Re: Soviet Aircraft

From:         spagiola@FRI-nxt-Pagiola.Stanford.EDU (Stefano Pagiola)
Date:         09 Apr 93 15:03:10 PDT
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Karl Swartz writes
> Stefano Pagiola writes:
>>>That's an Ilyushin Il-62, the Soviet version of the Vickers VC-10

>>Do you (or anybody) have any evidence to back this claim?  I am  
>>continually hearing that such and such Soviet airliner is a `copy'
>>of that or the other Western airliner

> You're reading more into the words than was intended, though 
> given the common assumptions to which you allude that isn't 
> entirely unreasonable. Still, had I said that a DC-8 was 
> Douglas' version of the 707 or that the L-1011 was Lockheed's 
> version of the DC-10, would you have reacted the same way?  I 
> doubt it.

If you had claimed that the L-1011 was Lockheed's version of the  
DC-10, I would probably have chided you by E-Mail for sloppy  
language.  That assertion would simply be false as stated; saying  
something like `the L-1011 is Lochkeed's response to the requirements  
that also lead to the DC-10' would have been accurate.
In this case, I am quite confident, given your knowledge of aviation,  
that you didn't literally mean that the Il-62 was a `copy' of the  
VC-10.  But the statement reflected a common enough misperception in  
the aviation world that I thought it was worth addressing directly.  

> A while ago, someone,
> Robert Dorsett if I'm not mistaken, noted that aircraft design has
> become almost a cookbook approach -- the problems are sufficiently
> well understood that two independent teams working on a common
> target will produce remarkably similar designs.

My point exactly.
One thing I would add to that, though, is that particular design  
teams often develop extensive experience in certain parts of those  
cookbooks, so that aircraft from a given team often tend to meet even  
quite different requirements with similar designs.  Notice how all of  
DeHavilland Canada's designs are high-winged.  Initially, this was  
necessary for good rough-field performance.  But the Dash 8, for  
example, has no rough-field capability (someone correct me?) and yet  
retains a distinctive family resemblance to the earlier DHC designs.   
Similarly, the Tupolev 134 and 154 are quite obviously siblings;  
indeed the resemblance between them is to my mind much greater than  
any superficial resemblance they might share with the DC-9 and 727,  
The other nuance to consider is that the high cost of developing new  
designs means that historical choices can condition design for  
decades and more.  Witness Douglas' MD-90 and MD-11.

> The second point is that
> manufacturers are often working on the same set of requirements
> from the same set of airlines.  This latter point is perhaps 
> nowhere clearer than in the DC-10 and L-1011.

> In the case of the various Soviet aircraft which bear remarkable
> similarity at a superficial level, do these rules still apply?
> While the Soviets had (and the CIS countries still have, a fact 
> worth noting and not forgetting) some very talented aircraft 
> designers, it is not clear that they were working from the 
> same technological base.  In particular, similar or even 
> identical engine choices (e.g. DC-10 and L-1011 again, or 707 
> and DC-8) have pushed designs closer together, whereas my 
> impression has been that engine technology was where the 
> Soviets were furthest behind the West, with the possible 
> exception of avionics (...)
> As far as requirements, it seems to me that the Soviets 
> were working from a rather different set in most cases, 
> certainly from a different set of customers.

To the extent that these points (different technology for fundamental  
components such as engines and different requirements) are correct,  
then it becomes all the more evident that any resemblance of soviet  
designs to western designs is purely coincidental, since by the first  
point they _could not_ have copied western designs, and by the second  
would not have _wanted_ to.

The Il-86 is, I believe, an example of where soviet designers simply  
could not copy western designs.  While everybody in the West was  
designing and/or building big widebody twins, Soviet designers simply  
did not have powerful/reliable enough engines to power a large twin.  
Their response to the kind of requirements that lead to the A300/A310  
and 767, therefore, is a four-engined aircraft.

> None of which answers your real question.  No, I don't have
> any hard evidence, though I have vague recollections that
> there was a large amount of copying documented in at least
> one case, probably the Tu-144.

Yes, we can argue general principle all we want, but it would be nice  
if somebody could actually inject some evidence into the debate.  I  
do remember an article on the Tu-144 somewhere in my aviation  
library.  I'll look it up and report next week.

Stefano Pagiola
Food Research Institute, Stanford University (NeXTMail encouraged) (NeXTMail encouraged)