Every once in a while, I like to go wading in the "Radical New Aircraft Design" bin that is the United States Patent and Trademark Office. Occasionally I come out with something written in patent speak that only a rocket scientist can decipher and I just stare blankly at, however, this time I came out with a real gem.
I give you Patent Number 20080099633, which was published yesterday, called Aircraft airframe architectures, a wholly innocuous title. An engineer at Pratt & Whitney came up with a radical new design to improve the fuel efficiency of a shorthaul aircraft. Rather than have two engines, the design calls for a "single gas generator core including a forward compressor driven by a rearward turbine about a core axis and configured to remotely drive multiple bladed propulsion elements."
Now in English. What the designer describes here is one main gas core mounted in the tail of the aircraft that drives two fans or turboprops which are mounted to the sides of the aft fuselage.
The benefits :
-Improves fuel efficiency by adding a gearbox to the core which optimizes the speed of the core and fans.
-Improves fuel efficiency further by providing a significantly higher bypass ratio. That is to say the ratio of air that passes through the fans is significantly greater than the air that goes through the engine's core. Having two fans and a single core the thrust generated from the fans improves fuel burn.
-Reduces noise by evening the gases exiting the rear nozzle.
-There is also additional fuel and weight savings by only having a "single gas generator core" that drives the fans.
I put together a rendering of how the engines are mounted on the rear fuselage of an aircraft, based off of the diagrams enclosed in the patent application.
Read the complete post at http://www.flightglobal.com/blogs/flightblogger/2008/05/pratt-whitney-gets-radical-1.html
Sat, May 3 2008 1:27 AM
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