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Many designs for [[space plane]]s with [[scramjet]] engines make use of SERNs because of the weight reduction at large expansion ratios, or the additional lift at under-expansion. The [[X-43]], a test vehicle in [[NASA]]'s Hyper-X programme, is a flying example.
Many designs for [[space plane]]s with [[scramjet]] engines make use of SERNs because of the weight reduction at large expansion ratios, or the additional lift at under-expansion. The [[X-43]], a test vehicle in [[NASA]]'s Hyper-X programme, is a flying example.


One of the practical problems with the use of SERNs is the fact that they produce a (pitching)moment depending on the [[throttling]] of the engine, thereby requiring more control authority of the [[elevator]]s and more complex control systems.
One of the practical problems with the use of SERNs is the fact that they produce a (pitching)moment depending on the throttling of the engine, thereby requiring more control authority of the [[elevator:Elevator_(aircraft)]]s and more complex control systems.


[[Category:Spacecraft propulsion]]
[[Category:Spacecraft propulsion]]

Revision as of 07:53, 3 September 2008

Temperature distribution in and around a Scramjet vehicle with SERN

A SERN, which stands for single expansion ramp nozzle, is a type of linear expansion nozzle where the gas pressure transfers work only on one side. Traditional nozzles are axially symmetric, and therefore surround the expanding gas. Linear nozzles are not axially symmetric, but consist of a 2D configuration of two expansion ramps. A SERN could also be seen as a single sided aerospike engine.

Many designs for space planes with scramjet engines make use of SERNs because of the weight reduction at large expansion ratios, or the additional lift at under-expansion. The X-43, a test vehicle in NASA's Hyper-X programme, is a flying example.

One of the practical problems with the use of SERNs is the fact that they produce a (pitching)moment depending on the throttling of the engine, thereby requiring more control authority of the elevator:Elevator_(aircraft)s and more complex control systems.