Talk:Airco DH.6

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I have done a complete re-write of this - comments would be appreciated!

Soundofmusicals 23:23, 29 June 2007 (UTC)

Inline citations and references would strengthen the article. FWIW Bzuk (talk) 20:57, 8 January 2008 (UTC).

[edit] Stable or unstable?

Jackson in De Havilland Aircraft since 1915 has an entire section devoted to the turning of the DH 6 into a stable machine, completely at odds with the first statement. Jackson notes that one of the drawbacks of the later versions was that in creating an unstable version the DH 6 was poorly received in its role as maritime coastal patrol and bomber since it required so much effort to fly during long sorties. FWIW Bzuk (talk) 13:50, 16 January 2008 (UTC).

Must see if I can rustle up a copy of that one from somewhere! It doesn't fit well with any account I have ever seen. Many of the aircraft used for maritime patrols were D.H.6A - fitted with a Curtiss engine in a cowling like that of the "Jenny". This one also had back staggered wings, which must have made it look even stranger! Is this the version they were talking about, do you think? Soundofmusicals (talk) 18:14, 16 January 2008 (UTC)
Here is the exact wording: "It was a very remarkable aeroplane, which the designer deliberately made unstable so that it would be an efficient elementary trainer." (Jackson 1962, p. 53.) In regards to its use as an anti-submarine patrol bomber: "A report issued in the same month (July 1918) attributing the number of accidents to the difficulty of flying an unstable aeroplane on long patrols, was followed by a number of remedial experiments." (Jackson 1962, p. 54.) The author goes on to identify a number of modifications made to stagger, camber and chord of the elevators and wings by Airco in order to try to make the type more stable. FWIW Bzuk (talk) 23:29, 16 January 2008 (UTC).
Every other account I have read goes into considerable detail about the "forgiving" nature of the D.H.6 - one might almost suspect a typo! Seriously, somehow the Jackson quote looks incongruous - at the time the D.H.6 was designed trainers were actually supposed to as stable as possible - the idea that this was poor training for less easily managed service types came later. Of course stability and instability have several facets, and are subjective and ambiguous terms - an aircraft may be stable in one axis and highly unstable in the others, or unstable but easily controllable in one axis, while stable but responding poorly to the controls in another. This last would describe many early aircraft, which tended to be unstable fore and aft but with good elevator response - while being fairly stable in the rolling or lateral axis while possessing very unresponsive lateral control. An aircraft that was "stable" in the sense of not providing a flight pupil with any problems may still have been tiring to fly for a pilot on extended patrols (although here again - the D.H.6, even if fitted with extra tankage, could not have been capable of really lengthy patrols anyway!) Anyway I have ordered a second hand copy of Jackson from Amazon - not just for this question, I have several other Putman aviation books and they are all interesting. After all is said and done - most books have one or two howlers, and a few, even from authors one would expect to know better, have simply dozens - in which case we might have to go with the weight of the evidence. Soundofmusicals (talk) 03:48, 18 January 2008 (UTC)
Those "every other accounts" you keep mentioning, which exactly are those? I have checked John W.R. Taylor in Jane's Aircraft of the World and Combat Aircraft of the World and Molson and Taylor's Canadian Aircraft since 1909, finding no description of "stability" being built in, rather commentary about unsalient features of the DH.6 design.
As to aspects of aircraft design, British designers, specifically Geoffrey de Havilland, built in "unstable" characteristics into training aircraft, including the ubiquitous Tiger Moth. The Avro 504, as described by Jackson in Avro Aircraft since 1908 describes the selection of the 504 over the DH.6 as predicated on the 504's "light and powerful controls (that) quickly showed up faults in a pupil's training." (Jackson 1965, p. 63.)
There is no ambiguity in Jackson's research as he quotes from a report on the unstable features of the DH.6 and the efforts to remedy it, in detail. De havilland Aircraft since 1915 is considered a landmark work and, for decades, has been a authoritative resource for researchers. FWIW Bzuk (talk) 04:44, 18 January 2008 (UTC).
The Tiger Moth was designed years later than the D.H.6 - and long after the idea had first become apparent that trainer types should be not TOO easy to fly, but should show up a pupil's errors. Several sources point out that this was what the D.H.6 failed to do, and why it was passed over in favour of the older (pre-war) Avro type when training aircraft and methods in the British flying services were finally standardised in 1917/18.
The title of Jackson's work is De Havilland Aircraft since 1909 (or was the title changed between editions?). It cannot possibly be considered as a "primary" source for anything of course. I accept that is is likely to be an excellent secondary source (which is why I am acquiring my own copy). A primary source might be a copy of the report in question, or, perhaps, an account by a pilot who trained or instructed on D.H.6s in 1917 (preferably written in his diary at the time, or fairly soon afterwards).
The point of my last post was just that the word "stability" is not a simple one when applied to aircraft flight characteristics. Did you bother to read that bit? Have you any comments, in particular as to how this may explain an apparent contradiction between the different accounts? Might a flight instructor's definition of "overly stable" differ from that of a pilot having to fly a frail, underpowered aircraft with a rather unreliable engine for extended periods (well, two or three hours perhaps) while also keeping out a watch for U-Boats? We may even end up with an equivocal statement - this would not be the only instance of good (primary or secondary) sources contradicting each other.
Please accept that I'm genuinely unconcerned with point scoring - simply trying to arrive at a good, succinct article that covers the facts (as they are known!) in an interesting, literate manner. Please don't take everything personally - having to watch every word in order to avoid hurting your feelings is VERY wearing. Soundofmusicals (talk) 05:37, 18 January 2008 (UTC)
I am using both of Jackson's books on Avro and De Havilland Aircraft, and those are the titles of the editions. Unless there are verifiable, authoritative sources that contradict the quotes above, the DH.6 article requires attribution which A.J. Jackson's research provides. (Full disclosure: I have no abidding interest in this subject or even in this period; my primary interest is in research and writing about Canadian aviation. Information about the sole Canadian DH.6 prototype that was constructed in Canada during the First World War, is the reason for my involvement in this article.) As to the formative years of RAF training, Bernard Fitzsimons in RAF: The History of the Royal Air Force Through its Aircraft describes the choice of training aircraft in an entirely different light. "The 504 had been selected for the task because of its flying qualities, being fully aerobatic, it enabled pilots to experience the full possibilities of flying , whereas the earlier idea of using, slow, stable trainers had left pilots ill-prepared for the transfer to combat types." (Fitzsimons, 1983, p. 37.) The RAF had adopted a different standard for air training compared to the earlier RFC use of Caudrons, Farmans and Avros as trainers. Fitzsimons is referring to these types while both the DH.6 and Avro 504J were designed to fulfill a more rigorous training requirement. Michael Armitage in The Royal Air Force: An Illustrated History has a chapter on the origins of the RFC training and his picture of a rudimentary program which involved a mere 17-18 hours of dual instruction and solo flying. Aircraft types utilized in training were mainly low-powered, tractor and pusher biplanes harkening back to an earlier pioneering period of aviation. David Baker in Billy Bishop: The Man and the Aircraft He Flew recounts that the aircraft were "old, steady types." (Baker 1990, p. 33.) FWIW, what are the "sources" to which you refer? Bzuk (talk) 06:09, 18 January 2008 (UTC).