RM8B
In order to increase the thrust of the engine, the fan was increased with one stage at the cost of one low-pressure compressor stage. The fan in RM8B has 3 stages where as the fan in RM8A has 2. This modification stretched the RM8B by 7 cm and consequently the Viggen had to be stretched an equal amount to house the engine. One demand on the RM8B was that it had to be free of visible smoke. The RM8B made the JA 37 Viggen the most powerful single engine fighter ever.
As a total 173 RM8B where produced (9401 - 9573).
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