I surmise that these sales are Engine driven. What are the problems associated with maintaining Bristol poppet valve radials : lack of spare parts, certain parts that wear rapidly or a lack of North American engineering patience with engines that, in comparison to US radial engines of the same era, are spectacularly unsupported ?
It seems a shame that a well resourced institution, with a flying airframe philosophy, is letting go of unique aircraft that a realist would probably say will only go into static display moving forward.

My understanding, subject to illumination from more knowledgeable folk, is that a drawing with a mod listed in the title block would incorporate the mod within the new drawing. In other words, if you had an Issue 1 drawing, and Frank from the floor came back and told you that something within it was nonsense, and you modified the drawing accordingly, you would print an Issue 2 drawing, with a mod reference in the title block. The context of this is a drawing used for manufacture, not for subsequent maintenance, when Biggles would land and say that the wing tips had flutter, and the Service end user, in conjunction with the manufacturer would resolve a fix and document it in an Amendment Leaflet to a Vol II Maintenance AP.

I say this in context of digitising thousands of vintage AGS drawings ( http://www.silverbiplanes.com ) which were found in a stack, where earlier revisions were piled under later revisions. AGS are manufacturing drawings, sometimes revised up to 18 times. So the same AGS Issue 1 part for 1932 is not the same as the Issue 13 part for 1952. By comparing the 1932 with the 1952, you can see the modifications. No doubt there would be a separate manufacturing record detailing the nature and reasons for the mods. The point is that a 1952 AGS XXX may not be suitable for application within a 1932 design, unless the logic of the mod is understood. Upon this I anchor the contention that a drawing with mods in the title block incorporates all the latest revisions. It seems that the drawing office was kept busy re-drawing the same drawing over and over again, with changes. I cannot see it as being acceptable that an Issue 1 manufacturing drawing would be lazily issued onto the floor, with only a title block reference to a mod, with a requirement for a fitter to consult a second modification record to ensure that the part being made was correct. You can’t find too many Issue 1 drawings, because they went into the incinerator.

My interpretation of thousands of Hawker , deHavilland and Bristol manufacturing drawings is that a mod in a title block is incorporated within that drawing. It always pays to find the ‘latest’ drawing, as much as it pays to find an earlier drawing to unpick the logic. It’s not a single drawing that gives you what you need.

Recently I had to look at a humble shim for the DH Mosquito for which there was a UK drawing (1940), a Canadian drawing (1942) and an Australian drawing (1944) for the same part. By 1944 there are a lot of mods listed, and the same part is different to the 1940 version. Are you building a 1940 design or a 1944 design ? Will other 1940 parts match your 1944 shim ? How many folk died to show the 1940 version was no good ? Is the 1944 material different to the 1940 material ?

A further feature of Manufacturing drawings and documentation are Concessions, that is changes allowed on the shop floor by Works Inspection or AID.

I think you need five fingers to hold a beer :

1.Memoirs from designers, builders, operators, showing insight into design and build issues – eg the fatal flaws exposed in test flights.
2.As many original drawings/manufacturing documents/AP970 -design factors as possible, understanding that these are only part of the resolution of a puzzle.
3.Original parts as templates, understanding where they came from – is it a 1940 shim or a 1944 shim?
4.Materials knowledge – analysis of original parts, original material specs, context of use and modern substitutions.
5.Maintenance docs – for Service aircraft APs VolI-II/Amendment Leaflets

A lot of info to get a Bombay flying again, although I would prefer you did a Handley Page Heyford, Bob T !

DH Australia set up a separate facility for the manufacture of Hamilton Standard products under licence during WW2. Australian parts are identified by the Hamilton Standard part number preceded by an ‘A’. The inspection stamps on these parts use ‘DHA’ surrounded by a diamond shape, which supports the idea that the diamond shape was antipodean. The photos show Australian made CSUs and US made Merlin distribution valve with Australian inspection mark.

But, how can we definitivey say that the DHP stamp can only be an Australian production mark ? Going back to an original airframe logbook, under the WID (Works Inspection Directorate ) column for Bankstown, the DHP Inspection stamp appears, to corroborate the same style of stamp appearing on known Australian parts.

DHP Oi Oi Oi

Nicko, stirring the possum ! I grew to an understanding some time ago that DHP was an Australian production stamp, then you come along and force me to seek proof, when I could be enjoying myself scraping rust off parts ! So here it goes. These are all Mosquito parts, DH98. First, the correct corporate moniker, based on known Australian parts and documents. First, a dataplate from an Australian made undercarriage assembly, made by Wunderlich and a dataplate from an Australian made hydraulic ram, from James Kirby, all describing the entity as DE HAVILLAND PTY LTD. This concurs with an original Airframe certificate issued from Bankstown, as well as an Australian fuel tank panel.
So I concur that the Australian entity is DE HAVILLAND Proprietory Limited (shares held privately), not DE HAVILLAND Proprietory and the UK entity is DE HAVILLAND Company Limited (shares listed for public subscription).