Fedden himself was Bristol ‘Old Family’ certainly if he curbed his relentless energy he could have “fitted in” more easily, but he made it hard. He is one man who refused Churchill’s request to coordinate aircraft production during the war, citing his work at Bristols as being more pressing. So he certainly made it easier for his enemies to push him aside.

Here, for the sake of a contemporary and influential take on the sacking of Sir Roy Fedden, is the editorial from Aircraft Engineering, December 1942 :

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p&p

In your opinion, had it been available in quantity, using Duralumin in the manufacturing process of the Mosquito, would the all round performance of this aircraft been much better than the timber version or, about the same. Setting to one side suspicions about chemical solutions and airframe integrity.

Ahh, you have me ! The Mosquito. The question is like the scientific aphorism of Adam’s navel : If Adam was formed from dust, and did not come from a womb, would he have a navel ? The Ecclesiasticals therefore gave Adam, in image, a fig leaf to cover his belly button, not his modesty, as the question could not be satisfactorily answered. So too this question can never reach a satisfactory conclusion. But we are talking about something more important here than the birth of mankind, the Mosquito, so here goes :

Economically the timber Mosquito WAS better than the Duralumin Mosquito, the Duraquito, let’s call it. I mean in the context of 1940, when metals and metalworking capacity were scarce. Even before it flew it achieved that optimum defined by Von Clauswitz in “On War”, to apply the minimum economic effort for the maximum gain. You cannot argue against turning piano and furniture makers into agents for the delivery of Cookie bombs into the breakfast bowl of Adolf Hitler. I am reminded of the postwar analysis that exposed the Mosquito as the instrument that delivered more munitions into the hide of Nazi Germany at least cost of aircrew than any other weapons platform, so the choice of a timber platform linked to a hot engine design, because it could be built so quickly by an underutilised sector of industry, means that it IS better than the Duraquito.

In respect of the material, the timber ply, monocoque structure was as strong, if not stronger than the Duraquito. As we all know with a cardboard box, the forces it resists are carried in the paper surfaces that are separated by the corrugated centre. Larger corrugations make stronger boxes, separating the planes of stress. You get some corrugated cardboard boxes which are two or three layers thick, which you can park your car on. So the Mosquito had stress bearing birch ply layers separated by a quarter inch of balsa, a remarkably strong materials solution, that carried through to Vampire Jets and is revisited by today’s non aluminium honeycomb structures. Of course the Duraquito could be built to cope with similar stresses, but I go back to point 1, economy in war materials and manufacturing. Of course the Mosquito was designed as an unarmed, reconaissance platform, but was quickly pushed to carry extraordinary weapon combinations. In one recollection of a Navigator in a FB version, the cockpit floor would jump when the FOUR 20mm cannon were in communication mode with Panzers. In this case the modulus of flexibility in a wooden airframe is in demonstration, the whole structure absorbing the kickback, some of course through the chattering knees of the Nav. I do not think that an unarmed, recon Duraquito would have within its original aluminium structure the same ability to take punishment or be adapted to be a weapons platform as widely as the Mosquito, passed from devilish fitter to devilish fitter. I concede that four duralumin beams were installed behind the cannon in the Mosquito to dissipate the recoil force over a larger area of the timber structure, but I think many spanner wielding folk played this game called ‘see how much we can stuff into a Mosquito before it cracks in half,’ and the timber thing proved to be as tough as an old boot. In fact I am surprised that deHavillands DID NOT make a version out of old boots, the Booquito…

We can go on for a long time, but I have no smoke filled, sticky carpet bar in front of me, no half empty bottle of Penfolds Grange in front of me, so the fuel for my mind to generate more nonsense is lacking. I will however touch on the senses, most neglected in these types of discussions. Briefly, the Mosquito smelt good : it would be a pleasure to be in a woodworking shop, perhaps the whiff of pipe smoke in the air, genial conversation with some humble old furniture maker as the Mosquito was whittled into shape. Compare this with cruel light of a Duraquito plant, the incessant rattle of rivet guns and drills, all those women swapping Oxo soup recipes, a cacophony of smashing pots and pans and sisters staring at you with powerful drills. Then of course there is sound : the doped fabric/timber surface of the Mosquito created an extraordinary sound reflecting surface, in particular between the fuselage and the inboard exhaust stacks of the Merlins. This sound was cupped and reflected from the under surface of the huge wings. So first there would be a subsonic projected pressure wave, then the explosion of Merlin sound as the Mosquito flew over you, unpeeling the paper from the Gauloise in your mouth, as you jackbooted up and down the seawall at Normandy. Nothing like the Duraquito, which sounded like a Beech King Air with fouled spark plugs, only good to send as Lend Lease to Russia.

I trust I have been of assistance.;)

Tungum Tales

Another thing I like about XRF are instant answers that allow you to progress your thinking. As a child of cuppa soup and TV remote controls, I really don’t have the patience to wait for weeks to progress an inquiry, it becomes all too hard when there are better things to do like finger piano the iPhone and look on this forum !

So I think a Merlin coolant pipe might be Tungum, a copper alloy, but I don’t know, so I put it back on the shelf until it is picked up 15 years later at my estate sale. Instead, I get an instant PMI that let’s me know it is a simple copper alloy that needs to be manipulated differently to Tungum. I don not need to find a Tungum expert, I can wander down to the old blokes at the minature steam railway workshops and ask them about manipulating copper tube, without troubling them about Tungum. No doubt the old bloke I meet worked at Tungum in 1963, but we can steer the conversation forward rather than conclude we need a PMI first…

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Reads like an infomercial for a product.

Is it?

It wasn’t, but what a great idea ! Most of the information distilled out of all this clumsy experimentation and kite flying I will put here : http://www.silverbiplanes.com
Have a look, take a biscuit out of the jar, if you want, and put another different one back.

One day I might print tea towels with DTD specs matched to SAE standards !

I will always welcome constructive criticism : I do want to learn something from it. Give me some facts to take me further along my journey and I will send you a tea towel.:eagerness:

Here is the spindle holding the chain sprocket within the aileron gearbox from a Hawker Australian Demon.
I would assume a modern equivalent would be SAE 4130, but XRF shows 3% Nickel alloy steel, a high strength, highly flexible and fatigue resistant alloy,

The reported analysis matches BS S69, closest SAE equivalent is SAE 2330 – 2340.
BS S69 matches Rolls Royce specification 2063, 3.5% Nickel steel.
SAE 2330 is reported in “Aircraft Materials”, Titterton 1937, as “the standard Nickel steel, possessing good strength and great toughness..used for high grade machined parts such as aircraft bolts,turnbuckle eyes and tie rod terminals”.

Nickel steel was developed in the 1920’s for high stressed automotive applications such as steering columns.
Steels are remarkably varied and there is more than just SAE 4130-4140 out there !

Demon spindle

Here is the spindle holding the chain sprocket within the aileron gearbox from a Hawker Australian Demon.
I would assume a modern equivalent would be SAE 4130, but XRF shows 3% Nickel alloy steel, a high strength, highly flexible and fatigue resistant alloy, so I need to be careful with this anonymous component buried deeply within the structure of a wing, out of sight. The part is cadmium coated. XRF will only read 10 microns into the surface of the object, so if you do not have the context of the part you can get a “false” reading, if you apply the XRF to the cadmium coated part. In this case I have gone for the exposed threads to find the underlying metal. I am happy to get a cadmium reading, because I will not blast clean this part without some understanding of the toxic cadmium dust hazard.
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