8

Some aircraft with turbofans have an engine synchronization system for exactly that reason: reducing the beat resulting from different, but similar, frequencies for the two engines. MD-80: The McDonnell Douglas MD-80 can synchronize its engines by EPR, N1 or N2 when the autothrottle is engaged: Engine Synchronizer System The engine synchronizer ...


6

GE patented a synchrophaser system for turbofans in 1991 but I've never heard of the system being implemented. My experiences are with the CF34 family (both flying and on the technical side), both FADEC and non FADEC, and none of them had a dedicated synchrophasing system (except for N1 synching by the FADEc computers) and I can't find anything about ...


2

You are basically describing an ejector pump. This would not be very efficient, I'm afraid (I'll try to dig up some comparative figures). The arrangement in this case would be a jet engine used to accelerate an amount of air inside a duct. With a long enough duct, the end result would be a single airmass exiting at (somewhat) uniform speed. Unfortunately, ...


2

The idea is certainly valid. Busemann's original design could not generate lift, but modern variations can. Here are just three recent papers on how it can be done: Kusunose, Matsushima and Maruyama. (2011). "Supersonic biplane — A review". Progress in Aerospace Sciences 47. pp.53–87. Wu, Jamieson and Wang. (2012). "Adjoint based aerodynamic optimization ...


1

There are no historical aircraft with an aerospike nose, at least, none that I remember, and none that I could find after 30 mins of research. I'm not sure if there are any planned projects using it, but I doubt there are, given the purpose of aerospike noses - aerospike noses really only have one main purpose - to streamline a blunt body. This is commonly ...


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