What can we do to help insure these wings are preserved?

Bill,
A great forensic analysis. Here is a picture of a flying Siskin III from 1927 :

[ATTACH=CONFIG]242619[/ATTACH]

These wings are certainly a remarkable engineering dataset. Maybe, unless the structure that houses them is imperilled, they are safe where they are, in the hands of sympathetic, aviation minded folk. The spars are made of corrodible nickel chromium alloy steel, that would unlikely be safe for any future flying. They have lasted eighty odd years, shielded from the scrap man, sleet and snow. The most simple thing to do to preserve them is to attach a sacrificial aluminium or magnesium anode to the continuous steel structure, which would act in the same way as if the steel was sprayed with a zinc primer; a concept easier to grasp but less effective and undesirable from a preservation point of view. Sacrificial zinc anodes are used to preserve the hulls of century old steel ships in floating museums : this is a simple, cheap, effective way to make sure the roof structure will last.

Generally asbestos cement sheet absorbs some moisture and you would expect that the corrodible steel would be in poorer condition from being pressed against this. I wonder if there is some strange circumstance where the galvanic potential of asbestos cement and steel makes the cladding act as a sacrificial anode ? There also seems to be some furnace flue in the building : generally combustion puts a lot of moisture in the air but has the heat of this discouraged condensation on the underside of the roof? Whatever the reason it is amazing to find bits of Siskin III. It is amazing what is still out there.

This roof contains some secrets that could be gleaned without any needing to remove them :

1) Confirmation via metallurgical testing that the spars are DTD54a Nickel Chromium alloy and the bracing struts are 3% Nickel alloy T5 tube and the ribs are DTD98 or DTD99 Nickel Chromium alloy.
2) Confirmation of the gauge of these materials.
3) CAD drafting of the wing assemblies, showing details of assembly/riveting/support structures that may be missing for remnant drawings or be production improvements not detailed in remnant drawings.

A flying Siskin would have to be made from new materials – the fuselage was made from pin jointed T5 tube? At first glance these structures seem complex to an eye more used to monocoque structures, but they lend themselves to simple tools and a patience. Canadians are used to shovelling snow from driveways, so have the mindset! I understand there are a few AS Jaguars floating around – it seems that the plethora of AS Cheetahs can allow a far more simple step into this type than if a Bristol Jupiter were required.

The Canadian Siskin seems to occupy the same place in the history of the RCAF as the Hawker Australian Demon in the RAAF. Both are largely missing in their respective skies and both caught the imagination of their respective populations in prewar air displays. In a time of Depression they were an extravagant spend. By 1940, they were an embarrassment, which is perhaps why they were so readily scrapped by those who had progressed to Mosquitos and Spitfires. A flying Siskin in the UK would be good, but a flying Siskin in Canada would be a profound achievement for Canadian aviation history. So if anybody is going to do it, it might have to be a Canadian.

What’s stopping it is the lost art of strip steel construction : the DTD54a spars, the pin jointed T5 tubes of the fuselage which make it such a different proposition to a timber or monocoque aluminium restoration. When you look at a snow covered driveway it is disheartening. The only way to get to the finish is to just start shovelling ! So here is a hint : the T5 tube of the late 20’s and 30’s has the same characteristics as T45. Ostensibly it was a 50T tube but it never seemed to make this spec and was always regarded by the stressmen as a 45T tube. In order to get a real 50 T tube 3% Nickel alloy tube was developed in the 30’s with a true 50T strength. You can get T45 today so there is enough historical literature to get the concept of a T45 fuselage frame together without controversy. Its all tube with machined joint fittings. Then stick one of your Jaguars on the front and you are on your way ! It seems that there are wing remnants around which, if the custodians were sympathetic, you could survey to start building an understanding of what is required to build the wings. Really you need to find somebody with a coil of DTD54a Nickel Chrome spar material of the correct gauge – so what is the gauge? The coil might be available but a shame if a 1,000 m coil is run and the opportunity to output 100m in a gauge suitable for Siskin is lost, because I doubt it will ever be done again.

Have you seen GR Quick’s superb GA of the Siskin III :

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I have discussed the matter with someone who interviewed Jim Carmichael (Can Car) on this very topic. When asked what CC&F used for their Hurricane production, his answer was “whatever we could get our hands on”, which turned out to be 4130 as a substitute for the T.50.

A fascinating anecdote which would explain many questions, and of course to find some original documentation to verify this would be gold.
Where in the US or Canada could you buy cold drawn aircraft tube from in 1940-1 ?

Ian,
I have access to a Hurricane I Repair & Maintenance AP which predates CCF Hurricane X. In the case of repairs to centre section spars, made from BS S88c nickel chromium alloy, repair patches of S88c or DTD 166 stainless (same material used in the fuselage fish plates) are specified.

I have also tested known CCF Mk X centre section spar remains which report manganese alloy (DTD 138) spar booms, obviously different to the British made aircraft using nickel chromium booms (S88c). Subject to confirmation, the theory is that CCF used local materials for Mk X that were different to materials used in the UK. The link to your question is whether a RCAF AP would specify DTD138 for centre section spar boom repairs, which would be delightful to confirm, or a later RAF AP covering Mk X would do the same.

In thinking through this information I have the following reflections :

Repair & Maintenance APs were practical documents focused on the quick return to air of battle damaged aircraft. Therefore materials reasonably at hand of a repair unit would be specified. The great advantage of DTD 166 was its presentation as sheets of work hardened material with a strength of 50T minimum that could be work hardened to 65T and used to repair a wide scope of the Hurricane structure. I have seen in lists of equipment for Maintenance units dealing with Hart biplanes in the 1930’s in Iraq sheets of DTD 166, and it can be defensible to accept that this practice continued with the Hurricane, as the argument in the buildup to 1939 was there were trained fitters for this type of aircraft and they should be built in preference to the monocoque aluminium Spitfire types. There is no mention of sheets of S88c, which is a corrodible material which can only be supplied as heat treated coil, far less practical to a front line maintenance unit. I draw the conclusion that repairs using S88c where based on salvage material from written off aircraft.

To introduce a new material, DTD 138, into the mix would be an unwelcome complication in procurement and engineering management. It would make more sense for a CCF Mk X to be repairable with DTD 166 or salvaged S88c. They key is the performance values of this material, in that work hardened DTD166 would aquire strength values of 65T, in common with 65T S88c and 65T DTD138.

Where CCF did re-engineer the Mk X Hurricane structure, they would have taken care to meet the same strength values using DTD 138 as the original S88c. In other words spars would be absolutely interchangeable, and there would be no complication in a frontline maintenance unit in blending CCF parts with UK parts. In this respect the simple solution would be to allow the maintenance unit to rely on existing APs, without confusing them with questions about materials. If this is true then no maintenance AP will come to light that specifies DTD 138, though in the literature of the 1930’s DTD 138 is listed as a typical spar material.

I think today, that most folk would not recognise the use of DTD 138 in Hurricane construction. If the logic stands, that it is directly interchangeable with materials more commonly understood to be used in Hurricane construction, then it is largely just a curiosity. It does suggest, however, a considerable effort to re engineer the Hurricane structure in Canada that would be a fruitful body of work to rediscover. Consistent with this are the use of SAE 4130 spar liner tube in the CCF product rather than 3% nickel alloy T50 in the UK product and United States sourced EN 8630 nickel-chrome-moly fuselage tubes in the CCF product rather than 3% nickel alloy T50 in the UK product.

This is an example of wartime substitution which could greatly inform future restoration work concerned with strip steel and pin jointed construction. Clever Canadians.

One insightful journalist wrote recently that “the 21st Century is falling into place around our heads”. So much as Museums and restoration agendas make sense to children of the 20th Century, so the Museum in one hundred years will reflect the themes of this new century. I can sense the following :

1. The revitalization of Chinese, Indian and Japanese Museums as history becomes a tool justifying current readjustments in global affairs led by the resurgence of China. So as Anglophone Museums may wither, dynamic, New Museums with budgets will draw airframes and well renumerated staff from the Old to reinterpret the New. You may not like the New!

2. The Drone will become the most contentious display of the 21st Century Museum. It represents a failure of Anglophone imagination and thus it will become the principal display in any Museum wanting to diminish Western ideas. “They slaughtered us with These so they could keep Shopping.” Some young person will throw red paint on a drone display in the West and elderly Machine Centric Museum trustees will shake their heads and a further gap will open up between dusty displays and young people choosing to do other things. One rebel Museum in the West with no budget will display a drone with Wikileaks footage showing wedding parties being shredded but there will be queues to get in. I hope drone pilots do this because I already shudder to think about how abandoned they will be by Governments and Us once they wash out. There will be a need for a Truth and Reconciliation Drone Museum to at least help them avoid becoming the 21st Century’s marginalized Vietnam Vet. This Museum might also examine the successful use of airpower in Policing by the RAF in the 1930’s, when leaflets were dropped on Day 1, if no luck after 2 days, crops were set alight, if no luck after 2 days precision strikes were made on hold outs who had one week to get their women and children out of the way. Then the 1930 RAF Policing budget will be compared to the 2015 Drone budget and an Effectiveness analysis made. Do the same for Hitler’s Vengeance drones, the V1 and V2, which were at least honestly described by that government as devices of Terror. So we need a Hawker Hart biplane next to a V1 and Predator Drone and documentary interviews with drone strikers and survivors. A conversation, measured, confronting, indignant, chilling. No Museum will get more press coverage. It’s really about People applying technology, not the technology. Drones are the future, but test your ideas: how do you want your children or grandchildren treated by them in the 21st Century? The drones are coming. So give me a Museum that is about the future.

3. To the unborn, a Defiant, Spitfire, Hurricane, ME 109, BF 190, Mustang and Wildcat, as preposterous as it will be to the 20th Century student of the art, be look-alike monoplanes with dangerous paddles out the front, used in a world war which may have started in 1860 something, or 1933 something or 2002. History tends to compress. You might not know the difference between a 16th Century Portuguese Caravel and an 18th Century Man-o-War; they are all wooden boats with sails, but upon this technology great themes and Empires evolved. So certain aircraft types will travel into the preposterous future : The Spitfire versus the Stuka, the Mustang versus the Zero. Only because biplanes look different the Camel will not be confused with the Hurricane, although the short twenty years between them will invite abbreviation in future conciousness. The Youngsters of the 21st Century may be forced as school children to march through caverns of this stuff in dark Museums peopled by cranky, wrinkly, disapproving creatures. This will be caused by Museums thinking that it is their job to preserve Machines, and that Machines speak for themselves. One or two Museums will adopt Plato’s motto : “He who does not know what has come before him, will forever see the world as a child.” They will accordingly make their displays about People, so a young person can say “ That Person in the Display could be me.” So a display about a Pilot, preferably a young pilot who dies for their country and why, will make the Machine that remains start to speak. Museums will cross promote with Movie Makers, to have Blockbuster displays timed with the release of Movies about People in Machines. These Museums will be 80% storage and restoration, with 20% on display, display 100% rotated every six months based on themes about People. They will use shop display professionals to set these up, not cranky old goats. Really, many Museums are Men’s Sheds, which is not a bad thing, as long as the Men’s Shed doesn’t overawe the Museum. Because Museums are so badly led, they end up being dependant on free labour, being Old Goats, but nothing is free, and the Old Goats can mist over an organisation with other forms of compensation that turn it into a Goat Fiefdom. That’s OK in the storage zone, but the Shop Front and direction must absolutely be the domain of Young Roosters.

4. The day of Gloomy Museums having a monopoly on machines will, thankfully, pass. Modern manufacturing productivity improvements, aged metallurgy and keen people will make things fly, even if there is not an original rivet in it. So the Flying Museum will flourish and the Dark Cavern with Barriers will sink further into the gloom. The Flying Museum will negotiate tax arrangements to make it attractive to donate your aircraft in when you are ready to hang up your helmet. The Flying Museum may be virtual : it may simply be a network of individual aircraft owners who ‘flash mob’ a particular airfield at a given moment. The Flying Museum will offer vocational training courses to young people who leave school early, to teach them about engine rebuilding, welding, the English wheel. The Flying Museum will once a year do cross country flights and beat up small towns and land at a local airfield and set up a tent with displays about People and Machines. It will research ahead and find out that someone, totally forgotten, born in that small town flew in this Machine and died aged 21 in France in 1940. It will offer paid flights and change lives. The first woman on one of Jupiter’s moons will first take her first flight in a Spitfire flown by her great grandmother in a Transport Squadron.

That’s probably enough controversy for one post!!

Congratulations Matt, a remarkable insight and breakthrough. Probably too obtuse for most to understand, but then I don’t understand dark matter, E=MC2, and why the missus would rather sit on the beach rather than dig through mud for corroded aeroplane parts.

I wonder if you could crowd source more data by making up a downloadable Beermat-o-meter or diagram showing key dimensions that would allow folks on the other side of the planet to feed back ‘apples with apples’ data to support your insight ? Maybe like a stick of a fixed dimension that is laid against the blade root with adjustments for different shank sizes, marks for measuring key blade dimensions and a red letter warning : “Are the magnetos isolated?” Probably also one of those stickers with a human figure getting chopped in half with a prop blade, to avoid litigation, in case a wit becomes a half wit.

Fire in the hole

Anthony,
Don’t know if this is a A27N/106 mounting bracket but here are some pics of an old school Graviner automatic fire extinguishing system :

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Bottle contains methyl bromide which is still used today to fumigate shipping containers. It is basically a very heavy gas that displaces air and ‘suffocates’ fire. The bottle in the photo is actually still full so quite an uncomfortable thing to handle with it’s 70 year old seals. Below is a empty bracket, WW2 vintage.

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The other elements of the system are the flame switch normally situated on the firewall, and an impact or gravity switch which is the analogue equivalent of the modern day impact switch triggering the airbag in your car.

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There are earlier brackets for 1930’s type handheld extinguishers, which were sometimes activated by a cable pull system.