From: Mike Lorrey (mlorrey@datamann.com)
Date: Mon Jul 01 2002 - 07:09:00 MDT
"Robert J. Bradbury" wrote:
>
> Boeing may not be as uncompetitive as some recent posts
> have suggested.
>
> This article:
> Boeing's BWB -- a Super-Efficient Bat Jet
> http://abcnews.go.com/wire/SciTech/reuters20020628_291.html
>
> indicates they are working on blended wing body jets that
> would carry 480 people but use 32% less fuel than the Airbus
> A380-700.
>
> Anyone know what fraction of ticket costs are fuel?
>
> The article also cites that the design is derived from the
> B-47. Anyone know the history on the B-47? It was before
> my time.
http://www.fas.org/nuke/guide/usa/bomber/xb47-1_300-2.jpg <----- image
B-47 Stratojet
B-47 research and development began in 1945 with the first prototype
flight in December 1947. The Air Force wanted a high-altitude,
medium-range, subsonic bomber. At that time, four contractors were
developing bombers. Two designs were conventional bombers in the
mold of the B-29, while the more radical designs were the Northrop
flying wing and the Boeing swept wing jet. In this era before the SAM,
fighter aircraft were considered the main threat to bombers. World War
II had shown that stripped down B-29's with near-fighter speed and a
higher altitude ceiling could only be successfully intercepted from the
rear.
With the speed and maneuverability of the fighters of the late forties,
Boeing's swept-wing XB-47 won the bomber competition and swiftly
transformed the XB-46 and the XB-48 into aviation footnotes. Six Allison
J35-2 turbojet engines slung in pods beneath the swept-back
wings gave the prototype Stratojet nimble performance, and helped to
validate a design concept still widely used today. Although uprated
J47-GE-3s were soon substituted, the B-47 also carried mountings for 18
solid-fuel booster rockets in the aft fuselage to shorten the takeoff
roll. Flight testing continued through 1951, and B-47's began entering
the inventory in 1952. ICBMs and SLBMs did not yet exist, and the
penetrating bomber was the only nuclear strike vehicle available. A
total of 2,039 B-47's were funded and built in a serial production that
lasted until 1956.
The B-47 was the first pure jet strategic bomber whose many unique
features included six jet engines; a two-engine, pylon-mounted pod
under each wing near the fuselage; and a single-engine pod further
outboard. The wings were attached high on the fuselage and swept 35.
The design incorporated a revolutionary bicycle-type, retractable main
landing gear with single, two-wheel struts on the forward and aft
fuselage. Outrigger wheels added lateral stability and retracted into
the two-engine pod cowling. The B-47 was 107 feet long, 28 feet high at
the tail, and had a wing span of 116 feet. The crew consisted of a
pilot, copilot, and bombardier. With a maximum gross weight of about
204,000 pounds, it used rocket assist on takeoff. A tail chute was used
to slow down the aircraft during landings.
end quote.
I find it highly unlikely that a modern batwing transport would be based
on the B-47. I would, instead, think that the proper reference was the
B-48, a flying wing design by Northrup which lost out to both Boeing's
3,500 mile range design as well as to Vought's B-36 Peacekeeper long
range bomber. An interesting side note on the Vought/Northrup rivalry,
the first Secty of the Air Force, Stuart Symington, made the decision to
go with the B-36, then shortly after resigned from the Cabinet and
became President of Vought. Funny how that happened.
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