Sorry Ed they are all spoken for..except for the post war.

2 Demons!? :p

One way to work within the eBay system is to buy the offending object then provide negative feedback. This negative feedback cannot be screened by the seller.

There is a public interest aspect to this which, depending on the commercial instincts of the publisher, will be (a) met in some way or (b) get buried but recur.

There is an inter generational interest aspect to this, depending on the goodwill of veteran collectors, will (a) burn novice collectors or (b) nurture novice collectors to be in a position to fund veteran collectors’ superannuation.

I cannot tell you how foolish I feel when, driven by a love of history, I have ended up buying scrap. The love of history prevails through this, for me, to the point where after my fair share of mistakes, I am more confident now in my purchasing.

I do worry about the ease with which a cynical calculation on the use of relatively low cost letter writing can affect a business fighting through all the usual stresses of survival to turn a fair profit. I understand why a thread must be prudently pulled. But it may reward somebody feasting on the marrow of innocence.

So maybe one solution is to have a thread with no title, where a link to an item may be pasted, with NO COMMENT.
In silence, let anybody decide whatever they may decide.

Maxim, a most worthy bump, let’s call it the first positive signs of pregnancy for a flying Siskin…

S43 (and S40 I have seen referenced for late 20’s Bristol Bulldog sections) I hypothesise, are BESA standards, British Engineering Standards Association (1918 – 1931). BESA became British Standards Association after 1931 and I hyperventilate over a hyper-hypothesis that they dumped some archaic standards in 1931, as I have yet to find evidence in literature for these Standards and their characteristics. There is a real missing link for material Standards between 1918 and 1930.

I will hazard that S43 and S40 are 3% nickel alloy steels in sheet form, superseded by nickel -chromium sheet alloys from about 1928 onwards.

I will further hazard that GE100 is a proprietory appellation for an Armstrong Whitworth material, or even heap hazard upon hazard by further hazarding that it is a material specified by a certain Major Green who was leading research into strip steel structures from 1918 onwards.

What is interesting in the rib boom profile shown is :

1. Use of 8 thou thick material, basically a human hair thin structural component. This is consistent with Bristol Bulldog at 9 thou for a similar rib boom section, but less material once the profile is straightened out.
2. On a strength to weight ratio, this implies that the Bulldog’s S40 and Siskin’s S43 may accord with the use of DTD100 rib booms on Bulldog, Wapiti. DTD 100 is nickel chrome alloy steel, 45T ultimate strength, a balance of high strength with the ductility to enable the elaborate roll forming of the section.
3. While the drawing looks quite detailed, once the roll forming is set up, the material runs copiously, and the system of manufacture is not as fussy as first impressions tend to leave.

Surely the RCAF would have had maintenance support in the form of plans and material specifications to support the type? Where are interwar military records kept? What is the Canadian national archive?

Blades for Dummies. I am coming to a sense that blades are a school of aerodynamic thought entirely separate. That the permutations of design are equally valid being argued over a beer in the pub as much as the stern experimentation of a wind tunnel. From soaking in lots of information I make the following observations : (1). The difference between a radial blade and an inline blade is the round shank is longer on the radial, to keep the aerofoil doing the work chopping into clean air outside the engine front; unless a tweak is put closer in to drive cooling air over radial cylinders. (2). There are only a small group of aerofoils used for WW2 designs, shifted up and down the length of the blade(3) a blade is a system, where the blade design is integrated with spinner and cowling design (4) some modern blade re grinding is ‘eyeball engineering’ with results disguised by the fact that aircraft are not being pushed to limits (5) modern CAD program’s such as Solidworks are able to simulate and identify disturbed airflow over a cowling; modern 3d scanning is able to accurately measure real geometry, so combining the two techniques can resolve complicated performance issues in your shed.

Lancaster – Lincoln auto controls oil cooler

http://forum.keypublishing.com/showthread.php?131112-ID-oil-cooler&highlight=