Re: Soviet Aircraft

From:         weiss@turing.SEAS.UCLA.EDU (Michael Weiss)
Organization: SEASnet, University of California, Los Angeles
Date:         09 Apr 93 15:03:14 PDT
References:   1
Followups:    1 2 3
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In article <airliners.1993.326@ohareChicago.COM> libove@libove.alf.dec.com (Jay Vassos-Libove) writes:
>What are the pros and cons of putting engines in pairs like
>this on the tail, versus putting them under the wing (as on
>the 747)?

I had seen pictures of this aircraft before.  Strange appearence, eh?

I see two major cons:

1)  The deep stall problem of the high T-tail (the same as in the DC-9 and 727)
2)  Lack of double-redundancy in the engine pylons

Let me elaborate on #2 (since we have discussed to death #1).  On the 747, if
an engine pylon fails, you lose one engine.  If the pylon attaching an engine
to the fuselage fails on the Il-62, you lose TWO engines.  Continuing on this
theme, damage to the controls running through the pylon would behave the same.
In that case, it's much like the problem with the DC-10's hydraulic system,
where something that would damage one system would likely damage all systems
simply due to proximity.

I can't see too many pros, aside from the one that led designers to put the
engines on the tail in the first place, namely noise.  You can keep the rest of
the airplane quieter by concentrating the noise to the rear.  Nonetheless, the
advantage was not sufficient to keep the design for the 737, so I'm inclined to
believe that switching to turbofans (especially high-bypass turbofans) reduces
noise to the point that it's just not a big deal to have the engines on the
wings.
-- 
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-   Weiss   izzydp5@oac.ucla.edu  |   University of California, Los Angeles   -
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