Re: Older Aircraft

Date:         17 Sep 97 02:49:15 
From:         Steve Lacker <look@the.sig>
Organization: Applied Research Laboratories - The University of Texas at Austin
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Ed Treijs wrote:

Well, Hello, Ed! Fancy running into you here... :-)

> In article <airliners.1997.2148@ohare.Chicago.COM>, kls@ohare.Chicago.COM >
> Just wondering: is the inference (from above) that the 707 is mainly
> still in service for passengers, and the DC-8 mainly freight, valid or
> not?

Nope, not really.  As Karl pointed out, the DC-8 turns out to be better
optimized for a freighter than the 707. The 707 is used in that
capacity, but not as much. Also, I may be wrong, but looking back at my
older books it would appear that the 707 was initially MUCH more popular
with developing nation *passenger* carriers than was the DC-8. So the
707's went overseas and flew to the limits of their airframe life before
getting retired. Also, the US air force has bought a lot of parts from
old 707's, and quite a few complete airframes. The first re-engining of
the KC-135 was done by taking used JT3D's from passenger 707's and
installing them in place of the original J-57 Turbojets on the KC135.

> Also, something that puzzles me.  What makes the economics of air freight
> dictate older passenger jets?  Presumably some of the reasons passenger
> airlines are no longer flying DC-8s and 707s is that the turbojets are
> noisy and inefficient compared to turbofans.

Karl explained the economics well (low cycles/hours on older airframes
when used for freight). But another aspect is the lack of any other
choice! True, there are some smallish freighters, but the original
front-line USAF jet freighters (C-141 and C5) were never made available
to cargo carriers. There had been some talk of marketing the new C-17 to
private industry, but I doubt that the biggies like Airborne and FedEx
would buy fleets of them. And quite honestly, they wouldn't be
appreciably better at the job most overnight package carriers do than
DC-8's and 727's and MD-11's.  Sure, they have a rear (ans/or front)
ramp, but not much cargo needs to be shipped that could really take
advantage of that. The money is in cargo that fits in standard
containers, which fit just fine in the side cargo doors of converted
passenger planes (or passenger airliner-derived dedicated frieghters
like the MD-11F and purpose-built 727 freighters).

 Ed (is Air North's service in the Yukon with DC-3s scheduled?) Treijs

--
Stephen Lacker
Applied Research Laboratories, The University of Texas at Austin
PO Box 8029, Austin TX 78713-8029
512-835-3286	slacker@arlut.utexas.edu