Questions tagged [ramjet]

A jet engine that uses solely ram pressure to compress the air it takes in, rather than using a turbocompressor.

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117 views

Rocket Thrust vs Air breathing jet engine why is a rocket better [duplicate]

What are design dynamics that give the rocket engine higher thrust than an air breathing jet engine of similar size in comparison to a turbo jet engine, turbo fan engine, high by pass turbo fan engine,...
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1answer
90 views

About ramjet efficiency in supersonic speed. Is there an optimal speed?

I know there is an optimal speed for ramjet. This are the results of my research. The reason the efficiency increases with supersonic speed to an optimal value then decreases is related to the ...
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3answers
164 views

Could the Aurora D8 have Ramjets instead of traditional jet engines?

By the design of the Aurora D8, the engines would receive the boundary layer of air atop the fuselage, however, because jets have what I am calling "moving parts", and the pressure differences would ...
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Does/Can combustion instabilities occur in SCRAM jet?

I was told that combustion occurs at Supersonic speeds in SCRAM jet. So acoustic disturbances/ pressure fluctuations can't travel into incoming jet stream. Does this avoids combustion instabilities in ...
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1answer
212 views

Could liquid alkali metal fuels be used for ramjet/scramjet propulsion?

In particular, I'm thinking about lithium, but sodium could be considered as well. Lithium has low molecular weight, very high propellant density, and low melting point. At sufficiently high ...
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2answers
457 views

What is the minimum size of a ramjet?

Having recently learned that 155 mm ramjet artillery shells are now a thing, I wonder how much ramjet engines can be miniaturized. Could we see ramjet tank shells? Man-portable recoilless guns? ...
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6answers
852 views

What are the advantages of using a ramjet in an air-to-surface missile?

Which are the advantages of using a ramjet compared to a rocket engine in an air-to-surface missile? I suppose the cost rises a lot, so why do some countries use ramjets as a way of propelling ASM ...
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1answer
325 views

Do ramjets use variable geometry supersonic inlets?

Ramjets are very often portrayed as super simple, I've read on few occasions that the only moving parts in a ramjet are the fuel pumps. However, turbojets operating at similiar speeds (mach 2 - mach 3)...
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3answers
236 views

What mechanism or design aspect prevents jet blast from escaping the front of a Ramjet or scram jet?

Enormous air pressures result in the thrust of a Scram jet or ramjet engine, more so the pressure required to drive the aircraft forward at supersonic and hypersonic speeds. Given that these engines ...
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2answers
529 views

How can a modified ramjet produce static thrust without a turbine?

A big selling point of the ramjet is its absence of moving parts (hence why it can be translated as "statojet" from other languages). However, an even bigger drawback is that a ramjet cannot produce ...
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0answers
573 views

What is the effect of Mach number on efficiency, thrust and specific fuel consumption of a ramjet engine?

My graphs show that overall efficiency and thrust first increase, reach a peak and then fall in the supersonic range (M=1-5) whereas SFC first and then increases rapidly near M 5. Why does this ...
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3answers
7k views

Are there any planes that have ramjet or scramjet engines?

Are there any planes that have ramjet or scramjet engines? If so, how did they reach the required mach speed for the engines to start functioning?
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Was there any progress in ramjet-powered helicopters after 1960?

It seems in 1950's some countries investigated production of helicopters powered by ramjet engines on rotor tips - examples include American Hiller YH-32 Hornet or Polish JK-1 Trzmiel. The enthusiasm ...
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4answers
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What is a ramjet?

What is a ramjet? Was it used on the SR-71 Blackbird?