Copying- its role in engineering product development

“Copying”-  its role in engineering product development.

Prof. Prodyut Das.

Whilst teaching “Synthesis of Design” I used to programme several lectures in the way an engineering product could be designed starting with direct or “Chinese” copying and ending with Barnes Wallis’s design-actually a near invention- of the Dam Busting bombs which I labeled as “Design by Genius”.

Design by copying is a misunderstood method. For India, with design capabilities lagging due to many reason including the very restrictive Industrial Policy Resolution of 1956 which depressed demands for Engineering, production and quality control skills for decades, product design by copying is of special interest. Given below is a summary of the lecture with examples suitably amended to keep in tune with the interests of this blog. It is expected that the interested will look up the Net for further details on the examples cited.

Perhaps because of its association with copying in school examinations “copying” as a technique in engineering product development is subject to a certain amount of derision and unease. There can be no doubt that an originator has a moral right to enjoying the fruits of his efforts but the questions of morality as regards copying in Industry is also not clear cut and questions will remain. To understand the question of morality and ethics we must first examine what are the types of  copying and what is involved in copyng.

Types of copying

“Chinese” Copy;

I have no idea why this is called Chinese copy but it implies a perfect copy with an insinuation of not understanding or caring what is involved. It was well known that Chinese artisans were incredibly clever and could copy overnight any piece of furniture, shoes or clothing given to them without bothering at all about the function or the end use of the object.  Perhaps that is the origin but I will include here a story. It appears that when the first Bleriot monoplane arrived at Beijing somewhere in the 1910s the pilots were surprised next morning to find an Bleriot monoplane parked next to their own original. Not only was it in perfect detail but even the Anzani radial engine had been copied. When the propeller was rotated by hand the “engine” even made a buzzing noise. The story goes that the ingenious Chinese workmen had filled the engine replica with bees. I doubt if the story is true being originated in Colonial times but it illustrates the way Copying is viewed.  In India this type of copying is popularly and more politely known as “ditto copying”.

Though the Chinese – along with the Japanese -got a bad name for copying it was the Soviets who actually put it to great use in producing a much needed product in the shortest possible time which is  the great utility of “copying”. The following two examples will be illustrative:

Just before the Second World War at the time of the Molotov Ribbentrop Non Aggression Pact  the German visiting delegation had presented some examples of the Fiesler “Storch” aircraft to the Soviet Leadership. The Storch had remarkable STOL and slow flying capabilities approaching that of a helicopter and was extremely useful as a army liaison aircraft. Oleg Konstantin Antonov, then a young Designer with some experience in designing sports gliders (OKA-1,-3, Standart, Leningrad etc)   was instructed by the Supreme Soviet to produce a “Chinese” copy of the aircraft. He did so in a fairly short time and probably took the “Chinese” copy part a bit too seriously because he named his first powered aircraft “Aist” which in Russian means a “Storch” or “Stork”. I don’t blame him. Stalin was a ruthless boss if you disobeyed. Unfortunately for the then young Oleg Antonov his powered aircraft was destroyed before its first flight when the city of Kiev was overrun by the Germans in July 1941 during the invasion.

It was the Soviets again who “Chinese copied” on a much more impressive scale. The Russians had been working on the atom bomb during the War and needed a carrier for the weapon without which the thing was useless. By good fortune (for the Soviets!) or who knows what three examples of the B 29 landed in the Soviet Union and ally or no ally, these aircraft were promptly impounded and turned over for copying. The leading Soviet OKB for large aircraft, Andrei Tupolev’s, was tasked and by an incredible effort the Soviet’s had examined the aircraft and produced the design suitable for mass production in a period of 36 months! 

The Soviets had the key technologies – Large airframe for long range aircraft designs, pressurization, remote control of the weapons barbettes etc which made the B 29 such a formidable  aircraft. Given adequate time the Soviet Industry could have come up with a suitable original answer. What copying gave to the programme was “Surefootedness”( which our programmes seem to badly lack)and importantly cut down time required for certification. In a country like India Certification is a process more painful than design because of the organizations working in “silos” and the general Bureaucratic approach.

Even in this copying the Soviets had difficulty and therefore initially bypassed critical features. Externally though the TU 4 looked very much like the B 29 it lacked the integral fuel tank ( which gave the B 29 its ( then) phenomenal range and the connecting tunnel between the forward and the aft pressurized cabins. It was also about 5% heavier and 10% more powerful than the original.

 The Soviets needed something in a hurry and by copying they got to first base within the shortest time. The TU 4 was soon to be rendered obsolete by the advent of Jet propulsion; Copying made it relevant for that short period when it played an invaluable role in setting up SOPs for the Soviet Dalnayia Aviatsya which was their equivalent or the Strategic Air Command. It will be noted however that the Tupolev “copied” over many features of the B 29 such as the remote gun barbettes, the nose position design for example into their first and second generation jet Bombers.

A second form of “copying“ is when aggregates are combined to create a new product. The Rockwell /DASA 31 ultra maneuverable fighter tested during the ‘nineties and no doubt awaiting its turn for the market is a case to the point. Much of the aircraft is a “cobbling” ( i.e. non optimized-pl.note!) together aggregates of six or seven “in service” aircraft.  The “copying” in this design –to produce an experimental “data generator” in the shortest possible time can be applied to our own LCA /MRCA programme. Of interest to those following the LCA programme will be the previous post in this blog where it is proposed to mate the wing of the LCA with a fuselage and empennage of the MiG 27. Many of the concessions of the LCA mk1- shortage of “real estate”, gun firing, Pilot and systems protection, undercarriage etc indicate a redesign of the fuselage. Using the firm and proven base of a MIg 27 fuselage and the LCA wing has a greater certainty of meeting the Mk2 requirement. Such a project will entail hard work but a back up will have the common sense attribute being available by 2023.. Unfortunately such alternative studies have always been carefully stymied by “It’s too late, the LCA is just around the corner” lobby for decades and now we are staring at compulsory imports or a rundown of our own air strength in the light fighter.

Other forms of copying

Apart from direct copying which is fairly rare- there are always some deviations enforced by circumstances, there are many subtle gradations and these are outlined below:

Copying of features:

When Antonov designed his first original design powered aircraft , the remarkable AN2 of which 20,000 had been produced before the Soviet Union collapsed he transferred many of the features of the Fieseler Storch – the slotted flap and slats and the remarkable “bug eye” cockpit glazing feature of the Storch which enabled the pilot to look directly below the aircraft - a most useful feature in a Rural economy aircraft operating out of rough isolated airstrips. The slots and slats allowed the AN2 to fly as slow as 45 kts. in complete control and operate from very small strips. It is my opinion that Antonov also copied the double door of the AN2 from the Dakota whose Cargo/Passenger door he would have been familiar with from the license built Lisunov 2 aircraft.

Copying of engineering design practices

The Vespa scooter could only have been designed by an aeronautical engineer or someone steeped in Aeronautical Engineering practice. The way the wheel are mounted, the cowling, cooling and concealment of the engine, the levered suspension and indeed every little thing that makes a scooter engineering wise so different from a motorcycle is because the designer Corradino D’Ascania “scaled down” well tested aeronautical engineering practice and applied them to two wheeler engineering. Indeed the “cultural” differences were so strong many great motorcycle engineering companies tried and failed to make a successful scooter and even Honda- one of the very few great motorcycle companies that succeeded in making a great scooter- will betray their motorcycle heritage in their front wheel suspension! Indeed this fascinating clash of cultures and the design of a product by “conformal mapping” of technology practice was the subject of one of the lectures.

Copying of design philosophies

The standard German main battle tank in 1941 was the Kpf.Pz.W IV. It had small road wheel, a short gun and a modest 300 hp petrol engine and was the master of all the tanks that it had hitherto faced. It was however completely out classed when it met the Soviet T 34 with its well sloped armour, long barreled (therefore high velocity!) 75 mm gun with overhang which the Western Designers were remarkably unsure of copying, almost double the engine power and large diameter “Christie “suspension road wheels. Though the Germans contained the T 34 threat with superior experience and training they were so shocked that some of their leading Panzer Generals even advocated the “Chinese” copying of the T 34. As so often happens in such cases it was not possible to make a “Chinese” copy- there was not enough supplies of aluminium required for the D2 -12 engine crankcase for example but the Germans absorbed the “philosophy” of sloped armour, long barreled gun,diesel engines and broad tracks which gave the T 34 its excellent mobility. The Panther was not a copy of the T 34 yet it accepted totally the “philosophy” of the Soviet tank

Copying of an inspiration

The last form of copying is when one uses an idea as an inspiration. No one will argue that the Supermarine Spitfire was the most beautiful fighter ever produced ( to which I would add the Hawker Hunter as the most beautiful of the Jets!) . It had a very distinctive elliptical wings and empennage. Though much was made at that time of the supposed efficiency of the elliptical shape this was not quite true as near the tip the wing was operating at far too low a Reynolds number and therefore suboptimal. Elliptical  wings were difficult to tool up and produce. It was however undeniably beautiful. It has been never officially acknowledged that it is possible that Reginald Mitchell was inspired by the beautiful elliptical wings of the Heinkel He 70 Blitz designed by the Gunther Brothers. Rolls Royce had imported an example of the He 70 Blitz as a test bed and no doubt Reginald Mitchell would have been very familiar with the aircraft.  I find it amusing that the legendary British fighter had a shape inspired by an aircraft that was designed by a nation that was to give the British a lot of trouble.

I cannot resist ending this section on copying with an example where the British were too willing to copy an Indian Military weapon.

Tipu Sultan of Mysore had developed the Rocket as an effective bombardment weapon and had organized several rocket brigades. His innovation was the use of a metal casing for the rocket which allowed much greater combustion pressures and thus more thrust and range and kinetic energy. The Rockets used by Tipu caused great alarm to the British. Indeed after the First Mysore War one of the British Commanders was so distraught with the poor showing against Tipu that he attempted to commit suicide. He must have been singularly inept because he failed in that also! After Tipu death and defeat in 1799 examples of Tipu’s Rockets were shipped to England where they were copied, finally by William Congreve, who used sheet metal to form the powder chamber. Sheet Metal reduced chamber weight, improved strength – due to rolling effect which in turn allowed higher chamber pressures and therefore performance and reduced cost. There is an example of Tipu’s rocket in the British Museum. To the modern eye it looks somewhat forlorn and tawdry and it is bemusing that about two hundred and thirty years ago this was “Advanced Technology” which Britain was glad to copy. Congreve improved the design considerably and his Rockets served in the British Regiments – hence the name Fusiliers to many British Regiments- for about fifty years until out moded by the Breech loading field gun.

The Tasks in Copying

Having identified the various degrees of Copying we return to put into perspective the achievements of the Tupolev Design Bureau even in copying. We should discuss what are the tasks involved in copying and it will be fairly clear how much acumen and information is needed to make a successful copy.

Let us consider what is the information needed to complete the drawing of even a fairly simple component in the Aerospace Industry.

1, the shape of the part involving several dimensions.

2. Fit, finish tolerance.

3.The chemical and physical characteristics of the material

4. The location of the part in the aggregate

5. The manufacturing methods to achieve the required levels of 2 above.

6. The heat treatment

7. The surface treatment/plating etc.

9. The quality control parameters

9. The location and marking of the part number.

10.  Storage, packing and disposal instructions.

To remember is that any non-attainability in any of the major factors-the manufacturing methods, scale of production etc may significantly affect the degree or indeed the advisability of copying possible.

The Engineering Knowledge required to copy.

The availability of the component can help deciding the first four items of the above list but one can go surprisingly wrong on the rest of the list and it is required to tread with caution. There is rarely an universal “best” product or configuration and one can end up copying something that is not the “best” for one’s own operating environment or going astray on some detail which causes problems in service. The following examples are illustrative.

The braking of a railway train is more complex than one usually imagines. One of the problems is that the braking effort of the locomotive must be matched by the braking effort of the train. If, for example, the train is over braked with respect to the locomotive then train parting will occur. On the Indian Railways of forty years ago the locomotive was air braked at 3.5 atmospheres whilst the wagons were braked at minimum 22 inches vacuum. A mechanical device, the Westinghouse VA 1 B servo valve, was used to overcome the problem of proportional braking. By a system of diaphragms and springs the Locomotive air brake pressure and the Wagons vacuum brake pressure were sensed and normally held in equilibrium. Any change in Locomotive Brake pipe pressure would cause proportionate change in the Wagon’s Vaccum brake pipe pressure and hence proportion the applied brake effort. At the heart of this was a very closely finished spool valve, consisting of a very close tolerance mirror finish spool sliding in a similarly finished tube which had apertures to take the two brake pressures. Since this had to be very sensitive it was not possible to use the standard methods  such as “o” rings, to achieve the required sealing between the two different pressure. Reliance was placed on extremely close tolerances and very high hardness and hence the finish to achieve the sealing and sensitivity. It was here that the problem was hidden.

The customer , the Indian Railways , had been using unlicensed locally manufacture “Chinese copies” of the VA1B valves and complained that whilst the valves worked perfectly during acceptance tests they began to stick or jam after several months of service causing erratic application of brakes which can be very disturbing with three thousand ton trailing load behind the locomotive. You can imagine the effects of the erratic and uncontrolled kinetic energy!

Analysis showed that the spool and the cage had been hardened to 65 Rc of the original sample to reduce the friction, wear and the mirror finish required. The unlicensed vendor had achieved the hardness using normal hardening procedures on high carbon steel. He had achieved the results upfront but it is well known that high temperature hardening involves quenching which causes locked in stresses. In addition Martensitic grain growth is present. Over time as the locked in stresses were released and martensitic grain growth occurred the very fine tolerances were disturbed causing the spool to stick in the sleeve.

The solution was in lowering the locked in stresses. One could have used two stage martempering with stepped quenching followed by gradual cooling but in this case given the very fine clearances it would be a doubtful solution as given the very tight tolerance no distortion due to release of stresses was allowable.

The technically correct solution was to go in for a low temperature hardening process such as Nitriding where the object is heated to only 500 degrees centigrade (as opposed to 800 plus degrees in Martensitic hardening) and then exposed to a stream of nascent nitrogen to form a layer of iron nitride Fe₃N. Being a low temperature process with none of the quenching stresses occured and the nitrided valves whilst achieving the required R_c 65 did not distort in service.

Even getting the heat treatment right is not enough.There is a further “trap” Nitriding is also used for corrosion resistance. Two British Standard nitriding steels then available in India e.g. EN 42 for corrosion protection and En 42B for both hardening and corrosion resistance. The latter has a small amount of aluminum and the Engineer has to specify En 42B and not En 42A. The aluminum helps to lock the hard plates of Fe₃N together to get the required hardness. You are advised to check up on the Net for the details of the exact mechanism of hardening by nitriding but the point I wish to make is the detail one has to go into and the knowledge required to make a successful “Chinese” copy! The Hindustani aphorism “Nakal key liye Akkal Chhaiyey”- you need intelligence to copy- is no old wives tale!

The perils of “shallow” copying

One of the problems for someone making an exact copy or even basing on an existing design is that he often faces the problem of substituting a material the original has used.. For example the MiG 21s wing spar uses a GOST 35XГСА material. An exact Indian substitute will not be available. There will be occasions when the import will not be possible. The danger of an arbitrary choice can be illustrated with the following example.

An oil bath air cleaner for a fairly large automotive diesel engine (25 hp/cyl) had a swirl vane type centrifuge pre-cleaner to get rid of the dirt and small stones. The swirl vanes are  topped by a dome shaped cap which  acted as the plenum chamber for the down draft tube. Producing the hemispherical cap required Extra Deep Drawing (EDD) steel which was not readily available in India of the 80s. An unthinking change was made to a shallower inverted “frying pan” head dome which seemed to solve the production problem without any side effects. Some more similar changes including the angle of the outlet pipe were made to ease the problem of materials supply and assembly. It was later found that the modifications were increasing the engine BHP loss of 1.3 BHP. Considering that peak velocities within the aircleaner were reacing Mach 0.3 this was not surprising. Restoration of the original feature, using additional annealing processes in between stages of deep drawing to overcome the material problems, resulted in the horse power loss coming down to 0.8 BHP.

Automotive air cleaners, automotive engines and plastic blown film plants have a surprising amount of internal aerodynamics in them. If this is not taken into consideration one can make a change to solve one problem only to end up with a problem in another area.

Using a wrong model

There is also always the danger that one may choose a wrong example to copy. For example in the  VA1B case cited above it would be “wrong” to copy the design today as today the same function can be realized by using pressure transducers, micro processors and electronics for faster and more reliable braking.

There was also the case about three decades ago of an Indian Establishment that attempted to design and build an all composite club training aircraft. It was ,in my view somewhat unfortunate that the “inspiration” ( the Indian group did NOT “Chinese” copy) for the design was a very successful German design. The German company had long experience in “glass” sailplane design and so their club trainer was largely based on the sailplane with the addition of a power source. That made good common sense to the German team. Much of the subsequent difficulties faced by the copier lay in the fact that the “inspiration” had a fairly high aspect ratio wing which is always heavier for a given area and stressing level than a lower aspect ratio wing. Not unexpectedly the Indian aircraft came out much heavier than allowed for because the Indian team was much less experience d in glass fibre. Indeed the unkind joke at that time was that the aircraft could either carry the pilot or the fuel but not both! Matters were not helped by the copying team’s failure to absorb and carefully copy the very good finish, fit and tolerances and general lines of the “inspiration”. The net result was though the Indian design was well meant and had potential it never achieved it.

What should the Indian team done? The first thing was to measure the size of one’s cloth before cutting the coat! Their design experience was just one home built composite aircraft of an American design. They knew how to build and certificate a composite aircraft. They should have taken a much more structurally conventional aircraft- I would go for a junk airframe of the stubby ( i.e. structurally rigid!) Victa Airtourer or even at a pinch even the HPT 32 airframe which was then in production as a basis. The relatively low aspect ratio wing would have been easier and lighter to stress and fabricate. This would have reduced the design load to just getting the composite airframe klim bim –as the Prussians used to say-without having to worry about a hundred other things like systems design, control runs, aerodynamics etc and the team would be free to the real possibilities of composites- refining the form to an extent not permitted by metal fabrication. Note the experienced Russian copying the Tu 4 set self limits and abandoned a lot of areas in getting the product into service.

I have discussed to problems from actual experience in the Indian Industry to caution that copying  is full of hidden mines and one has to literally get in to the original designer’s shoes ( and brains!) to decide what to copy and what to reject or modify.

As is well known the British for reasons best known to the then Labour Government sold the design rights of what was then the most powerful jet engine in the world The Rolls Royce Nene to the Soviet Union. The fact that the British Establishment had more than its fair share of Communists may have been a factor. An incredulous Joseph Stalin jumped at the offer and mass produced the Nene as the Klimov VK 1 and the VK1A along with the RR Derwent to power the first generation Soviet jet fighters including the famous – and world class- MiG 15,MiG 17 F, Ilyushin 28 and the lesser known Lavochkin 15. The design then drifted to China where the produced another 18, 000 of them. One of these engines was examined by the original designer , Sir Stanley Hooker, who convulsed his Chinese hosts by remarking “ They did a good job of copying – they even copied my mistakes.” Since we are discussing “copying” and its applicability I will add that Klimov was of course a piston engine man who, starting with the 860-960 hp Hispano Suiza HS 12Y XX engine first redesigned to make it easier to mass produce and then by careful improvements to detail boosted it to 1250 hp from the same basic engine albeit at some cost to engine life but the Soviets were quite happy with a life of 100 hrs. as the average combat life of the aircraft was well below that.

Modern aids to copying

When Tupolev copied the Boeing B 29 he probably had to use wooden patterns to generate the external contours and relied on gravimetric analysis to find the comnposition of the various alloys used. There was the possibility that one would be missing out an element- for example the aluminum in the above EN 42B example- if you did not know what to look for. These methods can be used even today. Over the past eighty years there are hosts of equipment mainly simple which can expedite the speed at which one can copy. Laser scanner s can generate envelope which would otherwise take weeks to generate, portable spark spectrographs can give in situ indications of the constituents if not the actual compositions, thickness indicators can give the gauges of materials used and three D computerized 3 axis Coordinates measuring machines can reduce the work of days to hours. The data generated may not be perfect but it is more than adequate to allow a skilled designer to “see” his way through the fog. Even with all the data a certain amount of uncertainity will exist and it is here that the Chief Designer ‘s experience and judgment will be invaluable. Assuming that the B 29 had a hundred thousand parts it is almost certain that Andrei Tupolev would have used his vast experience to “truncate” certain areas of copying and focus where copying was simply not possible. The Shvetsov Ash73TK 1790 kW engines available to Tupolev were heavier and more powerful than the B 29’s1641 kW Wright Cyclone R 3350-23    engines and that would mean that the stresses on the wings, the aerodynamics of the cowling ,the problem of engine cooling  etc would require careful rechecking if not actual re-design.  Yet at the end I terms of national interests it was supremely worthwhile.

The Morality of Copying

The question of morality in copying is very complex and is centred around the of making money which is at the core of all engineering. An originator has a moral right to make reasonable profits from his enterprise. It is here that the problem becomes incoherent because the questions centre around what are reasonable profits and for how long, what is the enforceability as well as when does the “morality” angle kick in. A country lie India can claim that because e of the long period of Colonization when it was systematically de-industrialized it should be re- compensated by being allowed to copy! There is also the moral debate going on;  Indian Drug Companies are accused of “copying” western Drugs and providing- at a profit let it be said –of exorbitantly expensive – to the African patients at least- drugs which are literally matter of life and death.. What is the moral angle to that?

It is beyond my expertise to take a stand but if one remembers that even to copy competitively one has to reach a certain enviable level of competence. The copier is best served by making sufficient changes so as to make it difficult to claim infringements which as we have seen is almost inevitable. As long as both parties approach the problem reasonably and recognize the skills involved and be it said the inevitability of being copied the solution would lie in a reasonable dialogue.

The potency of copying

The potency of copying in its various forms is exemplified by the rise of China as a major weapons exporter given the fact that they never had a weapons Industry till 1949. By 1965 they were exporting “Chinese copies “ of the PPSHG automatic rifles, MiG 19 ( as the F6) and the T54 ( as the T 59). Under Deng Xiao Ping’s “Four Modernizations” the Chinese progressed up the various types of copying to produce a complete range of weaponry- from Infantry small arms to Aircraft Carriers- which belittles our efforts so far. To deride the quality and shortcomings of these weapons and to compare them with western equivalents is to make two mistakes. Firstly this attitude accepts that the western specifications are universally relevant. The second oversight is that the Weapons have a political purpose. The Chinese Weapons ,whatever their alleged shortcomings, have made it impossible for the West  to impose another Opium War or a burning of their Imperial Summer Palace- events which to the Chinese is as mortifying as our  defeat in the 1962 war.

Given our own political aspirations we must develop our own view on copying and integrate it into our own strategic programmes. With 70% of the weaponery imported, the continuing shortfalls in essential stores indicate that we have probably reached the limits of the present arrangements in fiscal terms at least. The quoted price of imported weaponry has no basis of reasonable profits. Derived or copied Indian designs made in India by efficient production management is the only way we can attain the desired levels of meeting requirement. By increasingly creative c opying the Chinese have developed a complete range of weapons and it is possible that their procurement budget is not too much bigger than our procurement budgets. We need to take an organized look at the possibilities of copying.

  5093 word.