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By Robert Espey. Ramjets. What is a Ramjet?. A ramjet is a jet engine that relies on forward momentum to create pressure instead of a moving piston or fan Requires forward motion to produce thrust Uses continuous combustion. How Does it Work?. Incoming air is slowed to subsonic by cone - PowerPoint PPT Presentation
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ByRobert Espey
A ramjet is a jet engine that relies on forward momentum to create pressure instead of a moving piston or fan
Requires forward motion to produce thrust
Uses continuous combustion
Incoming air is slowed to subsonic by cone
Slowed air creates pressure needed for combustion
Fuel injected into pressurized air
Flame ignites mixture Air expands and flows
through nozzle Exhaust generates
forward thrust
Must be at least Mach1 before operating
The thrust produced is based on pressure differentials at different sides of the plane
Limited by excessive temperatures and pressures at higher speeds and low pressure differentials at low speeds
No moving parts Higher efficiencies Speeds limited
only by temperatures and pressures engine can handle
Schematic of a Ramjet
Schematic of a Scramjet (air remains supersonic)
VS.
Low Fuel Efficiency Caused by low compression ratios High speed creates drag
Only operates at speeds above Mach1
Ramjets and Scramjets have been used in missiles, helicopters, and the SR71 Blackbird with varying degrees of success.
The United States funded a nuclear scramjet project for missiles called ‘Project Pluto” Realized that ICBM’s did the job better and that
low flying radioactive reactors weren’t the best idea
“Ramjet Engines.” 3 Dec. 2008 <http://www.aardvark.co.nz/pjet/ramjets.htm>
“The Ramjet/Scramjet Engine.” 2 Dec. 2008 <http://www.aviation-history.com/engines/ramjet.htm>
“Here Comes the Flying Stovepipe.” Time Magazine. 3 Dec. 2008 <http://www.time.com/time/magazine/article/0,9171,834721-1,00.html>
“Ramjet.” Wikipedia. 2 Dec. 2008 <http://en.wikipedia.org/wiki/Ramjet>