## Ramjet ignition

What airspeed do I need to ignite a ramjet?

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 Are you asking "what is the required velocity of air inside the combustion chamber in order for it to ignite with a decent efficienty?" This is a tough question, I could write an essay about it just in this post.
 I was thinking about the airspeed of the vehicle, but both airspeeds would be appreciated (vehicle and combustion chamber). So with a state of the art ramjet what would be those speeds to ignite with 60% efficiency. And if you don't mind say the vehicle weighs 500 pounds and is carrying 1,000 pounds of fuel (1,500 pounds total weight) how long would it take it to accelerate to maximum efficiency. What is maximum efficiency for a state of the art ramjet? And are they rated in specific impulse or pounds of thrust? Thank-you very much.

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## Ramjet ignition

 Quote by joaquinwalkin I was thinking about the airspeed of the vehicle, but both airspeeds would be appreciated (vehicle and combustion chamber). So with a state of the art ramjet what would be those speeds to ignite with 60% efficiency. And if you don't mind say the vehicle weighs 500 pounds and is carrying 1,000 pounds of fuel (1,500 pounds total weight) how long would it take it to accelerate to maximum efficiency. What is maximum efficiency for a state of the art ramjet? And are they rated in specific impulse or pounds of thrust? Thank-you very much.
Welcome to the PF.

Have you been doing any reading on your own so far? Here is an intro article:

http://en.wikipedia.org/wiki/Ramjet

.

 Thanks, but I don't consider wikipedia a reliable source of information.
 Wikipedia = Anonymous editors writing articles PhysicsForums = Anonymous posters answering physics questions In theory they aren't any different in terms of potential for being wrong.

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 Quote by joaquinwalkin Thanks, but I don't consider wikipedia a reliable source of information.