Re: Soviet Aircraft

From:         spagiola@FRI-nxt-Pagiola.Stanford.EDU (Stefano Pagiola)
Date:         08 Apr 93 15:37:57 PDT
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Karl Swartz wrote:
>>... the plane had four jet engines, all at the tail, attached
>> with two on either side

> That's an Ilyushin Il-62, the Soviet version of the Vickers VC-10
> [lots more deleted]

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 (Il-62/VC-10, Tu-134/DC-9,  
Tu-154/727, Tu-144/Concorde).  Why do we assume this?  Is the Boeing  
727 a `copy' of the British Trident?   Is the Boeing 767 a `copy' of  
the Airbus A300?  Are the DC-8 and CV-880/990 `copies' of the 707?   
Are the DC-9 and F28 `copies' of the Caravelle?  Or is it simply that  
similar requirements and similar technology leads to broadly similar  
solutions?   Look at how close to each other Douglas' and Lockheed's  
designs for tri-jet widebodies came out, and yet neither can be  
claimed to be copies of each other since they were developed  
simultaneously.  There is a finite number of configurations that  
airliners can take, and it seems to me fairly likely that if one  
manufacturer's engineers find that a particular approach solves a  
given set of problems, that other engineers can also come to the same  
conclusion.  Of course, if a particular configuration has already  
been adopted by company A, company B might be encouraged to give that  
configuration a closer look in its own design studies.  Does it make  
the two resulting aircraft copies of each other?

If you look at the VC-10 and Il-62, I think you'll find that at the  
time they were designed, there was no getting around the need for  
four engines in a long-range aircraft (both for total thrust and for  
reliability reasons on overwater segments).  Many manufacturers  
(Boeing, Douglas, Convair) addressed this by placing the four engines  
in pods under the wings.  One placed them in the wing roots (De  
Havilland).  At the time, there was also considerable debate over the  
advantages of having a nice clean wing (such as on the  
Caravelle--which made it, BTW, a superb glider) and of placing the  
engines in the tail (lower cabin noise, better ground clearance and  
hence protection from FOD damage).  That some manufacturers should  
try to bring these advantages to long-range aircraft, and therefore  
place the necessary 4 engines together on the rear fuselage is not  
surprising.  As Karl's post pointed out, this arrangement does have  
disadvantages.  In particular, one needs a pretty heavy structure to  
handle 4 rear-mounted engines, and the possibilities for growth are  
limited.  This may well explain why neither aircraft was very  
successful.  But that still doesn't make the two aircraft copies of  
each other.

I think it is time that we lay this old canard about soviet airliners  
being copies of Western designs to rest, unless somebody can come up  
with some convincing evidence.  Simple sequence in time is not  
evidence (if it were, then christmas card sales would `cause'  
christmas).  Neither is knowledge by one manufacturer of another's  
design (after all, why did Ilyuschin not copy Boeing or Douglas?)

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