powerandpassionWould love to go to this but an ocean or two away…hopefully the presentation can be videoed and put on youtube…
powerandpassionOi Oi Oi
Contact ANAM Moorabbin Museum Archives (me!) to obtain a scan of the RAAF Mirage III instrument list and manual. Pretty thick book, cost of scanning only, might take a while…. Plenty of dinkum gauges around, you don’t want any cheese or Gauloise smelling gauges in an Aussie Mirage. Completely different to the French setup, no wine glass holders or reverse lights or buzzers in the RAAF version…:dev2:
powerandpassionGriffon 61’s wanted
Graham A, thank you for the Rotol goldmine, great holiday reading!
Can somebody please advise me where the two Griffon 61’s returned by the Australian Govt to the UK govt went to, please?;)
powerandpassionUnder the terms of the Anzac Treaty…
Much of this problem was addressed by the monumental work ” United States and British Commonwealth of Nations Aircraft Materials” published by the US AAF, published in 1944 and revised in 1946.
ColdKiwi, AN 01-1A-9 is ” United States and British Commonwealth of Nations Aircraft Materials” which I am digitizing at the moment, but if you have an e-copy already, will you share? I am doing 1946 now. If you don’t have an e-copy, can you digitize 1944 only, and share?
This is a stunning document, very detailed and helpful.
powerandpassionWoof woof
Blue background
powerandpassionProps were, when a a RH tractor R-2800 radial was proposed, 6519-12 Mosquito/Lancaster blades on a Hamilton Standard 24E60 4 blade hub, 12′ 6″ dia.
Of course, only the inline LH tractor Griffon 61 powered version flew, same 12′ 6″ dia, same 4 blade setup, but using Rotol hydraulic prop with Jablo blades….almost like a……Napier Sabre powered Typhoon could……there’s some CA-15 prop info floating about, I will look in the cupboards and report!
powerandpassionBeing a US Govt publication it’s cheap … pdf version here
Gottit, thank you, good reading.
powerandpassionDo you have a copy of AC 43.13 1B-2B?
No sir.
powerandpassionNo worries John. There seems to be a lot of crossover these days between aerospace and the latest racing yachts, some quite wonderful and expensive technology.
powerandpassionSomewhere tucked up in all that, I sense a ‘competent engineer’ or a ‘materials scientist’ itching to provide us with an aluminium Mosquito, perhaps using monel rivets.
I am allowed to talk about this because it involves an airfoil…in the recent Sydney Hobart yacht race, the Super Maxi, Wild Oats, retired with a mechanical failure, I understand a key bolt in the hydraulic actuating mechanism for the fancy airfoil keel failed. There were perhaps millions of dollars expended in preparing the yacht and 20 crew members who trained exhaustively for months, and the yacht was in the lead, breaking the race record. But all defeated by one bolt breaking. In explaining the issue, it was stated that everything that could be done in preparation, including x-raying bolts, was done, and ‘no cracks were revealed in the bolt.’
Now I have to assume that if they were using the same bolt as last year, and because it is marine best practice, the bolt was stainless steel. Now as you all know, austenitic stainless steel work hardens. As you all know, the stainless steel flying and landing wires you invest in for your Tiger Moth or Stearman biplane, because they do not rust, do work harden as they flutter in use, making them more brittle, and prone to sudden failure, as, under a peak load, the material does not have the elasticity to safely absorb and dissipate the peak load. As you all know, stainless steel flying and landing wires might time expire and should be replaced, even though they look good.
Because the highly paid, competent, experienced designers and engineers behind Wild Oats don’t read this humble forum, they might have overlooked the work hardening issue for a highly stressed, cyclically loaded stainless steel bolt, even though it looked good and they x rayed it. No particular drama, as no one died, the billionaire who owns it has plenty of folding, and ‘bad luck’ gets you plenty of conciliatory whiskeys in the yacht club bar.
Now, if it was me, I would look at a corrodible steel alloy for the bolt, high strength, elastic, capable of cyclical loading, like they use for Hurricane wing spar pins or Merlin conrod bolts or 1928 Hawker Hart UC, and replace it every year. But the old salts at the yachtie bar would guffaw me out of the room, “fancy that, not using stainless steel in seawater!” And, even worse, I am not a metallurgist. Not an engineer. Can’t issue a big invoice on fancy paper. Better just keep my head down. Mutter into the beer. Let the fookers burn another $5 million and pop another bolt.
But I do care about historic aircraft. I am very interested in materials. Because I don’t have any gravitas, I can ask lots of dumb questions. Because aircraft drop, I really want to understand the logic behind things, because I don’t want to find out at 20,000 feet. I find plain speaking is best. I find it hard when somebody assumes I know stuff, because in climbing this mountain, you want to know that every peg driven into the rock face is sound, in case you or your fellow climber fall down a few. So my rule is that you cannot assume knowledge, you need to explain and take the shy with you.
So a monel rivetted aluminium sheet Mosquito should fail for a number of reasons :
1. Electrolytic corrosion between high copper containing monel rivets and aluminium, particularly pure alumiunium coated Alclad will dramatically shorten structure life.
2. Timber Mosquito structure relies on wall thickness (ply-balsa-ply) to develop strength in its monocoque structure, so a sheet aluminium monocoque structure will change internal dimensions, which means folk with little stumpy arms may not be able to reach between throttle and mag switches, which means it can only be flown by basketballers, if the emergency canopy panel is removed.
3. A different material structure will change the centre of gravity of the design, requiring the permanent fixing of the lengthened TT nose configuration to balance it out, meaning spectators will not see the aircraft fly, as they will be dry retching into their crisps whenever it comes over.
I am off to the yachties bar now, to go stir the possum…
powerandpassionWell that didn’t take long….
Good, plain language document, evidencing a lot of cooperative effort behind the scenes between regulators who like old aircraft and operators who like new regulators.
powerandpassionThank you Avro Avian and Bruce, appreciate the kind words. Forum members GrahamA, Stan Smith (bloody Kiwis everywhere), Bulldogbuilder (eccentric Englishman trapped in the body of a US west coaster!), Australian National Aviation Museum – ANAM Moorabbin and the RRHT Bristol have been immensely helpful in the search for obsolete Standards, so it is a true common-wealth effort.
powerandpassionMaterial Substitution Charts
These charts and publications deal with the fact that even original equipment manufacturers had to deal with material substitution problems as they build aeroplanes of foreign design out of local materials or materials and processes evolved during manufacture.
Material substitution issues were an intrinsic challenge to Canadian and Australian manufacturers, for example in CCF Hurricanes made from North American materials or DAP Beaufighters made from Australian materials. Much of this problem was addressed by the monumental work ” United States and British Commonwealth of Nations Aircraft Materials” published by the US AAF, published in 1944 and revised in 1946. Much of the 1944 material was incorporated into the RAAF Engineering Publication 314 “RAAF Aeronautical Engineering Handbook”. These publications provide direct and allied substitutions between US, British, Australian and Canadian materials, but are made obscure to modern enquiry by the use of obsolete material standards. Nevertheless they are a fundamental compass. These publications are in the process of digitizing and will be available in February 2017.
DeHavilland Australia material chart summerizes materials in use for the manufacture of Mosquitos,Tiger Moths.
Government Aircraft Factory (GAF Australia, formerly Department of Aircraft Production, DAP) charts deal with materials and processes involved in the manufacture of Bristol Beauforts, Beaufighters, Avro Lincoln, EE Canberra, Dassault Mirage, F/A-18 Hornet.
SBAC (Society of British Aircraft Constructors) Technical Specification TS96 deals with tables of similar materials and can provide a birds eye view over the substitution landscape.
It is necessary to really understand the context of use of materials and there is no such thing as an instant translation between a historic material and a modern substitution. It requires a competent engineer or materials scientist to gather all the information together, understand the application and make a decision, recognising that it may test their professional indemnity insurance premiums. But it is not unduly complex or impossible. The most time consuming task is gathering the original material, and if you can lay this in an organised fashion before the engineer, you will save a lot of time and money.
Recognise that when you stand before the desk of the most imposing and disapproving engineer-deity peering over their glasses at you, they will be as lost as the next lamb in understanding the nomenclature of obsolete standards, unless they are 100 years old. Many of the original materials DO exist today, but are cloaked by multiple somersaults of renaming through evolving material classification systems. All you have to do is look at the chemical and mechanical properties in the obsolete standards, and a grey hair with a good understanding of modern materials should be able to make a match.
Most useful is to understand WHY a material was chosen. Many wartime materials reflect wartime shortages, the use of ersatz coffee in place of the real bean. Just because the original structure was made with an inferior material it may be less safe to ‘do as they did’. Many British wartime aluminium monocoque structures were riveted together with magnesium rivets, to save, under the duress of war, the time it took to heat treat duralumin rivets. This was OK where historic structures were only counted on to last for hours, but a dreadful mistake by today’s restorer seeking to preserve a structure indefinitely, as electrolytic corrosion turns the magnesium rivets to dust.
I undertaking the journey into WHY, the modern restorer intrudes between two difficult neighbors, the modern regulator and the engineer ghosts of the past. The ghosts of the past are a whole room of stressmen, mathematicians, ingenious founders and engineers, supported by the development laboratories of steel and aluminium and bakelite firms and the gaze of test pilots as they clamboured in and tested their theories. There were literally hundreds of rapier smart people involved in the decision of selecting a material, and this decision was tested in use. So your other neighbour, the modern regulator, has more trust in the ghosts of the past than you. He or she will not know the appropriate substitution for BS S2 in a 1935 aerostructure. Most want to help and want to see no harm come from your eccentric endeavours. So if you can build a case, by laying out the evidence, then they may help.
Putting this material out there for everybody, helps everybody.
powerandpassionBritish Standards
British Standards originated in 1901 as an effort to standardise steel sections and later screw threads used in manufacturing, up until 1931 being called the British Engineering Standards Association, or BESA. After this time it was renamed the British Standards Institute and continues to operate to this day as BSI Group. After WW1, an effort was made to specify many of the new aircraft materials developed during the conflict as a body of Aircraft Material Standards. These introduced groupings of materials recognized by a suffix such as ‘S’ for steel, ‘L’ for light metals such as aluminium and magnesium, ‘T’ for tubes and ‘V’ for timbers. Modern versions of some of these Standards continue today and can be secured from the BSI Group.
Where British Standards are revised, the later version will contain a sequential number at the beginning of the title, eg S28, 2S28, 3S28
These Standards were often designed to be disposed off when obsolete, so early revisions are often difficult to find. An earlier version of a Standard does much to explain the material design constraints and possibilities of the day, so the automatic application of a later revision to an earlier design may not be appropriate. An example may be in the use of a modern aluminium sheet with mechanical properties superior to a vintage sheet material, but the higher strength may make the complex forming of a vintage shape, that relied on lower mechanical properties, impossible. Accordingly, multiple revisions and their dates of publication are listed.
powerandpassionDirectorate of Technical Development UK DTD Standards
The Directorate of Technical Development (DTD) was established by the UK Air Ministry in 1924 with a focus on research and application of emerging materials, technologies and processes for the Royal Air Force. It issued a series of DTD Standards until its functions were reorganised and absorbed after WW2 into Britain’s continuing defence research effort. DTD Standards persisted until being officially deemed obsolete in 1999. Many interwar, WW2 and early jet age aircraft and engines use DTD specifications. Where a DTD Standard grew into extensive use, it was often promulgated as a British Standard. In general, new DTD Standards described newly invented and sometimes secret materials, while those that persisted in the DTD format in later years described rarely used but nevertheless important materials.
Where DTD Standards are revised, the later version will contain a sequential letter at the end of title, eg DTD36, DTD36B, DTD36C
DTD Standards are supported by an INDEX document, that often indicates a Standard’s later adoption as an equivalent British Standard.
More DTD Standards are available. A small number are presented here and the work of scanning the balance continues. Where you wish to secure a copy of a DTD Standard not yet listed here, please get in contact to enquire if it is available.
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