Stargazer2006 said:Has the designation for this magnificent "blended arrow" design been found? I seem to recall it was associated to the "Top Secret" V-540 slot in some topic but I can't find it right now.
Bill S said:Blended Arrow Supercruiser
overscan said:I think V-540 can be ruled out as the plans are marked "Confidential" not "Top Secret".
overscan said:Its possible. "AI" studies span late 1960s to early 1970s and, almost certainly, V-518 was an version of one or more of these studies. I would hesitate to assume that the Blended Arrow Supercruiser is V-518 specifically without more evidence though.
Evaluation of the influences of fuels and lubricants on a next generation Air Force Mach 3+ interceptor required definition of representative designs for the aircraft and engines, their operating conditions, and a complete design definition of the fuel and lubrication system for the engines. The first tasks were the definition of a representative interceptor mission and corresponding
aircraft chacteristics. USAF Contract F33615-71-C-1014 studies of the Quick Response Interceptor (QRI), performed by Vought Aeronautics, were used as the basis for the typical interceptor mission described in Volume I.
The mission consisted of a required high rate of acceleration to cruise, Mach 31 cruise, combat maneuvers, cruise back at Mach 3+, descent, and nominal loiter before landing. USAF Technical Report No. ASB70-12 ASB/MAD, prepared under the same Vought Aeronautics contract, also provided the aircraft configuration, lift, and drag characteristics (contained in Volume I) that were used
to determine apprcpriate engine type and size.
The candidate Pratt & Whitney Aircraft (P&WA™) study engines for the mission were the STJ346A afterburning turbojet and the STF378 duct heating turbofan. Tbe computer program used to compare and size the engines was developed at P&WA while supporting Vought Aeronautics with engine information.
Pratt and Whitney has proposed the use of a variable stream control
engine (VSCE). This engine is similar to a conventional twospool
turbofan but incorporates a low emissions duct burner
located in the bypass duct and a co-annular exit nozzle. By
burning fuel in the outer bypass duct that surrounds the core, a
form of distributed propulsion may be achieved because the
burners may be operated at independent throttle settings. The
operation of this engine is described by Hines . At takeoff,
the primary core burner is operated at an intermediate setting
while the duct burner operates at maximum temperature. This
effectively achieves an inverted velocity profile in which the
bypass jet velocity is 60% higher than that of the primary jet
core. This reduces jet noise by 8 decibels relative to a first
generation SST engine. This velocity profile achieves a
significant reduction in takeoff jet noise relative to a constant
velocity profile. During subsonic cruise, both burners are
operated at partial power, achieving a uniform velocity profile,
therefore providing a 20% lower fuel consumption at subsonic
cruise relative to first generation turbojets. At supersonic
cruise the primary burner is increased to takeoff conditions
and the duct burner is operated at partial power. At supersonic
cruise the VSCE is estimated to approach the efficiency of a
Orionblamblam said:Are dimensions, performance etc. given?