page_title: Ramjet
section_title: Nozzles
hierarchical_section_title: Ramjet / Construction / Nozzles
caption_attribution_description: English: One of the two Thor ramjet engines of a Bloodhound missile at Bristol Industrial Museum, Bristol, England. This is not a model. Taken by Adrian Pingstone in August 2004 and released to the public domain.Note that Bristol Industrial Museum was closed at the end of 2006 and the aero engines collection is no longer on display.
context_page_description: A ramjet, sometimes referred to as a flying stovepipe or an athodyd, is a form of airbreathing jet engine that uses the engine's forward motion to compress incoming air without an axial compressor or a centrifugal compressor. Because ramjets cannot produce thrust at zero airspeed, they cannot move an aircraft from a standstill. A ramjet-powered vehicle, therefore, requires an assisted take-off like a rocket assist to accelerate it to a speed where it begins to produce thrust. Ramjets work most efficiently at supersonic speeds around Mach 3. This type of engine can operate up to speeds of Mach 6.
  Ramjets can be particularly useful in applications requiring a small and simple mechanism for high-speed use, such as missiles. The US, Canada, and UK had widespread ramjet powered missile defenses during the 1960s onward, such as the CIM-10 Bomarc and Bloodhound. Weapon designers are looking to use ramjet technology in artillery shells to give added range; a 120 mm mortar shell, if assisted by a ramjet, is thought to be able to attain a range of 35 km. They have also been used successfully, though not efficiently, as tip jets on the ends of helicopter rotors.
context_section_description: The propelling nozzle is a critical part of a ramjet design, since it accelerates exhaust flow to produce thrust.
  For a ramjet operating at a subsonic-flight Mach number, exhaust flow is accelerated through a converging nozzle. For a supersonic-flight Mach number, acceleration is typically achieved by a convergent–divergent nozzle.
caption: One of the two Bristol Thor ramjet engines on a Bristol Bloodhound missile
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