Why don't Turbojet engines use the De Laval Nozzle?

In fact, it seems that in a typical turbojet, the output nozzle contracts, not expands.

As the temperature of exhaust gases is high -- it should be possible to extract more energy out of it in this case.


closed as off-topic by Manishearth Jul 12 '13 at 14:20

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  • 2
    $\begingroup$ en.wikipedia.org/wiki/Turbojet#Nozzle says that De Laval Nozzle can be more efficient, but is often not used because weight, complexity, and that the shape of the nozzle needs to be variable for different throttling. $\endgroup$ – Willie Wong May 2 '12 at 12:48

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