Date: 21 Nov 97 01:59:55 From: firstname.lastname@example.org (Joel Harris) Organization: AT&T WorldNet Services References: 1 2 3
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On 03 Oct 97 01:18:34 , Steve Lacker <email@example.com> wrote: >I came across an interesting claim the other day. I've always assumed >that from the very beginning, jet aircraft airconditioning systems have >operated on the same principle they do today. Ie, take hot bleed air, >cool it while still highly pressurized in a heat exchanger, pass it >through an expander valve so that it expands and gets cold. However, I >was snooping around Carrier's web site (the air conditioning company) >and they claimed the following as one of their "firsts": > >1955: With the advent of jet passenger service, Carrier develops an > air-turbine-driven centrifugal refrigeration machine to cool the > Douglas Aircraft Company's DC 8. Although small enough to fit > inside a small piece of carry-on luggage, it was powerful enough > to air condition seven average sized homes. I'm not sure WRT the DC-8's environmental system, but AA's 707 fleet were equipped with 2 electrically driven air conditioning packs. I'm not exactly sure who manufactured them. I do know that if both packs were started while the plane was hooked to the ground electrical unit (which at BNA was a 125 KVA diesel-powered Hobart truck-mounted generator) it had a bad habit of stalling the GPU. This was not a good thing, since a generator bearing locked up one day and promptly flipped a 3-ton truck that the package was mounted on. AFAIK, most everything since the days of the 707 have been equipped with air cycle machine environmental systems.