the DC-2 propellers, it was actually compromised in performance and safety (due to the Heath-Robinson airflow pitch-change mechanism) and irreversible, so could jam, act asymmetrically, and critically, in the case of an aborted take-off or landing or a go-around, was unable to regain course pitch. They were replaced on the Comet type as soon as possible and when the Comet Racer was restored at Shuttleworth, there was no question of using this poor interim design.

    Further, de Havilland (note spacing and capitalisation) did not develop their own propeller design pre-war, they set up de Havilland Propellers in 1935 (note date) by licencing Hamilton Standard designs from - America.

    Next, the engines. The Comet Racer's unarguably marvellous design and performance was achieved by using a dedicated race engine operating at maximum performance - one of G-ACSS' engines having a partial failure before finishing the race. No-one would argue that was a remarkable achievement, but the point in terms of aircraft development and performance was that the KLM crew, using standard airliner engines at standard cruise power, oil and fuel came in less than a day later (you could argue the loss of eight hours at Albury covers most of that time anyway, in terms of aircraft performance as opposed to race achievement, but let it pass.) As I pointed out, the Boeing 247 was obsolete, and they came in third only by pushing the Boeing's engines - by arrival, they were un-usable for further flight.

    Why the obsession with brochure data? It has and remains an aspect of PR not reality. No airline did by its aircraft on the brochure performance, certainly not KLM nor the American airlines sponsoring the type. It's irrelevant, and hardly surprising in the run up to a race. The performance fact was that no British airliner could touch the Douglas in 1934.

    You say "Now, the DH86 was not the most successful of aircraft..." It wasn't that - it was an unsafe, unairworthy disgrace, unfit for safe airline flight. It's structural and fundamental design failures led directly to at least one fatal accident on introduction to service, almost certainly more, and I remain unconvinced that after modification it was a sound design, given the obfuscation de Havilland and the British Air Ministry undertook when challenged over the fatal structural failures initially. The reaction of the British to the Australian suspension of its certificate tells us a lot of Colonial attitudes of the time, and the change demanded by Qantas' Chief pilot from a single pilot cabin to dual to address pilot fatigue tells us a lot about de Havilland's poor understanding of the job, and aerodynamics - few if any other airliners were single pilot by this time. I don't know and don't care whether de Havilland's brochures on the 86 were ‘accurate’, the fact that they argued that a two-pilot nose would be slower is telling of their aerodynamic understanding - it proved faster. (See MacArther Job's writing.)

    The DH-89 was indeed a good aircraft according to its category. (I'm vaguely curious as to what 'disposable lift' might be. Payload is what the industry uses.) But it was too small, too slow and too delicate for major use for main routes by airlines. It takes a one-eye British industry booster to see the 1934 DH-89 as ‘equal’ to the 1935 Lockheed 10. The de Havilland airliner also came in tenth in the Great Air Race, well after the obsolete Boeing and the brand new Douglas.

    The DH89 Dragon Rapide was not in the same class for performance as the DC-2 or even the Lockheed 10 while the maintenance and care requirements for wood and fabric de Havilland types were significant, while the metal aircraft were simply more cost-effective, easier to inspect and could be left out in the rain. In case anyone assumes an American metal vs British wood bias, note that in Papua New Guinea, the world's greatest freight operation of the inter-war period used German Junkers all-metal aircraft because they were the only type able to do the job. In Canada, de Havilland types were found inadequate for bush flying, and the record setter for the flight across Canada in the late 1930s was the Lockheed 12, while Junkers types being popular despite their extra tariff-driven cost.

    Any airline that could switched from DH86 Express, DH84 Dragon and DH89 Dragon Rapide to metal aircraft as quickly as was possible, and only went back when metal aircraft were unavailable. Only war kept those types in production and use until 1945.

    The main reason the Commonwealth bought British airliners in the 1930s was because they had to - through Empire Preference tariffs and bans on the importation of US (and I presume other nationality) types. I don't know if that's why de Havilland types were second rate, but it's certainly how they managed to make enough sales.

    I'm not sure where Correlli Barnet comes in - if he need to at all. I’m not pro- or anti- any group – there was great achievement and innovation by British aero industry, but not perhaps as much as their story would have, although the development of the Comet principle onto the lovely but ill-timed Albatross and then the truly great Mosquito is case enough of de Havilland success in particular. Meanwhile American designs (and German) were certainly not perfect either. But were I buying an airliner in the mid-1930s, I’d know what would be best. The race sponsor, Sir Macpherson Robertson, de Havilland, Douglas, KLM both Imperial Airways and Qantas saw what the race showed and drew their conclusions. Which is where we came in.


  12. Erik Lund

    To begin at the end, Lord Keynes once said something about the world's so-called practical men actually simply being followers of obsolete theories. Corelli Barnett (himself echoing Nineteenth Century Nonconformists) claimed that British culture made it impossible for Britons to innovate. Proximately, this justified the Thatcher-era culture war. In a deeper sense, his argument still informs social development theorising, vid Joel Mokyr or David Landes.
    This brings us back, or ought to bring us back, to his technique, which is to dig up an exhaustive array of British patentees, subsidiaries, and secondary adopters, combined with often ill-informed critiques of specific British products. and throwing them at the reader like some mad old physical culturalist throwing a medicine ball. The very idea of fact checking _Audit of War_ is so exhausting that one is tempted to give up before one begins.
    At least the DC-2 provides us with a grip. Was it as good as they say, specifically in one of Barnett's favourite citations, a minor mid-60s controversy in the the pages of the _Journal of Economic History_? This duscussion purported to use published statistics (hence my concern with published information about the DC-2) over whether the Douglas airliner showed that the British aviation industry had comprehensively failed to innovate. (I want to say that Roy Ferron was involved, although I think that he was the "anti-," and I cannot for the life of me remember the "pro.")
    This is an especially interesting conversation because we should never have been having it. The MacRobertson race demolished Douglas' claims at the time, showing a 20mph gap between the firm's claimed cruising speed and realised performance, and demonstrating what any passenger knew anyway by looking out the window: that the time for metal-skinned wings was not yet. (Had it been possible to make practical metal-skinned flaps and tail planes in 1933, there would have been a strong maintenance argument for them. As it is, the literature resorts to political explanations.)
    Let's be clear about something: KLM did not "choose" to lose. It was beaten by a plane that was faster than it was; a plane that was not supposed to be faster than it by contemporary publicity, or by Barnett's theorising.
    Still, we do owe Douglas due weight of consideration. First, the firm had no choice. There was a Congressional mandate for an all-metal plane. Second, plasticised Egyptian aeronautical grade cotton was very expensive in the United States in 1933, due to preferential tariffs on imported cottons and the cost of importing Cellon dope. Third, the structure of American air mail subsidies pushed American manufacturers in the direction of higher cruising speeds at the expense of disposable lift (What's left over when you subtract engine and structure weight from all up weight). Fourth, the somewhat specious safe takeoff requirements for high altitude Rocky Mountain airfields, combined with the retractile undercarriage adopted to increase cruising speed, leading to the low wing configuration, practically forced Douglas in the direction of the two-speed adjustable airscrew, and subsequent variable pitch and, eventually, constant speed airscrews. As we all know, of course, had American aeroengine manufacturers been faster in adopting reduction-geared engines, the aerodynamic inefficencies and weigtht penalties resulting from the premature adoption of this technology could have been avoided, and the path to the smooth adoption of two-speed or even multistage superchargers made more straightforward. Did Curtiss-Wright and Whitney delay the adoption of reduction gearing because their main customers already used adjustable pitch airscrews of various designs, or was it just a matter of not having R&D money during the Thirties? An economically endogenous account of technological innovation will have its own bearing on the Barnett-Mokyr ("There is so such a thing as a free lunch" ) model of innovation.
    (As I said, the development of the airscrew is a rather complicated one.)

    The facts here should not be in dispute. Metal structures are more efficient than wood ones, but the short-run developmental potential of plasticised wood materials favoured by Russian designers and by de Havilland were not exhausted until the early jet age. That is why the RAF and DCA shifted over to metal structures in the 1920s, while de Havilland continued to explore "wood" planes until the Hornet. Aerodynamic cladding is a different matter. Again, the potential of plasticised material ("doped" cotton) was not exhausted until much later than is sometimes assumed. Not only the DC-2, but the B-24 and early Spitfires had fabric control surfaces. The presence of fabric surfaces greatly reduced the clear maitenance advantages of metal cladding; although of course the need for metal structure for tropical operations was obvious.
    So, for a designer, the question is whether you favour payload, operability, however defined, or passengers. Fabric-covered biplanes had a huge payload advantage over metal-covered monoplanes and a lower landing speed, the major determinant of operability, especially on "Empire" routes. What degree of speed advantage offsets this? Clearly if the DC-2's speed advantage over the DH-86 is more in the range of 30mph than 60, this is going to influence orders. If the DH-86 then turns out to be an unairworthy plane, then it is time to start talking, very loudly, about Rutbah Wells, and hope to get a replacement flying quickly.
    One more word about airscrews: patents. De Havilland wanted to supply airscrews as well as engines. All very well, but the Hele-Shaw patents were already assigned in Britain. Hamilton's patents were clearly sound, so De Havilland had good reason to go for them. As far as I know, the Ratier used on the Comet would automatically revert to the low speed mode if it stalled, unlike the Hamilton in use in the MacRobertson, a safety feature rather than bug, albeit a pretty expensive one if it happened in cruising flight and overspeeded an engine. I could be wrong, though. When I try to think about the relationship between reduction gearing, superchargers and propeller pitch change mechanisms, my head explodes and my face turns a funny shaped. If it freezes that way I might as well kiss my chances at the girl down at the game shop goodbye, so please use short words and easy similes to explain my errors.

  13. Erik Lund

    I thought I was being slimy enough bringing up Rutbah Wells! Borrowing a C. G. Grey talking point? I need a shower....

  14. Erik: Were you thinking of Peter Fearon and AJ Robertson in the Journal of Economic History in the 70s?

    On wooden structures, the only stuff I've read is Erik Schatzberg's 1994 article "Ideology and Technical Choice: The Decline of the Wooden Airplane in the United States, 1920-1945" Technology and Culture 35(1); I haven't read his book, never having seen a copy of it at a reasonable price, and my uni library doesn't have it.

    On structural efficiencies more generally, I don't know how Richard K. Smith's "The Intercontinental Airliner and the Essence of Airplane Performance, 1929-1939" (T&C again, 24(3) - 1983) has stood up, but I recall it suggesting that US weight control in design was superior. Of course, whether this is evidence of UK technical inferiority or simply different contexts for their airliners is another matter entirely.

    I can only say I heartily agree on the difficulties of visualising the effects on prop pitch of supercharge and gearing - I always seem to end up with a bad case of fighter pilot's hands...

  15. Erik Lund

    Fearon and Robertson sounds about right. Truly an aertefact of another age. Nowadays you can't walk through the lobby of a big bookstore without being handed a splatbook with a description of the B-18. (Okay, maybe I exaggerate.)
    For political imperatives and wood construction, I was referencing Schatzberg. It's just that I kept visualising Vicenti and thinking, "that can't be right..." I may have seen the book, can't recall now....
    I missed Richard K. Smith's article entirely. I'll track it down it down the next time I'm at the library, along with Higham on Bede (thanks for the tip, Brett!) *
    I'd be interested in knowing what aircraft he is comparing to what, though. The first British intercontinental airliner that can really be compared with an American is the Ensign. On the one hand, I'll buy that the Ensign was structurally inefficient compared to any American aircraft you'd want to name. On the other hand, I'd make a lone exception for the (first) DC-4, its only obvious competition.

    *By the way, you youngsters have no idea what it's like being an "independent scholar" with a fulltime job. Why, in my day... Oops, sorry, wrong diatribe. I think I need to work up a classic "don't make my mistakes" lecture instead.

  16. Erik Lund

    Okay, then:
    Richard K. Smith, "The Intercontinental Airliner and the Essence of Airplane Performance, 1929-1939," Technology and Culture, Vol. 24, No. 3, July 1983: 428--449.
    How interesting --essentially a comparison of two planes that basically weren't intercontinental airliners, the Short Empire "C" class flying boats, and the Sikorsky S-42.
    That said, Smith has an interesting point to make. The Pan-American clippers did have their part to play in the development of civil aviation, and the fact that they, like all American flying boats before 1940 or so look a little old-fashioned doesn't mean that we shouldn't look inside.
    Unfortunately, that's where we go astray, specifically into the deep weeds of (once again) advertising. Taking published Sikorsky numbers seriously, the S-42 was a more efficient weight lifter than the great bombers of 1944. Smith concludes that American design offices were incredibly good at weight control.
    And, presumably, lost those skills when they turned to military projects.
    A more likely conclusion is that Sikorsky's claim that "the bare weght" of the S-52 was under 20,000lbs was a little nose-stretcher. I've linked below to a 1941 accident report that debunks another of his claims (the 62mph landing speed at full flaps). Unfortunately, I haven't turned up a structural analysis.
    Can we cut through the p.r.? Both Empire boats and S-42s were issued British Civil Aviation Certificates of Airworthiness as modified for the Atlantic proving flights of the summer 1937 Atlantic proving flights. They were published in _Flight_ for 15 July, 1937, page 70, and are very different from Smith's numbers.
    The rest can be put down to a failure to grasp why it was easier to fly long distances in tropical latitudes in the 1930s, although the slam against the safety and sructural strength of the aircraft that became the Short Sunderland from a partisan of the S-42 is, well, kettle, pot, black.

  17. ok this is my first venture on to this web this information is going to take a while to digest....but the only thing i can contribute to all of this is....i read some where and maybe it was flight mag. that the reason the comets did'nt use the standard british variable pitch prop. was that the comet engines were too small to fit the device...that said.....might i bring to someones attention that "three" comets were entered in the race....and only one finished.....and that one under great much for the comets............leaving that to be is my opinion that besides american airplanes....american airplane engines shoud also be a great degree..... yours truly................

  18. Ian Evans

    Yes, the Hamilton-Standard unit wasn't used because no one knew how it would behave on such small engines and there was no time to test it.
    No, three Comets were entered, two finished, and the one that came fourth in the race turned round and flew back to the UK with newsreel films of the finish to the race.

  19. Black Dog.

    This is a very old thread now, but I thought it worthy of a few comments, as there is some highly misleading ‘information’ being disseminated here.
    Firstly with regard to the Comet.
    There is a wealth of information available if one roots around. All my library and archives are in storage as I'm relocating at present, so this is all from memory, but it's easy enough to verify.
    The Comets were ALWAYS intended to fly with the DH PD30 airscrews. Period. DH's always intended to produce two versions of the Gipsy Six. The original Six had a tapered, solid crankshaft, suited to fixed-pitch airscrews. The Six Series II, had the SBAC1 splines to suit the PD30, and was of course hollow. The 'R' engines were simply a hybrid to save time in the few months that they had as the DHGSix Series II wasn’t quite ready. The ‘R’s were Six's, with a raised compression-ratio and a few other minor tweaks, but fitted with the DH Gipsy Six hollow crankshaft with the SBAC1 splines to accept the new PD30. DH's had sent a team to tour the USA to look into VP airscrews some time before, and, as a consequence, had reached an agreement with Hamilton's to produce the units under Licence in the UK. There was NEVER for any moment any reason to doubt that they would not work on a smaller power unit. To suggest otherwise is utter nonsense. The fact was, however, that all the off the shelf units from Hamiltons were for the much larger American engines, the DH Gipsy Six being a relative minnow. DH's settled upon the SBAC1 splining to suit the size of the DHGS's crankshaft. (Many years later enlarged to the SBACII for the DHGQ30 et al.) That's why the Comets engines had that spline fitted, and NOT specifically for the Ratiers. The first Comet to fly in fact had the PD30 units fitted and they worked perfectly. In truth, all the development work took longer than anticipated. DH's proved very consistently that they could magic-up an a/c from paper to flying prototype in double-quick time over and over again – one of the advantages of wooden construction. Getting engines and airscrews working reliably and optimally was always going to take longer. This was still all quite new technology at the time after all. Despite the fact that the PD30's worked, they were simply not sufficiently tested. Additionally, owing to the very wide speed-range of the Comet, it exceeded to original design parameters, both in terms of the blade-form and the pitch-range. (This was precisely the problem that affected the Mew Gulls of that era.) They needed speed and they needed range.
    JDK's comments about the Ratier units are very ignorant. The Ratier units were simple, efficient and well engineered. Clearly, after all the effort to get the Comets ready for the race, to develop the ‘R’s and rush through the PD30, the change to the Ratier, for such a prestigious event, upon which DH’s had their reputation riding, was not taken lightly. It was an informed and well reasoned decision, and, in the circumstances, the decision was entirely logical. Both the Ratier airscrews and the ‘R’ engines performed very well under the circumstances. Much has been made of the apparent failure of ‘SS’s engine(s). After the event, I’m pretty sure that it was simply found to be a faulty oil pressure gauge. The other Comets engines worked well – when not supplied with the wrong fuel….! Remember Cathcart Jones flew directly back to the UK with the same engines. JDK;- I think that you will find that ‘SS’s engine didn’t ‘Lose Power’ over the Timor Sea, as you state, but that, rather, C.W.A.Scott throttled it back because of the faulty gauge. He wrote all that-up in a book just after the even. ‘Scotts Story’ it may have been named.
    Still on the subject of the Ratier airscrews; Jump forward to 1936 and the Schlesinger Race. Several machines changed to Ratier airscrews (Albeit the electrically actuated version.) at the last moment. Why? Efficiency. Ratiers were faster. Alex’ Henshaw fitted the same unit to’XF for exactly the same reason. Ironically, he was forced to remove it for the Kings Cup and fit a DH PD30, as only British units were allowed at that time (Bloody good job that rule doesn’t apply today..!). Consequently, his machine was around 34mph slower. Res ipsa loquitor. Henshaw would have re-fitted the Ratier for the Cape Record too, but the basic simplicity and reliability of the PD30 won out, as it was another long flight. There was also an issue with the spinners for the Schlesinger event, but I digress.
    Thus;-“ "DeHavilland ... leveraging its developmental effort into an attack on the airscrew market." Not true in any aspect. They didn't have a propeller to do the job, there was not a British design that could, and so they chose what can politely called an 'interim' design from Ratier.” JDK as usual, pontificating - and wrong.

    "The Ratier was certainly a peculiar design. It was more aerodynamically efficient and more useful than the two-pitch on the Douglas." I would be interested in where you get the data to suggest the Ratier was a better propeller than the DC-2's Hamilton Standard. Not only was the Ratier inferior to the DC-2 propellers, it was actually compromised in performance and safety (due to the Heath-Robinson airflow pitch-change mechanism) and irreversible, so could jam, act asymmetrically, and critically, in the case of an aborted take-off or landing or a go-around, was unable to regain course pitch. They were replaced on the Comet type as soon as possible and when the Comet Racer was restored at Shuttleworth, there was no question of using this poor interim design. Further, de Havilland (note spacing and capitalisation) did not develop their own propeller design pre-war, they set up de Havilland Propellers in 1935 (note date) by licencing Hamilton Standard designs from - America.
    As far as I’m aware, JDK isn’t a pilot, or an engineer, as the above clearly shows. Seems he’s not much a a historian either. Neither am I, but I don’t pop-up on every forum on the web promoting myself as such to the irritation of all and sundry…. We aren’t talking about an Airfix kit or correct colour schemes here. The words ‘better’, ‘poor’ or ‘inferior’ are quite irrelevant in this context. As for the pitch change mechanism itself, yes, it was a well known characteristic that the pitch-change initiation could, and probably would occur asynchronously. Every pilot flying them was well aware of that. Duh. DH’s decision to use the Ratiers was a bold move and was utterly vindicated. I might also add, that, the Hamilton/PD30 airscrews were also unfeatherable, as were all ‘Bracket-Type’ airscrews. ‘SS now uses the PD30, but the rebuilt ‘Black Magic’ will, on good advice, use the Hydromatic which is fully featherable, as it’s using Q30’s. All the DH Hydromatics on Gipsys need an SBACII ya see. JDK has allowed the 1935 date of the setting-up, administratively, of DH’s separate airscrew division to mislead him. The tour to the USA and the agreements probably date to 1933 from memory. Check Flights archives, it’s all in there.
    The Centenary Race; A minor point first – I seem to recall that the DC2 did have extra fuel capacity fitted. I don’t think it had a standard interior either, but as I was never much interested, I may well be wrong on these two points.
    I also seem to recall that the Comet actually won both the Speed AND the Handicap race, but the rules prevented Scott & Black from claiming both, so, understandably, they opted for the speed prize. JDK is quite right to point-out that the DC2’s performance was very respectable, and a portent of things to come. He is however wrong, as he often is, to be so dismissive of the Comets performance. The Comet would have arrived in Oz even sooner had the (Bogus.) oil pressure issue not delayed them significantly. In previous years, aircraft arriving in the antipodes took weeks and made dozens of stops. Some even had to be rebuilt several times along the way. I think ‘SS made just four stops. Formula One races are won by hundredths of a second. This wasn’t a sprint special for a few minutes around the pylons, it was the other side of the globe, in all weathers, and, in the case of Cathcart Jones, all the way back. The effort required to increase speed is basically always exponential, so at the time, given the relatively tiny engines fitted to the Comet, it was somewhat akin to the 1969 moonshot. The DC2 may well have given birth to the DC3, but the Comet gave birth to the Mosquito, a much more significant leap.
    Just because one has ridden-in and crawled all over a/c doesn’t make one an authority, no matter how tiresomely enthusiastic one is. There is more. I could go on but I have much more pressing aviation matters to address.

  20. Post author

    Wow, that's a comment and a half, Black Dog! Anyone who has read this blog for any amount of time knows that the finer technical points of aeronautical engineering are not my strong suit, so I won't (can't!) respond to most of this. But I will say a couple of things. I'm in the camp which argues that the DC-2 coming second was more significant than the DH-88 coming first. This is partly because that was a common reaction at the time, but also because while the Comet-inspired Mosquito was a superlative light bomber, in the end it was just that, another bomber. Where are its descendants today? The DC-2 and DC-3, meanwhile, set the stage for the routinisation of long distance civil aviation, and that's something we all take for granted today.

    Secondly, it's clear that you have encountered JDK elsewhere and brought your animus against him to my blog. Whether he's right or wrong on this issue JDK is a friend of mine, so if you want to keep commenting here, I'd ask you to keep your feelings to yourself and stick to your technical arguments. In my experience, personal attacks (satisfying though they may be) don't help get a point across; quite the opposite.

  21. 'Black Dog' - Thanks for the additional information and some of the corrections. Someday I may well actually research and write up the background to the Ratier story after all, it's been on the list since this original discussion.

    As there seems to be some confusion - I don't call myself (or claim to be) an historian, I respect those who've earned the title through qualification, although it's not a requirement. For clarification, I'm a professional writer, as anyone can see from my linked details provided to the posts here. I also have never claimed to be a pilot or engineer, nor immune from error - nor am I anonymous.

    Having just returned from an overseas trip where I met - among others - several professional historic aviation pilots and engineers as a result of corresponding through online forums, while I may not agree or be agreed with, I'm certainly not "irritating all" although I accept annoying "sundry" does happen. I've also never claimed to be an authority - I just have based my opinions on the understanding of a number of people who are qualified to comment, including a couple of modern (post-Ratier) Comet pilots, and Comet re/builders.

    Regarding the much disputed facts - several points you are attempting to 'correct' me on aren't mine, but Erik's - where I was disputing his views. I'm not sure where that leaves your view in those cases.

    I'd suggest you are missing a core performance / safety issue of the air-pressure operated Ratier - as any twin-qualified pilot would observe on understanding the mechanism and its risks in the circuit. (Later Ratier developments remove the issue.) It was an 'interim' design, and bicycle-pump operation doesn't just seem Heath Robinson, it's a 'poor' (second-rate, if you prefer) engineering solution - if that were not the case, the technical approach would've been more widely (or longer) used. I agree it was the best solution available in that critical time window, but on your account because the other solutions (better and/or replacements) were not available. If you'd care to show otherwise - not anonymously, please - I'm interested.

    Regarding the correction on the engine issue/s over the Timor Sea - Scott's book, while a useful period account (I was looking at a copy last week in a friend's collection, incidentally, but didn't realise I was going to need to check the facts) may not state - as David Ogilvy's The Racing Comets does, that the Comet's engine ran roughly even after the clogged oil filter had been cleaned after landing at Darwin, after the Timor Sea crossing. Ogilvy wasn't writing for the popular media of the time. I certainly agree the Comet and the DH 'R' engine did a remarkable job at the time, as did the crews; but it remains a fact that G-ACSR's engines didn't run without issue on the way out, nor the way back, getting parts from G-ACSP at Allahabad. Referenced corrections welcome, but at the moment, my brief research stands.

    We could go on regarding appropriate adjectives and excusing performance shortfalls or recognising compromises as to the props; I think on your own argument the PD30s were evidently not the answer at the time. Conflating the benefits of feathering versus semi-controlled pitch changes is basic technical stuff, perhaps not best argued here given Brett's comment above. However non-anonymous properly-referenced corrections will be welcome on my blog when (if!) I get around to writing up the Ratiers.

    Finally, there seems some perhaps genuine misunderstanding of opinion. I'm not "dismissive" of the Comet's performance - in 1934 it was the fastest long distance aircraft on the planet, and deserved most of the accolades heaped upon it; and I rather like the type, personally. However the original point, disputed and re-disputed as it may be, was that a standard airliner was hot on its heels.


  22. Black Dog.

    'Animus', what a lovely word Brett.....
    Sure the DC2 put up a great show. I just find it rather irritating that people unfairly use this as a stick to beat the Comet with. It was a race after all… That said, the DC2 embodied a trend at the time, it was just bigger, but it wasn't pressurised, which is central to the concept of what we think of as a 'real' airliner - that ability to fly (Punters) over the weather. That and the arrival of the jet engine was the real quantum leap. The 1934 Comet didn't pretend to be an airliner, but it did show what could be done with a small amount of power and an aerodynamically efficient airframe.
    Mr. Tweedy has again missed the point on the Ratiers. I’m perfectly well aware of the elementary issues with regard to the obvious limitations of those airscrews. The Ratiers were simple, reliable, efficient and available, and the pilots were well aware of obvious issues such as asymmetric deployment. Placing any sort of modern frame of reference over their shortcomings at that time is meaningless. At the time, they were just accepted attributes. The Camel suffered from a difficult to control engine and large amounts of torque and gyroscopic effects that some later Great War fighters such as the FD7 & the SE5a didn’t have – but it didn’t stop it being the Allies highest-scoring fighter. As far as the Ratiers greater efficiency is concerned, it’s worth noting that a number of the Schlesinger machines (Between 2 & 4 from memory.), a good two years later, swapped from the PD30 to Ratiers, albeit the electrically actuated version of the Helices Ratier product. As mentioned before, Alex Henshaw’s Mew was much faster with the Ratier fitted. Not only was the Ratiers blade design more efficient, but the available pitch range on the original PD30 was limited. The later PD30/211/1 fitted to the likes of the Queen II engined Proctors etc. had an increased availability of pitch range over the original PD30 of course.
    At the risk of further ‘thread-drift’, I’d also make a couple of comments about the Comets flying characteristics, because they dovetail into the issue of the Ratiers. Some older a/c, and the Comet is a good example, have attracted a good deal of negative comment. This has accumulated over the years, bestowing such machines with quite undeserved reputations to the casual reader. There are two reasons for this. Firstly, when contemporary comments were made, most pilots were used to very simple, slow, basic draggy biplanes. Anything that didn’t slow-down quickly and easily was viewed as a hot-ship and such features as flaps and retracts were new territory for most pilots. None of these features in themselves would draw comment from the most basic pilot today. Now jump forward to today. Modern pilots, whilst well used to such complexities - and much more, are not used to some of the foibles of older machines. Many older aircraft exhibit characteristics that would be considered wholly unacceptable today, yet which hardly drew any comment when they were originally operated. (Interestingly, in the case of the Comet, the replica built it the USA incorporates, I have been told, added washout. The resulting ‘improvement’ was reputed to be zero..!). Neither, remember, was the Comet ever intended for any casual amateur to jolly around in.
    Modern pilots flying the Comet have thus approached it with deserved caution. One may read their factual reports for the details. I know that some of these pilots were highly experienced test pilots and the like and one may suppose that an average-joe would come a cropper. However, remember this;- Back in the 1930’s, the Comets were flown with much, much higher loads, through appalling conditions and without the added bells and whistles fitted today. Indeed, deHavillands themselves were only able to give the Comet a very perfunctory evaluation, before they were all loaded with fuel and raced…..! Clearly they were not overly concerned. The Mollisons did manage to drop a wing on landing at Mildenhall for the start of the 1934 race, but otherwise, no one had any real dramas with the airframe, and off the top of my head, I can’t recall any adverse comments from the six pilots in the race, or, later, from Campbell Black or Clousdon, both of whom raced the a/c in meteorological conditions which no comparable a/c would be flown in today. In fact, what is remarkable, is what little comment Scott, Black & Clousdon et al made. They were almost exclusively ex-military pilots of course. Martlesham Heath, I think, later evaluated ‘SS, and I’m sure their report would be a good read, as they often still are. The original Gipsy Six’s (Not the ‘R’s of course.) had a TBO of much less than 500hrs, only 300 I think. This was later stretched, after a few mods and field experience, to about 1,000hrs (If you were lucky..!). Today, any old Continental or Lycoming is expected to last to at least 2,000hrs, and many go ‘On Condition’, for much longer.
    My point is of course….it is again rather futile to drop a modern frame of reference over these old machines and equipment. If we go down that road, we’ll end-up castigating the Camel for it’s ‘shortcomings’, and the fact that it was an ‘interim’ design. Aren’t they all?
    (As for the ‘anon’ issue. It’s a matter of choice. Just as adverting who you are on sundry forums.)
    As they say in Brooklyn, - ‘Enough already’, - back to the aeroplanes.

  23. It's a pity that 'Black Dog' is so determined to pick fault, rather than just bringing material (and debate) to the discussion. As well as being able to sign off as myself and back my own words, I'm happy to be corrected with factual analysis or data. Again, as well as patronisation ('Mr. Tweedy' - leave it elsewhere, thanks.) there's a telling scattering of caveats 'from memory' 'off the top of my head, I can’t recall' showing despite the time lapse since my last response to the points made, no actual research has been undertaken.

    I'm not guessing - as Black Dog is - about modern Comet pilot views, I've interviewed, written up and checked back articles with pilots of the US replica and the UK 'original'. Relating to that, I'm not impressed at having my own research and writing fed back to me as an anonymous critique of my analysis - viz the new washout on the US Comet replica and its efficacy or lack of - which I've written about in at least two articles.

    As to the long digression on the Sopwith Camel, I was recently chatting the a man who very reasonably reckons to be the world's highest time Camel pilot, and was putting on an excellent display of Camel flying, with an original rotary engine fitted.

    And that's the nub of my original point - you can certify an aircraft to fly with a rotary engine today, in a number of countries. I don't believe you could get a Ratier-prop (of the Comet's use) equipped aircraft certified in a first world country today. I would be delighted to hear that checked for a fact either way.

    But it is a fact there's not a single vintage aircraft flying with that mechanism.

    For that reason the Ratier can be filed along with the Messerschmitt Komet's engine as an acceptable technical solution at the time, just not acceptable now. We have airworthy-certifiable Comets and an airworthy glider Komet, but neither look likely to fly with the original power-setup.

    I'm well aware of the differences and difficulties of modern test-pilot expectations when applied to historic aircraft, and am in the process of assisting on that very matter for a period replica and modern test-pilots requirements. Anonymous opinion, without data, won't cut it there.

    I'm not sure of the point of saying "it is again rather futile to drop a modern frame of reference over these old machines and equipment", except that seem definitely to be the case when dismissing the DC-2 as failing modern airliner standards earlier in the same post!

    As I stated at the end of my last post, I regard the Comet and its crews achievements highly. You can see the KLM DC-2's performance as noteworthy or not, it is a personal rating if you wish.

    I'm well aware of the Comet's performance and how and why it wasn't an issue at the time. I'm not sure what point/s Black Dog is trying to make, except at base it's vital to attack me, whether I'm right or wrong.

    On that basis, my details are available, I can be contacted or corrected, but I don't propose to indulge anyone in anonymous personal attacks from someone hiding as a depression.

  24. Black Dog.

    JDK;- 'Mr Tweedy' is YOUR own self-created epithet, not for the rest, you have simply underlined that you still 'don't get it' and are unlikely to do so. Further discussion is obviously pointless. Were deHavillands bothered about whether the Ratier was going to be certifiable in 2011..? Hardly. They just wanted to win the race. Which they did. Did the Ratiers do the job? Yes. - Res ipsa loquitur. Finito. Phew.

    There are a plethora of easily available expert test reports on historic a/c, and have been since flying began. I don’t think Mr.Tweedy has exclusive access. Yet.
    'As for relating to that, I'm not impressed at having my own research and writing fed back to me as an anonymous critique of my analysis'
    .....My information on that came from an aviation business contact (Pilot, Aircraft Engineer etc etc.) who had spoken directly to the builders many years ago, not from your articles, which, like most people, I was blissfully unaware of. Again, JDK’s view is, to say the least, geocentric.

  25. It's 'Mr Tweed', it would be 'egocentric', not geocentric and it's de Havilland, with a space. Such minor errors (along with the failure to factually address any of the responses to the initial queries) are indicative. I agree that further discussion is pointless - in my case I feel with someone unable to provide evidence rather than insults.

    It is a pity that an obvious personal issue has spoiled an opportunity to have a useful educational discussion.

    I agree that we need have nothing more to say to each other.

  26. Phil Vabre

    This has been a jolly interesting discussion to someone who has come to it late in the piece. Apart from the personal attacks, that is.

    " can certify an aircraft to fly with a rotary engine today, in a number of countries. I don't believe you could get a Ratier-prop (of the Comet's use) equipped aircraft certified in a first world country today."

    Just to take one small point only, JDK, I think we need to be careful about the use of the term 'certification' in this context. It would likely be near impossible to certificate an aircraft powered by one of the original rotary engines today under any of the full airworthiness standards, and as you point out the same goes for a Ratier-equipped Comet or whatever. The Camel, the example you use, as an airframe, let alone with a rotary engine, would not come within a bull's roar of meeting, say, FAR or JAR 23 standards (Normal or Utility category aircraft).

    However, as the various Camels, etc, flying show, it is possible to certificate these sorts of aircraft under limited airworthiness standards. And I have no doubt the same would go for an aircraft with Ratier props, should anybody choose to do so.

    Which is, of course, a completely different question.

  27. Nice to see you here, Phil! Pity it brings up some pretty less than appropriate discussions.

    It's coincidental that I recently had to refresh my memory on the Ratier and Comet saga recently, thanks to an article coming to an aviation magazine near you...

    Fair point that most (all?) rotary powered aircraft are flying under some form of limited certification. (They are, let's agree, still 'certified', rather than flown illegally or by chancers.) It's certainly possible that if someone proposed to fly a Ratier Pneumatic variable pitch airscrew equipped aircraft they could get it certified under the same kind of limited category.

    But of the one restoration flying and one replica Comet flying - and the two more Comets due to fly sometime, no-one has ever proposed the Ratier Pneumatic type prop.

    I don't think anyone feels it's necessary, and so the question of "is it wise?" does not get asked. However of the Comet pilots and rebuilders I've talked to, none think the pneumatic Ratier is a good idea. (And just to be clear 'Black Dog' chose to propose I lumped later electric-actuated Raiers with the Heath-Robinson pneumatic ones - not at all; the issue was with the pneumatics that did well enough for a limited period in history.)

    I make no claims to be either a qualified historian or a pilot; however when it comes to the Ratier Pneumatic prop saga, I defer to David Ogilvy and the US, NZ and UK people who have, or propose to operate Comets without Ratiers - that's what has formed my opinion.

  28. Phil Vabre

    I don't pretend to be an expert on Ratier, de Havilland or anything else in this discussion but I do think, and this is perhaps one of the points that Black Dog was trying to make, that we should be careful in thinking about these things through the prism of the present.

    The Ratier prop was a quick, simple, lightweight and cheap solution to a particular problem of the day. Would they have made sense in a commercial context? Of course not. But for racing they undeniably did the job on a specialised aircraft. Sure they had their idiosyncrasies and 'gotchas', but then so did the Comet airframe. But, once again, this was a specialised aircraft flown by highly experienced pilots.

    Just because they were a technological dead-end doesn't mean they weren't effective in their time and place.

    Back to the DC-2...

    Erik Lund quoted Flight re DC-2 cruising speeds: "Those facts are: i) the DC-2 was entered into the MacRobertson Race with a claimed 75% power (1400hp max) cruising speed of 196mph, 62% power cruising speed of 183mph" Erik's view was that these speeds were inflated.

    In the period 1937-39, ANA in Australia was able to achieve an average block speed of 158 miles per hour, averaged over several thousand hours of flying (data from DCA Annual Reports 1937-38 and 1938-39 calculated by dividing route miles flown by hours flown). This probably puts a cruising speed of 183 mph within the realm of possibility but not, I would say, 196 mph.

    Incidentally, Guinea Airways achieved a very similar block speed with their Lockheed 14s.

    By way of comparison, using the Empire flying boats, Qantas was able to achieve an average block speed of just over 138 mph over the Sydney-Singapore route, not including time spent on the water at en route stops. This was a relatively small improvement over the 128 mph block speed achieved using the D.H.86.

  29. Certainly the Ratier pneumatic was effective for the air race (and a short period after) and one of de Havilland's less-appreciated tough but correct decisions was deciding to discard the hydromatic propthe first Comet flew with, given the issues they had with them, and go for the Ratier instead.

    At the time, it was the right answer - absolutely.

    But it was technically an inferior engineering solution, even at the time (given that other aircraft had other types of variable pitch props then, and including in the race) to the hydromatic props, and a technical dead end. The modern take is a technical view with hindsight, and reinforces those points - if Comets could only fly now with Ratiers, it would be another performance issue of the type, which has been noted, had a number already.

    I'm afraid given that Black Dog's posts ceased to engage given the need to anonymously insult my daring to have an opinion. The funny thing is, having recently re-read several accounts of the Comet and Ratiers, they are consistently highlighted as an odd piece of kit, at best. So I'll let anyone who wishes to argue they are much misunderstood, take it up with those who offered firsthand opinions on the props - I'm done with that, given Black Dog's lack of respect in the debate.

    As to the DC-2's 'brochure' performance, my response remains it's interesting - but compared to the type's actual performance in general and in the race, it's irrelevant.

    Thanks to Phil for bringing some actual service data to the discussion. Checking my copy of the 4+ book The Douglas DC-2 by Dudek, Ovcacik & Susa (apologies for the lack of accents!) the 'book' cruise is 190 mph at 8,000 ft, (no source listed) while interestingly the Army military derivatives are all slower, albeit at lower/no heights quoted. The R2D-1 offered 190 mph at 8,000 ft. My standardising work, Wheale's Combat Aircraft of W.W.II gives a C-32A as 190 mph cruise without an altitude quoted.

    We are all aware of book performance vs real-world achievements, which brings us back to the performance of Uiver, and that was and is remarkable - to most of us.

Leave a Reply

Your email address will not be published. Required fields are marked *